BEZSURF.C

/* 
 * (c) Copyright 1993, Silicon Graphics, Inc. 
 *               1993-1995 Microsoft Corporation 
 * 
 * ALL RIGHTS RESERVED 
 * 
 * Please refer to OpenGL/readme.txt for additional information 
 * 
 */ 
 
/*  bezmesh.c 
 *  This program renders a wireframe Bezier surface, 
 *  using two-dimensional evaluators. 
 */ 
#include "glos.h" 
 
#include <GL/gl.h> 
#include <GL/glu.h> 
#include <GL/glaux.h> 
 
void myinit(void); 
void CALLBACK myReshape(GLsizei w, GLsizei h); 
void CALLBACK display(void); 
 
GLfloat ctrlpoints[4][4][3] = { 
    {{-1.5, -1.5, 4.0}, {-0.5, -1.5, 2.0},  
{0.5, -1.5, -1.0}, {1.5, -1.5, 2.0}},  
    {{-1.5, -0.5, 1.0}, {-0.5, -0.5, 3.0},  
{0.5, -0.5, 0.0}, {1.5, -0.5, -1.0}},  
    {{-1.5, 0.5, 4.0}, {-0.5, 0.5, 0.0},  
{0.5, 0.5, 3.0}, {1.5, 0.5, 4.0}},  
    {{-1.5, 1.5, -2.0}, {-0.5, 1.5, -2.0},  
{0.5, 1.5, 0.0}, {1.5, 1.5, -1.0}} 
}; 
 
void CALLBACK display(void) 
{ 
    int i, j; 
 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    glColor3f(1.0, 1.0, 1.0); 
    glPushMatrix (); 
    glRotatef(85.0, 1.0, 1.0, 1.0); 
    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(); 
    } 
    glPopMatrix (); 
    glFlush(); 
} 
 
void myinit(void) 
{ 
    glClearColor (0.0, 0.0, 0.0, 1.0); 
    glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 
    0, 1, 12, 4, &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 CALLBACK myReshape(GLsizei w, GLsizei h) 
{ 
    if (!h) return; 
    glViewport(0, 0, w, h); 
    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    if (w <= h) 
glOrtho(-4.0, 4.0, -4.0*(GLfloat)h/(GLfloat)w,  
    4.0*(GLfloat)h/(GLfloat)w, -4.0, 4.0); 
    else 
glOrtho(-4.0*(GLfloat)w/(GLfloat)h,  
    4.0*(GLfloat)w/(GLfloat)h, -4.0, 4.0, -4.0, 4.0); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
} 
 
int main(int argc, char** argv) 
{ 
    auxInitDisplayMode (AUX_SINGLE | AUX_RGB | AUX_DEPTH16); 
    auxInitPosition (0, 0, 500, 500); 
    auxInitWindow ("Wireframe Bezier Surface"); 
    myinit(); 
    auxReshapeFunc (myReshape); 
    auxMainLoop(display); 
    return(0); 
}