progs/tests/tex1d.c

   1
   2 /* Exercise 1D textures
   3  */
   4
   5 #include <assert.h>
   6 #include <math.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include "GL/glew.h"
  11 #include "GL/glut.h"
  12
  13 static GLuint Window = 0;
  14 static GLuint TexObj[2];
  15 static GLfloat Angle = 0.0f;
  16
  17
  18 static void draw( void )
  19 {
  20    glClear( GL_COLOR_BUFFER_BIT );
  21
  22    glColor3f( 1.0, 1.0, 1.0 );
  23
  24    /* draw first polygon */
  25    glPushMatrix();
  26    glTranslatef( -1.0, 0.0, 0.0 );
  27    glRotatef( Angle, 0.0, 0.0, 1.0 );
  28    glBindTexture( GL_TEXTURE_1D, TexObj[0] );
  29    glBegin( GL_POLYGON );
  30    glTexCoord1f( 0.0 );   glVertex2f( -1.0, -1.0 );
  31    glTexCoord1f( 1.0 );   glVertex2f(  1.0, -1.0 );
  32    glTexCoord1f( 1.0 );   glVertex2f(  1.0,  1.0 );
  33    glTexCoord1f( 0.0 );   glVertex2f( -1.0,  1.0 );
  34    glEnd();
  35    glPopMatrix();
  36
  37    glutSwapBuffers();
  38 }
  39
  40
  41
  42 static void idle( void )
  43 {
  44    Angle += 2.0;
  45    glutPostRedisplay();
  46 }
  47
  48
  49
  50 /* change view Angle, exit upon ESC */
  51 static void key(unsigned char k, int x, int y)
  52 {
  53    (void) x;
  54    (void) y;
  55    switch (k) {
  56       case 27:
  57          exit(0);
  58    }
  59 }
  60
  61
  62
  63 /* new window size or exposure */
  64 static void reshape( int width, int height )
  65 {
  66    glViewport(0, 0, (GLint)width, (GLint)height);
  67    glMatrixMode(GL_PROJECTION);
  68    glLoadIdentity();
  69    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
  70    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
  71    glMatrixMode(GL_MODELVIEW);
  72    glLoadIdentity();
  73    glTranslatef( 0.0, 0.0, -8.0 );
  74 }
  75
  76
  77 static void init( void )
  78 {
  79    GLubyte tex[256][3];
  80    GLint i;
  81
  82
  83    glDisable( GL_DITHER );
  84
  85    /* Setup texturing */
  86    glEnable( GL_TEXTURE_1D );
  87    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
  88
  89
  90    /* generate texture object IDs */
  91    glGenTextures( 2, TexObj );
  92
  93    /* setup first texture object */
  94    glBindTexture( GL_TEXTURE_1D, TexObj[0] );
  95
  96
  97    for (i = 0; i < 256; i++) {
  98       GLfloat f;
  99
 100       /* map 0..255 to -PI .. PI */
 101       f = ((i / 255.0) - .5) * (3.141592 * 2);
 102
 103       f = sin(f);
 104
 105       /* map -1..1 to 0..255 */
 106       tex[i][0] = (f+1.0)/2.0 * 255.0;
 107       tex[i][1] = 0;
 108       tex[i][2] = 0;
 109    }
 110
 111    glTexImage1D( GL_TEXTURE_1D, 0, 3, 256, 0, GL_RGB, GL_UNSIGNED_BYTE, tex );
 112    glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 113    glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 114    glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 115    glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 116 }
 117
 118
 119
 120 int main( int argc, char *argv[] )
 121 {
 122    glutInit(&argc, argv);
 123    glutInitWindowPosition(0, 0);
 124    glutInitWindowSize(300, 300);
 125    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 126
 127    Window = glutCreateWindow("Texture Objects");
 128    glewInit();
 129    if (!Window) {
 130       exit(1);
 131    }
 132
 133    init();
 134
 135    glutReshapeFunc( reshape );
 136    glutKeyboardFunc( key );
 137 /*    glutIdleFunc( idle ); */
 138    glutDisplayFunc( draw );
 139    glutMainLoop();
 140    return 0;
 141 }