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 /*
  43 static void idle( void )
  44 {
  45    Angle += 2.0;
  46    glutPostRedisplay();
  47 }
  48 */
  49
  50
  51
  52 /* change view Angle, exit upon ESC */
  53 static void key(unsigned char k, int x, int y)
  54 {
  55    (void) x;
  56    (void) y;
  57    switch (k) {
  58       case 27:
  59          exit(0);
  60    }
  61 }
  62
  63
  64
  65 /* new window size or exposure */
  66 static void reshape( int width, int height )
  67 {
  68    glViewport(0, 0, (GLint)width, (GLint)height);
  69    glMatrixMode(GL_PROJECTION);
  70    glLoadIdentity();
  71    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
  72    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
  73    glMatrixMode(GL_MODELVIEW);
  74    glLoadIdentity();
  75    glTranslatef( 0.0, 0.0, -8.0 );
  76 }
  77
  78
  79 static void init( void )
  80 {
  81    GLubyte tex[256][3];
  82    GLint i;
  83
  84
  85    glDisable( GL_DITHER );
  86
  87    /* Setup texturing */
  88    glEnable( GL_TEXTURE_1D );
  89    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
  90
  91
  92    /* generate texture object IDs */
  93    glGenTextures( 2, TexObj );
  94
  95    /* setup first texture object */
  96    glBindTexture( GL_TEXTURE_1D, TexObj[0] );
  97
  98
  99    for (i = 0; i < 256; i++) {
 100       GLfloat f;
 101
 102       /* map 0..255 to -PI .. PI */
 103       f = ((i / 255.0) - .5) * (3.141592 * 2);
 104
 105       f = sin(f);
 106
 107       /* map -1..1 to 0..255 */
 108       tex[i][0] = (f+1.0)/2.0 * 255.0;
 109       tex[i][1] = 0;
 110       tex[i][2] = 0;
 111    }
 112
 113    glTexImage1D( GL_TEXTURE_1D, 0, 3, 256, 0, GL_RGB, GL_UNSIGNED_BYTE, tex );
 114    glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 115    glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 116    glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 117    glTexParameteri( GL_TEXTURE_1D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 118 }
 119
 120
 121
 122 int main( int argc, char *argv[] )
 123 {
 124    glutInit(&argc, argv);
 125    glutInitWindowPosition(0, 0);
 126    glutInitWindowSize(300, 300);
 127    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 128
 129    Window = glutCreateWindow("Texture Objects");
 130    glewInit();
 131    if (!Window) {
 132       exit(1);
 133    }
 134
 135    init();
 136
 137    glutReshapeFunc( reshape );
 138    glutKeyboardFunc( key );
 139 /*    glutIdleFunc( idle ); */
 140    glutDisplayFunc( draw );
 141    glutMainLoop();
 142    return 0;
 143 }