skia2/include/gpu/gl/SkGLContextHelper.h
2013-08-17 00:02:59 +00:00

78 lines
2.1 KiB
C++

/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkGLContextHelper_DEFINED
#define SkGLContextHelper_DEFINED
#include "GrGLExtensions.h"
#include "GrGLInterface.h"
/**
* Create an offscreen opengl context with an RGBA8 / 8bit stencil FBO.
* Provides a GrGLInterface struct of function pointers for the context.
*/
class SkGLContextHelper : public SkRefCnt {
public:
SK_DECLARE_INST_COUNT(SkGLContextHelper)
SkGLContextHelper();
virtual ~SkGLContextHelper();
/**
* Initializes the context and makes it current.
*/
bool init(const int width, const int height);
int getFBOID() const { return fFBO; }
const GrGLInterface* gl() const { return fGL; }
virtual void makeCurrent() const = 0;
bool hasExtension(const char* extensionName) const {
SkASSERT(NULL != fGL);
return fExtensions.has(extensionName);
}
protected:
/**
* Subclass implements this to make a GL context. The returned GrGLInterface
* should be populated with functions compatible with the context. The
* format and size of backbuffers does not matter since an FBO will be
* created.
*/
virtual const GrGLInterface* createGLContext() = 0;
/**
* Subclass should destroy the underlying GL context.
*/
virtual void destroyGLContext() = 0;
private:
GrGLExtensions fExtensions;
GrGLuint fFBO;
GrGLuint fColorBufferID;
GrGLuint fDepthStencilBufferID;
const GrGLInterface* fGL;
typedef SkRefCnt INHERITED;
};
/**
* Helper macros for using the GL context through the GrGLInterface. Example:
* SK_GL(glCtx, GenTextures(1, &texID));
*/
#define SK_GL(ctx, X) (ctx).gl()->f ## X; \
SkASSERT(GR_GL_NO_ERROR == (ctx).gl()->fGetError())
#define SK_GL_RET(ctx, RET, X) (RET) = (ctx).gl()->f ## X; \
SkASSERT(GR_GL_NO_ERROR == (ctx).gl()->fGetError())
#define SK_GL_NOERRCHECK(ctx, X) (ctx).gl()->f ## X
#define SK_GL_RET_NOERRCHECK(ctx, RET, X) (RET) = (ctx).gl()->f ## X
#endif