MultiMedia/cdxlplay/opengl.c

   1 #include "cdxlplay.h"
   2
   3 static GLuint textures[1] = {0};
   4
   5 static void glEnable2D () {
   6         GLint viewport[4];
   7         glGetIntegerv(GL_VIEWPORT, viewport);
   8         glMatrixMode(GL_PROJECTION);
   9         glPushMatrix();
  10         glLoadIdentity();
  11         glOrtho(viewport[0], viewport[0]+viewport[2],
  12                 viewport[1]+viewport[3], viewport[1], -1, 1);
  13         glMatrixMode(GL_MODELVIEW);
  14         glPushMatrix();
  15         glLoadIdentity();
  16         glPushAttrib(GL_DEPTH_BUFFER_BIT|GL_LIGHTING_BIT);
  17         glDisable(GL_DEPTH_TEST);
  18         glDisable(GL_LIGHTING);
  19 }
  20
  21 static void glDisable2D () {
  22         glPopAttrib();
  23         glMatrixMode(GL_PROJECTION);
  24         glPopMatrix();
  25         glMatrixMode(GL_MODELVIEW);
  26         glPopMatrix();
  27 }
  28
  29 void GLInit (int w, int h) {
  30         glViewport(0, 0, w, h);
  31         glDisable(GL_LIGHTING);
  32         glDisable(GL_DITHER);
  33         glDisable(GL_DEPTH_TEST);
  34         glClearColor(0.0, 0.0, 0.0, 1.0);
  35         glEnable(GL_TEXTURE_2D);
  36         glDisable(GL_BLEND);
  37         glEnable2D();
  38         glGenTextures(1, textures);
  39         glBindTexture(GL_TEXTURE_2D, textures[0]);
  40         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  41         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  42         glClear(GL_COLOR_BUFFER_BIT);
  43 }
  44
  45 void GLExit () {
  46         glDeleteTextures(1, textures);
  47         glDisable2D();
  48 }
  49
  50 void GLScaleSurface(SDL_Surface *source, SDL_Surface *dest, uint32_t pix_ratio) {
  51         uint32_t src_w = source->w;
  52         uint32_t src_h = source->h;
  53         uint32_t dst_x = 0;
  54         uint32_t dst_y = 0;
  55         uint32_t dst_w = dest->w;
  56         uint32_t dst_h = dest->h;
  57         uint32_t x_ratio, y_ratio;
  58         uint32_t x_factor, y_factor;
  59
  60         if (pix_ratio < 0x10000UL) {
  61                 x_factor = 1;
  62                 y_factor = 0x10000UL / pix_ratio;
  63         } else {
  64                 x_factor = pix_ratio / 0x10000UL;
  65                 y_factor = 1;
  66         }
  67
  68         x_ratio = (dst_w << 16) / (src_w * x_factor);
  69         y_ratio = (dst_h << 16) / (src_h * y_factor);
  70         if (x_ratio < y_ratio) {
  71                 dst_h = (src_h * x_ratio * y_factor) >> 16;
  72                 dst_y = (dest->h - dst_h) >> 1;
  73         } else {
  74                 dst_w = (src_w * y_ratio * x_factor) >> 16;
  75                 dst_x = (dest->w - dst_w) >> 1;
  76         }
  77
  78         SDL_LockSurface(source);
  79         glTexImage2D(GL_TEXTURE_2D, 0, 4, src_w, src_h, 0, GL_RGBA,
  80                 GL_UNSIGNED_BYTE, source->pixels);
  81         SDL_UnlockSurface(source);
  82
  83         glBegin(GL_QUADS);
  84         glTexCoord2i(0, 0);
  85         glVertex2i(dst_x, dst_y);
  86         glTexCoord2i(1, 0);
  87         glVertex2i(dst_x + dst_w, dst_y);
  88         glTexCoord2i(1, 1);
  89         glVertex2i(dst_x + dst_w, dst_y + dst_h);
  90         glTexCoord2i(0, 1);
  91         glVertex2i(dst_x, dst_y + dst_h);
  92         glEnd();
  93 }