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 
getDC()156     HDC getDC() const { return fDC; }
getGLRC()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