src/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 "glad/glad.h"
  13 #include "glut_wrap.h"
  14
  15 static GLuint Window = 0;
  16 static GLboolean Anim = GL_FALSE;
  17 static GLfloat Angle = 0.0f;
  18
  19
  20
  21 static void
  22 first_texture(void)
  23 {
  24    static int width=8, height=8;
  25    static GLubyte tex1[] = {
  26      0, 0, 0, 0, 0, 0, 0, 0,
  27      0, 0, 0, 0, 1, 0, 0, 0,
  28      0, 0, 0, 1, 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, 0, 1, 0, 0, 0,
  32      0, 0, 0, 1, 1, 1, 0, 0,
  33      0, 0, 0, 0, 0, 0, 0, 0 };
  34
  35    GLubyte tex[64][3];
  36    GLint i, j;
  37
  38    /* red on white */
  39    for (i=0;i<height;i++) {
  40       for (j=0;j<width;j++) {
  41          int p = i*width+j;
  42          if (tex1[(height-i-1)*width+j]) {
  43             tex[p][0] = 255;   tex[p][1] = 0;     tex[p][2] = 0;
  44          }
  45          else {
  46             tex[p][0] = 255;   tex[p][1] = 255;   tex[p][2] = 255;
  47          }
  48       }
  49    }
  50
  51    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
  52                  GL_RGB, GL_UNSIGNED_BYTE, tex );
  53 }
  54
  55
  56 static void
  57 second_texture(void)
  58 {
  59    static int width=8, height=8;
  60
  61    static GLubyte tex2[] = {
  62      0, 0, 0, 0, 0, 0, 0, 0,
  63      0, 0, 0, 2, 2, 0, 0, 0,
  64      0, 0, 2, 0, 0, 2, 0, 0,
  65      0, 0, 0, 0, 0, 2, 0, 0,
  66      0, 0, 0, 0, 2, 0, 0, 0,
  67      0, 0, 0, 2, 0, 0, 0, 0,
  68      0, 0, 2, 2, 2, 2, 0, 0,
  69      0, 0, 0, 0, 0, 0, 0, 0 };
  70
  71    GLubyte tex[64][3];
  72    GLint i, j;
  73
  74    /* green on blue */
  75    for (i=0;i<height;i++) {
  76       for (j=0;j<width;j++) {
  77          int p = i*width+j;
  78          if (tex2[(height-i-1)*width+j]) {
  79             tex[p][0] = 0;     tex[p][1] = 255;   tex[p][2] = 0;
  80          }
  81          else {
  82             tex[p][0] = 0;     tex[p][1] = 0;     tex[p][2] = 255;
  83          }
  84       }
  85    }
  86 #if 0
  87    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
  88                  GL_RGB, GL_UNSIGNED_BYTE, tex );
  89 #else
  90    glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height,
  91                  GL_RGB, GL_UNSIGNED_BYTE, tex );
  92 #endif
  93 }
  94
  95
  96
  97 static void draw( void )
  98 {
  99    glClear( GL_COLOR_BUFFER_BIT );
 100
 101    glColor3f( 1.0, 1.0, 1.0 );
 102
 103    /* draw first polygon */
 104    glPushMatrix();
 105    glTranslatef( -1.0, 0.0, 0.0 );
 106    glRotatef( Angle, 0.0, 0.0, 1.0 );
 107
 108    first_texture();
 109
 110    glBegin( GL_POLYGON );
 111    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
 112    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
 113    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
 114    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
 115    glEnd();
 116    glPopMatrix();
 117
 118    /* draw second polygon */
 119    glPushMatrix();
 120    glTranslatef( 1.0, 0.0, 0.0 );
 121    glRotatef( Angle-90.0, 0.0, 1.0, 0.0 );
 122
 123    second_texture();
 124
 125    glBegin( GL_POLYGON );
 126    glTexCoord2f( 0.0, 0.0 );   glVertex2f( -1.0, -1.0 );
 127    glTexCoord2f( 1.0, 0.0 );   glVertex2f(  1.0, -1.0 );
 128    glTexCoord2f( 1.0, 1.0 );   glVertex2f(  1.0,  1.0 );
 129    glTexCoord2f( 0.0, 1.0 );   glVertex2f( -1.0,  1.0 );
 130    glEnd();
 131    glPopMatrix();
 132
 133    glutSwapBuffers();
 134 }
 135
 136
 137
 138 static void idle( void )
 139 {
 140    static double t0 = -1.;
 141    double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
 142    if (t0 < 0.0)
 143       t0 = t;
 144    dt = t - t0;
 145    t0 = t;
 146    Angle += 120.0*dt;
 147    glutPostRedisplay();
 148 }
 149
 150
 151
 152 /* change view Angle, exit upon ESC */
 153 static void key(unsigned char k, int x, int y)
 154 {
 155    (void) x;
 156    (void) y;
 157    switch (k) {
 158    case 'a':
 159       Anim = !Anim;
 160       if (Anim)
 161          glutIdleFunc( idle );
 162       else
 163          glutIdleFunc( NULL );
 164       break;
 165    case 27:
 166       glutDestroyWindow(Window);
 167       exit(0);
 168    }
 169 }
 170
 171
 172
 173 /* new window size or exposure */
 174 static void reshape( int width, int height )
 175 {
 176    glViewport(0, 0, (GLint)width, (GLint)height);
 177    glMatrixMode(GL_PROJECTION);
 178    glLoadIdentity();
 179    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
 180    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
 181    glMatrixMode(GL_MODELVIEW);
 182    glLoadIdentity();
 183    glTranslatef( 0.0, 0.0, -8.0 );
 184 }
 185
 186
 187 static void init( void )
 188 {
 189    /* Setup texturing */
 190    glEnable( GL_TEXTURE_2D );
 191    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
 192
 193
 194    glBindTexture( GL_TEXTURE_2D, 0 );
 195    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 196    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 197    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 198    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 199 }
 200
 201
 202
 203 int main( int argc, char *argv[] )
 204 {
 205    glutInit(&argc, argv);
 206    glutInitWindowPosition(0, 0);
 207    glutInitWindowSize(300, 300);
 208    glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
 209
 210    Window = glutCreateWindow("Texture Objects");
 211    gladLoadGL();
 212    if (!Window) {
 213       exit(1);
 214    }
 215
 216    init();
 217
 218    glutReshapeFunc( reshape );
 219    glutKeyboardFunc( key );
 220    if (Anim)
 221       glutIdleFunc( idle );
 222    glutDisplayFunc( draw );
 223    glutMainLoop();
 224    return 0;
 225 }