src/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/glew.h"
  20 #include "glut_wrap.h"
  21
  22 static GLuint Window = 0;
  23
  24 static GLuint TexObj[2];
  25 static GLfloat Angle = 0.0f;
  26 static GLboolean UseArrays = 1, Anim = 0;
  27
  28 static GLfloat VertArray[4][2] = {
  29    {-1.2, -1.2}, {1.2, -1.2}, {1.2, 1.2}, {-1.2, 1.2}
  30 };
  31
  32 static GLfloat Tex0Array[4][2] = {
  33    {0, 0}, {1, 0}, {1, 1}, {0, 1}
  34 };
  35
  36 static GLfloat Tex1Array[4][2] = {
  37    {0, 0}, {1, 0}, {1, 1}, {0, 1}
  38 };
  39
  40
  41 static void init_arrays(void)
  42 {
  43    glVertexPointer(2, GL_FLOAT, 0, VertArray);
  44    glEnableClientState(GL_VERTEX_ARRAY);
  45
  46    glClientActiveTextureARB(GL_TEXTURE0_ARB);
  47    glTexCoordPointer(2, GL_FLOAT, 0, Tex0Array);
  48    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  49
  50    glClientActiveTextureARB(GL_TEXTURE1_ARB);
  51    glTexCoordPointer(2, GL_FLOAT, 0, Tex1Array);
  52    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
  53 }
  54
  55
  56 static void draw( void )
  57 {
  58    glClear( GL_COLOR_BUFFER_BIT );
  59
  60    glColor3f( 0.0, 0.0, 0.0 );
  61
  62    /* draw first polygon */
  63    glPushMatrix();
  64       glRotatef( Angle, 0.0, 0.0, 1.0 );
  65
  66       if (UseArrays) {
  67          glDrawArrays(GL_POLYGON, 0, 4);
  68       }
  69       else {
  70          glBegin( GL_POLYGON );
  71             glTexCoord2f( 0.0, 0.0 );
  72             glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 0.0);
  73             glVertex2f( -1.0, -1.0 );
  74
  75             glTexCoord2f( 1.0, 0.0 );
  76             glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 1.0, 0.0);
  77             glVertex2f(  1.0, -1.0 );
  78
  79             glTexCoord2f( 1.0, 1.0 );
  80             glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 1.0, 1.0);
  81             glVertex2f(  1.0,  1.0 );
  82
  83             glTexCoord2f( 0.0, 1.0 );
  84             glMultiTexCoord2fARB(GL_TEXTURE1_ARB, 0.0, 1.0);
  85             glVertex2f( -1.0,  1.0 );
  86          glEnd();
  87       }
  88
  89    glPopMatrix();
  90
  91    glutSwapBuffers();
  92 }
  93
  94
  95
  96 static void idle( void )
  97 {
  98    Angle += 2.0;
  99    glutPostRedisplay();
 100 }
 101
 102
 103
 104 /* change view Angle, exit upon ESC */
 105 static void key(unsigned char k, int x, int y)
 106 {
 107    (void) x;
 108    (void) y;
 109    switch (k) {
 110       case 'a':
 111          UseArrays = !UseArrays;
 112          printf("UseArrays: %d\n", UseArrays);
 113          break;
 114       case ' ':
 115          Anim = !Anim;
 116          if (Anim)
 117             glutIdleFunc(idle);
 118          else
 119             glutIdleFunc(NULL);
 120          break;
 121       case 27:
 122          glDeleteTextures( 2, TexObj );
 123          glutDestroyWindow(Window);
 124          exit(0);
 125    }
 126    glutPostRedisplay();
 127 }
 128
 129
 130
 131 /* new window size or exposure */
 132 static void reshape( int width, int height )
 133 {
 134    glViewport(0, 0, (GLint)width, (GLint)height);
 135    glMatrixMode(GL_PROJECTION);
 136    glLoadIdentity();
 137    /*   glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
 138    glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
 139    glMatrixMode(GL_MODELVIEW);
 140    glLoadIdentity();
 141    glTranslatef( 0.0, 0.0, -8.0 );
 142 }
 143
 144
 145 static void init( void )
 146 {
 147    static int width=8, height=8;
 148    GLubyte tex[64][3];
 149    GLint i, j;
 150
 151    /* generate texture object IDs */
 152    glGenTextures( 2, TexObj );
 153
 154    /*
 155     * setup first texture object
 156     */
 157    glActiveTextureARB(GL_TEXTURE0_ARB);
 158    glEnable( GL_TEXTURE_2D );
 159    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_ADD );
 160
 161    glBindTexture( GL_TEXTURE_2D, TexObj[0] );
 162    assert(glIsTexture(TexObj[0]));
 163
 164    /* red over black */
 165    for (i=0;i<height;i++) {
 166       for (j=0;j<width;j++) {
 167          int p = i*width+j;
 168          if (i < height / 2) {
 169             tex[p][0] = 0;   tex[p][1] = 0;   tex[p][2] = 0;
 170          }
 171          else {
 172             tex[p][0] = 255;   tex[p][1] = 0;     tex[p][2] = 0;
 173          }
 174       }
 175    }
 176
 177    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 178                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 179    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 180    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 181    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 182    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 183
 184
 185    /*
 186     * setup second texture object
 187     */
 188    glActiveTextureARB(GL_TEXTURE1_ARB);
 189    glEnable( GL_TEXTURE_2D );
 190    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_ADD );
 191
 192    glBindTexture( GL_TEXTURE_2D, TexObj[1] );
 193    assert(glIsTexture(TexObj[1]));
 194
 195    /* left=green, right = blue */
 196    for (i=0;i<height;i++) {
 197       for (j=0;j<width;j++) {
 198          int p = i*width+j;
 199          if (j < width / 2) {
 200             tex[p][0] = 0;     tex[p][1] = 255;   tex[p][2] = 0;
 201          }
 202          else {
 203             tex[p][0] = 0;     tex[p][1] = 0;     tex[p][2] = 255;
 204          }
 205       }
 206    }
 207    glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
 208                  GL_RGB, GL_UNSIGNED_BYTE, tex );
 209    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
 210    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
 211    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
 212    glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
 213 }
 214
 215
 216
 217 int main( int argc, char *argv[] )
 218 {
 219    glutInit(&argc, argv);
 220    glutInitWindowPosition(0, 0);
 221    glutInitWindowSize(300, 300);
 222    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 223
 224    Window = glutCreateWindow("Texture Objects");
 225    glewInit();
 226    if (!Window) {
 227       exit(1);
 228    }
 229
 230    init();
 231    init_arrays();
 232
 233    glutReshapeFunc( reshape );
 234    glutKeyboardFunc( key );
 235    if (Anim)
 236       glutIdleFunc( idle );
 237    glutDisplayFunc( draw );
 238    glutMainLoop();
 239    return 0;
 240 }