Shamusworld >> Repos - virtualjaguar/blob - src/sdlemu_opengl.c

   1 /*
   2  * SDLEMU library - Free sdl related functions library
   3  * Copyrigh(c) 1999-2002 sdlemu development crew
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include "sdlemu_opengl.h"
  21
  22 static SDL_Surface *texture      = 0;
  23 static GLuint       texid        = 0;
  24 static GLfloat      texcoord[4];
  25
  26 static inline int power_of_two(int input)
  27 {
  28         int value = 1;
  29
  30         while (value < input)
  31                 value <<= 1;
  32
  33         return value;
  34 }
  35
  36 void sdlemu_init_opengl(SDL_Surface * src, int texturetype, int size, int glfilter)
  37 {
  38         int w, h;
  39
  40         printf("\nOpenGL driver information :\n");
  41         printf("\n");
  42         printf("Vendor            : %s\n", glGetString(GL_VENDOR));
  43         printf("Renderer          : %s\n", glGetString(GL_RENDERER));
  44         printf("Version           : %s\n", glGetString(GL_VERSION));
  45         printf("OpenGL drawmethod : ");
  46
  47         switch (texturetype)
  48         {
  49         case 1:
  50                 printf("GL_QUAD rendering\n\n");
  51                 break;
  52         default:
  53                 printf("GL_TRIANGLE rendering\n\n");
  54                 break;
  55         }
  56
  57         // Texture width/height should be power of 2
  58         // So, find the largest power of two that will contain both the width and height
  59         w = power_of_two(src->w);
  60         h = power_of_two(src->h);
  61
  62         // create texture surface
  63         texture = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32,
  64         #if SDL_BYTEORDER == SDL_LIL_ENDIAN
  65                 0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000);
  66         #else
  67                 0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF);
  68         #endif
  69
  70         // setup 2D gl environment
  71         glPushAttrib(GL_ENABLE_BIT);
  72         glDisable(GL_DEPTH_TEST);
  73         glDisable(GL_CULL_FACE);
  74         glEnable(GL_TEXTURE_2D);
  75
  76         glViewport(0, 0, src->w * size, src->h * size);
  77
  78         glMatrixMode(GL_PROJECTION);
  79         glPushMatrix();
  80         glLoadIdentity();
  81
  82         glOrtho(0.0, (GLdouble)(src->w * size), (GLdouble)(src->h * size), 0.0, 0.0, 1.0);
  83         glMatrixMode(GL_MODELVIEW);
  84         glPushMatrix();
  85         glLoadIdentity();
  86
  87         // texture coordinates
  88         texcoord[0] = 0.0f;
  89         texcoord[1] = 0.0f;
  90         texcoord[2] = (GLfloat)(src->w) / texture->w;
  91         texcoord[3] = (GLfloat)(src->h) / texture->h;
  92
  93         // create an RGBA texture for the texture surface
  94         glGenTextures(1, &texid);
  95         glBindTexture(GL_TEXTURE_2D, texid);
  96
  97         if (glfilter)
  98         {
  99        printf("OpenGL filters : enabled\n");
 100            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 101            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 102         }
 103         else
 104         {
 105        printf("OpenGL filters : disabled\n");
 106            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 107            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 108     }
 109
 110         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture->w, texture->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
 111 }
 112
 113 void sdlemu_draw_texture(SDL_Surface * dst, SDL_Surface * src, int texturetype)
 114 {
 115
 116         // convert color-indexed surface to RGB texture
 117         SDL_BlitSurface(src, NULL, texture, NULL);
 118
 119         // Texturemap complete texture to surface so we have free scaling
 120         // and antialiasing
 121         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, texture->w, texture->h,
 122                 GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
 123
 124         switch (texturetype)
 125         {
 126         case 1:
 127         glBegin(GL_QUADS);
 128                 glTexCoord2f(texcoord[0], texcoord[1]);
 129                 glVertex2f(0, 0);
 130                 glTexCoord2f(texcoord[2], texcoord[1]);
 131                 glVertex2f(dst->w , 0);
 132                 glTexCoord2f(texcoord[2], texcoord[3]);
 133                 glVertex2f(dst->w , dst->h );
 134                 glTexCoord2f(texcoord[0], texcoord[3]);
 135                 glVertex2f(0, dst->h );
 136         glEnd();
 137
 138         default:
 139                 glBegin(GL_TRIANGLE_STRIP);
 140                                 glTexCoord2f(texcoord[0], texcoord[1]); glVertex3i(0, 0, 0);
 141                                 glTexCoord2f(texcoord[2], texcoord[1]); glVertex3i(dst->w, 0, 0);
 142                                 glTexCoord2f(texcoord[0], texcoord[3]); glVertex3i(0, dst->h, 0);
 143                                 glTexCoord2f(texcoord[2], texcoord[3]); glVertex3i(dst->w, dst->h, 0);
 144                 glEnd();
 145         }
 146
 147         SDL_GL_SwapBuffers();
 148 }
 149
 150 void sdlemu_close_opengl(void)
 151 {
 152         if (texture)
 153                 SDL_FreeSurface(texture);
 154 }
 155
 156
 157 //
 158 // Resize the texture
 159 // This should honor the glFilter flag that is passed in to the initialization code,
 160 // but, at the moment, it doesn't...
 161 //
 162 void sdlemu_resize_texture(SDL_Surface * src, SDL_Surface * dst)
 163 {
 164         // Texture width/height should be power of 2
 165         // So, find the largest power of two that will contain both the width and height
 166         int w = power_of_two(src->w), h = power_of_two(src->h);
 167
 168         // Delete old texture (if allocated)
 169         if (texture)
 170                 SDL_FreeSurface(texture);
 171
 172         // create texture surface
 173 //NOTE: Seems the byte order here *is* important! (Perhaps only for 32 BPP?)
 174         texture = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32,
 175         #if SDL_BYTEORDER == SDL_LIL_ENDIAN
 176                 0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000);
 177         #else
 178                 0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF);
 179         #endif
 180
 181         // setup 2D gl environment
 182         glPushAttrib(GL_ENABLE_BIT);
 183         glDisable(GL_DEPTH_TEST);
 184         glDisable(GL_CULL_FACE);
 185         glEnable(GL_TEXTURE_2D);
 186
 187         glViewport(0, 0, dst->w, dst->h);
 188
 189         glMatrixMode(GL_PROJECTION);
 190         glPushMatrix();
 191         glLoadIdentity();
 192
 193         glOrtho(0.0, (GLdouble)dst->w, (GLdouble)dst->h, 0.0, 0.0, 1.0);
 194         glMatrixMode(GL_MODELVIEW);
 195         glPushMatrix();
 196         glLoadIdentity();
 197
 198         // texture coordinates
 199         texcoord[0] = 0.0f, texcoord[1] = 0.0f,
 200         texcoord[2] = (GLfloat)(src->w) / texture->w,
 201         texcoord[3] = (GLfloat)(src->h) / texture->h;
 202
 203         // create an RGBA texture for the texture surface
 204         glGenTextures(1, &texid);
 205         glBindTexture(GL_TEXTURE_2D, texid);
 206
 207 /*      if (glfilter)
 208         {
 209        printf("OpenGL filters : enabled\n");
 210            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 211            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 212         }
 213         else*/
 214         {
 215        printf("OpenGL filters : disabled\n");
 216            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 217            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 218     }
 219
 220         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture->w, texture->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
 221 }