Implementation of a GL-virtualization layer for Skia. This allows for

environments using skia to specify a GL implementation at run-time, instead of
relying on the linker to pull in the appropriate GL impl.

A new structure, GrGLInterface is exposed.  This struct contains a set of
function pointers that should point to an appropriate GL implementation.

This change also removes the reliance on GLew on windows builds.

Review: http://codereview.appspot.com/4254059/



git-svn-id: http://skia.googlecode.com/svn/trunk@937 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 270 insertions, 0 deletions

diff --git a/gpu/include/GrGLInterface.h b/gpu/include/GrGLInterface.h
new file mode 100644
index 0000000000..0c2a2d9bad
--- /dev/null
+++ b/gpu/include/GrGLInterface.h
@@ -0,0 +1,270 @@
+/*
+    Copyright 2011 Google Inc.
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+         http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+ */
+
+
+#ifndef GrGLInterface_DEFINED
+#define GrGLInterface_DEFINED
+
+#include "GrGLPlatformIncludes.h"
+
+#if !defined(GR_GL_FUNCTION_TYPE)
+    #define GR_GL_FUNCTION_TYPE
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+
+/**
+ * Helpers for glGetString()
+ */
+bool has_gl_extension(const char* ext);
+void gl_version(int* major, int* minor);
+
+////////////////////////////////////////////////////////////////////////////////
+
+/*
+ * Routines managing the global interface used to invoke OpenGL calls.
+ */
+struct GrGLInterface;
+extern GrGLInterface* GrGLGetGLInterface();
+extern void GrGLSetGLInterface(GrGLInterface* gl_interface);
+
+/*
+ * Populates the global GrGLInterface pointer with an instance pointing to the
+ * GL implementation linked with the executable.
+ */
+extern void GrGLSetDefaultGLInterface();
+
+extern "C" {
+/*
+ * The following interface exports the OpenGL entry points used by the system.
+ * Use of OpenGL calls is disallowed.  All calls should be invoked through
+ * the global instance of this struct, defined above.
+ *
+ * IMPORTANT NOTE: The OpenGL entry points exposed here include both core GL
+ * functions, and extensions.  The system assumes that the address of the
+ * extension pointer will be valid across contexts.
+ */
+struct GrGLInterface {
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLActiveTextureProc)(GLenum texture);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLAttachShaderProc)(GLuint program, GLuint shader);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLBindAttribLocationProc)(GLuint program, GLuint index, const char* name);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLBindBufferProc)(GLenum target, GLuint buffer);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLBindTextureProc)(GLenum target, GLuint texture);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLBlendFuncProc)(GLenum sfactor, GLenum dfactor);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLBufferDataProc)(GLenum target, GLsizei size, const void* data, GLenum usage);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLBufferSubDataProc)(GLenum target, GLint offset, GLsizei size, const void* data);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLClearProc)(GLbitfield mask);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLClearColorProc)(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLClearStencilProc)(GLint s);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLClientActiveTextureProc)(GLenum texture);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLColor4ubProc)(GLubyte red, GLubyte green, GLubyte blue, GLubyte alpha);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLColorMaskProc)(GLboolean red, GLboolean green, GLboolean blue, GLboolean alpha);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLColorPointerProc)(GLint size, GLenum type, GLsizei stride, const GLvoid* pointer);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLCompileShaderProc)(GLuint shader);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLCompressedTexImage2DProc)(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLsizei imageSize, const void* data);
+    typedef GLuint (GR_GL_FUNCTION_TYPE *GrGLCreateProgramProc)(void);
+    typedef GLuint (GR_GL_FUNCTION_TYPE *GrGLCreateShaderProc)(GLenum type);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLCullFaceProc)(GLenum mode);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDeleteBuffersProc)(GLsizei n, const GLuint* buffers);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDeleteProgramProc)(GLuint program);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDeleteShaderProc)(GLuint shader);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDeleteTexturesProc)(GLsizei n, const GLuint* textures);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDepthMaskProc)(GLboolean flag);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDisableProc)(GLenum cap);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDisableClientStateProc)(GLenum array);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDisableVertexAttribArrayProc)(GLuint index);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDrawArraysProc)(GLenum mode, GLint first, GLsizei count);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDrawElementsProc)(GLenum mode, GLsizei count, GLenum type, const void* indices);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLEnableProc)(GLenum cap);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLEnableClientStateProc)(GLenum cap);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLEnableVertexAttribArrayProc)(GLuint index);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLFrontFaceProc)(GLenum mode);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGenBuffersProc)(GLsizei n, GLuint* buffers);
+    typedef GLenum (GR_GL_FUNCTION_TYPE *GrGLGetErrorProc)(void);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGenTexturesProc)(GLsizei n, GLuint* textures);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGetBufferParameterivProc)(GLenum target, GLenum pname, GLint* params);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGetIntegervProc)(GLenum pname, GLint* params);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGetProgramInfoLogProc)(GLuint program, GLsizei bufsize, GLsizei* length, char* infolog);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGetProgramivProc)(GLuint program, GLenum pname, GLint* params);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGetShaderInfoLogProc)(GLuint shader, GLsizei bufsize, GLsizei* length, char* infolog);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGetShaderivProc)(GLuint shader, GLenum pname, GLint* params);
+    typedef const GLubyte* (GR_GL_FUNCTION_TYPE *GrGLGetStringProc)(GLenum name);
+    typedef GLint (GR_GL_FUNCTION_TYPE *GrGLGetUniformLocationProc)(GLuint program, const char* name);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLLineWidthProc)(GLfloat width);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLLinkProgramProc)(GLuint program);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLLoadMatrixfProc)(const GLfloat* m);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLMatrixModeProc)(GLenum mode);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLPixelStoreiProc)(GLenum pname, GLint param);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLPointSizeProc)(GLfloat size);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLReadPixelsProc)(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format, GLenum type, void* pixels);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLScissorProc)(GLint x, GLint y, GLsizei width, GLsizei height);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLShadeModelProc)(GLenum mode);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLShaderSourceProc)(GLuint shader, GLsizei count, const char** str, const GLint* length);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLStencilFuncProc)(GLenum func, GLint ref, GLuint mask);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLStencilFuncSeparateProc)(GLenum face, GLenum func, GLint ref, GLuint mask);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLStencilMaskProc)(GLuint mask);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLStencilMaskSeparateProc)(GLenum face, GLuint mask);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLStencilOpProc)(GLenum fail, GLenum zfail, GLenum zpass);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLStencilOpSeparateProc)(GLenum face, GLenum fail, GLenum zfail, GLenum zpass);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLTexCoordPointerProc)(GLint size, GLenum type, GLsizei stride, const GLvoid* pointer);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLTexEnviProc)(GLenum target, GLenum pname, GLint param);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLTexImage2DProc)(GLenum target, GLint level, GLint internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, const void* pixels);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLTexParameteriProc)(GLenum target, GLenum pname, GLint param);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLTexSubImage2DProc)(GLenum target, GLint level, GLint xoffset, GLint yoffset, GLsizei width, GLsizei height, GLenum format, GLenum type, const void* pixels);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLUniform1fvProc)(GLint location, GLsizei count, const GLfloat* v);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLUniform1iProc)(GLint location, GLint x);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLUniform4fvProc)(GLint location, GLsizei count, const GLfloat* v);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLUniformMatrix3fvProc)(GLint location, GLsizei count, GLboolean transpose, const GLfloat* value);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLUseProgramProc)(GLuint program);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLVertexAttrib4fvProc)(GLuint indx, const GLfloat* values);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLVertexAttribPointerProc)(GLuint indx, GLint size, GLenum type, GLboolean normalized, GLsizei stride, const void* ptr);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLVertexPointerProc)(GLint size, GLenum type, GLsizei stride, const GLvoid* pointer);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLViewportProc)(GLint x, GLint y, GLsizei width, GLsizei height);
+
+    // FBO Extension Functions
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLBindFramebufferProc)(GLenum target, GLuint framebuffer);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLBindRenderbufferProc)(GLenum target, GLuint renderbuffer);
+    typedef GLenum (GR_GL_FUNCTION_TYPE *GrGLCheckFramebufferStatusProc)(GLenum target);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDeleteFramebuffersProc)(GLsizei n, const GLuint *framebuffers);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLDeleteRenderbuffersProc)(GLsizei n, const GLuint *renderbuffers);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLFramebufferRenderbufferProc)(GLenum target, GLenum attachment, GLenum renderbuffertarget, GLuint renderbuffer);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLFramebufferTexture2DProc)(GLenum target, GLenum attachment, GLenum textarget, GLuint texture, GLint level);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGenFramebuffersProc)(GLsizei n, GLuint *framebuffers);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLGenRenderbuffersProc)(GLsizei n, GLuint *renderbuffers);
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLRenderbufferStorageProc)(GLenum target, GLenum internalformat, GLsizei width, GLsizei height);
+
+    // Multisampling Extension Functions
+    // same prototype for ARB_FBO, EXT_FBO, GL 3.0, & Apple ES extension
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLRenderbufferStorageMultisampleProc)(GLenum target, GLsizei samples, GLenum internalformat, GLsizei width, GLsizei height);
+    // desktop: ext_fbo_blit, arb_fbo, gl 3.0
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLBlitFramebufferProc)(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter);
+    // apple's es extension
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLResolveMultisampleFramebufferProc)();
+
+    // IMG'e es extension
+    typedef GLvoid (GR_GL_FUNCTION_TYPE *GrGLFramebufferTexture2DMultisampleProc)(GLenum target, GLenum attachment, GLenum textarget, GLuint texture, GLint level, GLsizei samples);
+
+    // Buffer mapping (extension in ES).
+    typedef GLvoid* (GR_GL_FUNCTION_TYPE *GrGLMapBufferProc)(GLenum target, GLenum access);
+    typedef GLboolean (GR_GL_FUNCTION_TYPE *GrGLUnmapBufferProc)(GLenum target);
+
+    GrGLActiveTextureProc fActiveTexture;
+    GrGLAttachShaderProc fAttachShader;
+    GrGLBindAttribLocationProc fBindAttribLocation;
+    GrGLBindBufferProc fBindBuffer;
+    GrGLBindTextureProc fBindTexture;
+    GrGLBlendFuncProc fBlendFunc;
+    GrGLBufferDataProc fBufferData;
+    GrGLBufferSubDataProc fBufferSubData;
+    GrGLClearProc fClear;
+    GrGLClearColorProc fClearColor;
+    GrGLClearStencilProc fClearStencil;
+    GrGLClientActiveTextureProc fClientActiveTexture;
+    GrGLColor4ubProc fColor4ub;
+    GrGLColorMaskProc fColorMask;
+    GrGLColorPointerProc fColorPointer;
+    GrGLCompileShaderProc fCompileShader;
+    GrGLCompressedTexImage2DProc fCompressedTexImage2D;
+    GrGLCreateProgramProc fCreateProgram;
+    GrGLCreateShaderProc fCreateShader;
+    GrGLCullFaceProc fCullFace;
+    GrGLDeleteBuffersProc fDeleteBuffers;
+    GrGLDeleteProgramProc fDeleteProgram;
+    GrGLDeleteShaderProc fDeleteShader;
+    GrGLDeleteTexturesProc fDeleteTextures;
+    GrGLDepthMaskProc fDepthMask;
+    GrGLDisableProc fDisable;
+    GrGLDisableClientStateProc fDisableClientState;
+    GrGLDisableVertexAttribArrayProc fDisableVertexAttribArray;
+    GrGLDrawArraysProc fDrawArrays;
+    GrGLDrawElementsProc fDrawElements;
+    GrGLEnableProc fEnable;
+    GrGLEnableClientStateProc fEnableClientState;
+    GrGLEnableVertexAttribArrayProc fEnableVertexAttribArray;
+    GrGLFrontFaceProc fFrontFace;
+    GrGLGenBuffersProc fGenBuffers;
+    GrGLGenTexturesProc fGenTextures;
+    GrGLGetBufferParameterivProc fGetBufferParameteriv;
+    GrGLGetErrorProc fGetError;
+    GrGLGetIntegervProc fGetIntegerv;
+    GrGLGetProgramInfoLogProc fGetProgramInfoLog;
+    GrGLGetProgramivProc fGetProgramiv;
+    GrGLGetShaderInfoLogProc fGetShaderInfoLog;
+    GrGLGetShaderivProc fGetShaderiv;
+    GrGLGetStringProc fGetString;
+    GrGLGetUniformLocationProc fGetUniformLocation;
+    GrGLLineWidthProc fLineWidth;
+    GrGLLinkProgramProc fLinkProgram;
+    GrGLLoadMatrixfProc fLoadMatrixf;
+    GrGLMatrixModeProc fMatrixMode;
+    GrGLPixelStoreiProc fPixelStorei;
+    GrGLPointSizeProc fPointSize;
+    GrGLReadPixelsProc fReadPixels;
+    GrGLScissorProc fScissor;
+    GrGLShadeModelProc fShadeModel;
+    GrGLShaderSourceProc fShaderSource;
+    GrGLStencilFuncProc fStencilFunc;
+    GrGLStencilFuncSeparateProc fStencilFuncSeparate;
+    GrGLStencilMaskProc fStencilMask;
+    GrGLStencilMaskSeparateProc fStencilMaskSeparate;
+    GrGLStencilOpProc fStencilOp;
+    GrGLStencilOpSeparateProc fStencilOpSeparate;
+    GrGLTexCoordPointerProc fTexCoordPointer;
+    GrGLTexEnviProc fTexEnvi;
+    GrGLTexImage2DProc fTexImage2D;
+    GrGLTexParameteriProc fTexParameteri;
+    GrGLTexSubImage2DProc fTexSubImage2D;
+    GrGLUniform1fvProc fUniform1fv;
+    GrGLUniform1iProc fUniform1i;
+    GrGLUniform4fvProc fUniform4fv;
+    GrGLUniformMatrix3fvProc fUniformMatrix3fv;
+    GrGLUseProgramProc fUseProgram;
+    GrGLVertexAttrib4fvProc fVertexAttrib4fv;
+    GrGLVertexAttribPointerProc fVertexAttribPointer;
+    GrGLVertexPointerProc fVertexPointer;
+    GrGLViewportProc fViewport;
+
+    // FBO Extension Functions
+    GrGLBindFramebufferProc fBindFramebuffer;
+    GrGLBindRenderbufferProc fBindRenderbuffer;
+    GrGLCheckFramebufferStatusProc fCheckFramebufferStatus;
+    GrGLDeleteFramebuffersProc fDeleteFramebuffers;
+    GrGLDeleteRenderbuffersProc fDeleteRenderbuffers;
+    GrGLFramebufferRenderbufferProc fFramebufferRenderbuffer;
+    GrGLFramebufferTexture2DProc fFramebufferTexture2D;
+    GrGLGenFramebuffersProc fGenFramebuffers;
+    GrGLGenRenderbuffersProc fGenRenderbuffers;
+    GrGLRenderbufferStorageProc fRenderbufferStorage;
+
+    // Multisampling Extension Functions
+    // same prototype for ARB_FBO, EXT_FBO, GL 3.0, & Apple ES extension
+    GrGLRenderbufferStorageMultisampleProc fRenderbufferStorageMultisample;
+    // desktop: ext_fbo_blit, arb_fbo, gl 3.0
+    GrGLBlitFramebufferProc fBlitFramebuffer;
+    // apple's es extension
+    GrGLResolveMultisampleFramebufferProc fResolveMultisampleFramebuffer;
+
+    // IMG'e es extension
+    GrGLFramebufferTexture2DMultisampleProc fFramebufferTexture2DMultisample;
+
+    // Buffer mapping (extension in ES).
+    GrGLMapBufferProc fMapBuffer;
+    GrGLUnmapBufferProc fUnmapBuffer;
+};
+
+}  // extern "C"
+
+#endif