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      1 
      2 /*
      3  * Copyright 2011 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 #include "SkRefCnt.h"
     10 
     11 #ifndef SkWGL_DEFINED
     12 #define SkWGL_DEFINED
     13 
     14 /**
     15  * Working with WGL extensions can be a pain. Among the reasons is that You must
     16  * have a GL context to get the proc addresses, but you want to use the procs to
     17  * create a context in the first place. So you have to create a dummy GL ctx to
     18  * get the proc addresses.
     19  *
     20  * This file helps by providing SkCreateWGLInterface(). It returns a struct of
     21  * function pointers that it initializes. It also has a helper function to query
     22  * for WGL extensions. It handles the fact that wglGetExtensionsString is itself
     23  * an extension.
     24  */
     25 
     26 #if !defined(WIN32_LEAN_AND_MEAN)
     27     #define WIN32_LEAN_AND_MEAN
     28     #define SK_LOCAL_LEAN_AND_MEAN
     29 #endif
     30 #include <windows.h>
     31 #if defined(SK_LOCAL_LEAN_AND_MEAN)
     32     #undef WIN32_LEAN_AND_MEAN
     33     #undef SK_LOCAL_LEAN_AND_MEAN
     34 #endif
     35 
     36 #define SK_WGL_DRAW_TO_WINDOW                       0x2001
     37 #define SK_WGL_ACCELERATION                         0x2003
     38 #define SK_WGL_SUPPORT_OPENGL                       0x2010
     39 #define SK_WGL_DOUBLE_BUFFER                        0x2011
     40 #define SK_WGL_COLOR_BITS                           0x2014
     41 #define SK_WGL_ALPHA_BITS                           0x201B
     42 #define SK_WGL_STENCIL_BITS                         0x2023
     43 #define SK_WGL_FULL_ACCELERATION                    0x2027
     44 #define SK_WGL_SAMPLE_BUFFERS                       0x2041
     45 #define SK_WGL_SAMPLES                              0x2042
     46 #define SK_WGL_CONTEXT_MAJOR_VERSION                0x2091
     47 #define SK_WGL_CONTEXT_MINOR_VERSION                0x2092
     48 #define SK_WGL_CONTEXT_LAYER_PLANE                  0x2093
     49 #define SK_WGL_CONTEXT_FLAGS                        0x2094
     50 #define SK_WGL_CONTEXT_PROFILE_MASK                 0x9126
     51 #define SK_WGL_CONTEXT_DEBUG_BIT                    0x0001
     52 #define SK_WGL_CONTEXT_FORWARD_COMPATIBLE_BIT       0x0002
     53 #define SK_WGL_CONTEXT_CORE_PROFILE_BIT             0x00000001
     54 #define SK_WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT    0x00000002
     55 #define SK_WGL_CONTEXT_ES2_PROFILE_BIT              0x00000004
     56 #define SK_ERROR_INVALID_VERSION                    0x2095
     57 #define SK_ERROR_INVALID_PROFILE                    0x2096
     58 
     59 class SkWGLExtensions {
     60 public:
     61     SkWGLExtensions();
     62     /**
     63      * Determines if an extensions is available for a given DC.
     64      * WGL_extensions_string is considered a prerequisite for all other
     65      * extensions. It is necessary to check this before calling other class
     66      * functions.
     67      */
     68     bool hasExtension(HDC dc, const char* ext) const;
     69 
     70     const char* getExtensionsString(HDC hdc) const;
     71     BOOL choosePixelFormat(HDC hdc, const int*, const FLOAT*, UINT, int*, UINT*) const;
     72     BOOL getPixelFormatAttribiv(HDC, int, int, UINT, const int*, int*) const;
     73     BOOL getPixelFormatAttribfv(HDC hdc, int, int, UINT, const int*, FLOAT*) const;
     74     HGLRC createContextAttribs(HDC, HGLRC, const int *) const;
     75 
     76     /**
     77      * WGL doesn't have precise rules for the ordering of formats returned
     78      * by wglChoosePixelFormat. This function helps choose among the set of
     79      * formats returned by wglChoosePixelFormat. The rules in decreasing
     80      * priority are:
     81      *     * Choose formats with the smallest sample count that is >=
     82      *       desiredSampleCount (or the largest sample count if all formats have
     83      *       fewer samples than desiredSampleCount.)
     84      *     * Choose formats with the fewest color samples when coverage sampling
     85      *       is available.
     86      *     * If the above rules leave multiple formats, choose the one that
     87      *       appears first in the formats array parameter.
     88      */
     89     int selectFormat(const int formats[],
     90                      int formatCount,
     91                      HDC dc,
     92                      int desiredSampleCount);
     93 private:
     94     typedef const char* (WINAPI *GetExtensionsStringProc)(HDC hdc);
     95     typedef BOOL (WINAPI *ChoosePixelFormatProc)(HDC hdc, const int *, const FLOAT *, UINT, int *, UINT *);
     96     typedef BOOL (WINAPI *GetPixelFormatAttribivProc)(HDC, int, int, UINT, const int*, int*);
     97     typedef BOOL (WINAPI *GetPixelFormatAttribfvProc)(HDC hdc, int, int, UINT, const int*, FLOAT*);
     98     typedef HGLRC (WINAPI *CreateContextAttribsProc)(HDC hDC, HGLRC, const int *);
     99 
    100     GetExtensionsStringProc fGetExtensionsString;
    101     ChoosePixelFormatProc fChoosePixelFormat;
    102     GetPixelFormatAttribfvProc fGetPixelFormatAttribfv;
    103     GetPixelFormatAttribivProc fGetPixelFormatAttribiv;
    104     CreateContextAttribsProc fCreateContextAttribs;
    105 };
    106 
    107 /**
    108  * Helper to create an OpenGL context for a DC using WGL. Configs with a sample count >= to
    109  * msaaSampleCount are preferred but if none is available then a context with a lower sample count
    110  * (including non-MSAA) will be created. If preferCoreProfile is true but a core profile cannot be
    111  * created then a compatible profile context will be created.
    112  */
    113 HGLRC SkCreateWGLContext(HDC dc, int msaaSampleCount, bool preferCoreProfile);
    114 
    115 #endif
    116