src/libANGLE/validationES2.cpp

//
// Copyright (c) 2013-2014 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

// validationES2.cpp: Validation functions for OpenGL ES 2.0 entry point parameters

#include "libANGLE/validationES2.h"
#include "libANGLE/validationES.h"
#include "libANGLE/Context.h"
#include "libANGLE/Texture.h"
#include "libANGLE/Framebuffer.h"
#include "libANGLE/Renderbuffer.h"
#include "libANGLE/formatutils.h"
#include "libANGLE/FramebufferAttachment.h"

#include "common/mathutil.h"
#include "common/utilities.h"

namespace gl
{

namespace
{

bool IsPartialBlit(gl::Context *context,
                   const FramebufferAttachment *readBuffer,
                   const FramebufferAttachment *writeBuffer,
                   GLint srcX0,
                   GLint srcY0,
                   GLint srcX1,
                   GLint srcY1,
                   GLint dstX0,
                   GLint dstY0,
                   GLint dstX1,
                   GLint dstY1)
{
    const Extents &writeSize = writeBuffer->getSize();
    const Extents &readSize  = readBuffer->getSize();

    if (srcX0 != 0 || srcY0 != 0 || dstX0 != 0 || dstY0 != 0 || dstX1 != writeSize.width ||
        dstY1 != writeSize.height || srcX1 != readSize.width || srcY1 != readSize.height)
    {
        return true;
    }

    if (context->getState().isScissorTestEnabled())
    {
        const Rectangle &scissor = context->getState().getScissor();
        return scissor.x > 0 || scissor.y > 0 || scissor.width < writeSize.width ||
               scissor.height < writeSize.height;
    }

    return false;
}

}  // anonymous namespace

bool ValidateES2TexImageParameters(Context *context, GLenum target, GLint level, GLenum internalformat, bool isCompressed, bool isSubImage,
                                   GLint xoffset, GLint yoffset, GLsizei width, GLsizei height,
                                   GLint border, GLenum format, GLenum type, const GLvoid *pixels)
{
    if (!ValidTexture2DDestinationTarget(context, target))
    {
        context->recordError(Error(GL_INVALID_ENUM));
        return false;
    }

    if (!ValidImageSizeParameters(context, target, level, width, height, 1, isSubImage))
    {
        context->recordError(Error(GL_INVALID_VALUE));
        return false;
    }

    if (level < 0 || xoffset < 0 ||
        std::numeric_limits<GLsizei>::max() - xoffset < width ||
        std::numeric_limits<GLsizei>::max() - yoffset < height)
    {
        context->recordError(Error(GL_INVALID_VALUE));
        return false;
    }

    if (!isSubImage && !isCompressed && internalformat != format)
    {
        context->recordError(Error(GL_INVALID_OPERATION));
        return false;
    }

    const gl::Caps &caps = context->getCaps();

    if (target == GL_TEXTURE_2D)
    {
        if (static_cast<GLuint>(width) > (caps.max2DTextureSize >> level) ||
            static_cast<GLuint>(height) > (caps.max2DTextureSize >> level))
        {
            context->recordError(Error(GL_INVALID_VALUE));
            return false;
        }
    }
    else if (IsCubeMapTextureTarget(target))
    {
        if (!isSubImage && width != height)
        {
            context->recordError(Error(GL_INVALID_VALUE));
            return false;
        }

        if (static_cast<GLuint>(width) > (caps.maxCubeMapTextureSize >> level) ||
            static_cast<GLuint>(height) > (caps.maxCubeMapTextureSize >> level))
        {
            context->recordError(Error(GL_INVALID_VALUE));
            return false;
        }
    }
    else
    {
        context->recordError(Error(GL_INVALID_ENUM));
        return false;
    }

    gl::Texture *texture = context->getTargetTexture(IsCubeMapTextureTarget(target) ? GL_TEXTURE_CUBE_MAP : target);
    if (!texture)
    {
        context->recordError(Error(GL_INVALID_OPERATION));
        return false;
    }

    if (isSubImage)
    {
        if (format != GL_NONE)
        {
            if (gl::GetSizedInternalFormat(format, type) != texture->getInternalFormat(target, level))
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
        }

        if (static_cast<size_t>(xoffset + width) > texture->getWidth(target, level) ||
            static_cast<size_t>(yoffset + height) > texture->getHeight(target, level))
        {
            context->recordError(Error(GL_INVALID_VALUE));
            return false;
        }
    }
    else
    {
        if (texture->getImmutableFormat())
        {
            context->recordError(Error(GL_INVALID_OPERATION));
            return false;
        }
    }

    // Verify zero border
    if (border != 0)
    {
        context->recordError(Error(GL_INVALID_VALUE));
        return false;
    }

    if (isCompressed)
    {
        GLenum actualInternalFormat =
            isSubImage ? texture->getInternalFormat(target, level) : internalformat;
        switch (actualInternalFormat)
        {
          case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
          case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
            if (!context->getExtensions().textureCompressionDXT1)
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_COMPRESSED_RGBA_S3TC_DXT3_ANGLE:
            if (!context->getExtensions().textureCompressionDXT1)
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_COMPRESSED_RGBA_S3TC_DXT5_ANGLE:
            if (!context->getExtensions().textureCompressionDXT5)
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_ETC1_RGB8_OES:
            if (!context->getExtensions().compressedETC1RGB8Texture)
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_ETC1_RGB8_LOSSY_DECODE_ANGLE:
              if (!context->getExtensions().lossyETCDecode)
              {
                  context->recordError(
                      Error(GL_INVALID_ENUM, "ANGLE_lossy_etc_decode extension is not supported"));
                  return false;
              }
              break;
          default:
              context->recordError(Error(
                  GL_INVALID_ENUM, "internalformat is not a supported compressed internal format"));
              return false;
        }
        if (!ValidCompressedImageSize(context, actualInternalFormat, width, height))
        {
            context->recordError(Error(GL_INVALID_OPERATION));
            return false;
        }
    }
    else
    {
        // validate <type> by itself (used as secondary key below)
        switch (type)
        {
          case GL_UNSIGNED_BYTE:
          case GL_UNSIGNED_SHORT_5_6_5:
          case GL_UNSIGNED_SHORT_4_4_4_4:
          case GL_UNSIGNED_SHORT_5_5_5_1:
          case GL_UNSIGNED_SHORT:
          case GL_UNSIGNED_INT:
          case GL_UNSIGNED_INT_24_8_OES:
          case GL_HALF_FLOAT_OES:
          case GL_FLOAT:
            break;
          default:
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }

        // validate <format> + <type> combinations
        // - invalid <format> -> sets INVALID_ENUM
        // - invalid <format>+<type> combination -> sets INVALID_OPERATION
        switch (format)
        {
          case GL_ALPHA:
          case GL_LUMINANCE:
          case GL_LUMINANCE_ALPHA:
            switch (type)
            {
              case GL_UNSIGNED_BYTE:
              case GL_FLOAT:
              case GL_HALF_FLOAT_OES:
                break;
              default:
                  context->recordError(Error(GL_INVALID_OPERATION));
                  return false;
            }
            break;
          case GL_RED:
          case GL_RG:
              if (!context->getExtensions().textureRG)
              {
                  context->recordError(Error(GL_INVALID_ENUM));
                  return false;
              }
              switch (type)
              {
                case GL_UNSIGNED_BYTE:
                case GL_FLOAT:
                case GL_HALF_FLOAT_OES:
                  break;
                default:
                  context->recordError(Error(GL_INVALID_OPERATION));
                  return false;
              }
              break;
          case GL_RGB:
            switch (type)
            {
              case GL_UNSIGNED_BYTE:
              case GL_UNSIGNED_SHORT_5_6_5:
              case GL_FLOAT:
              case GL_HALF_FLOAT_OES:
                break;
              default:
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_RGBA:
            switch (type)
            {
              case GL_UNSIGNED_BYTE:
              case GL_UNSIGNED_SHORT_4_4_4_4:
              case GL_UNSIGNED_SHORT_5_5_5_1:
              case GL_FLOAT:
              case GL_HALF_FLOAT_OES:
                break;
              default:
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_BGRA_EXT:
            switch (type)
            {
              case GL_UNSIGNED_BYTE:
                break;
              default:
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_SRGB_EXT:
          case GL_SRGB_ALPHA_EXT:
            if (!context->getExtensions().sRGB)
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            switch (type)
            {
              case GL_UNSIGNED_BYTE:
                break;
              default:
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:  // error cases for compressed textures are handled below
          case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
          case GL_COMPRESSED_RGBA_S3TC_DXT3_ANGLE:
          case GL_COMPRESSED_RGBA_S3TC_DXT5_ANGLE:
            break;
          case GL_DEPTH_COMPONENT:
            switch (type)
            {
              case GL_UNSIGNED_SHORT:
              case GL_UNSIGNED_INT:
                break;
              default:
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_DEPTH_STENCIL_OES:
            switch (type)
            {
              case GL_UNSIGNED_INT_24_8_OES:
                break;
              default:
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          default:
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }

        switch (format)
        {
          case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
          case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
            if (context->getExtensions().textureCompressionDXT1)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            else
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_COMPRESSED_RGBA_S3TC_DXT3_ANGLE:
            if (context->getExtensions().textureCompressionDXT3)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            else
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_COMPRESSED_RGBA_S3TC_DXT5_ANGLE:
            if (context->getExtensions().textureCompressionDXT5)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            else
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_ETC1_RGB8_OES:
            if (context->getExtensions().compressedETC1RGB8Texture)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            else
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_ETC1_RGB8_LOSSY_DECODE_ANGLE:
              if (context->getExtensions().lossyETCDecode)
              {
                  context->recordError(
                      Error(GL_INVALID_OPERATION,
                            "ETC1_RGB8_LOSSY_DECODE_ANGLE can't work with this type."));
                  return false;
              }
              else
              {
                  context->recordError(
                      Error(GL_INVALID_ENUM, "ANGLE_lossy_etc_decode extension is not supported."));
                  return false;
              }
              break;
          case GL_DEPTH_COMPONENT:
          case GL_DEPTH_STENCIL_OES:
            if (!context->getExtensions().depthTextures)
            {
                context->recordError(Error(GL_INVALID_VALUE));
                return false;
            }
            if (target != GL_TEXTURE_2D)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            // OES_depth_texture supports loading depth data and multiple levels,
            // but ANGLE_depth_texture does not
            if (pixels != NULL || level != 0)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          default:
            break;
        }

        if (type == GL_FLOAT)
        {
            if (!context->getExtensions().textureFloat)
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
        }
        else if (type == GL_HALF_FLOAT_OES)
        {
            if (!context->getExtensions().textureHalfFloat)
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
        }
    }

    return true;
}

bool ValidateES2CopyTexImageParameters(ValidationContext *context,
                                       GLenum target,
                                       GLint level,
                                       GLenum internalformat,
                                       bool isSubImage,
                                       GLint xoffset,
                                       GLint yoffset,
                                       GLint x,
                                       GLint y,
                                       GLsizei width,
                                       GLsizei height,
                                       GLint border)
{
    GLenum textureInternalFormat = GL_NONE;

    if (!ValidTexture2DDestinationTarget(context, target))
    {
        context->recordError(Error(GL_INVALID_ENUM, "Invalid texture target"));
        return false;
    }

    if (!ValidateCopyTexImageParametersBase(context, target, level, internalformat, isSubImage,
                                            xoffset, yoffset, 0, x, y, width, height, border, &textureInternalFormat))
    {
        return false;
    }

    const gl::Framebuffer *framebuffer = context->getState().getReadFramebuffer();
    GLenum colorbufferFormat = framebuffer->getReadColorbuffer()->getInternalFormat();
    const auto &internalFormatInfo = gl::GetInternalFormatInfo(textureInternalFormat);
    GLenum textureFormat = internalFormatInfo.format;

    // [OpenGL ES 2.0.24] table 3.9
    if (isSubImage)
    {
        switch (textureFormat)
        {
          case GL_ALPHA:
            if (colorbufferFormat != GL_ALPHA8_EXT &&
                colorbufferFormat != GL_RGBA4 &&
                colorbufferFormat != GL_RGB5_A1 &&
                colorbufferFormat != GL_RGBA8_OES)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_LUMINANCE:
              if (colorbufferFormat != GL_R8_EXT &&
                  colorbufferFormat != GL_RG8_EXT &&
                  colorbufferFormat != GL_RGB565 &&
                  colorbufferFormat != GL_RGB8_OES &&
                  colorbufferFormat != GL_RGBA4 &&
                  colorbufferFormat != GL_RGB5_A1 &&
                  colorbufferFormat != GL_RGBA8_OES)
              {
                  context->recordError(Error(GL_INVALID_OPERATION));
                  return false;
              }
              break;
          case GL_RED_EXT:
              if (colorbufferFormat != GL_R8_EXT &&
                  colorbufferFormat != GL_RG8_EXT &&
                  colorbufferFormat != GL_RGB565 &&
                  colorbufferFormat != GL_RGB8_OES &&
                  colorbufferFormat != GL_RGBA4 &&
                  colorbufferFormat != GL_RGB5_A1 &&
                  colorbufferFormat != GL_RGBA8_OES &&
                  colorbufferFormat != GL_R32F &&
                  colorbufferFormat != GL_RG32F &&
                  colorbufferFormat != GL_RGB32F &&
                  colorbufferFormat != GL_RGBA32F)
              {
                  context->recordError(Error(GL_INVALID_OPERATION));
                  return false;
              }
              break;
          case GL_RG_EXT:
              if (colorbufferFormat != GL_RG8_EXT &&
                  colorbufferFormat != GL_RGB565 &&
                  colorbufferFormat != GL_RGB8_OES &&
                  colorbufferFormat != GL_RGBA4 &&
                  colorbufferFormat != GL_RGB5_A1 &&
                  colorbufferFormat != GL_RGBA8_OES &&
                  colorbufferFormat != GL_RG32F &&
                  colorbufferFormat != GL_RGB32F &&
                  colorbufferFormat != GL_RGBA32F)
              {
                  context->recordError(Error(GL_INVALID_OPERATION));
                  return false;
              }
              break;
          case GL_RGB:
            if (colorbufferFormat != GL_RGB565 &&
                colorbufferFormat != GL_RGB8_OES &&
                colorbufferFormat != GL_RGBA4 &&
                colorbufferFormat != GL_RGB5_A1 &&
                colorbufferFormat != GL_RGBA8_OES &&
                colorbufferFormat != GL_RGB32F &&
                colorbufferFormat != GL_RGBA32F)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_LUMINANCE_ALPHA:
          case GL_RGBA:
            if (colorbufferFormat != GL_RGBA4 &&
                colorbufferFormat != GL_RGB5_A1 &&
                colorbufferFormat != GL_RGBA8_OES &&
                colorbufferFormat != GL_RGBA32F)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
          case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
          case GL_COMPRESSED_RGBA_S3TC_DXT3_ANGLE:
          case GL_COMPRESSED_RGBA_S3TC_DXT5_ANGLE:
          case GL_ETC1_RGB8_OES:
          case GL_ETC1_RGB8_LOSSY_DECODE_ANGLE:
            context->recordError(Error(GL_INVALID_OPERATION));
            return false;
          case GL_DEPTH_COMPONENT:
          case GL_DEPTH_STENCIL_OES:
            context->recordError(Error(GL_INVALID_OPERATION));
            return false;
          default:
            context->recordError(Error(GL_INVALID_OPERATION));
            return false;
        }

        if (internalFormatInfo.type == GL_FLOAT &&
            !context->getExtensions().textureFloat)
        {
            context->recordError(Error(GL_INVALID_OPERATION));
            return false;
        }
    }
    else
    {
        switch (internalformat)
        {
          case GL_ALPHA:
            if (colorbufferFormat != GL_ALPHA8_EXT &&
                colorbufferFormat != GL_RGBA4 &&
                colorbufferFormat != GL_RGB5_A1 &&
                colorbufferFormat != GL_BGRA8_EXT &&
                colorbufferFormat != GL_RGBA8_OES &&
                colorbufferFormat != GL_BGR5_A1_ANGLEX)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_LUMINANCE:
              if (colorbufferFormat != GL_R8_EXT &&
                  colorbufferFormat != GL_RG8_EXT &&
                  colorbufferFormat != GL_RGB565 &&
                  colorbufferFormat != GL_RGB8_OES &&
                  colorbufferFormat != GL_RGBA4 &&
                  colorbufferFormat != GL_RGB5_A1 &&
                  colorbufferFormat != GL_BGRA8_EXT &&
                  colorbufferFormat != GL_RGBA8_OES &&
                  colorbufferFormat != GL_BGR5_A1_ANGLEX)
              {
                  context->recordError(Error(GL_INVALID_OPERATION));
                  return false;
              }
              break;
          case GL_RED_EXT:
              if (colorbufferFormat != GL_R8_EXT &&
                  colorbufferFormat != GL_RG8_EXT &&
                  colorbufferFormat != GL_RGB565 &&
                  colorbufferFormat != GL_RGB8_OES &&
                  colorbufferFormat != GL_RGBA4 &&
                  colorbufferFormat != GL_RGB5_A1 &&
                  colorbufferFormat != GL_BGRA8_EXT &&
                  colorbufferFormat != GL_RGBA8_OES &&
                  colorbufferFormat != GL_BGR5_A1_ANGLEX)
              {
                  context->recordError(Error(GL_INVALID_OPERATION));
                  return false;
              }
              break;
          case GL_RG_EXT:
              if (colorbufferFormat != GL_RG8_EXT &&
                  colorbufferFormat != GL_RGB565 &&
                  colorbufferFormat != GL_RGB8_OES &&
                  colorbufferFormat != GL_RGBA4 &&
                  colorbufferFormat != GL_RGB5_A1 &&
                  colorbufferFormat != GL_BGRA8_EXT &&
                  colorbufferFormat != GL_RGBA8_OES &&
                  colorbufferFormat != GL_BGR5_A1_ANGLEX)
              {
                  context->recordError(Error(GL_INVALID_OPERATION));
                  return false;
              }
              break;
          case GL_RGB:
            if (colorbufferFormat != GL_RGB565 &&
                colorbufferFormat != GL_RGB8_OES &&
                colorbufferFormat != GL_RGBA4 &&
                colorbufferFormat != GL_RGB5_A1 &&
                colorbufferFormat != GL_BGRA8_EXT &&
                colorbufferFormat != GL_RGBA8_OES &&
                colorbufferFormat != GL_BGR5_A1_ANGLEX)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_LUMINANCE_ALPHA:
          case GL_RGBA:
            if (colorbufferFormat != GL_RGBA4 &&
                colorbufferFormat != GL_RGB5_A1 &&
                colorbufferFormat != GL_BGRA8_EXT &&
                colorbufferFormat != GL_RGBA8_OES &&
                colorbufferFormat != GL_BGR5_A1_ANGLEX)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            break;
          case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
          case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
            if (context->getExtensions().textureCompressionDXT1)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            else
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_COMPRESSED_RGBA_S3TC_DXT3_ANGLE:
            if (context->getExtensions().textureCompressionDXT3)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            else
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_COMPRESSED_RGBA_S3TC_DXT5_ANGLE:
            if (context->getExtensions().textureCompressionDXT5)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            else
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_ETC1_RGB8_OES:
            if (context->getExtensions().compressedETC1RGB8Texture)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            else
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
            break;
          case GL_ETC1_RGB8_LOSSY_DECODE_ANGLE:
              if (context->getExtensions().lossyETCDecode)
              {
                  context->recordError(Error(GL_INVALID_OPERATION,
                                             "ETC1_RGB8_LOSSY_DECODE_ANGLE can't be copied to."));
                  return false;
              }
              else
              {
                  context->recordError(
                      Error(GL_INVALID_ENUM, "ANGLE_lossy_etc_decode extension is not supported."));
                  return false;
              }
              break;
          case GL_DEPTH_COMPONENT:
          case GL_DEPTH_COMPONENT16:
          case GL_DEPTH_COMPONENT32_OES:
          case GL_DEPTH_STENCIL_OES:
          case GL_DEPTH24_STENCIL8_OES:
            if (context->getExtensions().depthTextures)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
            else
            {
                context->recordError(Error(GL_INVALID_ENUM));
                return false;
            }
          default:
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }
    }

    // If width or height is zero, it is a no-op.  Return false without setting an error.
    return (width > 0 && height > 0);
}

bool ValidateES2TexStorageParameters(Context *context, GLenum target, GLsizei levels, GLenum internalformat,
                                     GLsizei width, GLsizei height)
{
    if (target != GL_TEXTURE_2D && target != GL_TEXTURE_CUBE_MAP)
    {
        context->recordError(Error(GL_INVALID_ENUM));
        return false;
    }

    if (width < 1 || height < 1 || levels < 1)
    {
        context->recordError(Error(GL_INVALID_VALUE));
        return false;
    }

    if (target == GL_TEXTURE_CUBE_MAP && width != height)
    {
        context->recordError(Error(GL_INVALID_VALUE));
        return false;
    }

    if (levels != 1 && levels != gl::log2(std::max(width, height)) + 1)
    {
        context->recordError(Error(GL_INVALID_OPERATION));
        return false;
    }

    const gl::InternalFormat &formatInfo = gl::GetInternalFormatInfo(internalformat);
    if (formatInfo.format == GL_NONE || formatInfo.type == GL_NONE)
    {
        context->recordError(Error(GL_INVALID_ENUM));
        return false;
    }

    const gl::Caps &caps = context->getCaps();

    switch (target)
    {
      case GL_TEXTURE_2D:
        if (static_cast<GLuint>(width) > caps.max2DTextureSize ||
            static_cast<GLuint>(height) > caps.max2DTextureSize)
        {
            context->recordError(Error(GL_INVALID_VALUE));
            return false;
        }
        break;
      case GL_TEXTURE_CUBE_MAP:
        if (static_cast<GLuint>(width) > caps.maxCubeMapTextureSize ||
            static_cast<GLuint>(height) > caps.maxCubeMapTextureSize)
        {
            context->recordError(Error(GL_INVALID_VALUE));
            return false;
        }
        break;
      default:
        context->recordError(Error(GL_INVALID_ENUM));
        return false;
    }

    if (levels != 1 && !context->getExtensions().textureNPOT)
    {
        if (!gl::isPow2(width) || !gl::isPow2(height))
        {
            context->recordError(Error(GL_INVALID_OPERATION));
            return false;
        }
    }

    switch (internalformat)
    {
      case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
      case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
        if (!context->getExtensions().textureCompressionDXT1)
        {
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }
        break;
      case GL_COMPRESSED_RGBA_S3TC_DXT3_ANGLE:
        if (!context->getExtensions().textureCompressionDXT3)
        {
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }
        break;
      case GL_COMPRESSED_RGBA_S3TC_DXT5_ANGLE:
        if (!context->getExtensions().textureCompressionDXT5)
        {
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }
        break;
      case GL_ETC1_RGB8_OES:
        if (!context->getExtensions().compressedETC1RGB8Texture)
        {
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }
        break;
      case GL_ETC1_RGB8_LOSSY_DECODE_ANGLE:
          if (!context->getExtensions().lossyETCDecode)
          {
              context->recordError(
                  Error(GL_INVALID_ENUM, "ANGLE_lossy_etc_decode extension is not supported."));
              return false;
          }
          break;
      case GL_RGBA32F_EXT:
      case GL_RGB32F_EXT:
      case GL_ALPHA32F_EXT:
      case GL_LUMINANCE32F_EXT:
      case GL_LUMINANCE_ALPHA32F_EXT:
        if (!context->getExtensions().textureFloat)
        {
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }
        break;
      case GL_RGBA16F_EXT:
      case GL_RGB16F_EXT:
      case GL_ALPHA16F_EXT:
      case GL_LUMINANCE16F_EXT:
      case GL_LUMINANCE_ALPHA16F_EXT:
        if (!context->getExtensions().textureHalfFloat)
        {
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }
        break;
      case GL_R8_EXT:
      case GL_RG8_EXT:
      case GL_R16F_EXT:
      case GL_RG16F_EXT:
      case GL_R32F_EXT:
      case GL_RG32F_EXT:
        if (!context->getExtensions().textureRG)
        {
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }
        break;
      case GL_DEPTH_COMPONENT16:
      case GL_DEPTH_COMPONENT32_OES:
      case GL_DEPTH24_STENCIL8_OES:
        if (!context->getExtensions().depthTextures)
        {
            context->recordError(Error(GL_INVALID_ENUM));
            return false;
        }
        if (target != GL_TEXTURE_2D)
        {
            context->recordError(Error(GL_INVALID_OPERATION));
            return false;
        }
        // ANGLE_depth_texture only supports 1-level textures
        if (levels != 1)
        {
            context->recordError(Error(GL_INVALID_OPERATION));
            return false;
        }
        break;
      default:
        break;
    }

    gl::Texture *texture = context->getTargetTexture(target);
    if (!texture || texture->id() == 0)
    {
        context->recordError(Error(GL_INVALID_OPERATION));
        return false;
    }

    if (texture->getImmutableFormat())
    {
        context->recordError(Error(GL_INVALID_OPERATION));
        return false;
    }

    return true;
}

// check for combinations of format and type that are valid for ReadPixels
bool ValidES2ReadFormatType(Context *context, GLenum format, GLenum type)
{
    switch (format)
    {
      case GL_RGBA:
        switch (type)
        {
          case GL_UNSIGNED_BYTE:
            break;
          default:
            return false;
        }
        break;
      case GL_BGRA_EXT:
        switch (type)
        {
          case GL_UNSIGNED_BYTE:
          case GL_UNSIGNED_SHORT_4_4_4_4_REV_EXT:
          case GL_UNSIGNED_SHORT_1_5_5_5_REV_EXT:
            break;
          default:
            return false;
        }
        break;
      case GL_RG_EXT:
      case GL_RED_EXT:
        if (!context->getExtensions().textureRG)
        {
            return false;
        }
        switch (type)
        {
          case GL_UNSIGNED_BYTE:
            break;
          default:
            return false;
        }
        break;

      default:
        return false;
    }
    return true;
}

bool ValidateDiscardFramebufferEXT(Context *context, GLenum target, GLsizei numAttachments,
                                   const GLenum *attachments)
{
    if (!context->getExtensions().discardFramebuffer)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    bool defaultFramebuffer = false;

    switch (target)
    {
      case GL_FRAMEBUFFER:
        defaultFramebuffer = (context->getState().getTargetFramebuffer(GL_FRAMEBUFFER)->id() == 0);
        break;
      default:
        context->recordError(Error(GL_INVALID_ENUM, "Invalid framebuffer target"));
        return false;
    }

    return ValidateDiscardFramebufferBase(context, target, numAttachments, attachments, defaultFramebuffer);
}

bool ValidateBindVertexArrayOES(Context *context, GLuint array)
{
    if (!context->getExtensions().vertexArrayObject)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    return ValidateBindVertexArrayBase(context, array);
}

bool ValidateDeleteVertexArraysOES(Context *context, GLsizei n)
{
    if (!context->getExtensions().vertexArrayObject)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    return ValidateDeleteVertexArraysBase(context, n);
}

bool ValidateGenVertexArraysOES(Context *context, GLsizei n)
{
    if (!context->getExtensions().vertexArrayObject)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    return ValidateGenVertexArraysBase(context, n);
}

bool ValidateIsVertexArrayOES(Context *context)
{
    if (!context->getExtensions().vertexArrayObject)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    return true;
}

bool ValidateProgramBinaryOES(Context *context,
                              GLuint program,
                              GLenum binaryFormat,
                              const void *binary,
                              GLint length)
{
    if (!context->getExtensions().getProgramBinary)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    return ValidateProgramBinaryBase(context, program, binaryFormat, binary, length);
}

bool ValidateGetProgramBinaryOES(Context *context,
                                 GLuint program,
                                 GLsizei bufSize,
                                 GLsizei *length,
                                 GLenum *binaryFormat,
                                 void *binary)
{
    if (!context->getExtensions().getProgramBinary)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    return ValidateGetProgramBinaryBase(context, program, bufSize, length, binaryFormat, binary);
}

static bool ValidDebugSource(GLenum source, bool mustBeThirdPartyOrApplication)
{
    switch (source)
    {
        case GL_DEBUG_SOURCE_API:
        case GL_DEBUG_SOURCE_SHADER_COMPILER:
        case GL_DEBUG_SOURCE_WINDOW_SYSTEM:
        case GL_DEBUG_SOURCE_OTHER:
            // Only THIRD_PARTY and APPLICATION sources are allowed to be manually inserted
            return !mustBeThirdPartyOrApplication;

        case GL_DEBUG_SOURCE_THIRD_PARTY:
        case GL_DEBUG_SOURCE_APPLICATION:
            return true;

        default:
            return false;
    }
}

static bool ValidDebugType(GLenum type)
{
    switch (type)
    {
        case GL_DEBUG_TYPE_ERROR:
        case GL_DEBUG_TYPE_DEPRECATED_BEHAVIOR:
        case GL_DEBUG_TYPE_UNDEFINED_BEHAVIOR:
        case GL_DEBUG_TYPE_PERFORMANCE:
        case GL_DEBUG_TYPE_PORTABILITY:
        case GL_DEBUG_TYPE_OTHER:
        case GL_DEBUG_TYPE_MARKER:
        case GL_DEBUG_TYPE_PUSH_GROUP:
        case GL_DEBUG_TYPE_POP_GROUP:
            return true;

        default:
            return false;
    }
}

static bool ValidDebugSeverity(GLenum severity)
{
    switch (severity)
    {
        case GL_DEBUG_SEVERITY_HIGH:
        case GL_DEBUG_SEVERITY_MEDIUM:
        case GL_DEBUG_SEVERITY_LOW:
        case GL_DEBUG_SEVERITY_NOTIFICATION:
            return true;

        default:
            return false;
    }
}

bool ValidateDebugMessageControlKHR(Context *context,
                                    GLenum source,
                                    GLenum type,
                                    GLenum severity,
                                    GLsizei count,
                                    const GLuint *ids,
                                    GLboolean enabled)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    if (!ValidDebugSource(source, false) && source != GL_DONT_CARE)
    {
        context->recordError(Error(GL_INVALID_ENUM, "Invalid debug source."));
        return false;
    }

    if (!ValidDebugType(type) && type != GL_DONT_CARE)
    {
        context->recordError(Error(GL_INVALID_ENUM, "Invalid debug type."));
        return false;
    }

    if (!ValidDebugSeverity(severity) && severity != GL_DONT_CARE)
    {
        context->recordError(Error(GL_INVALID_ENUM, "Invalid debug severity."));
        return false;
    }

    if (count > 0)
    {
        if (source == GL_DONT_CARE || type == GL_DONT_CARE)
        {
            context->recordError(Error(
                GL_INVALID_OPERATION,
                "If count is greater than zero, source and severity cannot be GL_DONT_CARE."));
            return false;
        }

        if (severity != GL_DONT_CARE)
        {
            context->recordError(
                Error(GL_INVALID_OPERATION,
                      "If count is greater than zero, severity must be GL_DONT_CARE."));
            return false;
        }
    }

    return true;
}

bool ValidateDebugMessageInsertKHR(Context *context,
                                   GLenum source,
                                   GLenum type,
                                   GLuint id,
                                   GLenum severity,
                                   GLsizei length,
                                   const GLchar *buf)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    if (!context->getState().getDebug().isOutputEnabled())
    {
        // If the DEBUG_OUTPUT state is disabled calls to DebugMessageInsert are discarded and do
        // not generate an error.
        return false;
    }

    if (!ValidDebugSeverity(severity))
    {
        context->recordError(Error(GL_INVALID_ENUM, "Invalid debug severity."));
        return false;
    }

    if (!ValidDebugType(type))
    {
        context->recordError(Error(GL_INVALID_ENUM, "Invalid debug type."));
        return false;
    }

    if (!ValidDebugSource(source, true))
    {
        context->recordError(Error(GL_INVALID_ENUM, "Invalid debug source."));
        return false;
    }

    size_t messageLength = (length < 0) ? strlen(buf) : length;
    if (messageLength > context->getExtensions().maxDebugMessageLength)
    {
        context->recordError(
            Error(GL_INVALID_VALUE, "Message length is larger than GL_MAX_DEBUG_MESSAGE_LENGTH."));
        return false;
    }

    return true;
}

bool ValidateDebugMessageCallbackKHR(Context *context,
                                     GLDEBUGPROCKHR callback,
                                     const void *userParam)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    return true;
}

bool ValidateGetDebugMessageLogKHR(Context *context,
                                   GLuint count,
                                   GLsizei bufSize,
                                   GLenum *sources,
                                   GLenum *types,
                                   GLuint *ids,
                                   GLenum *severities,
                                   GLsizei *lengths,
                                   GLchar *messageLog)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    if (bufSize < 0 && messageLog != nullptr)
    {
        context->recordError(
            Error(GL_INVALID_VALUE, "bufSize must be positive if messageLog is not null."));
        return false;
    }

    return true;
}

bool ValidatePushDebugGroupKHR(Context *context,
                               GLenum source,
                               GLuint id,
                               GLsizei length,
                               const GLchar *message)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    if (!ValidDebugSource(source, true))
    {
        context->recordError(Error(GL_INVALID_ENUM, "Invalid debug source."));
        return false;
    }

    size_t messageLength = (length < 0) ? strlen(message) : length;
    if (messageLength > context->getExtensions().maxDebugMessageLength)
    {
        context->recordError(
            Error(GL_INVALID_VALUE, "Message length is larger than GL_MAX_DEBUG_MESSAGE_LENGTH."));
        return false;
    }

    size_t currentStackSize = context->getState().getDebug().getGroupStackDepth();
    if (currentStackSize >= context->getExtensions().maxDebugGroupStackDepth)
    {
        context->recordError(
            Error(GL_STACK_OVERFLOW,
                  "Cannot push more than GL_MAX_DEBUG_GROUP_STACK_DEPTH debug groups."));
        return false;
    }

    return true;
}

bool ValidatePopDebugGroupKHR(Context *context)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    size_t currentStackSize = context->getState().getDebug().getGroupStackDepth();
    if (currentStackSize <= 1)
    {
        context->recordError(Error(GL_STACK_UNDERFLOW, "Cannot pop the default debug group."));
        return false;
    }

    return true;
}

static bool ValidateObjectIdentifierAndName(Context *context, GLenum identifier, GLuint name)
{
    switch (identifier)
    {
        case GL_BUFFER:
            if (context->getBuffer(name) == nullptr)
            {
                context->recordError(Error(GL_INVALID_VALUE, "name is not a valid buffer."));
                return false;
            }
            return true;

        case GL_SHADER:
            if (context->getShader(name) == nullptr)
            {
                context->recordError(Error(GL_INVALID_VALUE, "name is not a valid shader."));
                return false;
            }
            return true;

        case GL_PROGRAM:
            if (context->getProgram(name) == nullptr)
            {
                context->recordError(Error(GL_INVALID_VALUE, "name is not a valid program."));
                return false;
            }
            return true;

        case GL_VERTEX_ARRAY:
            if (context->getVertexArray(name) == nullptr)
            {
                context->recordError(Error(GL_INVALID_VALUE, "name is not a valid vertex array."));
                return false;
            }
            return true;

        case GL_QUERY:
            if (context->getQuery(name) == nullptr)
            {
                context->recordError(Error(GL_INVALID_VALUE, "name is not a valid query."));
                return false;
            }
            return true;

        case GL_TRANSFORM_FEEDBACK:
            if (context->getTransformFeedback(name) == nullptr)
            {
                context->recordError(
                    Error(GL_INVALID_VALUE, "name is not a valid transform feedback."));
                return false;
            }
            return true;

        case GL_SAMPLER:
            if (context->getSampler(name) == nullptr)
            {
                context->recordError(Error(GL_INVALID_VALUE, "name is not a valid sampler."));
                return false;
            }
            return true;

        case GL_TEXTURE:
            if (context->getTexture(name) == nullptr)
            {
                context->recordError(Error(GL_INVALID_VALUE, "name is not a valid texture."));
                return false;
            }
            return true;

        case GL_RENDERBUFFER:
            if (context->getRenderbuffer(name) == nullptr)
            {
                context->recordError(Error(GL_INVALID_VALUE, "name is not a valid renderbuffer."));
                return false;
            }
            return true;

        case GL_FRAMEBUFFER:
            if (context->getFramebuffer(name) == nullptr)
            {
                context->recordError(Error(GL_INVALID_VALUE, "name is not a valid framebuffer."));
                return false;
            }
            return true;

        default:
            context->recordError(Error(GL_INVALID_ENUM, "Invalid identifier."));
            return false;
    }

    return true;
}

bool ValidateObjectLabelKHR(Context *context,
                            GLenum identifier,
                            GLuint name,
                            GLsizei length,
                            const GLchar *label)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    if (!ValidateObjectIdentifierAndName(context, identifier, name))
    {
        return false;
    }

    size_t labelLength = (length < 0) ? strlen(label) : length;
    if (labelLength > context->getExtensions().maxLabelLength)
    {
        context->recordError(
            Error(GL_INVALID_VALUE, "Label length is larger than GL_MAX_LABEL_LENGTH."));
        return false;
    }

    return true;
}

bool ValidateGetObjectLabelKHR(Context *context,
                               GLenum identifier,
                               GLuint name,
                               GLsizei bufSize,
                               GLsizei *length,
                               GLchar *label)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    if (bufSize < 0)
    {
        context->recordError(Error(GL_INVALID_VALUE, "bufSize cannot be negative."));
        return false;
    }

    if (!ValidateObjectIdentifierAndName(context, identifier, name))
    {
        return false;
    }

    // Can no-op if bufSize is zero.
    return bufSize > 0;
}

static bool ValidateObjectPtrName(Context *context, const void *ptr)
{
    if (context->getFenceSync(reinterpret_cast<GLsync>(const_cast<void *>(ptr))) == nullptr)
    {
        context->recordError(Error(GL_INVALID_VALUE, "name is not a valid sync."));
        return false;
    }

    return true;
}

bool ValidateObjectPtrLabelKHR(Context *context,
                               const void *ptr,
                               GLsizei length,
                               const GLchar *label)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    if (!ValidateObjectPtrName(context, ptr))
    {
        return false;
    }

    size_t labelLength = (length < 0) ? strlen(label) : length;
    if (labelLength > context->getExtensions().maxLabelLength)
    {
        context->recordError(
            Error(GL_INVALID_VALUE, "Label length is larger than GL_MAX_LABEL_LENGTH."));
        return false;
    }

    return true;
}

bool ValidateGetObjectPtrLabelKHR(Context *context,
                                  const void *ptr,
                                  GLsizei bufSize,
                                  GLsizei *length,
                                  GLchar *label)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    if (bufSize < 0)
    {
        context->recordError(Error(GL_INVALID_VALUE, "bufSize cannot be negative."));
        return false;
    }

    if (!ValidateObjectPtrName(context, ptr))
    {
        return false;
    }

    // Can no-op if bufSize is zero.
    return bufSize > 0;
}

bool ValidateGetPointervKHR(Context *context, GLenum pname, void **params)
{
    if (!context->getExtensions().debug)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not enabled"));
        return false;
    }

    // TODO: represent this in Context::getQueryParameterInfo.
    switch (pname)
    {
        case GL_DEBUG_CALLBACK_FUNCTION:
        case GL_DEBUG_CALLBACK_USER_PARAM:
            break;

        default:
            context->recordError(Error(GL_INVALID_ENUM, "Invalid pname."));
            return false;
    }

    return true;
}

bool ValidateBlitFramebufferANGLE(Context *context,
                                  GLint srcX0,
                                  GLint srcY0,
                                  GLint srcX1,
                                  GLint srcY1,
                                  GLint dstX0,
                                  GLint dstY0,
                                  GLint dstX1,
                                  GLint dstY1,
                                  GLbitfield mask,
                                  GLenum filter)
{
    if (!context->getExtensions().framebufferBlit)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Blit extension not available."));
        return false;
    }

    if (srcX1 - srcX0 != dstX1 - dstX0 || srcY1 - srcY0 != dstY1 - dstY0)
    {
        // TODO(jmadill): Determine if this should be available on other implementations.
        context->recordError(Error(
            GL_INVALID_OPERATION,
            "Scaling and flipping in BlitFramebufferANGLE not supported by this implementation."));
        return false;
    }

    if (filter == GL_LINEAR)
    {
        context->recordError(Error(GL_INVALID_ENUM, "Linear blit not supported in this extension"));
        return false;
    }

    const Framebuffer *readFramebuffer = context->getState().getReadFramebuffer();
    const Framebuffer *drawFramebuffer = context->getState().getDrawFramebuffer();

    if (mask & GL_COLOR_BUFFER_BIT)
    {
        const FramebufferAttachment *readColorAttachment = readFramebuffer->getReadColorbuffer();
        const FramebufferAttachment *drawColorAttachment = drawFramebuffer->getFirstColorbuffer();

        if (readColorAttachment && drawColorAttachment)
        {
            if (!(readColorAttachment->type() == GL_TEXTURE &&
                  readColorAttachment->getTextureImageIndex().type == GL_TEXTURE_2D) &&
                readColorAttachment->type() != GL_RENDERBUFFER &&
                readColorAttachment->type() != GL_FRAMEBUFFER_DEFAULT)
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }

            for (size_t drawbufferIdx = 0;
                 drawbufferIdx < drawFramebuffer->getDrawbufferStateCount(); ++drawbufferIdx)
            {
                const FramebufferAttachment *attachment =
                    drawFramebuffer->getDrawBuffer(drawbufferIdx);
                if (attachment)
                {
                    if (!(attachment->type() == GL_TEXTURE &&
                          attachment->getTextureImageIndex().type == GL_TEXTURE_2D) &&
                        attachment->type() != GL_RENDERBUFFER &&
                        attachment->type() != GL_FRAMEBUFFER_DEFAULT)
                    {
                        context->recordError(Error(GL_INVALID_OPERATION));
                        return false;
                    }

                    // Return an error if the destination formats do not match
                    if (attachment->getInternalFormat() != readColorAttachment->getInternalFormat())
                    {
                        context->recordError(Error(GL_INVALID_OPERATION));
                        return false;
                    }
                }
            }

            int readSamples = readFramebuffer->getSamples(context->getData());

            if (readSamples != 0 &&
                IsPartialBlit(context, readColorAttachment, drawColorAttachment, srcX0, srcY0,
                              srcX1, srcY1, dstX0, dstY0, dstX1, dstY1))
            {
                context->recordError(Error(GL_INVALID_OPERATION));
                return false;
            }
        }
    }

    GLenum masks[]       = {GL_DEPTH_BUFFER_BIT, GL_STENCIL_BUFFER_BIT};
    GLenum attachments[] = {GL_DEPTH_ATTACHMENT, GL_STENCIL_ATTACHMENT};
    for (size_t i = 0; i < 2; i++)
    {
        if (mask & masks[i])
        {
            const FramebufferAttachment *readBuffer =
                readFramebuffer->getAttachment(attachments[i]);
            const FramebufferAttachment *drawBuffer =
                drawFramebuffer->getAttachment(attachments[i]);

            if (readBuffer && drawBuffer)
            {
                if (IsPartialBlit(context, readBuffer, drawBuffer, srcX0, srcY0, srcX1, srcY1,
                                  dstX0, dstY0, dstX1, dstY1))
                {
                    // only whole-buffer copies are permitted
                    ERR(
                        "Only whole-buffer depth and stencil blits are supported by this "
                        "implementation.");
                    context->recordError(Error(GL_INVALID_OPERATION));
                    return false;
                }

                if (readBuffer->getSamples() != 0 || drawBuffer->getSamples() != 0)
                {
                    context->recordError(Error(GL_INVALID_OPERATION));
                    return false;
                }
            }
        }
    }

    return ValidateBlitFramebufferParameters(context, srcX0, srcY0, srcX1, srcY1, dstX0, dstY0,
                                             dstX1, dstY1, mask, filter);
}

bool ValidateClear(ValidationContext *context, GLbitfield mask)
{
    const Framebuffer *framebufferObject = context->getState().getDrawFramebuffer();
    ASSERT(framebufferObject);

    if (framebufferObject->checkStatus(context->getData()) != GL_FRAMEBUFFER_COMPLETE)
    {
        context->recordError(Error(GL_INVALID_FRAMEBUFFER_OPERATION));
        return false;
    }

    if ((mask & ~(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT)) != 0)
    {
        context->recordError(Error(GL_INVALID_VALUE));
        return false;
    }

    return true;
}

bool ValidateDrawBuffersEXT(ValidationContext *context, GLsizei n, const GLenum *bufs)
{
    if (!context->getExtensions().drawBuffers)
    {
        context->recordError(Error(GL_INVALID_OPERATION, "Extension not supported."));
        return false;
    }

    return ValidateDrawBuffersBase(context, n, bufs);
}

}  // namespace gl