vcs.maemo.org Git - neverball/blob - share/glext.c

   1 /*
   2  * Copyright (C) 2003-2011 Neverball authors
   3  *
   4  * NEVERBALL is  free software; you can redistribute  it and/or modify
   5  * it under the  terms of the GNU General  Public License as published
   6  * by the Free  Software Foundation; either version 2  of the License,
   7  * or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT  ANY  WARRANTY;  without   even  the  implied  warranty  of
  11  * MERCHANTABILITY or  FITNESS FOR A PARTICULAR PURPOSE.   See the GNU
  12  * General Public License for more details.
  13  */
  14
  15 #include <SDL.h>
  16 #include <stdio.h>
  17
  18 #include "glext.h"
  19
  20 /*---------------------------------------------------------------------------*/
  21
  22 #if !ENABLE_OPENGLES
  23
  24 PFNGLCLIENTACTIVETEXTURE_PROC glClientActiveTexture_;
  25 PFNGLACTIVETEXTURE_PROC       glActiveTexture_;
  26
  27 PFNGLGENBUFFERS_PROC          glGenBuffers_;
  28 PFNGLBINDBUFFER_PROC          glBindBuffer_;
  29 PFNGLBUFFERDATA_PROC          glBufferData_;
  30 PFNGLBUFFERSUBDATA_PROC       glBufferSubData_;
  31 PFNGLDELETEBUFFERS_PROC       glDeleteBuffers_;
  32 PFNGLISBUFFER_PROC            glIsBuffer_;
  33
  34 PFNGLPOINTPARAMETERFV_PROC    glPointParameterfv_;
  35
  36 #endif
  37
  38 /*---------------------------------------------------------------------------*/
  39
  40 int glext_check(const char *needle)
  41 {
  42     const GLubyte *haystack, *c;
  43
  44     /* Search for the given string in the OpenGL extension strings. */
  45
  46     for (haystack = glGetString(GL_EXTENSIONS); *haystack; haystack++)
  47     {
  48         for (c = (const GLubyte *) needle; *c && *haystack; c++, haystack++)
  49             if (*c != *haystack)
  50                 break;
  51
  52         if ((*c == 0) && (*haystack == ' ' || *haystack == '\0'))
  53             return 1;
  54     }
  55
  56     return 0;
  57 }
  58
  59 int glext_assert(const char *ext)
  60 {
  61     if (!glext_check(ext))
  62     {
  63         fprintf(stderr, "Missing required OpenGL extension (%s)\n", ext);
  64         return 0;
  65     }
  66     return 1;
  67 }
  68
  69 /*---------------------------------------------------------------------------*/
  70
  71 #define SDL_GL_GFPA(fun, str) do {       \
  72     ptr = SDL_GL_GetProcAddress(str);    \
  73     memcpy(&fun, &ptr, sizeof (void *)); \
  74 } while(0)
  75
  76 /*---------------------------------------------------------------------------*/
  77
  78 int glext_init(void)
  79 {
  80 #if !ENABLE_OPENGLES
  81
  82     void *ptr;
  83
  84     if (glext_assert("ARB_multitexture"))
  85     {
  86         SDL_GL_GFPA(glClientActiveTexture_, "glClientActiveTextureARB");
  87         SDL_GL_GFPA(glActiveTexture_,       "glActiveTextureARB");
  88     }
  89     else
  90         return 0;
  91
  92     if (glext_assert("ARB_vertex_buffer_object"))
  93     {
  94         SDL_GL_GFPA(glGenBuffers_,          "glGenBuffersARB");
  95         SDL_GL_GFPA(glBindBuffer_,          "glBindBufferARB");
  96         SDL_GL_GFPA(glBufferData_,          "glBufferDataARB");
  97         SDL_GL_GFPA(glBufferSubData_,       "glBufferSubDataARB");
  98         SDL_GL_GFPA(glDeleteBuffers_,       "glDeleteBuffersARB");
  99         SDL_GL_GFPA(glIsBuffer_,            "glIsBufferARB");
 100     }
 101     else
 102         return 0;
 103
 104     if (glext_assert("ARB_point_parameters"))
 105         SDL_GL_GFPA(glPointParameterfv_,   "glPointParameterfvARB");
 106     else
 107         return 0;
 108
 109     return 1;
 110
 111 #else
 112
 113     return 1;
 114
 115 #endif
 116 }
 117
 118 /*---------------------------------------------------------------------------*/
 119
 120 void glClipPlane4f_(GLenum p, GLfloat a, GLfloat b, GLfloat c, GLfloat d)
 121 {
 122 #if ENABLE_OPENGLES
 123
 124     GLfloat v[4];
 125
 126     v[0] = a;
 127     v[1] = b;
 128     v[2] = c;
 129     v[3] = d;
 130
 131     glClipPlanef(p, v);
 132
 133 #else
 134
 135     GLdouble v[4];
 136
 137     v[0] = a;
 138     v[1] = b;
 139     v[2] = c;
 140     v[3] = d;
 141
 142     glClipPlane(p, v);
 143
 144 #endif
 145 }
 146
 147 /*---------------------------------------------------------------------------*/