progs/tests/multitexarray.c

   1 /*
   2  * Test vertex arrays and multitexture.
   3  * Press 'a' to toggle vertex arrays on/off.
   4  * When you run this program you should see a square with four colors:
   5  *
   6  *      +------+------+
   7  *      |yellow| pink |
   8  *      +------+------+
   9  *      |green | blue |
  10  *      +------+------+
  11  */
  12
  13
  14 #include <assert.h>
  15 #include <math.h>
  16 #include <stdlib.h>
  17 #include <stdio.h>
  18 #include <string.h>
  19 #include "GL/glut.h"
  20
  21 static GLuint Window = 0;
  22
  23 static GLuint TexObj[2];
  24 static GLfloat Angle = 0.0f;
  25 static GLboolean UseArrays = 1, Anim = 0;
  26
  27 static GLfloat VertArray[4][2] = {
  28    {-1.2, -1.2}, {1.2, -1.2}, {1.2, 1.2}, {-1.2, 1.2}
  29 };
  30
  31 static GLfloat Tex0Array[4][2] = {
  32    {0, 0}, {1, 0}, {1, 1}, {0, 1}
  33 };
  34
  35 static GLfloat Tex1Array[4][2] = {
  36    {0, 0}, {1, 0}, {1, 1}, {0, 1}
  37 };
  38
  39
  40 static void init_arrays(void)
  41 {
  42    glVertexPointer(2, GL_FLOAT, 0, VertArray);
  43    glEnableClientState(GL_VERTEX_ARRAY);
  44
  45    glClientActiveTextureARB(GL_TEXTURE0_ARB);
  46    glTexCoordPointer(2, GL_FLOAT, 0, Tex0Array);
  47    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  48
  49    glClientActiveTextureARB(GL_TEXTURE1_ARB);
  50    glTexCoordPointer(2, GL_FLOAT, 0, Tex1Array);
  51    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  52 }
  53
  54
  55 static void draw( void )
  56 {
  57    glClear( GL_COLOR_BUFFER_BIT );
  58
  59    glColor3f( 0.0, 0.0, 0.0 );
  60
  61    /* draw first polygon */
  62    glPushMatrix();
  63       glRotatef( Angle, 0.0, 0.0, 1.0 );
  64
  65       if (UseArrays) {
  66          glDrawArrays(GL_POLYGON, 0, 4);
  67       }
  68       else {
  69          glBegin( GL_POLYGON );
  70             glTexCoord2f( 0.0, 0.0 );
  71             glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 0.0);
  72             glVertex2f( -1.0, -1.0 );
  73
  74             glTexCoord2f( 1.0, 0.0 );
  75             glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 1.0, 0.0);
  76             glVertex2f(  1.0, -1.0 );
  77
  78             glTexCoord2f( 1.0, 1.0 );
  79             glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 1.0, 1.0);
  80             glVertex2f(  1.0,  1.0 );
  81
  82             glTexCoord2f( 0.0, 1.0 );
  83             glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 1.0);
  84             glVertex2f( -1.0,  1.0 );
  85          glEnd();
  86       }
  87
  88    glPopMatrix();
  89
  90    glutSwapBuffers();
  91 }
  92
  93
  94
  95 static void idle( void )
  96 {
  97    Angle += 2.0;
  98    glutPostRedisplay();
  99 }
 100
 101
 102
 103 /* change view Angle, exit upon ESC */
 104 static void key(unsigned char k, int x, int y)
 105 {
 106    (void) x;
 107    (void) y;
 108    switch (k) {
 109       case 'a':
 110          UseArrays = !UseArrays;
 111          printf("UseArrays: %d\n", UseArrays);
 112          break;
 113       case ' ':
 114          Anim = !Anim;
 115          if (Anim)
 116             glutIdleFunc(idle);
 117          else
 118             glutIdleFunc(NULL);
 119          break;
 120       case 27:
 121          glDeleteTextures( 2, TexObj );
 122          glutDestroyWindow(Window);
 123          exit(0);
 124    }
 125    glutPostRedisplay();
 126 }
 127
 128
 129
 130 /* new window size or exposure */
 131 static void reshape( int width, int height )
 132 {
 133    glViewport(0, 0, (GLint)width, (GLint)height);
 134    glMatrixMode(GL_PROJECTION);
 135    glLoadIdentity();
 136    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
 137    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
 138    glMatrixMode(GL_MODELVIEW);
 139    glLoadIdentity();
 140    glTranslatef( 0.0, 0.0, -8.0 );
 141 }
 142
 143
 144 static void init( void )
 145 {
 146    static int width=8, height=8;
 147    GLubyte tex[64][3];
 148    GLint i, j;
 149
 150    /* generate texture object IDs */
 151    glGenTextures( 2, TexObj );
 152
 153    /*
 154     * setup first texture object
 155     */
 156    glActiveTextureARB(GL_TEXTURE0_ARB);
 157    glEnable( GL_TEXTURE_2D );
 158    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_ADD );
 159
 160    glBindTexture( GL_TEXTURE_2D, TexObj[0] );
 161    assert(glIsTexture(TexObj[0]));
 162
 163    /* red over black */
 164    for (i=0;i<height;i++) {
 165       for (j=0;j<width;j++) {
 166          int p = i*width+j;
 167          if (i < height / 2) {
 168             tex[p][0] = 0;   tex[p][1] = 0;   tex[p][2] = 0;
 169          }
 170          else {
 171             tex[p][0] = 255;   tex[p][1] = 0;     tex[p][2] = 0;
 172          }
 173       }
 174    }
 175
 176    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 177                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 178    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 179    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 180    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 181    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 182
 183
 184    /*
 185     * setup second texture object
 186     */
 187    glActiveTextureARB(GL_TEXTURE1_ARB);
 188    glEnable( GL_TEXTURE_2D );
 189    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_ADD );
 190
 191    glBindTexture( GL_TEXTURE_2D, TexObj[1] );
 192    assert(glIsTexture(TexObj[1]));
 193
 194    /* left=green, right = blue */
 195    for (i=0;i<height;i++) {
 196       for (j=0;j<width;j++) {
 197          int p = i*width+j;
 198          if (j < width / 2) {
 199             tex[p][0] = 0;     tex[p][1] = 255;   tex[p][2] = 0;
 200          }
 201          else {
 202             tex[p][0] = 0;     tex[p][1] = 0;     tex[p][2] = 255;
 203          }
 204       }
 205    }
 206    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 207                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 208    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 209    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 210    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 211    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 212 }
 213
 214
 215
 216 int main( int argc, char *argv[] )
 217 {
 218    glutInit(&argc, argv);
 219    glutInitWindowPosition(0, 0);
 220    glutInitWindowSize(300, 300);
 221    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 222
 223    Window = glutCreateWindow("Texture Objects");
 224    if (!Window) {
 225       exit(1);
 226    }
 227
 228    init();
 229    init_arrays();
 230
 231    glutReshapeFunc( reshape );
 232    glutKeyboardFunc( key );
 233    if (Anim)
 234       glutIdleFunc( idle );
 235    glutDisplayFunc( draw );
 236    glutMainLoop();
 237    return 0;
 238 }