share/image.c

   1 /*
   2  * Copyright (C) 2003 Robert Kooima
   3  *
   4  * NEVERBALL is  free software; you can redistribute  it and/or modify
   5  * it under the  terms of the GNU General  Public License as published
   6  * by the Free  Software Foundation; either version 2  of the License,
   7  * or (at your 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.h>
  16 #include <SDL_ttf.h>
  17 #include <SDL_image.h>
  18 #include <string.h>
  19 #include <math.h>
  20
  21 #include "glext.h"
  22 #include "image.h"
  23 #include "config.h"
  24
  25 /*---------------------------------------------------------------------------*/
  26
  27 void image_snap(char *filename)
  28 {
  29     int w = config_get_d(CONFIG_WIDTH);
  30     int h = config_get_d(CONFIG_HEIGHT);
  31     int i;
  32
  33     SDL_Surface *buf = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 24,
  34                                             RMASK, GMASK, BMASK, 0);
  35     SDL_Surface *img = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 24,
  36                                             RMASK, GMASK, BMASK, 0);
  37
  38     glReadPixels(0, 0, w, h, GL_RGB, GL_UNSIGNED_BYTE, buf->pixels);
  39
  40     for (i = 0; i < h; i++)
  41         memcpy((GLubyte *) img->pixels + 3 * w * i,
  42                (GLubyte *) buf->pixels + 3 * w * (h - i), 3 * w);
  43
  44     SDL_SaveBMP(img, filename);
  45
  46     SDL_FreeSurface(img);
  47     SDL_FreeSurface(buf);
  48 }
  49
  50 void image_size(int *W, int *H, int w, int h)
  51 {
  52     *W = 1;
  53     *H = 1;
  54
  55     while (*W < w) *W *= 2;
  56     while (*H < h) *H *= 2;
  57 }
  58
  59 /*---------------------------------------------------------------------------*/
  60
  61 static const GLenum format[5] = {
  62     0,
  63     GL_LUMINANCE,
  64     GL_LUMINANCE_ALPHA,
  65     GL_RGB,
  66     GL_RGBA
  67 };
  68
  69 /*
  70  * Create on  OpenGL texture  object using the  given SDL  surface and
  71  * format,  scaled  using the  current  scale  factor.  When  scaling,
  72  * assume dimensions are used only for layout and lie about the size.
  73  */
  74 GLuint make_image_from_surf(int *w, int *h, SDL_Surface *s)
  75 {
  76     int t = config_get_d(CONFIG_TEXTURES);
  77
  78     GLuint o = 0;
  79
  80     glGenTextures(1, &o);
  81     glBindTexture(GL_TEXTURE_2D, o);
  82
  83     if (t > 1)
  84     {
  85         int w = s->w / t;
  86         int h = s->h / t;
  87
  88         /* Create a new buffer and copy the scaled image to it. */
  89
  90         SDL_Surface *d = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h,
  91                                               s->format->BitsPerPixel,
  92                                               s->format->Rmask,
  93                                               s->format->Gmask,
  94                                               s->format->Bmask,
  95                                               s->format->Amask);
  96         if (d)
  97         {
  98             SDL_LockSurface(s);
  99             SDL_LockSurface(d);
 100             {
 101                 if (s->format->BitsPerPixel == 32)
 102                     gluScaleImage(GL_RGBA,
 103                                   s->w, s->h, GL_UNSIGNED_BYTE, s->pixels,
 104                                   d->w, d->h, GL_UNSIGNED_BYTE, d->pixels);
 105                 else
 106                     gluScaleImage(GL_RGB,
 107                                   s->w, s->h, GL_UNSIGNED_BYTE, s->pixels,
 108                                   d->w, d->h, GL_UNSIGNED_BYTE, d->pixels);
 109             }
 110             SDL_UnlockSurface(d);
 111             SDL_UnlockSurface(s);
 112
 113             /* Load the scaled image. */
 114
 115             if (s->format->BitsPerPixel == 32)
 116                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, d->w, d->h, 0,
 117                              GL_RGBA, GL_UNSIGNED_BYTE, d->pixels);
 118             else
 119                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB,  d->w, d->h, 0,
 120                              GL_RGB,  GL_UNSIGNED_BYTE, d->pixels);
 121
 122             SDL_FreeSurface(d);
 123         }
 124     }
 125     else
 126     {
 127         /* Load the unscaled image. */
 128
 129         if (s->format->BitsPerPixel == 32)
 130             glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, s->w, s->h, 0,
 131                          GL_RGBA, GL_UNSIGNED_BYTE, s->pixels);
 132         else
 133             glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB,  s->w, s->h, 0,
 134                          GL_RGB,  GL_UNSIGNED_BYTE, s->pixels);
 135     }
 136
 137     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 138     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 139
 140     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 141     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 142
 143     if (w) *w = s->w;
 144     if (h) *h = s->h;
 145
 146     return o;
 147 }
 148
 149 /*---------------------------------------------------------------------------*/
 150
 151 /*
 152  * Load  an image  from the  named file.   If the  image is  not RGBA,
 153  * convert it to RGBA.  Return an OpenGL texture object.
 154  */
 155 GLuint make_image_from_file(int *W, int *H,
 156                             int *w, int *h, const char *name)
 157 {
 158     SDL_Surface *src;
 159     SDL_Surface *dst;
 160     SDL_Rect rect;
 161
 162     GLuint o = 0;
 163
 164     /* Load the file. */
 165
 166     if ((src = IMG_Load(config_data(name))))
 167     {
 168         int w2;
 169         int h2;
 170
 171         image_size(&w2, &h2, src->w, src->h);
 172
 173         if (w) *w = src->w;
 174         if (h) *h = src->h;
 175
 176         /* Create a new destination surface. */
 177
 178         if ((dst = SDL_CreateRGBSurface(SDL_SWSURFACE, w2, h2, 32,
 179                                         RMASK, GMASK, BMASK, AMASK)))
 180         {
 181             /* Copy source pixels to the center of the destination. */
 182
 183             rect.x = (Sint16) (w2 - src->w) / 2;
 184             rect.y = (Sint16) (h2 - src->h) / 2;
 185
 186             SDL_SetAlpha(src, 0, 0);
 187             SDL_BlitSurface(src, NULL, dst, &rect);
 188
 189             o = make_image_from_surf(W, H, dst);
 190
 191             SDL_FreeSurface(dst);
 192         }
 193         SDL_FreeSurface(src);
 194     }
 195     return o;
 196 }
 197
 198 /*---------------------------------------------------------------------------*/
 199
 200 /*
 201  * Render the given  string using the given font.   Transfer the image
 202  * to a  surface of  power-of-2 size large  enough to fit  the string.
 203  * Return an OpenGL texture object.
 204  */
 205 GLuint make_image_from_font(int *W, int *H,
 206                             int *w, int *h, const char *text, TTF_Font *font)
 207 {
 208     SDL_Color fg = { 0xFF, 0xFF, 0xFF, 0xFF };
 209
 210     SDL_Surface *src;
 211     SDL_Surface *dst;
 212     SDL_Rect rect;
 213
 214     GLuint o = 0;
 215
 216     /* Render the text. */
 217
 218     if (text && strlen(text) > 0)
 219     {
 220         if ((src = TTF_RenderText_Blended(font, text, fg)))
 221         {
 222             int w2;
 223             int h2;
 224
 225             image_size(&w2, &h2, src->w, src->h);
 226
 227             if (w) *w = src->w;
 228             if (h) *h = src->h;
 229
 230             /* Create a new destination surface. */
 231
 232             if ((dst = SDL_CreateRGBSurface(SDL_SWSURFACE, w2, h2, 32,
 233                                             RMASK, GMASK, BMASK, AMASK)))
 234             {
 235                 /* Copy source pixels to the center of the destination. */
 236
 237                 rect.x = (Sint16) (w2 - src->w) / 2;
 238                 rect.y = (Sint16) (h2 - src->h) / 2;
 239
 240                 SDL_SetAlpha(src, 0, 0);
 241                 SDL_BlitSurface(src, NULL, dst, &rect);
 242
 243                 glPushAttrib(GL_PIXEL_MODE_BIT);
 244                 {
 245                     /* Clamp RGB to white so glyphs are alpha-blended cleanly. */
 246
 247                     glPixelTransferf(GL_RED_BIAS,   1.0f);
 248                     glPixelTransferf(GL_GREEN_BIAS, 1.0f);
 249                     glPixelTransferf(GL_BLUE_BIAS,  1.0f);
 250
 251                     /* Create the image using the new surface. */
 252
 253                     o = make_image_from_surf(W, H, dst);
 254                 }
 255                 glPopAttrib();
 256
 257                 SDL_FreeSurface(dst);
 258             }
 259             SDL_FreeSurface(src);
 260         }
 261     }
 262     else
 263     {
 264         if (W) *W = 0;
 265         if (H) *H = 0;
 266         if (w) *w = 0;
 267         if (h) *h = 0;
 268     }
 269     return o;
 270 }
 271
 272 /*---------------------------------------------------------------------------*/