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 static unsigned int glFilter;
  26
  27 static inline int power_of_two(int input)
  28 {
  29         int value = 1;
  30
  31         while (value < input)
  32                 value <<= 1;
  33
  34         return value;
  35 }
  36
  37 void sdlemu_init_opengl(SDL_Surface * src, int texturetype, float size, int filter)
  38 {
  39         int w, h;
  40
  41         printf("\nOpenGL driver information :\n");
  42         printf("\n");
  43         printf("Vendor:            %s\n", glGetString(GL_VENDOR));
  44         printf("Renderer:          %s\n", glGetString(GL_RENDERER));
  45         printf("Version:           %s\n", glGetString(GL_VERSION));
  46         printf("OpenGL drawmethod: ");
  47
  48         switch (texturetype)
  49         {
  50         case 1:
  51                 printf("GL_QUAD rendering\n\n");
  52                 break;
  53         default:
  54                 printf("GL_TRIANGLE rendering\n\n");
  55                 break;
  56         }
  57
  58         glFilter = filter;
  59
  60         // Texture width/height should be power of 2
  61         // So, find the largest power of two that will contain both the width and height
  62         w = power_of_two(src->w);
  63         h = power_of_two(src->h);
  64
  65         // create texture surface
  66         texture = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32,
  67         #if SDL_BYTEORDER == SDL_LIL_ENDIAN
  68                 0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000);
  69         #else
  70                 0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF);
  71         #endif
  72
  73         // setup 2D gl environment
  74         glPushAttrib(GL_ENABLE_BIT);
  75         glDisable(GL_DEPTH_TEST);
  76         glDisable(GL_CULL_FACE);
  77         glEnable(GL_TEXTURE_2D);
  78
  79         glViewport(0, 0, src->w * size, src->h * size);
  80
  81         glMatrixMode(GL_PROJECTION);
  82         glPushMatrix();
  83         glLoadIdentity();
  84
  85         glOrtho(0.0, (GLdouble)(src->w * size), (GLdouble)(src->h * size), 0.0, 0.0, 1.0);
  86         glMatrixMode(GL_MODELVIEW);
  87         glPushMatrix();
  88         glLoadIdentity();
  89
  90         // texture coordinates
  91         texcoord[0] = 0.0f;
  92         texcoord[1] = 0.0f;
  93         texcoord[2] = (GLfloat)(src->w) / texture->w;
  94         texcoord[3] = (GLfloat)(src->h) / texture->h;
  95
  96         // create an RGBA texture for the texture surface
  97         glGenTextures(1, &texid);
  98         glBindTexture(GL_TEXTURE_2D, texid);
  99
 100         if (glFilter)
 101         {
 102        printf("OpenGL filters: enabled\n");
 103            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 104            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 105         }
 106         else
 107         {
 108        printf("OpenGL filters: disabled\n");
 109            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 110            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 111     }
 112
 113         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture->w, texture->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
 114 }
 115
 116 void sdlemu_draw_texture(SDL_Surface * dst, SDL_Surface * src, int texturetype)
 117 {
 118
 119         // convert color-indexed surface to RGB texture
 120         SDL_BlitSurface(src, NULL, texture, NULL);
 121
 122         // Texturemap complete texture to surface so we have free scaling
 123         // and antialiasing
 124         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, texture->w, texture->h,
 125                 GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
 126
 127         switch (texturetype)
 128         {
 129         case 1:
 130         glBegin(GL_QUADS);
 131                 glTexCoord2f(texcoord[0], texcoord[1]);
 132                 glVertex2f(0, 0);
 133                 glTexCoord2f(texcoord[2], texcoord[1]);
 134                 glVertex2f(dst->w , 0);
 135                 glTexCoord2f(texcoord[2], texcoord[3]);
 136                 glVertex2f(dst->w , dst->h );
 137                 glTexCoord2f(texcoord[0], texcoord[3]);
 138                 glVertex2f(0, dst->h );
 139         glEnd();
 140
 141         default:
 142                 glBegin(GL_TRIANGLE_STRIP);
 143                                 glTexCoord2f(texcoord[0], texcoord[1]); glVertex3i(0, 0, 0);
 144                                 glTexCoord2f(texcoord[2], texcoord[1]); glVertex3i(dst->w, 0, 0);
 145                                 glTexCoord2f(texcoord[0], texcoord[3]); glVertex3i(0, dst->h, 0);
 146                                 glTexCoord2f(texcoord[2], texcoord[3]); glVertex3i(dst->w, dst->h, 0);
 147                 glEnd();
 148         }
 149
 150         SDL_GL_SwapBuffers();
 151 }
 152
 153 void sdlemu_close_opengl(void)
 154 {
 155         if (texture)
 156                 SDL_FreeSurface(texture);
 157 }
 158
 159
 160 //
 161 // Resize the texture
 162 // This should honor the glFilter flag that is passed in to the initialization code,
 163 // but, at the moment, it doesn't...
 164 // Now it does...!
 165 //
 166 void sdlemu_resize_texture(SDL_Surface * src, SDL_Surface * dst, int filter)
 167 {
 168         // Texture width/height should be power of 2
 169         // So, find the largest power of two that will contain both the width and height
 170         int w = power_of_two(src->w), h = power_of_two(src->h);
 171
 172         // Delete old texture (if allocated)
 173         if (texture)
 174                 SDL_FreeSurface(texture);
 175
 176         // create texture surface
 177 //NOTE: Seems the byte order here *is* important! (Perhaps only for 32 BPP?)
 178         texture = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 32,
 179         #if SDL_BYTEORDER == SDL_LIL_ENDIAN
 180                 0x000000FF, 0x0000FF00, 0x00FF0000, 0xFF000000);
 181         #else
 182                 0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF);
 183         #endif
 184
 185         // setup 2D gl environment
 186         glPushAttrib(GL_ENABLE_BIT);
 187         glDisable(GL_DEPTH_TEST);
 188         glDisable(GL_CULL_FACE);
 189         glEnable(GL_TEXTURE_2D);
 190
 191         glViewport(0, 0, dst->w, dst->h);
 192
 193         glMatrixMode(GL_PROJECTION);
 194         glPushMatrix();
 195         glLoadIdentity();
 196
 197         glOrtho(0.0, (GLdouble)dst->w, (GLdouble)dst->h, 0.0, 0.0, 1.0);
 198         glMatrixMode(GL_MODELVIEW);
 199         glPushMatrix();
 200         glLoadIdentity();
 201
 202         // texture coordinates
 203         texcoord[0] = 0.0f, texcoord[1] = 0.0f,
 204         texcoord[2] = (GLfloat)(src->w) / texture->w,
 205         texcoord[3] = (GLfloat)(src->h) / texture->h;
 206
 207         // create an RGBA texture for the texture surface
 208         glGenTextures(1, &texid);
 209         glBindTexture(GL_TEXTURE_2D, texid);
 210
 211 //      if (glFilter)
 212         if (filter)
 213         {
 214        printf("OpenGL filters: enabled\n");
 215            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 216            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 217         }
 218         else
 219         {
 220        printf("OpenGL filters: disabled\n");
 221            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 222            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 223     }
 224
 225         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture->w, texture->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture->pixels);
 226 }