/* Lab exercise on texture mapping

   Scott D. Anderson
   Fall 2004
*/

#include <math.h>
#include <stdio.h>
#include <tw.h>

/* ================================================================ */

GLfloat texWidth=1, texHeight=1;

void texinit() {
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    twError();
    twPPM_Tex2D("buffy.ppm",true,texWidth,texHeight);
    twError();
    printf("%f x %f\n",texWidth,texHeight);
}    

void display() {
    twDisplayInit();
    twCamera();

    glEnable(GL_TEXTURE_2D);

    glBegin(GL_QUADS);
    // front
    glTexCoord2f(0,0);                glVertex3f( 0,1,1); 
    glTexCoord2f(0,texHeight);        glVertex3f( 0,0,1); 
    glTexCoord2f(texWidth,texHeight); glVertex3f( 1,0,1); 
    glTexCoord2f(texWidth,0);         glVertex3f( 1,1,1); 
    // top 
    glTexCoord2f(0,0); glVertex3f( 0,1,1); 
    glTexCoord2f(0,1); glVertex3f( 1,1,1); 
    glTexCoord2f(1,1); glVertex3f( 1,1,0); 
    glTexCoord2f(1,0); glVertex3f( 0,1,0); 
    // left
    glTexCoord2f(0,0); glVertex3f( 0,1,1); 
    glTexCoord2f(0,1); glVertex3f( 0,1,0); 
    glTexCoord2f(1,1); glVertex3f( 0,0,0); 
    glTexCoord2f(1,0); glVertex3f( 0,0,1); 

    glEnd();

    glFlush();
    glutSwapBuffers();
}

/* ================================================================ */
int main(int argc, char **argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    twInitWindowSize(500, 500);
    glutCreateWindow(argv[0]);
    glutDisplayFunc(display);
    twBoundingBox(0,1,0,1,0,1);
    twMainInit();
    texinit();
    glutMainLoop();                   
}