src/image.c

   1 /*
   2  *   Copyright (C) 2003 Robert Kooima
   3  *
   4  *   SUPER EMPTY BALL is free software; you can redistribute it and/or modify
   5  *   it under the terms of the GNU General Public License as published by the
   6  *   Free Software Foundation;  either version 2 of the  License, or (at your
   7  *   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/SDL_image.h>
  16
  17 #include "gl.h"
  18 #include "image.h"
  19
  20 /*---------------------------------------------------------------------------*/
  21
  22 static const GLenum format[5] = {
  23     0,
  24     GL_LUMINANCE,
  25     GL_LUMINANCE_ALPHA,
  26     GL_RGB,
  27     GL_RGBA
  28 };
  29
  30 int image_load(struct image *image, const char *filename)
  31 {
  32     if ((image->s = IMG_Load(filename)))
  33     {
  34         void *p = image->s->pixels;
  35         int   w = image->s->w;
  36         int   h = image->s->h;
  37         int   b = image->s->format->BytesPerPixel;
  38         int   f = format[b];
  39
  40         glGenTextures(1, &image->o);
  41         glBindTexture(GL_TEXTURE_2D, image->o);
  42
  43         glTexImage2D(GL_TEXTURE_2D, 0, b, w, h, 0, f, GL_UNSIGNED_BYTE, p);
  44
  45         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  46         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  47
  48         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  49         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  50
  51         return 1;
  52     }
  53     return 0;
  54 }
  55
  56 int image_test(struct image *image)
  57 {
  58     return (image->s && glIsTexture(image->o)) ? 1 : 0;
  59 }
  60
  61 void image_free(struct image *image)
  62 {
  63     if (image->o) glDeleteTextures(1, &image->o);
  64     if (image->s) SDL_FreeSurface(image->s);
  65
  66     image->s = NULL;
  67     image->o = 0;
  68 }
  69
  70 /*---------------------------------------------------------------------------*/
  71
  72 void image_bind(struct image *image)
  73 {
  74     glBindTexture(GL_TEXTURE_2D, image->o);
  75 }
  76
  77 void image_rect(struct image *image,
  78                 double x0, double y0,
  79                 double x1, double y1, double a)
  80 {
  81     glMatrixMode(GL_PROJECTION);
  82     {
  83         glPushMatrix();
  84         glLoadIdentity();
  85         glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
  86     }
  87     glMatrixMode(GL_MODELVIEW);
  88
  89     glBindTexture(GL_TEXTURE_2D, image->o);
  90
  91     glPushAttrib(GL_ENABLE_BIT);
  92     {
  93         glDisable(GL_LIGHTING);
  94         glDisable(GL_DEPTH_TEST);
  95         glEnable(GL_COLOR_MATERIAL);
  96
  97         glBegin(GL_QUADS);
  98         {
  99             glColor4d(1.0, 1.0, 1.0, a);
 100
 101             glTexCoord2d(0.0, 1.0); glVertex2d(x0, y0);
 102             glTexCoord2d(1.0, 1.0); glVertex2d(x1, y0);
 103             glTexCoord2d(1.0, 0.0); glVertex2d(x1, y1);
 104             glTexCoord2d(0.0, 0.0); glVertex2d(x0, y1);
 105         }
 106         glEnd();
 107     }
 108     glPopAttrib();
 109
 110     glMatrixMode(GL_PROJECTION);
 111     {
 112         glPopMatrix();
 113     }
 114     glMatrixMode(GL_MODELVIEW);
 115 }
 116
 117 /*---------------------------------------------------------------------------*/
 118