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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 DECLARE_HANDLE(HPBUFFER);
     60 
     61 class SkWGLExtensions {
     62 public:
     63     SkWGLExtensions();
     64     /**
     65      * Determines if an extensions is available for a given DC.
     66      * WGL_extensions_string is considered a prerequisite for all other
     67      * extensions. It is necessary to check this before calling other class
     68      * functions.
     69      */
     70     bool hasExtension(HDC dc, const char* ext) const;
     71 
     72     const char* getExtensionsString(HDC hdc) const;
     73     BOOL choosePixelFormat(HDC hdc, const int*, const FLOAT*, UINT, int*, UINT*) const;
     74     BOOL getPixelFormatAttribiv(HDC, int, int, UINT, const int*, int*) const;
     75     BOOL getPixelFormatAttribfv(HDC hdc, int, int, UINT, const int*, FLOAT*) const;
     76     HGLRC createContextAttribs(HDC, HGLRC, const int *) const;
     77 
     78     BOOL swapInterval(int interval) const;
     79 
     80     HPBUFFER createPbuffer(HDC, int , int, int, const int*) const;
     81     HDC getPbufferDC(HPBUFFER) const;
     82     int releasePbufferDC(HPBUFFER, HDC) const;
     83     BOOL destroyPbuffer(HPBUFFER) const;
     84 
     85     /**
     86      * WGL doesn't have precise rules for the ordering of formats returned
     87      * by wglChoosePixelFormat. This function helps choose among the set of
     88      * formats returned by wglChoosePixelFormat. The rules in decreasing
     89      * priority are:
     90      *     * Choose formats with the smallest sample count that is >=
     91      *       desiredSampleCount (or the largest sample count if all formats have
     92      *       fewer samples than desiredSampleCount.)
     93      *     * Choose formats with the fewest color samples when coverage sampling
     94      *       is available.
     95      *     * If the above rules leave multiple formats, choose the one that
     96      *       appears first in the formats array parameter.
     97      */
     98     int selectFormat(const int formats[],
     99                      int formatCount,
    100                      HDC dc,
    101                      int desiredSampleCount) const;
    102 private:
    103     typedef const char* (WINAPI *GetExtensionsStringProc)(HDC);
    104     typedef BOOL (WINAPI *ChoosePixelFormatProc)(HDC, const int *, const FLOAT *, UINT, int *, UINT *);
    105     typedef BOOL (WINAPI *GetPixelFormatAttribivProc)(HDC, int, int, UINT, const int*, int*);
    106     typedef BOOL (WINAPI *GetPixelFormatAttribfvProc)(HDC, int, int, UINT, const int*, FLOAT*);
    107     typedef HGLRC (WINAPI *CreateContextAttribsProc)(HDC, HGLRC, const int *);
    108     typedef BOOL (WINAPI* SwapIntervalProc)(int);
    109     typedef HPBUFFER (WINAPI* CreatePbufferProc)(HDC, int , int, int, const int*);
    110     typedef HDC (WINAPI* GetPbufferDCProc)(HPBUFFER);
    111     typedef int (WINAPI* ReleasePbufferDCProc)(HPBUFFER, HDC);
    112     typedef BOOL (WINAPI* DestroyPbufferProc)(HPBUFFER);
    113 
    114     GetExtensionsStringProc fGetExtensionsString;
    115     ChoosePixelFormatProc fChoosePixelFormat;
    116     GetPixelFormatAttribfvProc fGetPixelFormatAttribfv;
    117     GetPixelFormatAttribivProc fGetPixelFormatAttribiv;
    118     CreateContextAttribsProc fCreateContextAttribs;
    119     SwapIntervalProc fSwapInterval;
    120     CreatePbufferProc fCreatePbuffer;
    121     GetPbufferDCProc fGetPbufferDC;
    122     ReleasePbufferDCProc fReleasePbufferDC;
    123     DestroyPbufferProc fDestroyPbuffer;
    124 };
    125 
    126 enum SkWGLContextRequest {
    127     /** Requests to create core profile context if possible, otherwise
    128         compatibility profile. */
    129     kGLPreferCoreProfile_SkWGLContextRequest,
    130     /** Requests to create compatibility profile context if possible, otherwise
    131         core profile. */
    132     kGLPreferCompatibilityProfile_SkWGLContextRequest,
    133     /** Requests to create GL ES profile context. */
    134     kGLES_SkWGLContextRequest
    135 };
    136 /**
    137  * Helper to create an OpenGL context for a DC using WGL. Configs with a sample count >= to
    138  * msaaSampleCount are preferred but if none is available then a context with a lower sample count
    139  * (including non-MSAA) will be created. If preferCoreProfile is true but a core profile cannot be
    140  * created then a compatible profile context will be created.
    141  */
    142 HGLRC SkCreateWGLContext(HDC dc, int msaaSampleCount, SkWGLContextRequest context);
    143 
    144 /**
    145  * Helper class for creating a pbuffer context and deleting all the handles when finished. This
    146  * requires that a device context has been created. However, the pbuffer gets its own device
    147  * context. The original device context can be released once the pbuffer context is created.
    148  */
    149 class SkWGLPbufferContext : public SkRefCnt {
    150 public:
    151     static SkWGLPbufferContext* Create(HDC parentDC, int msaaSampleCount,
    152                                        SkWGLContextRequest contextType);
    153 
    154     virtual ~SkWGLPbufferContext();
    155 
    156     HDC getDC() const { return fDC; }
    157     HGLRC getGLRC() const { return fGLRC; }
    158 
    159 private:
    160     SkWGLPbufferContext(HPBUFFER pbuffer, HDC dc, HGLRC glrc);
    161 
    162     HPBUFFER        fPbuffer;
    163     HDC             fDC;
    164     HGLRC           fGLRC;
    165     SkWGLExtensions fExtensions;
    166 };
    167 
    168 #endif
    169