/* Displays a texture loaded using the netpbm library and put on a unit square.

   Scott D. Anderson
   Fall 2006
*/

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

/* The following come from the texture file, and are also used as the unit
   in world space for the size of the quad. */

GLfloat textureHeight;
GLfloat textureWidth;

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

    glEnable(GL_TEXTURE_2D);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);

    glBegin(GL_QUADS);
    glTexCoord2f(0,0); glVertex2f(0,1); // upper left
    glTexCoord2f(0,1); glVertex2f(0,0); // lower left
    glTexCoord2f(1,1); glVertex2f(1,0); // lower right
    glTexCoord2f(1,0); glVertex2f(1,1); // upper right
    glEnd();

    glPopAttrib();
    glFlush();
    glutSwapBuffers();
}

int main(int argc, char* argv[]) {
    char buf[256];
    char* filename;
    
    if( argc <= 1 ) {
        printf("What texture file to load? ");
        scanf(buf,sizeof(buf),stdin);
        filename = buf;
    } else {
        filename = argv[1];
    }

    /* Ready to start doing OpenGL */

    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(500,500);
    glutCreateWindow(argv[0]);
    glutDisplayFunc(display);

    /* load the texture file */
    int fail=twPPM_Tex2D(filename, true, textureWidth, textureHeight);
    if( fail ) {
        exit(1);
    }
    printf("%f %f\n",textureWidth,textureHeight);
    
    twBoundingBox(0,1,0,1,0,0.01); // essentially flat
    twMainInit();
    glutMainLoop();
    return (0);
}