src/gpu/gl/GrGLCaps.h - platform/external/skqp - Gitiles

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */


 #ifndef GrGLCaps_DEFINED
 #define GrGLCaps_DEFINED

 #include "GrDrawTargetCaps.h"
 #include "GrGLStencilBuffer.h"
 #include "SkTArray.h"
 #include "SkTDArray.h"

 class GrGLContextInfo;

 /**
  * Stores some capabilities of a GL context. Most are determined by the GL
  * version and the extensions string. It also tracks formats that have passed
  * the FBO completeness test.
  */
 class GrGLCaps : public GrDrawTargetCaps {
 public:
     SK_DECLARE_INST_COUNT(GrGLCaps)

     typedef GrGLStencilBuffer::Format StencilFormat;

     /**
      * The type of MSAA for FBOs supported. Different extensions have different
      * semantics of how / when a resolve is performed.
      */
     enum MSFBOType {
         /**
          * no support for MSAA FBOs
          */
         kNone_MSFBOType = 0,
         /**
          * GL3.0-style MSAA FBO (GL_ARB_framebuffer_object).
          */
         kDesktop_ARB_MSFBOType,
         /**
          * earlier GL_EXT_framebuffer* extensions
          */
         kDesktop_EXT_MSFBOType,
         /**
          * Similar to kDesktop_ARB but with additional restrictions on glBlitFramebuffer.
          */
         kES_3_0_MSFBOType,
         /**
          * GL_APPLE_framebuffer_multisample ES extension
          */
         kES_Apple_MSFBOType,
         /**
          * GL_IMG_multisampled_render_to_texture. This variation does not have MSAA renderbuffers.
          * Instead the texture is multisampled when bound to the FBO and then resolved automatically
          * when read. It also defines an alternate value for GL_MAX_SAMPLES (which we call
          * GR_GL_MAX_SAMPLES_IMG).
          */
         kES_IMG_MsToTexture_MSFBOType,
         /**
          * GL_EXT_multisampled_render_to_texture. Same as the IMG one above but uses the standard
          * GL_MAX_SAMPLES value.
          */
         kES_EXT_MsToTexture_MSFBOType,

         kLast_MSFBOType = kES_EXT_MsToTexture_MSFBOType
     };

     enum FBFetchType {
         kNone_FBFetchType,
         /** GL_EXT_shader_framebuffer_fetch */
         kEXT_FBFetchType,
         /** GL_NV_shader_framebuffer_fetch */
         kNV_FBFetchType,

         kLast_FBFetchType = kNV_FBFetchType,
     };

     /**
      * Creates a GrGLCaps that advertises no support for any extensions,
      * formats, etc. Call init to initialize from a GrGLContextInfo.
      */
     GrGLCaps();

     GrGLCaps(const GrGLCaps& caps);

     GrGLCaps& operator = (const GrGLCaps& caps);

     /**
      * Resets the caps such that nothing is supported.
      */
     virtual void reset() SK_OVERRIDE;

     /**
      * Initializes the GrGLCaps to the set of features supported in the current
      * OpenGL context accessible via ctxInfo.
      */
     void init(const GrGLContextInfo& ctxInfo, const GrGLInterface* interface);

     /**
      * Call to note that a color config has been verified as a valid color
      * attachment. This may save future calls to glCheckFramebufferStatus
      * using isConfigVerifiedColorAttachment().
      */
     void markConfigAsValidColorAttachment(GrPixelConfig config) {
         fVerifiedColorConfigs.markVerified(config);
     }

     /**
      * Call to check whether a config has been verified as a valid color
      * attachment.
      */
     bool isConfigVerifiedColorAttachment(GrPixelConfig config) const {
         return fVerifiedColorConfigs.isVerified(config);
     }

     /**
      * Call to note that a color config / stencil format pair passed
      * FBO status check. We may skip calling glCheckFramebufferStatus for
      * this combination in the future using
      * isColorConfigAndStencilFormatVerified().
      */
     void markColorConfigAndStencilFormatAsVerified(
                     GrPixelConfig config,
                     const GrGLStencilBuffer::Format& format);

     /**
      * Call to check whether color config / stencil format pair has already
      * passed FBO status check.
      */
     bool isColorConfigAndStencilFormatVerified(
                     GrPixelConfig config,
                     const GrGLStencilBuffer::Format& format) const;

     /**
      * Reports the type of MSAA FBO support.
      */
     MSFBOType msFBOType() const { return fMSFBOType; }

     /**
      * Does the supported MSAA FBO extension have MSAA renderbuffers?
      */
     bool usesMSAARenderBuffers() const {
         return kNone_MSFBOType != fMSFBOType &&
                kES_IMG_MsToTexture_MSFBOType != fMSFBOType &&
                kES_EXT_MsToTexture_MSFBOType != fMSFBOType;
     }

     /**
      * Is the MSAA FBO extension one where the texture is multisampled when bound to an FBO and
      * then implicitly resolved when read.
      */
     bool usesImplicitMSAAResolve() const {
         return kES_IMG_MsToTexture_MSFBOType == fMSFBOType ||
                kES_EXT_MsToTexture_MSFBOType == fMSFBOType;
     }

     FBFetchType fbFetchType() const { return fFBFetchType; }

     /**
      * Returs a string containeng the caps info.
      */
     virtual SkString dump() const SK_OVERRIDE;

     /**
      * Gets an array of legal stencil formats. These formats are not guaranteed
      * to be supported by the driver but are legal GLenum names given the GL
      * version and extensions supported.
      */
     const SkTArray<StencilFormat, true>& stencilFormats() const {
         return fStencilFormats;
     }

     /// The maximum number of fragment uniform vectors (GLES has min. 16).
     int maxFragmentUniformVectors() const { return fMaxFragmentUniformVectors; }

     /// maximum number of attribute values per vertex
     int maxVertexAttributes() const { return fMaxVertexAttributes; }

     /// maximum number of texture units accessible in the fragment shader.
     int maxFragmentTextureUnits() const { return fMaxFragmentTextureUnits; }

     /// maximum number of fixed-function texture coords, or zero if no fixed-function.
     int maxFixedFunctionTextureCoords() const { return fMaxFixedFunctionTextureCoords; }

     /// ES requires an extension to support RGBA8 in RenderBufferStorage
     bool rgba8RenderbufferSupport() const { return fRGBA8RenderbufferSupport; }

     /// Is GL_BGRA supported
     bool bgraFormatSupport() const { return fBGRAFormatSupport; }

     /**
      * Depending on the ES extensions present the BGRA external format may
      * correspond either a BGRA or RGBA internalFormat. On desktop GL it is
      * RGBA.
      */
     bool bgraIsInternalFormat() const { return fBGRAIsInternalFormat; }

     /// GL_ARB_texture_swizzle support
     bool textureSwizzleSupport() const { return fTextureSwizzleSupport; }

     /// Is there support for GL_UNPACK_ROW_LENGTH
     bool unpackRowLengthSupport() const { return fUnpackRowLengthSupport; }

     /// Is there support for GL_UNPACK_FLIP_Y
     bool unpackFlipYSupport() const { return fUnpackFlipYSupport; }

     /// Is there support for GL_PACK_ROW_LENGTH
     bool packRowLengthSupport() const { return fPackRowLengthSupport; }

     /// Is there support for GL_PACK_REVERSE_ROW_ORDER
     bool packFlipYSupport() const { return fPackFlipYSupport; }

     /// Is there support for texture parameter GL_TEXTURE_USAGE
     bool textureUsageSupport() const { return fTextureUsageSupport; }

     /// Is there support for glTexStorage
     bool texStorageSupport() const { return fTexStorageSupport; }

     /// Is there support for GL_RED and GL_R8
     bool textureRedSupport() const { return fTextureRedSupport; }

     /// Is GL_ARB_IMAGING supported
     bool imagingSupport() const { return fImagingSupport; }

     /// Is GL_ARB_fragment_coord_conventions supported?
     bool fragCoordConventionsSupport() const { return fFragCoordsConventionSupport; }

     /// Is there support for Vertex Array Objects?
     bool vertexArrayObjectSupport() const { return fVertexArrayObjectSupport; }

     /// Use indices or vertices in CPU arrays rather than VBOs for dynamic content.
     bool useNonVBOVertexAndIndexDynamicData() const {
         return fUseNonVBOVertexAndIndexDynamicData;
     }

     /// Does ReadPixels support the provided format/type combo?
     bool readPixelsSupported(const GrGLInterface* intf,
                              GrGLenum format,
                              GrGLenum type) const;

     bool isCoreProfile() const { return fIsCoreProfile; }

     bool fixedFunctionSupport() const { return fFixedFunctionSupport; }

     /// Is there support for discarding the frame buffer
     bool discardFBSupport() const { return fDiscardFBSupport; }

     bool fullClearIsFree() const { return fFullClearIsFree; }

 private:
     /**
      * Maintains a bit per GrPixelConfig. It is used to avoid redundantly
      * performing glCheckFrameBufferStatus for the same config.
      */
     struct VerifiedColorConfigs {
         VerifiedColorConfigs() {
             this->reset();
         }

         void reset() {
             for (int i = 0; i < kNumUints; ++i) {
                 fVerifiedColorConfigs[i] = 0;
             }
         }

         static const int kNumUints = (kGrPixelConfigCnt  + 31) / 32;
         uint32_t fVerifiedColorConfigs[kNumUints];

         void markVerified(GrPixelConfig config) {
 #if !GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT
                 return;
 #endif
             int u32Idx = config / 32;
             int bitIdx = config % 32;
             fVerifiedColorConfigs[u32Idx] |= 1 << bitIdx;
         }

         bool isVerified(GrPixelConfig config) const {
 #if !GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT
             return false;
 #endif
             int u32Idx = config / 32;
             int bitIdx = config % 32;
             return SkToBool(fVerifiedColorConfigs[u32Idx] & (1 << bitIdx));
         }
     };

     void initFSAASupport(const GrGLContextInfo&, const GrGLInterface*);
     void initStencilFormats(const GrGLContextInfo&);
     // This must be called after initFSAASupport().
     void initConfigRenderableTable(const GrGLContextInfo&);

     // tracks configs that have been verified to pass the FBO completeness when
     // used as a color attachment
     VerifiedColorConfigs fVerifiedColorConfigs;

     SkTArray<StencilFormat, true> fStencilFormats;
     // tracks configs that have been verified to pass the FBO completeness when
     // used as a color attachment when a particular stencil format is used
     // as a stencil attachment.
     SkTArray<VerifiedColorConfigs, true> fStencilVerifiedColorConfigs;

     int fMaxFragmentUniformVectors;
     int fMaxVertexAttributes;
     int fMaxFragmentTextureUnits;
     int fMaxFixedFunctionTextureCoords;

     MSFBOType fMSFBOType;

     FBFetchType fFBFetchType;

     bool fRGBA8RenderbufferSupport : 1;
     bool fBGRAFormatSupport : 1;
     bool fBGRAIsInternalFormat : 1;
     bool fTextureSwizzleSupport : 1;
     bool fUnpackRowLengthSupport : 1;
     bool fUnpackFlipYSupport : 1;
     bool fPackRowLengthSupport : 1;
     bool fPackFlipYSupport : 1;
     bool fTextureUsageSupport : 1;
     bool fTexStorageSupport : 1;
     bool fTextureRedSupport : 1;
     bool fImagingSupport  : 1;
     bool fTwoFormatLimit : 1;
     bool fFragCoordsConventionSupport : 1;
     bool fVertexArrayObjectSupport : 1;
     bool fUseNonVBOVertexAndIndexDynamicData : 1;
     bool fIsCoreProfile : 1;
     bool fFixedFunctionSupport : 1;
     bool fDiscardFBSupport : 1;
     bool fFullClearIsFree : 1;

     typedef GrDrawTargetCaps INHERITED;
 };

 #endif
	/*
	* Copyright 2012 Google Inc.
	*
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*/


	#ifndef GrGLCaps_DEFINED
	#define GrGLCaps_DEFINED

	#include "GrDrawTargetCaps.h"
	#include "GrGLStencilBuffer.h"
	#include "SkTArray.h"
	#include "SkTDArray.h"

	class GrGLContextInfo;

	/**
	* Stores some capabilities of a GL context. Most are determined by the GL
	* version and the extensions string. It also tracks formats that have passed
	* the FBO completeness test.
	*/
	class GrGLCaps : public GrDrawTargetCaps {
	public:
	SK_DECLARE_INST_COUNT(GrGLCaps)

	typedef GrGLStencilBuffer::Format StencilFormat;

	/**
	* The type of MSAA for FBOs supported. Different extensions have different
	* semantics of how / when a resolve is performed.
	*/
	enum MSFBOType {
	/**
	* no support for MSAA FBOs
	*/
	kNone_MSFBOType = 0,
	/**
	* GL3.0-style MSAA FBO (GL_ARB_framebuffer_object).
	*/
	kDesktop_ARB_MSFBOType,
	/**
	* earlier GL_EXT_framebuffer* extensions
	*/
	kDesktop_EXT_MSFBOType,
	/**
	* Similar to kDesktop_ARB but with additional restrictions on glBlitFramebuffer.
	*/
	kES_3_0_MSFBOType,
	/**
	* GL_APPLE_framebuffer_multisample ES extension
	*/
	kES_Apple_MSFBOType,
	/**
	* GL_IMG_multisampled_render_to_texture. This variation does not have MSAA renderbuffers.
	* Instead the texture is multisampled when bound to the FBO and then resolved automatically
	* when read. It also defines an alternate value for GL_MAX_SAMPLES (which we call
	* GR_GL_MAX_SAMPLES_IMG).
	*/
	kES_IMG_MsToTexture_MSFBOType,
	/**
	* GL_EXT_multisampled_render_to_texture. Same as the IMG one above but uses the standard
	* GL_MAX_SAMPLES value.
	*/
	kES_EXT_MsToTexture_MSFBOType,

	kLast_MSFBOType = kES_EXT_MsToTexture_MSFBOType
	};

	enum FBFetchType {
	kNone_FBFetchType,
	/** GL_EXT_shader_framebuffer_fetch */
	kEXT_FBFetchType,
	/** GL_NV_shader_framebuffer_fetch */
	kNV_FBFetchType,

	kLast_FBFetchType = kNV_FBFetchType,
	};

	/**
	* Creates a GrGLCaps that advertises no support for any extensions,
	* formats, etc. Call init to initialize from a GrGLContextInfo.
	*/
	GrGLCaps();

	GrGLCaps(const GrGLCaps& caps);

	GrGLCaps& operator = (const GrGLCaps& caps);

	/**
	* Resets the caps such that nothing is supported.
	*/
	virtual void reset() SK_OVERRIDE;

	/**
	* Initializes the GrGLCaps to the set of features supported in the current
	* OpenGL context accessible via ctxInfo.
	*/
	void init(const GrGLContextInfo& ctxInfo, const GrGLInterface* interface);

	/**
	* Call to note that a color config has been verified as a valid color
	* attachment. This may save future calls to glCheckFramebufferStatus
	* using isConfigVerifiedColorAttachment().
	*/
	void markConfigAsValidColorAttachment(GrPixelConfig config) {
	fVerifiedColorConfigs.markVerified(config);
	}

	/**
	* Call to check whether a config has been verified as a valid color
	* attachment.
	*/
	bool isConfigVerifiedColorAttachment(GrPixelConfig config) const {
	return fVerifiedColorConfigs.isVerified(config);
	}

	/**
	* Call to note that a color config / stencil format pair passed
	* FBO status check. We may skip calling glCheckFramebufferStatus for
	* this combination in the future using
	* isColorConfigAndStencilFormatVerified().
	*/
	void markColorConfigAndStencilFormatAsVerified(
	GrPixelConfig config,
	const GrGLStencilBuffer::Format& format);

	/**
	* Call to check whether color config / stencil format pair has already
	* passed FBO status check.
	*/
	bool isColorConfigAndStencilFormatVerified(
	GrPixelConfig config,
	const GrGLStencilBuffer::Format& format) const;

	/**
	* Reports the type of MSAA FBO support.
	*/
	MSFBOType msFBOType() const { return fMSFBOType; }

	/**
	* Does the supported MSAA FBO extension have MSAA renderbuffers?
	*/
	bool usesMSAARenderBuffers() const {
	return kNone_MSFBOType != fMSFBOType &&
	kES_IMG_MsToTexture_MSFBOType != fMSFBOType &&
	kES_EXT_MsToTexture_MSFBOType != fMSFBOType;
	}

	/**
	* Is the MSAA FBO extension one where the texture is multisampled when bound to an FBO and
	* then implicitly resolved when read.
	*/
	bool usesImplicitMSAAResolve() const {
	return kES_IMG_MsToTexture_MSFBOType == fMSFBOType \|\|
	kES_EXT_MsToTexture_MSFBOType == fMSFBOType;
	}

	FBFetchType fbFetchType() const { return fFBFetchType; }

	/**
	* Returs a string containeng the caps info.
	*/
	virtual SkString dump() const SK_OVERRIDE;

	/**
	* Gets an array of legal stencil formats. These formats are not guaranteed
	* to be supported by the driver but are legal GLenum names given the GL
	* version and extensions supported.
	*/
	const SkTArray<StencilFormat, true>& stencilFormats() const {
	return fStencilFormats;
	}

	/// The maximum number of fragment uniform vectors (GLES has min. 16).
	int maxFragmentUniformVectors() const { return fMaxFragmentUniformVectors; }

	/// maximum number of attribute values per vertex
	int maxVertexAttributes() const { return fMaxVertexAttributes; }

	/// maximum number of texture units accessible in the fragment shader.
	int maxFragmentTextureUnits() const { return fMaxFragmentTextureUnits; }

	/// maximum number of fixed-function texture coords, or zero if no fixed-function.
	int maxFixedFunctionTextureCoords() const { return fMaxFixedFunctionTextureCoords; }

	/// ES requires an extension to support RGBA8 in RenderBufferStorage
	bool rgba8RenderbufferSupport() const { return fRGBA8RenderbufferSupport; }

	/// Is GL_BGRA supported
	bool bgraFormatSupport() const { return fBGRAFormatSupport; }

	/**
	* Depending on the ES extensions present the BGRA external format may
	* correspond either a BGRA or RGBA internalFormat. On desktop GL it is
	* RGBA.
	*/
	bool bgraIsInternalFormat() const { return fBGRAIsInternalFormat; }

	/// GL_ARB_texture_swizzle support
	bool textureSwizzleSupport() const { return fTextureSwizzleSupport; }

	/// Is there support for GL_UNPACK_ROW_LENGTH
	bool unpackRowLengthSupport() const { return fUnpackRowLengthSupport; }

	/// Is there support for GL_UNPACK_FLIP_Y
	bool unpackFlipYSupport() const { return fUnpackFlipYSupport; }

	/// Is there support for GL_PACK_ROW_LENGTH
	bool packRowLengthSupport() const { return fPackRowLengthSupport; }

	/// Is there support for GL_PACK_REVERSE_ROW_ORDER
	bool packFlipYSupport() const { return fPackFlipYSupport; }

	/// Is there support for texture parameter GL_TEXTURE_USAGE
	bool textureUsageSupport() const { return fTextureUsageSupport; }

	/// Is there support for glTexStorage
	bool texStorageSupport() const { return fTexStorageSupport; }

	/// Is there support for GL_RED and GL_R8
	bool textureRedSupport() const { return fTextureRedSupport; }

	/// Is GL_ARB_IMAGING supported
	bool imagingSupport() const { return fImagingSupport; }

	/// Is GL_ARB_fragment_coord_conventions supported?
	bool fragCoordConventionsSupport() const { return fFragCoordsConventionSupport; }

	/// Is there support for Vertex Array Objects?
	bool vertexArrayObjectSupport() const { return fVertexArrayObjectSupport; }

	/// Use indices or vertices in CPU arrays rather than VBOs for dynamic content.
	bool useNonVBOVertexAndIndexDynamicData() const {
	return fUseNonVBOVertexAndIndexDynamicData;
	}

	/// Does ReadPixels support the provided format/type combo?
	bool readPixelsSupported(const GrGLInterface* intf,
	GrGLenum format,
	GrGLenum type) const;

	bool isCoreProfile() const { return fIsCoreProfile; }

	bool fixedFunctionSupport() const { return fFixedFunctionSupport; }

	/// Is there support for discarding the frame buffer
	bool discardFBSupport() const { return fDiscardFBSupport; }

	bool fullClearIsFree() const { return fFullClearIsFree; }

	private:
	/**
	* Maintains a bit per GrPixelConfig. It is used to avoid redundantly
	* performing glCheckFrameBufferStatus for the same config.
	*/
	struct VerifiedColorConfigs {
	VerifiedColorConfigs() {
	this->reset();
	}

	void reset() {
	for (int i = 0; i < kNumUints; ++i) {
	fVerifiedColorConfigs[i] = 0;
	}
	}

	static const int kNumUints = (kGrPixelConfigCnt + 31) / 32;
	uint32_t fVerifiedColorConfigs[kNumUints];

	void markVerified(GrPixelConfig config) {
	#if !GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT
	return;
	#endif
	int u32Idx = config / 32;
	int bitIdx = config % 32;
	fVerifiedColorConfigs[u32Idx] \|= 1 << bitIdx;
	}

	bool isVerified(GrPixelConfig config) const {
	#if !GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT
	return false;
	#endif
	int u32Idx = config / 32;
	int bitIdx = config % 32;
	return SkToBool(fVerifiedColorConfigs[u32Idx] & (1 << bitIdx));
	}
	};

	void initFSAASupport(const GrGLContextInfo&, const GrGLInterface*);
	void initStencilFormats(const GrGLContextInfo&);
	// This must be called after initFSAASupport().
	void initConfigRenderableTable(const GrGLContextInfo&);

	// tracks configs that have been verified to pass the FBO completeness when
	// used as a color attachment
	VerifiedColorConfigs fVerifiedColorConfigs;

	SkTArray<StencilFormat, true> fStencilFormats;
	// tracks configs that have been verified to pass the FBO completeness when
	// used as a color attachment when a particular stencil format is used
	// as a stencil attachment.
	SkTArray<VerifiedColorConfigs, true> fStencilVerifiedColorConfigs;

	int fMaxFragmentUniformVectors;
	int fMaxVertexAttributes;
	int fMaxFragmentTextureUnits;
	int fMaxFixedFunctionTextureCoords;

	MSFBOType fMSFBOType;

	FBFetchType fFBFetchType;

	bool fRGBA8RenderbufferSupport : 1;
	bool fBGRAFormatSupport : 1;
	bool fBGRAIsInternalFormat : 1;
	bool fTextureSwizzleSupport : 1;
	bool fUnpackRowLengthSupport : 1;
	bool fUnpackFlipYSupport : 1;
	bool fPackRowLengthSupport : 1;
	bool fPackFlipYSupport : 1;
	bool fTextureUsageSupport : 1;
	bool fTexStorageSupport : 1;
	bool fTextureRedSupport : 1;
	bool fImagingSupport : 1;
	bool fTwoFormatLimit : 1;
	bool fFragCoordsConventionSupport : 1;
	bool fVertexArrayObjectSupport : 1;
	bool fUseNonVBOVertexAndIndexDynamicData : 1;
	bool fIsCoreProfile : 1;
	bool fFixedFunctionSupport : 1;
	bool fDiscardFBSupport : 1;
	bool fFullClearIsFree : 1;

	typedef GrDrawTargetCaps INHERITED;
	};

	#endif