glshim.c revision 35c4bbdf 
1/*
2 * File: glshim.c
3 * Purpose: GL shim which redirects to a specified DLL
4 *
5 * Copyright (c) Jon TURNEY 2013
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a
8 * copy of this software and associated documentation files (the "Software"),
9 * to deal in the Software without restriction, including without limitation
10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
11 * and/or sell copies of the Software, and to permit persons to whom the
12 * Software is furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE ABOVE LISTED COPYRIGHT HOLDER(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
21 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
23 * DEALINGS IN THE SOFTWARE.
24 */
25
26/*
27   A GL shim which redirects to a specified DLL
28
29   XWin is statically linked with this, rather than the system libGL, so that
30   GL calls can be directed to mesa cygGL-1.dll, or cygnativeGLthunk.dll
31   (which contains cdecl-to-stdcall thunks to the native openGL32.dll)
32*/
33
34#ifdef HAVE_XWIN_CONFIG_H
35#include <xwin-config.h>
36#endif
37
38#define GL_GLEXT_LEGACY
39#define GL_GLEXT_PROTOTYPES
40#include <GL/gl.h>
41#undef GL_ARB_imaging
42#undef GL_VERSION_1_3
43#include <GL/glext.h>
44
45#include <X11/Xwindows.h>
46#include <os.h>
47#include "glwindows.h"
48#include <glx/glxserver.h>
49
50extern void *glXGetProcAddressARB(const char *);
51
52static HMODULE hMod = NULL;
53
54/*
55  Implement the __glGetProcAddress function by just using GetProcAddress() on the selected DLL
56*/
57void *glXGetProcAddressARB(const char *symbol)
58{
59    void *proc;
60
61    /* Default to the mesa GL implementation if one hasn't been selected yet */
62    if (!hMod)
63        glWinSelectImplementation(0);
64
65    proc = GetProcAddress(hMod, symbol);
66
67    if (glxWinDebugSettings.enableGLcallTrace)
68        ErrorF("glXGetProcAddressARB: Resolved '%s' in %p to %p\n", symbol, hMod, proc);
69
70    return proc;
71}
72
73/*
74  Select a GL implementation DLL
75*/
76int glWinSelectImplementation(int native)
77{
78    const char *dllname;
79
80    if (native) {
81        dllname = "cygnativeGLthunk.dll";
82    }
83    else {
84        dllname = "cygGL-1.dll";
85    }
86
87    hMod = LoadLibraryEx(dllname, NULL, 0);
88    if (hMod == NULL) {
89        ErrorF("glWinSelectGLimplementation: Could not load '%s'\n", dllname);
90        return -1;
91    }
92
93    ErrorF("glWinSelectGLimplementation: Loaded '%s'\n", dllname);
94
95    /* Connect __glGetProcAddress() to our implementation of glXGetProcAddressARB() above */
96    __glXsetGetProcAddress((glx_gpa_proc)glXGetProcAddressARB);
97
98    return 0;
99}
100
101#define RESOLVE_RET(proctype, symbol, retval) \
102    proctype proc = (proctype)glXGetProcAddressARB(symbol);   \
103    if (proc == NULL) return retval;
104
105#define RESOLVE(proctype, symbol) RESOLVE_RET(proctype, symbol,)
106#define RESOLVED_PROC proc
107
108/* Include generated shims for direct linkage to GL functions which are in the ABI */
109#include "generated_gl_shim.c"
110
111/*
112  Special wrapper for glAddSwapHintRectWIN for copySubBuffers
113
114  Only used with native GL if the GL_WIN_swap_hint extension is present, so we enable
115  GLX_MESA_copy_sub_buffer
116*/
117typedef void (__stdcall * PFNGLADDSWAPHINTRECTWIN) (GLint x, GLint y,
118                                                    GLsizei width,
119                                                    GLsizei height);
120
121void
122glAddSwapHintRectWINWrapper(GLint x, GLint y, GLsizei width,
123                            GLsizei height)
124{
125    RESOLVE(PFNGLADDSWAPHINTRECTWIN, "glAddSwapHintRectWIN");
126    RESOLVED_PROC(x, y, width, height);
127}
128