PassRefPtr<DrawingBuffer> DrawingBuffer::create(PassOwnPtr<WebGraphicsContext3DProvider> contextProvider, const IntSize& size, bool premultipliedAlpha, bool wantAlphaChannel, bool wantDepthBuffer, bool wantStencilBuffer, bool wantAntialiasing, PreserveDrawingBuffer preserve)
{
ASSERT(contextProvider);
if (shouldFailDrawingBufferCreationForTesting) {
shouldFailDrawingBufferCreationForTesting = false;
return nullptr;
}
OwnPtr<Extensions3DUtil> extensionsUtil = Extensions3DUtil::create(contextProvider->contextGL());
if (!extensionsUtil->isValid()) {
// This might be the first time we notice that the GL context is lost.
return nullptr;
}
ASSERT(extensionsUtil->supportsExtension("GL_OES_packed_depth_stencil"));
extensionsUtil->ensureExtensionEnabled("GL_OES_packed_depth_stencil");
bool multisampleSupported = wantAntialiasing
&& (extensionsUtil->supportsExtension("GL_CHROMIUM_framebuffer_multisample")
|| extensionsUtil->supportsExtension("GL_EXT_multisampled_render_to_texture"))
&& extensionsUtil->supportsExtension("GL_OES_rgb8_rgba8");
if (multisampleSupported) {
extensionsUtil->ensureExtensionEnabled("GL_OES_rgb8_rgba8");
if (extensionsUtil->supportsExtension("GL_CHROMIUM_framebuffer_multisample"))
extensionsUtil->ensureExtensionEnabled("GL_CHROMIUM_framebuffer_multisample");
else
extensionsUtil->ensureExtensionEnabled("GL_EXT_multisampled_render_to_texture");
}
bool discardFramebufferSupported = extensionsUtil->supportsExtension("GL_EXT_discard_framebuffer");
if (discardFramebufferSupported)
extensionsUtil->ensureExtensionEnabled("GL_EXT_discard_framebuffer");
RefPtr<DrawingBuffer> drawingBuffer = adoptRef(new DrawingBuffer(std::move(contextProvider), extensionsUtil.release(), discardFramebufferSupported, wantAlphaChannel, premultipliedAlpha, preserve, wantDepthBuffer, wantStencilBuffer));
if (!drawingBuffer->initialize(size, multisampleSupported)) {
drawingBuffer->beginDestruction();
return PassRefPtr<DrawingBuffer>();
}
return drawingBuffer.release();
}
