Source/WebCore/platform/graphics/efl/GraphicsContext3DEfl.cpp - WebKit - Git at Google

 /*
     Copyright (C) 2012 Samsung Electronics
     Copyright (C) 2012 Intel Corporation.

     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.

     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Library General Public License for more details.

     You should have received a copy of the GNU Library General Public License
     along with this library; see the file COPYING.LIB.  If not, write to
     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
 */

 #include "config.h"
 #include "GraphicsContext3D.h"

 #include "GLDefs.h"
 #include "GraphicsContext3DPrivate.h"
 #include "Image.h"
 #include "ImageSource.h"
 #include "NotImplemented.h"
 #include "PlatformContextCairo.h"

 namespace WebCore {

 PassRefPtr<GraphicsContext3D> GraphicsContext3D::create(GraphicsContext3D::Attributes attrs, HostWindow* hostWindow, RenderStyle renderStyle)
 {
     RefPtr<GraphicsContext3D> context = adoptRef(new GraphicsContext3D(attrs, hostWindow, renderStyle));
     return context->m_private ? context.release() : 0;
 }

 GraphicsContext3D::GraphicsContext3D(GraphicsContext3D::Attributes attrs, HostWindow* hostWindow, GraphicsContext3D::RenderStyle renderStyle)
     : m_currentWidth(0)
     , m_currentHeight(0)
     , m_compiler(isGLES2Compliant() ? SH_ESSL_OUTPUT : SH_GLSL_OUTPUT)
     , m_attrs(attrs)
     , m_renderStyle(renderStyle)
     , m_texture(0)
     , m_compositorTexture(0)
     , m_fbo(0)
 #if USE(OPENGL_ES_2)
     , m_depthBuffer(0)
     , m_stencilBuffer(0)
 #endif
     , m_depthStencilBuffer(0)
     , m_layerComposited(false)
     , m_internalColorFormat(0)
     , m_multisampleFBO(0)
     , m_multisampleDepthStencilBuffer(0)
     , m_multisampleColorBuffer(0)
     , m_private(GraphicsContext3DPrivate::create(this, hostWindow))
 {
     if (!m_private)
         return;

     validateAttributes();

     if (renderStyle == RenderOffscreen) {
         // Create buffers for the canvas FBO.
         glGenFramebuffers(1, &m_fbo);

         // Create a texture to render into.
         glGenTextures(1, &m_texture);
         glBindTexture(GraphicsContext3D::TEXTURE_2D, m_texture);
         glTexParameterf(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_MAG_FILTER, GraphicsContext3D::LINEAR);
         glTexParameterf(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_MIN_FILTER, GraphicsContext3D::LINEAR);
         glTexParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_WRAP_S, GraphicsContext3D::CLAMP_TO_EDGE);
         glTexParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_WRAP_T, GraphicsContext3D::CLAMP_TO_EDGE);
         glBindTexture(GraphicsContext3D::TEXTURE_2D, 0);

         // Create a multisample FBO.
         if (m_attrs.antialias) {
             glGenFramebuffers(1, &m_multisampleFBO);
             glBindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_multisampleFBO);
             m_state.boundFBO = m_multisampleFBO;
             glGenRenderbuffers(1, &m_multisampleColorBuffer);
             if (m_attrs.stencil || m_attrs.depth)
                 glGenRenderbuffers(1, &m_multisampleDepthStencilBuffer);
         } else {
             // Bind canvas FBO.
             glBindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_fbo);
             m_state.boundFBO = m_fbo;
 #if USE(OPENGL_ES_2)
             if (m_attrs.depth)
                 glGenRenderbuffers(1, &m_depthBuffer);
             if (m_attrs.stencil)
                 glGenRenderbuffers(1, &m_stencilBuffer);
 #endif
             if (m_attrs.stencil || m_attrs.depth)
                 glGenRenderbuffers(1, &m_depthStencilBuffer);
         }
     }

     // ANGLE initialization.
     ShBuiltInResources ANGLEResources;
     ShInitBuiltInResources(&ANGLEResources);

     getIntegerv(GraphicsContext3D::MAX_VERTEX_ATTRIBS, &ANGLEResources.MaxVertexAttribs);
     getIntegerv(GraphicsContext3D::MAX_VERTEX_UNIFORM_VECTORS, &ANGLEResources.MaxVertexUniformVectors);
     getIntegerv(GraphicsContext3D::MAX_VARYING_VECTORS, &ANGLEResources.MaxVaryingVectors);
     getIntegerv(GraphicsContext3D::MAX_VERTEX_TEXTURE_IMAGE_UNITS, &ANGLEResources.MaxVertexTextureImageUnits);
     getIntegerv(GraphicsContext3D::MAX_COMBINED_TEXTURE_IMAGE_UNITS, &ANGLEResources.MaxCombinedTextureImageUnits);
     getIntegerv(GraphicsContext3D::MAX_TEXTURE_IMAGE_UNITS, &ANGLEResources.MaxTextureImageUnits);
     getIntegerv(GraphicsContext3D::MAX_FRAGMENT_UNIFORM_VECTORS, &ANGLEResources.MaxFragmentUniformVectors);

     // Always set to 1 for OpenGL ES.
     ANGLEResources.MaxDrawBuffers = 1;

     GC3Dint range[2], precision;
     getShaderPrecisionFormat(GraphicsContext3D::FRAGMENT_SHADER, GraphicsContext3D::HIGH_FLOAT, range, &precision);
     ANGLEResources.FragmentPrecisionHigh = (range[0] || range[1] || precision);

     m_compiler.setResources(ANGLEResources);

 #if !USE(OPENGL_ES_2)
     glEnable(GL_POINT_SPRITE);
     glEnable(GL_VERTEX_PROGRAM_POINT_SIZE);
 #endif
     if (renderStyle != RenderToCurrentGLContext)
         glClearColor(0.0, 0.0, 0.0, 0.0);
 }

 GraphicsContext3D::~GraphicsContext3D()
 {
     if (!m_private || (m_renderStyle == RenderToCurrentGLContext) || !makeContextCurrent())
         return;

     glBindFramebuffer(GL_FRAMEBUFFER, 0);
     glBindTexture(GL_TEXTURE_2D, 0);

     if (m_texture)
         glDeleteTextures(1, &m_texture);

     if (m_fbo)
         glDeleteFramebuffers(1, &m_fbo);

     if (m_attrs.antialias) {
         if (m_multisampleColorBuffer)
             glDeleteRenderbuffers(1, &m_multisampleColorBuffer);

         if (m_multisampleDepthStencilBuffer)
             glDeleteRenderbuffers(1, &m_multisampleDepthStencilBuffer);

         if (m_multisampleFBO)
             glDeleteFramebuffers(1, &m_multisampleFBO);
     } else if (m_attrs.stencil || m_attrs.depth) {
 #if USE(OPENGL_ES_2)
         if (m_depthBuffer)
             glDeleteRenderbuffers(1, &m_depthBuffer);

         if (m_stencilBuffer)
             glDeleteRenderbuffers(1, &m_stencilBuffer);
 #endif
         if (m_depthStencilBuffer)
             glDeleteRenderbuffers(1, &m_depthStencilBuffer);
     }
 }

 PlatformGraphicsContext3D GraphicsContext3D::platformGraphicsContext3D()
 {
     return m_private->platformGraphicsContext3D();
 }

 Platform3DObject GraphicsContext3D::platformTexture() const
 {
     return m_texture;
 }

 PlatformLayer* GraphicsContext3D::platformLayer() const
 {
 #if USE(TEXTURE_MAPPER_GL)
     return m_private.get();
 #else
     notImplemented();
     return 0;
 #endif
 }

 bool GraphicsContext3D::makeContextCurrent()
 {
     return m_private->makeContextCurrent();
 }

 bool GraphicsContext3D::isGLES2Compliant() const
 {
 #if USE(OPENGL_ES_2)
     return true;
 #else
     return false;
 #endif
 }

 void GraphicsContext3D::setContextLostCallback(PassOwnPtr<ContextLostCallback> callBack)
 {
     m_private->setContextLostCallback(callBack);
 }

 void GraphicsContext3D::setErrorMessageCallback(PassOwnPtr<ErrorMessageCallback>)
 {
     notImplemented();
 }

 void GraphicsContext3D::paintToCanvas(const unsigned char* imagePixels, int imageWidth, int imageHeight, int canvasWidth, int canvasHeight, PlatformContextCairo* context)
 {
     if (!imagePixels || imageWidth <= 0 || imageHeight <= 0 || canvasWidth <= 0 || canvasHeight <= 0 || !context)
         return;

     cairo_t* cr = context->cr();
     context->save();

     RefPtr<cairo_surface_t> imageSurface = adoptRef(cairo_image_surface_create_for_data(
         const_cast<unsigned char*>(imagePixels), CAIRO_FORMAT_ARGB32, imageWidth, imageHeight, imageWidth * 4));

     cairo_rectangle(cr, 0, 0, canvasWidth, canvasHeight);

     // OpenGL keeps the pixels stored bottom up, so we need to flip the image here.
     cairo_matrix_t matrix;
     cairo_matrix_init(&matrix, 1.0, 0.0, 0.0, -1.0, 0.0, imageHeight);
     cairo_set_matrix(cr, &matrix);
     cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
     cairo_set_source_surface(cr, imageSurface.get(), 0, 0);
     cairo_fill(cr);
     context->restore();
 }

 #if USE(GRAPHICS_SURFACE)
 void GraphicsContext3D::createGraphicsSurfaces(const IntSize& size)
 {
     m_private->didResizeCanvas(size);
 }
 #endif

 GraphicsContext3D::ImageExtractor::~ImageExtractor()
 {
     delete m_decoder;
 }

 bool GraphicsContext3D::ImageExtractor::extractImage(bool premultiplyAlpha, bool ignoreGammaAndColorProfile)
 {
     // This implementation is taken from GraphicsContext3DCairo.

     if (!m_image)
         return false;

     // We need this to stay in scope because the native image is just a shallow copy of the data.
     m_decoder = new ImageSource(premultiplyAlpha ? ImageSource::AlphaPremultiplied : ImageSource::AlphaNotPremultiplied, ignoreGammaAndColorProfile ? ImageSource::GammaAndColorProfileIgnored : ImageSource::GammaAndColorProfileApplied);

     if (!m_decoder)
         return false;

     ImageSource& decoder = *m_decoder;
     m_alphaOp = AlphaDoNothing;

     if (m_image->data()) {
         decoder.setData(m_image->data(), true);

         if (!decoder.frameCount() || !decoder.frameIsCompleteAtIndex(0))
             return false;

         m_imageSurface = decoder.createFrameAtIndex(0);
     } else {
         m_imageSurface = m_image->nativeImageForCurrentFrame();
         // 1. For texImage2D with HTMLVideoElment input, assume no PremultiplyAlpha had been applied and the alpha value is 0xFF for each pixel,
         // which is true at present and may be changed in the future and needs adjustment accordingly.
         // 2. For texImage2D with HTMLCanvasElement input in which Alpha is already Premultiplied in this port,
         // do AlphaDoUnmultiply if UNPACK_PREMULTIPLY_ALPHA_WEBGL is set to false.
         if (!premultiplyAlpha && m_imageHtmlDomSource != HtmlDomVideo)
             m_alphaOp = AlphaDoUnmultiply;
     }

     if (!m_imageSurface)
         return false;

     m_imageWidth = cairo_image_surface_get_width(m_imageSurface.get());
     m_imageHeight = cairo_image_surface_get_height(m_imageSurface.get());

     if (!m_imageWidth || !m_imageHeight)
         return false;

     if (cairo_image_surface_get_format(m_imageSurface.get()) != CAIRO_FORMAT_ARGB32)
         return false;

     uint srcUnpackAlignment = 1;
     size_t bytesPerRow = cairo_image_surface_get_stride(m_imageSurface.get());
     size_t bitsPerPixel = 32;
     unsigned padding = bytesPerRow - bitsPerPixel / 8 * m_imageWidth;

     if (padding) {
         srcUnpackAlignment = padding + 1;
         while (bytesPerRow % srcUnpackAlignment)
             ++srcUnpackAlignment;
     }

     m_imagePixelData = cairo_image_surface_get_data(m_imageSurface.get());
     m_imageSourceFormat = DataFormatBGRA8;
     m_imageSourceUnpackAlignment = srcUnpackAlignment;

     return true;
 }

 } // namespace WebCore
	/*
	Copyright (C) 2012 Samsung Electronics
	Copyright (C) 2012 Intel Corporation.

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Library General Public
	License as published by the Free Software Foundation; either
	version 2 of the License, or (at your option) any later version.

	This library is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	Library General Public License for more details.

	You should have received a copy of the GNU Library General Public License
	along with this library; see the file COPYING.LIB. If not, write to
	the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
	Boston, MA 02110-1301, USA.
	*/

	#include "config.h"
	#include "GraphicsContext3D.h"

	#include "GLDefs.h"
	#include "GraphicsContext3DPrivate.h"
	#include "Image.h"
	#include "ImageSource.h"
	#include "NotImplemented.h"
	#include "PlatformContextCairo.h"

	namespace WebCore {

	PassRefPtr<GraphicsContext3D> GraphicsContext3D::create(GraphicsContext3D::Attributes attrs, HostWindow* hostWindow, RenderStyle renderStyle)
	{
	RefPtr<GraphicsContext3D> context = adoptRef(new GraphicsContext3D(attrs, hostWindow, renderStyle));
	return context->m_private ? context.release() : 0;
	}

	GraphicsContext3D::GraphicsContext3D(GraphicsContext3D::Attributes attrs, HostWindow* hostWindow, GraphicsContext3D::RenderStyle renderStyle)
	: m_currentWidth(0)
	, m_currentHeight(0)
	, m_compiler(isGLES2Compliant() ? SH_ESSL_OUTPUT : SH_GLSL_OUTPUT)
	, m_attrs(attrs)
	, m_renderStyle(renderStyle)
	, m_texture(0)
	, m_compositorTexture(0)
	, m_fbo(0)
	#if USE(OPENGL_ES_2)
	, m_depthBuffer(0)
	, m_stencilBuffer(0)
	#endif
	, m_depthStencilBuffer(0)
	, m_layerComposited(false)
	, m_internalColorFormat(0)
	, m_multisampleFBO(0)
	, m_multisampleDepthStencilBuffer(0)
	, m_multisampleColorBuffer(0)
	, m_private(GraphicsContext3DPrivate::create(this, hostWindow))
	{
	if (!m_private)
	return;

	validateAttributes();

	if (renderStyle == RenderOffscreen) {
	// Create buffers for the canvas FBO.
	glGenFramebuffers(1, &m_fbo);

	// Create a texture to render into.
	glGenTextures(1, &m_texture);
	glBindTexture(GraphicsContext3D::TEXTURE_2D, m_texture);
	glTexParameterf(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_MAG_FILTER, GraphicsContext3D::LINEAR);
	glTexParameterf(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_MIN_FILTER, GraphicsContext3D::LINEAR);
	glTexParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_WRAP_S, GraphicsContext3D::CLAMP_TO_EDGE);
	glTexParameteri(GraphicsContext3D::TEXTURE_2D, GraphicsContext3D::TEXTURE_WRAP_T, GraphicsContext3D::CLAMP_TO_EDGE);
	glBindTexture(GraphicsContext3D::TEXTURE_2D, 0);

	// Create a multisample FBO.
	if (m_attrs.antialias) {
	glGenFramebuffers(1, &m_multisampleFBO);
	glBindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_multisampleFBO);
	m_state.boundFBO = m_multisampleFBO;
	glGenRenderbuffers(1, &m_multisampleColorBuffer);
	if (m_attrs.stencil \|\| m_attrs.depth)
	glGenRenderbuffers(1, &m_multisampleDepthStencilBuffer);
	} else {
	// Bind canvas FBO.
	glBindFramebuffer(GraphicsContext3D::FRAMEBUFFER, m_fbo);
	m_state.boundFBO = m_fbo;
	#if USE(OPENGL_ES_2)
	if (m_attrs.depth)
	glGenRenderbuffers(1, &m_depthBuffer);
	if (m_attrs.stencil)
	glGenRenderbuffers(1, &m_stencilBuffer);
	#endif
	if (m_attrs.stencil \|\| m_attrs.depth)
	glGenRenderbuffers(1, &m_depthStencilBuffer);
	}
	}

	// ANGLE initialization.
	ShBuiltInResources ANGLEResources;
	ShInitBuiltInResources(&ANGLEResources);

	getIntegerv(GraphicsContext3D::MAX_VERTEX_ATTRIBS, &ANGLEResources.MaxVertexAttribs);
	getIntegerv(GraphicsContext3D::MAX_VERTEX_UNIFORM_VECTORS, &ANGLEResources.MaxVertexUniformVectors);
	getIntegerv(GraphicsContext3D::MAX_VARYING_VECTORS, &ANGLEResources.MaxVaryingVectors);
	getIntegerv(GraphicsContext3D::MAX_VERTEX_TEXTURE_IMAGE_UNITS, &ANGLEResources.MaxVertexTextureImageUnits);
	getIntegerv(GraphicsContext3D::MAX_COMBINED_TEXTURE_IMAGE_UNITS, &ANGLEResources.MaxCombinedTextureImageUnits);
	getIntegerv(GraphicsContext3D::MAX_TEXTURE_IMAGE_UNITS, &ANGLEResources.MaxTextureImageUnits);
	getIntegerv(GraphicsContext3D::MAX_FRAGMENT_UNIFORM_VECTORS, &ANGLEResources.MaxFragmentUniformVectors);

	// Always set to 1 for OpenGL ES.
	ANGLEResources.MaxDrawBuffers = 1;

	GC3Dint range[2], precision;
	getShaderPrecisionFormat(GraphicsContext3D::FRAGMENT_SHADER, GraphicsContext3D::HIGH_FLOAT, range, &precision);
	ANGLEResources.FragmentPrecisionHigh = (range[0] \|\| range[1] \|\| precision);

	m_compiler.setResources(ANGLEResources);

	#if !USE(OPENGL_ES_2)
	glEnable(GL_POINT_SPRITE);
	glEnable(GL_VERTEX_PROGRAM_POINT_SIZE);
	#endif
	if (renderStyle != RenderToCurrentGLContext)
	glClearColor(0.0, 0.0, 0.0, 0.0);
	}

	GraphicsContext3D::~GraphicsContext3D()
	{
	if (!m_private \|\| (m_renderStyle == RenderToCurrentGLContext) \|\| !makeContextCurrent())
	return;

	glBindFramebuffer(GL_FRAMEBUFFER, 0);
	glBindTexture(GL_TEXTURE_2D, 0);

	if (m_texture)
	glDeleteTextures(1, &m_texture);

	if (m_fbo)
	glDeleteFramebuffers(1, &m_fbo);

	if (m_attrs.antialias) {
	if (m_multisampleColorBuffer)
	glDeleteRenderbuffers(1, &m_multisampleColorBuffer);

	if (m_multisampleDepthStencilBuffer)
	glDeleteRenderbuffers(1, &m_multisampleDepthStencilBuffer);

	if (m_multisampleFBO)
	glDeleteFramebuffers(1, &m_multisampleFBO);
	} else if (m_attrs.stencil \|\| m_attrs.depth) {
	#if USE(OPENGL_ES_2)
	if (m_depthBuffer)
	glDeleteRenderbuffers(1, &m_depthBuffer);

	if (m_stencilBuffer)
	glDeleteRenderbuffers(1, &m_stencilBuffer);
	#endif
	if (m_depthStencilBuffer)
	glDeleteRenderbuffers(1, &m_depthStencilBuffer);
	}
	}

	PlatformGraphicsContext3D GraphicsContext3D::platformGraphicsContext3D()
	{
	return m_private->platformGraphicsContext3D();
	}

	Platform3DObject GraphicsContext3D::platformTexture() const
	{
	return m_texture;
	}

	PlatformLayer* GraphicsContext3D::platformLayer() const
	{
	#if USE(TEXTURE_MAPPER_GL)
	return m_private.get();
	#else
	notImplemented();
	return 0;
	#endif
	}

	bool GraphicsContext3D::makeContextCurrent()
	{
	return m_private->makeContextCurrent();
	}

	bool GraphicsContext3D::isGLES2Compliant() const
	{
	#if USE(OPENGL_ES_2)
	return true;
	#else
	return false;
	#endif
	}

	void GraphicsContext3D::setContextLostCallback(PassOwnPtr<ContextLostCallback> callBack)
	{
	m_private->setContextLostCallback(callBack);
	}

	void GraphicsContext3D::setErrorMessageCallback(PassOwnPtr<ErrorMessageCallback>)
	{
	notImplemented();
	}

	void GraphicsContext3D::paintToCanvas(const unsigned char* imagePixels, int imageWidth, int imageHeight, int canvasWidth, int canvasHeight, PlatformContextCairo* context)
	{
	if (!imagePixels \|\| imageWidth <= 0 \|\| imageHeight <= 0 \|\| canvasWidth <= 0 \|\| canvasHeight <= 0 \|\| !context)
	return;

	cairo_t* cr = context->cr();
	context->save();

	RefPtr<cairo_surface_t> imageSurface = adoptRef(cairo_image_surface_create_for_data(
	const_cast<unsigned char>(imagePixels), CAIRO_FORMAT_ARGB32, imageWidth, imageHeight, imageWidth 4));

	cairo_rectangle(cr, 0, 0, canvasWidth, canvasHeight);

	// OpenGL keeps the pixels stored bottom up, so we need to flip the image here.
	cairo_matrix_t matrix;
	cairo_matrix_init(&matrix, 1.0, 0.0, 0.0, -1.0, 0.0, imageHeight);
	cairo_set_matrix(cr, &matrix);
	cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
	cairo_set_source_surface(cr, imageSurface.get(), 0, 0);
	cairo_fill(cr);
	context->restore();
	}

	#if USE(GRAPHICS_SURFACE)
	void GraphicsContext3D::createGraphicsSurfaces(const IntSize& size)
	{
	m_private->didResizeCanvas(size);
	}
	#endif

	GraphicsContext3D::ImageExtractor::~ImageExtractor()
	{
	delete m_decoder;
	}

	bool GraphicsContext3D::ImageExtractor::extractImage(bool premultiplyAlpha, bool ignoreGammaAndColorProfile)
	{
	// This implementation is taken from GraphicsContext3DCairo.

	if (!m_image)
	return false;

	// We need this to stay in scope because the native image is just a shallow copy of the data.
	m_decoder = new ImageSource(premultiplyAlpha ? ImageSource::AlphaPremultiplied : ImageSource::AlphaNotPremultiplied, ignoreGammaAndColorProfile ? ImageSource::GammaAndColorProfileIgnored : ImageSource::GammaAndColorProfileApplied);

	if (!m_decoder)
	return false;

	ImageSource& decoder = *m_decoder;
	m_alphaOp = AlphaDoNothing;

	if (m_image->data()) {
	decoder.setData(m_image->data(), true);

	if (!decoder.frameCount() \|\| !decoder.frameIsCompleteAtIndex(0))
	return false;

	m_imageSurface = decoder.createFrameAtIndex(0);
	} else {
	m_imageSurface = m_image->nativeImageForCurrentFrame();
	// 1. For texImage2D with HTMLVideoElment input, assume no PremultiplyAlpha had been applied and the alpha value is 0xFF for each pixel,
	// which is true at present and may be changed in the future and needs adjustment accordingly.
	// 2. For texImage2D with HTMLCanvasElement input in which Alpha is already Premultiplied in this port,
	// do AlphaDoUnmultiply if UNPACK_PREMULTIPLY_ALPHA_WEBGL is set to false.
	if (!premultiplyAlpha && m_imageHtmlDomSource != HtmlDomVideo)
	m_alphaOp = AlphaDoUnmultiply;
	}

	if (!m_imageSurface)
	return false;

	m_imageWidth = cairo_image_surface_get_width(m_imageSurface.get());
	m_imageHeight = cairo_image_surface_get_height(m_imageSurface.get());

	if (!m_imageWidth \|\| !m_imageHeight)
	return false;

	if (cairo_image_surface_get_format(m_imageSurface.get()) != CAIRO_FORMAT_ARGB32)
	return false;

	uint srcUnpackAlignment = 1;
	size_t bytesPerRow = cairo_image_surface_get_stride(m_imageSurface.get());
	size_t bitsPerPixel = 32;
	unsigned padding = bytesPerRow - bitsPerPixel / 8 * m_imageWidth;

	if (padding) {
	srcUnpackAlignment = padding + 1;
	while (bytesPerRow % srcUnpackAlignment)
	++srcUnpackAlignment;
	}

	m_imagePixelData = cairo_image_surface_get_data(m_imageSurface.get());
	m_imageSourceFormat = DataFormatBGRA8;
	m_imageSourceUnpackAlignment = srcUnpackAlignment;

	return true;
	}

	} // namespace WebCore