bezier_surface.cpp

#include <cstdlib>
#include <ctime>
#include <GLUT/glut.h>

const int num_wide = 5;
const int num_tall = 4;
const int num_dims = 3; // xyz

GLfloat ctrlpoints[num_wide][num_tall][num_dims];

void init_lights(void)
{
    GLfloat ambient[] = {0.2, 0.2, 0.2, 1.0};
    GLfloat position[] = {0.0, 0.0, 2.0, 1.0};
    GLfloat mat_diffuse[] = {1.0, 1.0, 1.0, 1.0};
    GLfloat mat_specular[] = {0.0, 0.0, 0.0, 1.0};
    GLfloat mat_shininess[] = {50.0};
    
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    
    glLightfv(GL_LIGHT0, GL_AMBIENT, ambient);
    glLightfv(GL_LIGHT0, GL_POSITION, position);
    
    glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
}

void init(void)
{
    srand(time(0));
    
    init_lights();
    
    for(size_t i = 0; i < num_wide; i++)
    {
        for(size_t j = 0; j < num_tall; j++)
        {
            ctrlpoints[i][j][0] = i;
            ctrlpoints[i][j][1] = j;
            
            // This should be set to something proportional to intensity.
            ctrlpoints[i][j][2] = float(rand()) / float(RAND_MAX) * 2.0;
        }
    }
    
    glClearColor (0.0, 0.0, 0.0, 0.0);
    glMap2f(GL_MAP2_VERTEX_3,
            0, 1, num_dims, num_tall,
            0, 1, num_dims*num_tall, num_wide,
            &ctrlpoints[0][0][0]);
    glEnable(GL_MAP2_VERTEX_3);
    glMapGrid2f(20, 0.0, 1.0, 20, 0.0, 1.0);
    glEnable(GL_DEPTH_TEST);
    glShadeModel(GL_FLAT);
}

void display(void)
{
    int i, j;
    
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glColor3f(1.0, 1.0, 1.0);
    glPushMatrix ();
    
    glRotatef(30.0, 1.0, 1.0, 1.0);
    
    glEvalMesh2(GL_FILL, 0, 20, 0, 20);
    
    glDisable(GL_LIGHTING);
    
    glColor3f(1.0, 0.5, 0.0);
    
    for (j = 0; j <= 8; j++)
    {
        glBegin(GL_LINE_STRIP);
        
        for (i = 0; i <= 30; i++)
            glEvalCoord2f((GLfloat)i/30.0, (GLfloat)j/8.0);
        
        glEnd();
        
        glBegin(GL_LINE_STRIP);
        
        for (i = 0; i <= 30; i++)
            glEvalCoord2f((GLfloat)j/8.0, (GLfloat)i/30.0);
        
        glEnd();
    }
   
    glEnable(GL_LIGHTING);
    
    glPopMatrix ();
    glFlush();
}

void reshape(int w, int h)
{
    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    if (w <= h)
        glOrtho(-5.0, 5.0, -5.0*(GLfloat)h/(GLfloat)w,
                5.0*(GLfloat)h/(GLfloat)w, -5.0, 5.0);
    else
        glOrtho(-5.0*(GLfloat)w/(GLfloat)h,
                5.0*(GLfloat)w/(GLfloat)h, -5.0, 5.0, -5.0, 5.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize (500, 500);
    glutInitWindowPosition (100, 100);
    glutCreateWindow (argv[0]);
    init ();
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutMainLoop();
    return 0;
}