src/glut/glx/glut_ppm.c

   1 /*
   2  * PPM file output
   3  * Brian Paul
   4  * 8 Dec 2008
   5  */
   6
   7 #include <assert.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include "glutint.h"
  11
  12
  13 static void
  14 write_ppm_file(const char *filename, const GLubyte *buffer,
  15                int width, int height)
  16 {
  17    const int binary = 1;
  18    FILE *f = fopen( filename, "w" );
  19    if (f) {
  20       const GLubyte *ptr = buffer;
  21       int i, x, y;
  22       if (binary) {
  23          fprintf(f,"P6\n");
  24          fprintf(f,"# ppm-file created by GLUT\n");
  25          fprintf(f,"%i %i\n", width, height);
  26          fprintf(f,"255\n");
  27          fclose(f);
  28          f = fopen( filename, "ab" );  /* reopen in binary append mode */
  29          for (y = height - 1; y >= 0; y--) {
  30             for (x = 0; x < width; x++) {
  31                i = (y * width + x) * 4;
  32                fputc(ptr[i], f);   /* write red */
  33                fputc(ptr[i+1], f); /* write green */
  34                fputc(ptr[i+2], f); /* write blue */
  35             }
  36          }
  37       }
  38       else {
  39          /*ASCII*/
  40          int counter = 0;
  41          fprintf(f,"P3\n");
  42          fprintf(f,"# ascii ppm file created by GLUT\n");
  43          fprintf(f,"%i %i\n", width, height);
  44          fprintf(f,"255\n");
  45          for (y = height - 1; y >= 0; y--) {
  46             for (x = 0; x < width; x++) {
  47                i = (y * width + x) * 4;
  48                fprintf(f, " %3d %3d %3d", ptr[i], ptr[i+1], ptr[i+2]);
  49                counter++;
  50                if (counter % 5 == 0)
  51                   fprintf(f, "\n");
  52             }
  53          }
  54       }
  55       fclose(f);
  56    }
  57 }
  58
  59
  60 /**
  61  * Called from SwapBuffers if the GLUT_PPM_FILE env var is set.
  62  */
  63 void __glutWritePPMFile(void)
  64 {
  65    int w = glutGet(GLUT_WINDOW_WIDTH);
  66    int h = glutGet(GLUT_WINDOW_HEIGHT);
  67    GLubyte *buf;
  68
  69    assert(__glutPPMFile);
  70
  71    buf = (GLubyte *) malloc(w * h * 4);
  72    if (buf) {
  73       /* XXX save/restore pixel packing */
  74       glReadPixels(0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, buf);
  75       write_ppm_file(__glutPPMFile, buf, w, h);
  76       free(buf);
  77    }
  78
  79    __glutPPMFile = NULL; /* only write one file */
  80 }