3 * Copyright 2011 Google Inc.
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
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.
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
26 #if !defined(WIN32_LEAN_AND_MEAN)
27 #define WIN32_LEAN_AND_MEAN
28 #define SK_LOCAL_LEAN_AND_MEAN
31 #if defined(SK_LOCAL_LEAN_AND_MEAN)
32 #undef WIN32_LEAN_AND_MEAN
33 #undef SK_LOCAL_LEAN_AND_MEAN
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
59 class SkWGLExtensions {
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
68 bool hasExtension(HDC dc, const char* ext) const;
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;
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
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
86 * * If the above rules leave multiple formats, choose the one that
87 * appears first in the formats array parameter.
89 int selectFormat(const int formats[],
92 int desiredSampleCount);
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 *);
100 GetExtensionsStringProc fGetExtensionsString;
101 ChoosePixelFormatProc fChoosePixelFormat;
102 GetPixelFormatAttribfvProc fGetPixelFormatAttribfv;
103 GetPixelFormatAttribivProc fGetPixelFormatAttribiv;
104 CreateContextAttribsProc fCreateContextAttribs;
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.
113 HGLRC SkCreateWGLContext(HDC dc, int msaaSampleCount, bool preferCoreProfile);