progs/tests/subtex.c

   1 /*
   2  * Test glTexSubImage mid-way through a frame.
   3  *
   4  * The same texture is used for both quads but it gets redefined
   5  * with glTexSubImage (or glTexImage) after the first quad.
   6  */
   7
   8
   9 #include <assert.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include "GL/glut.h"
  13
  14 static GLuint Window = 0;
  15 static GLboolean Anim = GL_FALSE;
  16 static GLfloat Angle = 0.0f;
  17
  18
  19
  20 static void
  21 first_texture(void)
  22 {
  23    static int width=8, height=8;
  24    static GLubyte tex1[] = {
  25      0, 0, 0, 0, 0, 0, 0, 0,
  26      0, 0, 0, 0, 1, 0, 0, 0,
  27      0, 0, 0, 1, 1, 0, 0, 0,
  28      0, 0, 0, 0, 1, 0, 0, 0,
  29      0, 0, 0, 0, 1, 0, 0, 0,
  30      0, 0, 0, 0, 1, 0, 0, 0,
  31      0, 0, 0, 1, 1, 1, 0, 0,
  32      0, 0, 0, 0, 0, 0, 0, 0 };
  33
  34    GLubyte tex[64][3];
  35    GLint i, j;
  36
  37    /* red on white */
  38    for (i=0;i<height;i++) {
  39       for (j=0;j<width;j++) {
  40          int p = i*width+j;
  41          if (tex1[(height-i-1)*width+j]) {
  42             tex[p][0] = 255;   tex[p][1] = 0;     tex[p][2] = 0;
  43          }
  44          else {
  45             tex[p][0] = 255;   tex[p][1] = 255;   tex[p][2] = 255;
  46          }
  47       }
  48    }
  49
  50    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
  51                  GL_RGB, GL_UNSIGNED_BYTE, tex );
  52 }
  53
  54
  55 static void
  56 second_texture(void)
  57 {
  58    static int width=8, height=8;
  59
  60    static GLubyte tex2[] = {
  61      0, 0, 0, 0, 0, 0, 0, 0,
  62      0, 0, 0, 2, 2, 0, 0, 0,
  63      0, 0, 2, 0, 0, 2, 0, 0,
  64      0, 0, 0, 0, 0, 2, 0, 0,
  65      0, 0, 0, 0, 2, 0, 0, 0,
  66      0, 0, 0, 2, 0, 0, 0, 0,
  67      0, 0, 2, 2, 2, 2, 0, 0,
  68      0, 0, 0, 0, 0, 0, 0, 0 };
  69
  70    GLubyte tex[64][3];
  71    GLint i, j;
  72
  73    /* green on blue */
  74    for (i=0;i<height;i++) {
  75       for (j=0;j<width;j++) {
  76          int p = i*width+j;
  77          if (tex2[(height-i-1)*width+j]) {
  78             tex[p][0] = 0;     tex[p][1] = 255;   tex[p][2] = 0;
  79          }
  80          else {
  81             tex[p][0] = 0;     tex[p][1] = 0;     tex[p][2] = 255;
  82          }
  83       }
  84    }
  85 #if 0
  86    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
  87                  GL_RGB, GL_UNSIGNED_BYTE, tex );
  88 #else
  89    glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height,
  90                  GL_RGB, GL_UNSIGNED_BYTE, tex );
  91 #endif
  92 }
  93
  94
  95
  96 static void draw( void )
  97 {
  98    glClear( GL_COLOR_BUFFER_BIT );
  99
 100    glColor3f( 1.0, 1.0, 1.0 );
 101
 102    /* draw first polygon */
 103    glPushMatrix();
 104    glTranslatef( -1.0, 0.0, 0.0 );
 105    glRotatef( Angle, 0.0, 0.0, 1.0 );
 106
 107    first_texture();
 108
 109    glBegin( GL_POLYGON );
 110    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
 111    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
 112    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
 113    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
 114    glEnd();
 115    glPopMatrix();
 116
 117    /* draw second polygon */
 118    glPushMatrix();
 119    glTranslatef( 1.0, 0.0, 0.0 );
 120    glRotatef( Angle-90.0, 0.0, 1.0, 0.0 );
 121
 122    second_texture();
 123
 124    glBegin( GL_POLYGON );
 125    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
 126    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
 127    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
 128    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
 129    glEnd();
 130    glPopMatrix();
 131
 132    glutSwapBuffers();
 133 }
 134
 135
 136
 137 static void idle( void )
 138 {
 139    static double t0 = -1.;
 140    double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
 141    if (t0 < 0.0)
 142       t0 = t;
 143    dt = t - t0;
 144    t0 = t;
 145    Angle += 120.0*dt;
 146    glutPostRedisplay();
 147 }
 148
 149
 150
 151 /* change view Angle, exit upon ESC */
 152 static void key(unsigned char k, int x, int y)
 153 {
 154    (void) x;
 155    (void) y;
 156    switch (k) {
 157    case 'a':
 158       Anim = !Anim;
 159       if (Anim)
 160          glutIdleFunc( idle );
 161       else
 162          glutIdleFunc( NULL );
 163       break;
 164    case 27:
 165       glutDestroyWindow(Window);
 166       exit(0);
 167    }
 168 }
 169
 170
 171
 172 /* new window size or exposure */
 173 static void reshape( int width, int height )
 174 {
 175    glViewport(0, 0, (GLint)width, (GLint)height);
 176    glMatrixMode(GL_PROJECTION);
 177    glLoadIdentity();
 178    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
 179    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
 180    glMatrixMode(GL_MODELVIEW);
 181    glLoadIdentity();
 182    glTranslatef( 0.0, 0.0, -8.0 );
 183 }
 184
 185
 186 static void init( void )
 187 {
 188    /* Setup texturing */
 189    glEnable( GL_TEXTURE_2D );
 190    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
 191
 192
 193    glBindTexture( GL_TEXTURE_2D, 0 );
 194    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 195    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 196    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 197    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 198 }
 199
 200
 201
 202 int main( int argc, char *argv[] )
 203 {
 204    glutInit(&argc, argv);
 205    glutInitWindowPosition(0, 0);
 206    glutInitWindowSize(300, 300);
 207    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 208
 209    Window = glutCreateWindow("Texture Objects");
 210    if (!Window) {
 211       exit(1);
 212    }
 213
 214    init();
 215
 216    glutReshapeFunc( reshape );
 217    glutKeyboardFunc( key );
 218    if (Anim)
 219       glutIdleFunc( idle );
 220    glutDisplayFunc( draw );
 221    glutMainLoop();
 222    return 0;
 223 }