src/gpu/gl/angle/SkANGLEGLContext.cpp

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

#include "gl/angle/SkANGLEGLContext.h"

#include <EGL/egl.h>
#include <EGL/eglext.h>

#define EGL_PLATFORM_ANGLE_ANGLE                0x3202
#define EGL_PLATFORM_ANGLE_TYPE_ANGLE           0x3203
#define EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE      0x3207
#define EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE     0x3208
#define EGL_PLATFORM_ANGLE_TYPE_OPENGL_ANGLE    0x320D

void* SkANGLEGLContext::GetD3DEGLDisplay(void* nativeDisplay, bool useGLBackend) {
    PFNEGLGETPLATFORMDISPLAYEXTPROC eglGetPlatformDisplayEXT;
    eglGetPlatformDisplayEXT =
        (PFNEGLGETPLATFORMDISPLAYEXTPROC)eglGetProcAddress("eglGetPlatformDisplayEXT");

    if (!eglGetPlatformDisplayEXT) {
        return eglGetDisplay(static_cast<EGLNativeDisplayType>(nativeDisplay));
    }

    EGLDisplay display = EGL_NO_DISPLAY;
    if (useGLBackend) {
        // Try for an ANGLE D3D11 context, fall back to D3D9.
        EGLint attribs[3] = {
              EGL_PLATFORM_ANGLE_TYPE_ANGLE,
              EGL_PLATFORM_ANGLE_TYPE_OPENGL_ANGLE,
              EGL_NONE
        };
        display = eglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE,
                                            nativeDisplay, attribs);
    } else {
        // Try for an ANGLE D3D11 context, fall back to D3D9, and finally GL.
        EGLint attribs[3][3] = {
            {
                EGL_PLATFORM_ANGLE_TYPE_ANGLE,
                EGL_PLATFORM_ANGLE_TYPE_D3D11_ANGLE,
                EGL_NONE
            },
            {
                EGL_PLATFORM_ANGLE_TYPE_ANGLE,
                EGL_PLATFORM_ANGLE_TYPE_D3D9_ANGLE,
                EGL_NONE
            },
            {
                EGL_PLATFORM_ANGLE_TYPE_ANGLE,
                EGL_PLATFORM_ANGLE_TYPE_OPENGL_ANGLE,
                EGL_NONE
            }
        };
        for (int i = 0; i < 3 && display == EGL_NO_DISPLAY; ++i) {
            display = eglGetPlatformDisplayEXT(EGL_PLATFORM_ANGLE_ANGLE,
                                                nativeDisplay, attribs[i]);
        }
    }
    return display;
}

SkANGLEGLContext::SkANGLEGLContext(bool useGLBackend)
    : fContext(EGL_NO_CONTEXT)
    , fDisplay(EGL_NO_DISPLAY)
    , fSurface(EGL_NO_SURFACE) {

    EGLint numConfigs;
    static const EGLint configAttribs[] = {
        EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
        EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
        EGL_RED_SIZE, 8,
        EGL_GREEN_SIZE, 8,
        EGL_BLUE_SIZE, 8,
        EGL_ALPHA_SIZE, 8,
        EGL_NONE
    };

    fDisplay = GetD3DEGLDisplay(EGL_DEFAULT_DISPLAY, useGLBackend);
    if (EGL_NO_DISPLAY == fDisplay) {
        SkDebugf("Could not create EGL display!");
        return;
    }

    EGLint majorVersion;
    EGLint minorVersion;
    eglInitialize(fDisplay, &majorVersion, &minorVersion);

    EGLConfig surfaceConfig;
    eglChooseConfig(fDisplay, configAttribs, &surfaceConfig, 1, &numConfigs);

    static const EGLint contextAttribs[] = {
        EGL_CONTEXT_CLIENT_VERSION, 2,
        EGL_NONE
    };
    fContext = eglCreateContext(fDisplay, surfaceConfig, nullptr, contextAttribs);


    static const EGLint surfaceAttribs[] = {
        EGL_WIDTH, 1,
        EGL_HEIGHT, 1,
        EGL_NONE
    };

    fSurface = eglCreatePbufferSurface(fDisplay, surfaceConfig, surfaceAttribs);

    eglMakeCurrent(fDisplay, fSurface, fSurface, fContext);

    SkAutoTUnref<const GrGLInterface> gl(GrGLCreateANGLEInterface());
    if (nullptr == gl.get()) {
        SkDebugf("Could not create ANGLE GL interface!\n");
        this->destroyGLContext();
        return;
    }
    if (!gl->validate()) {
        SkDebugf("Could not validate ANGLE GL interface!\n");
        this->destroyGLContext();
        return;
    }

    this->init(gl.detach());
}

SkANGLEGLContext::~SkANGLEGLContext() {
    this->teardown();
    this->destroyGLContext();
}

void SkANGLEGLContext::destroyGLContext() {
    if (fDisplay) {
        eglMakeCurrent(fDisplay, 0, 0, 0);

        if (fContext) {
            eglDestroyContext(fDisplay, fContext);
            fContext = EGL_NO_CONTEXT;
        }

        if (fSurface) {
            eglDestroySurface(fDisplay, fSurface);
            fSurface = EGL_NO_SURFACE;
        }

        //TODO should we close the display?
        fDisplay = EGL_NO_DISPLAY;
    }
}

void SkANGLEGLContext::onPlatformMakeCurrent() const {
    if (!eglMakeCurrent(fDisplay, fSurface, fSurface, fContext)) {
        SkDebugf("Could not set the context.\n");
    }
}

void SkANGLEGLContext::onPlatformSwapBuffers() const {
    if (!eglSwapBuffers(fDisplay, fSurface)) {
        SkDebugf("Could not complete eglSwapBuffers.\n");
    }
}

GrGLFuncPtr SkANGLEGLContext::onPlatformGetProcAddress(const char* name) const {
    return eglGetProcAddress(name);
}