skia2/include/utils/SkWGL.h
2012-04-17 12:43:00 +00:00

110 lines
4.6 KiB
C++

/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkRefCnt.h"
#ifndef SkWGL_DEFINED
#define SkWGL_DEFINED
/**
* Working with WGL extensions can be a pain. Among the reasons is that You must
* have a GL context to get the proc addresses, but you want to use the procs to
* create a context in the first place. So you have to create a dummy GL ctx to
* get the proc addresses.
*
* This file helps by providing SkCreateWGLInterface(). It returns a struct of
* function pointers that it initializes. It also has a helper function to query
* for WGL extensions. It handles the fact that wglGetExtensionsString is itself
* an extension.
*/
#if !defined(WIN32_LEAN_AND_MEAN)
#define WIN32_LEAN_AND_MEAN
#define SK_LOCAL_LEAN_AND_MEAN
#endif
#include <Windows.h>
#if defined(SK_LOCAL_LEAN_AND_MEAN)
#undef WIN32_LEAN_AND_MEAN
#undef SK_LOCAL_LEAN_AND_MEAN
#endif
#define SK_WGL_DRAW_TO_WINDOW 0x2001
#define SK_WGL_ACCELERATION 0x2003
#define SK_WGL_SUPPORT_OPENGL 0x2010
#define SK_WGL_DOUBLE_BUFFER 0x2011
#define SK_WGL_COLOR_BITS 0x2014
#define SK_WGL_ALPHA_BITS 0x201B
#define SK_WGL_STENCIL_BITS 0x2023
#define SK_WGL_FULL_ACCELERATION 0x2027
#define SK_WGL_SAMPLE_BUFFERS 0x2041
#define SK_WGL_SAMPLES 0x2042
#define SK_WGL_COVERAGE_SAMPLES 0x2042 /* same as SAMPLES */
#define SK_WGL_COLOR_SAMPLES 0x20B9
#define SK_WGL_CONTEXT_MAJOR_VERSION 0x2091
#define SK_WGL_CONTEXT_MINOR_VERSION 0x2092
#define SK_WGL_CONTEXT_LAYER_PLANE 0x2093
#define SK_WGL_CONTEXT_FLAGS 0x2094
#define SK_WGL_CONTEXT_PROFILE_MASK 0x9126
#define SK_WGL_CONTEXT_DEBUG_BIT 0x0001
#define SK_WGL_CONTEXT_FORWARD_COMPATIBLE_BIT 0x0002
#define SK_WGL_CONTEXT_CORE_PROFILE_BIT 0x00000001
#define SK_WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT 0x00000002
#define SK_WGL_CONTEXT_ES2_PROFILE_BIT 0x00000004
#define SK_ERROR_INVALID_VERSION 0x2095
#define SK_ERROR_INVALID_PROFILE 0x2096
class SkWGLExtensions {
public:
SkWGLExtensions();
/**
* Determines if an extensions is available for a given DC.
* WGL_extensions_string is considered a prerequisite for all other
* extensions. It is necessary to check this before calling other class
* functions.
*/
bool hasExtension(HDC dc, const char* ext) const;
const char* getExtensionsString(HDC hdc) const;
BOOL choosePixelFormat(HDC hdc, const int*, const FLOAT*, UINT, int*, UINT*) const;
BOOL getPixelFormatAttribiv(HDC, int, int, UINT, const int*, int*) const;
BOOL getPixelFormatAttribfv(HDC hdc, int, int, UINT, const int*, FLOAT*) const;
HGLRC createContextAttribs(HDC, HGLRC, const int *) const;
/**
* WGL doesn't have precise rules for the ordering of formats returned
* by wglChoosePixelFormat. This function helps choose among the set of
* formats returned by wglChoosePixelFormat. The rules in decreasing
* priority are:
* * Choose formats with the smallest sample count that is >=
* desiredSampleCount (or the largest sample count if all formats have
* fewer samples than desiredSampleCount.)
* * Choose formats with the fewest color samples when coverage sampling
* is available.
* * If the above rules leave multiple formats, choose the one that
* appears first in the formats array parameter.
*/
int selectFormat(const int formats[],
int formatCount,
HDC dc,
int desiredSampleCount);
private:
typedef const char* (WINAPI *GetExtensionsStringProc)(HDC hdc);
typedef BOOL (WINAPI *ChoosePixelFormatProc)(HDC hdc, const int *, const FLOAT *, UINT, int *, UINT *);
typedef BOOL (WINAPI *GetPixelFormatAttribivProc)(HDC, int, int, UINT, const int*, int*);
typedef BOOL (WINAPI *GetPixelFormatAttribfvProc)(HDC hdc, int, int, UINT, const int*, FLOAT*);
typedef HGLRC (WINAPI *CreateContextAttribsProc)(HDC hDC, HGLRC, const int *);
GetExtensionsStringProc fGetExtensionsString;
ChoosePixelFormatProc fChoosePixelFormat;
GetPixelFormatAttribfvProc fGetPixelFormatAttribfv;
GetPixelFormatAttribivProc fGetPixelFormatAttribiv;
CreateContextAttribsProc fCreateContextAttribs;
};
#endif