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// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This file implements the ViewGLContext and PbufferGLContext classes.
#include "app/gfx/gl/gl_context.h"
#include <GL/osmesa.h>
#include <OpenGL/OpenGL.h>
#include "app/gfx/gl/gl_bindings.h"
#include "app/gfx/gl/gl_context_osmesa.h"
#include "app/gfx/gl/gl_context_stub.h"
#include "app/gfx/gl/gl_implementation.h"
#include "base/basictypes.h"
#include "base/logging.h"
#include "base/scoped_ptr.h"
namespace gfx {
typedef CGLContextObj GLContextHandle;
typedef CGLPBufferObj PbufferHandle;
// This class is a wrapper around a GL context used for offscreen rendering.
// It is initially backed by a 1x1 pbuffer. Use it to create an FBO to do useful
// rendering.
class PbufferGLContext : public GLContext {
public:
PbufferGLContext()
: context_(NULL),
pbuffer_(NULL) {
}
// Initializes the GL context.
bool Initialize(GLContext* shared_context);
virtual void Destroy();
virtual bool MakeCurrent();
virtual bool IsCurrent();
virtual bool IsOffscreen();
virtual void SwapBuffers();
virtual gfx::Size GetSize();
virtual void* GetHandle();
private:
GLContextHandle context_;
PbufferHandle pbuffer_;
DISALLOW_COPY_AND_ASSIGN(PbufferGLContext);
};
bool GLContext::InitializeOneOff() {
static bool initialized = false;
if (initialized)
return true;
static const GLImplementation kAllowedGLImplementations[] = {
kGLImplementationDesktopGL,
kGLImplementationOSMesaGL
};
if (!InitializeBestGLBindings(
kAllowedGLImplementations,
kAllowedGLImplementations + arraysize(kAllowedGLImplementations))) {
return false;
}
initialized = true;
return true;
}
bool PbufferGLContext::Initialize(GLContext* shared_context) {
// Create a 1x1 pbuffer and associated context to bootstrap things.
static const CGLPixelFormatAttribute attribs[] = {
(CGLPixelFormatAttribute) kCGLPFAPBuffer,
(CGLPixelFormatAttribute) 0
};
CGLPixelFormatObj pixel_format;
GLint num_pixel_formats;
if (CGLChoosePixelFormat(attribs,
&pixel_format,
&num_pixel_formats) != kCGLNoError) {
DLOG(ERROR) << "Error choosing pixel format.";
Destroy();
return false;
}
if (!pixel_format) {
return false;
}
GLContextHandle shared_handle = NULL;
if (shared_context)
shared_handle = static_cast<GLContextHandle>(shared_context->GetHandle());
CGLError res = CGLCreateContext(pixel_format, shared_handle, &context_);
CGLDestroyPixelFormat(pixel_format);
if (res != kCGLNoError) {
DLOG(ERROR) << "Error creating context.";
Destroy();
return false;
}
if (CGLCreatePBuffer(1, 1,
GL_TEXTURE_2D, GL_RGBA,
0, &pbuffer_) != kCGLNoError) {
DLOG(ERROR) << "Error creating pbuffer.";
Destroy();
return false;
}
if (CGLSetPBuffer(context_, pbuffer_, 0, 0, 0) != kCGLNoError) {
DLOG(ERROR) << "Error attaching pbuffer to context.";
Destroy();
return false;
}
if (!MakeCurrent()) {
Destroy();
DLOG(ERROR) << "Couldn't make context current for initialization.";
return false;
}
if (!InitializeCommon()) {
Destroy();
return false;
}
return true;
}
void PbufferGLContext::Destroy() {
if (context_) {
CGLDestroyContext(context_);
context_ = NULL;
}
if (pbuffer_) {
CGLDestroyPBuffer(pbuffer_);
pbuffer_ = NULL;
}
}
bool PbufferGLContext::MakeCurrent() {
if (!IsCurrent()) {
if (CGLSetCurrentContext(context_) != kCGLNoError) {
DLOG(ERROR) << "Unable to make gl context current.";
return false;
}
}
return true;
}
bool PbufferGLContext::IsCurrent() {
return CGLGetCurrentContext() == context_;
}
bool PbufferGLContext::IsOffscreen() {
return true;
}
void PbufferGLContext::SwapBuffers() {
NOTREACHED() << "Cannot call SwapBuffers on a PbufferGLContext.";
}
gfx::Size PbufferGLContext::GetSize() {
NOTREACHED() << "Should not be requesting size of a PbufferGLContext.";
return gfx::Size(1, 1);
}
void* PbufferGLContext::GetHandle() {
return context_;
}
GLContext* GLContext::CreateOffscreenGLContext(GLContext* shared_context) {
switch (GetGLImplementation()) {
case kGLImplementationDesktopGL: {
scoped_ptr<PbufferGLContext> context(new PbufferGLContext);
if (!context->Initialize(shared_context))
return NULL;
return context.release();
}
case kGLImplementationOSMesaGL: {
scoped_ptr<OSMesaGLContext> context(new OSMesaGLContext);
if (!context->Initialize(OSMESA_RGBA, shared_context))
return NULL;
return context.release();
}
case kGLImplementationMockGL:
return new StubGLContext;
default:
NOTREACHED();
return NULL;
}
}
} // namespace gfx
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