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
59DECLARE_HANDLE(HPBUFFER);
60
61class SkWGLExtensions {
62public:
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;
102private:
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
126enum 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 */
142HGLRC 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 */
149class SkWGLPbufferContext : public SkRefCnt {
150public:
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
159private:
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