TEXSURF.C

/* 
 * (c) Copyright 1993, Silicon Graphics, Inc. 
 *               1993-1995 Microsoft Corporation 
 * 
 * ALL RIGHTS RESERVED 
 * 
 * Please refer to OpenGL/readme.txt for additional information 
 * 
 */ 
 
/*  texturesurf.c 
 *  This program uses evaluators to generate a curved 
 *  surface and automatically generated texture coordinates. 
 */ 
#include "glos.h" 
 
#include <GL/gl.h> 
#include <GL/glu.h> 
#include <GL/glaux.h> 
#include <math.h> 
 
void myinit(void); 
void makeImage(void); 
void CALLBACK display(void); 
void CALLBACK myReshape(GLsizei w, GLsizei h); 
 
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}} 
}; 
 
GLfloat texpts[2][2][2] = {{{0.0, 0.0}, {0.0, 1.0}},  
            {{1.0, 0.0}, {1.0, 1.0}}}; 
 
void CALLBACK display(void) 
{ 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    glColor3f(1.0, 1.0, 1.0); 
    glEvalMesh2(GL_FILL, 0, 20, 0, 20); 
    glFlush(); 
} 
 
#define imageWidth 64 
#define imageHeight 64 
GLubyte image[3*imageWidth*imageHeight]; 
 
void makeImage(void) 
{ 
    int i, j; 
    float ti, tj; 
     
    for (i = 0; i < imageWidth; i++) { 
    ti = 2.0*3.14159265*i/imageWidth; 
    for (j = 0; j < imageHeight; j++) { 
        tj = 2.0*3.14159265*j/imageHeight; 
 
        image[3*(imageHeight*i+j)] = (GLubyte) 127*(1.0+sin(ti)); 
        image[3*(imageHeight*i+j)+1] = (GLubyte) 127*(1.0+cos(2*tj)); 
        image[3*(imageHeight*i+j)+2] = (GLubyte) 127*(1.0+cos(ti+tj)); 
    } 
    } 
} 
 
void myinit(void) 
{ 
    glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4, 
        0, 1, 12, 4, &ctrlpoints[0][0][0]); 
    glMap2f(GL_MAP2_TEXTURE_COORD_2, 0, 1, 2, 2,  
        0, 1, 4, 2, &texpts[0][0][0]); 
    glEnable(GL_MAP2_TEXTURE_COORD_2); 
    glEnable(GL_MAP2_VERTEX_3); 
    glMapGrid2f(20, 0.0, 1.0, 20, 0.0, 1.0); 
    makeImage(); 
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); 
    glTexImage2D(GL_TEXTURE_2D, 0, 3, imageWidth, imageHeight, 0, 
         GL_RGB, GL_UNSIGNED_BYTE, image); 
    glEnable(GL_TEXTURE_2D); 
    glEnable(GL_DEPTH_TEST); 
    glEnable(GL_NORMALIZE); 
    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(); 
    glRotatef(85.0, 1.0, 1.0, 1.0); 
} 
 
int main(int argc, char** argv) 
{ 
    auxInitDisplayMode (AUX_SINGLE | AUX_RGB | AUX_DEPTH16); 
    auxInitPosition (0, 0, 300, 300); 
    auxInitWindow ("Evaluators"); 
    myinit(); 
    auxReshapeFunc (myReshape); 
    auxMainLoop(display); 
    return(0); 
}