opengl-rendering.c

   1 /*******************************************************************************
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   3 **      10        20        30        40        50        60        70        80
   4 **
   5 ** file:
   6 **    opengl-rendering.c
   7 **
   8 ** author:
   9 **    Mirco "MacSlow" Mueller <macslow@bangang.de>
  10 **
  11 ** copyright (C) Mirco Mueller, July 2006, placed under the terms of the LGPL
  12 **
  13 *******************************************************************************/
  14
  15 #include <stdio.h>
  16
  17 #include "SDL.h"
  18 #include "SDL_opengl.h"
  19 #include "opengl-rendering.h"
  20
  21 /* now this here is _really_ nasty, but I'm too lazy to do it right */
  22 #define GL_TEXTURE_RECTANGLE_ARB 0x84F5
  23
  24 void
  25 init_gl ()
  26 {
  27         printf ("OpenGL version: %s\n", glGetString (GL_VERSION));
  28         printf ("OpenGL vendor: %s\n", glGetString (GL_VENDOR));
  29         printf ("OpenGL renderer: %s\n", glGetString (GL_RENDERER));
  30
  31         glClearColor (0.0f, 0.0f, 0.0f, 0.0f);
  32         glDisable (GL_DEPTH_TEST);
  33     glEnable (GL_BLEND);
  34         glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
  35         glEnable (GL_TEXTURE_RECTANGLE_ARB);
  36 }
  37
  38 void
  39 draw_func (int iWidth,
  40                    int iHeight,
  41                    unsigned char* pucSurfaceData,
  42                    unsigned int uiTextureId)
  43 {
  44         if (!pucSurfaceData)
  45         {
  46                 printf ("draw_func() - No valid pointer to surface-data passed\n");
  47                 return;
  48         }
  49
  50         glMatrixMode (GL_MODELVIEW);
  51         glLoadIdentity ();
  52         glClear (GL_COLOR_BUFFER_BIT);
  53
  54         glPushMatrix ();
  55
  56         glBindTexture (GL_TEXTURE_RECTANGLE_ARB, uiTextureId);
  57         glTexImage2D (GL_TEXTURE_RECTANGLE_ARB,
  58                                   0,
  59                                   GL_RGBA,
  60                                   iWidth,
  61                                   iHeight,
  62                                   0,
  63                                   GL_BGRA,
  64                                   GL_UNSIGNED_BYTE,
  65                                   pucSurfaceData);
  66
  67         glColor3f (0.25f, 0.5f, 1.0f);
  68         glBegin (GL_QUADS);
  69         glTexCoord2f (0.0f, 0.0f);
  70         glVertex2f (0.0f, 0.0f);
  71         glTexCoord2f ((GLfloat) iWidth, 0.0f);
  72         glVertex2f (1.0f, 0.0f);
  73         glTexCoord2f ((GLfloat) iWidth, (GLfloat) iHeight);
  74         glVertex2f (1.0f, 1.0f);
  75         glTexCoord2f (0.0f, (GLfloat) iHeight);
  76         glVertex2f (0.0f, 1.0f);
  77         glEnd ();
  78
  79         glPopMatrix ();
  80
  81     SDL_GL_SwapBuffers();
  82 }
  83
  84 void
  85 resize_func (int iWidth,
  86                          int iHeight,
  87                          unsigned int* puiTextureId)
  88 {
  89         glViewport (0, 0, iWidth, iHeight);
  90         glMatrixMode (GL_PROJECTION);
  91         glLoadIdentity ();
  92         glOrtho (0.0f, 1.0f, 0.0f, 1.0f, -1.0f, 1.0f);
  93
  94         glClear (GL_COLOR_BUFFER_BIT);
  95
  96         glDeleteTextures (1, puiTextureId);
  97         glGenTextures (1, puiTextureId);
  98         glBindTexture (GL_TEXTURE_RECTANGLE_ARB, *puiTextureId);
  99         glTexImage2D (GL_TEXTURE_RECTANGLE_ARB,
 100                                   0,
 101                                   GL_RGBA,
 102                                   iWidth,
 103                                   iHeight,
 104                                   0,
 105                                   GL_BGRA,
 106                                   GL_UNSIGNED_BYTE,
 107                                   NULL);
 108         glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
 109 }