/* Displays an OBJ using the glm library call from Nate Robbins's library.
   The object is unitized and displayed in the unit cube with the origin
   at the center.

   Scott D. Anderson
   Fall 2006
*/

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

char* filename;                 // the filename for the OBJ file

GLMmodel* pmodel = NULL;        // the model object


void initmodel(void) {
    GLfloat BoundingBox[6];         // [minx,maxx,miny,maxy,minz,maxz]

    pmodel = glmReadOBJ(filename);
    if (!pmodel) exit(0);
    glmUnitize(pmodel);
    glmBoundingBox(pmodel,BoundingBox);
    printf("Bounding Box is (%f,%f,%f,%f,%f,%f)\n",
           BoundingBox[0], BoundingBox[1],
           BoundingBox[2], BoundingBox[3],
           BoundingBox[4], BoundingBox[5]);
    glmFacetNormals(pmodel);
    glmVertexNormals(pmodel, 90.0);
}

void display(void) {
    twDisplayInit();
    twCamera();
    glPushAttrib(GL_ALL_ATTRIB_BITS);
    GLfloat pos[] = { 0.0, 0.0, 1.0, 0.0 };
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glLightfv(GL_LIGHT0, GL_POSITION, pos);

    glmDraw(pmodel, GLM_SMOOTH | GLM_MATERIAL);

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

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

    /* Ready to start doing OpenGL */

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

    twBoundingBox(-1,1,-1,1,-1,1); // unit cube
    twMainInit();
    glutMainLoop();
    return (0);
}