MIPMAP.C

/* 
 * (c) Copyright 1993, Silicon Graphics, Inc. 
 *               1993-1995 Microsoft Corporation 
 * 
 * ALL RIGHTS RESERVED 
 * 
 * Please refer to OpenGL/readme.txt for additional information 
 * 
 */ 
 
/*  mipmap.c 
 *  This program demonstrates using mipmaps for texture maps. 
 *  To overtly show the effect of mipmaps, each mipmap reduction 
 *  level has a solidly colored, contrasting texture image. 
 *  Thus, the quadrilateral which is drawn is drawn with several 
 *  different colors. 
 */ 
#include "glos.h" 
 
#include <GL/gl.h> 
#include <GL/glu.h> 
#include <GL/glaux.h> 
 
void myinit(void); 
void makeImages(void); 
void CALLBACK display(void); 
void CALLBACK myReshape(GLsizei w, GLsizei h); 
 
GLubyte mipmapImage32[32][32][3]; 
GLubyte mipmapImage16[16][16][3]; 
GLubyte mipmapImage8[8][8][3]; 
GLubyte mipmapImage4[4][4][3]; 
GLubyte mipmapImage2[2][2][3]; 
GLubyte mipmapImage1[1][1][3]; 
 
void makeImages(void) 
{ 
    int i, j; 
     
    for (i = 0; i < 32; i++) { 
    for (j = 0; j < 32; j++) { 
        mipmapImage32[i][j][0] = 255; 
        mipmapImage32[i][j][1] = 255; 
        mipmapImage32[i][j][2] = 0; 
    } 
    } 
    for (i = 0; i < 16; i++) { 
    for (j = 0; j < 16; j++) { 
        mipmapImage16[i][j][0] = 255; 
        mipmapImage16[i][j][1] = 0; 
        mipmapImage16[i][j][2] = 255; 
    } 
    } 
    for (i = 0; i < 8; i++) { 
    for (j = 0; j < 8; j++) { 
        mipmapImage8[i][j][0] = 255; 
        mipmapImage8[i][j][1] = 0; 
        mipmapImage8[i][j][2] = 0; 
    } 
    } 
    for (i = 0; i < 4; i++) { 
    for (j = 0; j < 4; j++) { 
        mipmapImage4[i][j][0] = 0; 
        mipmapImage4[i][j][1] = 255; 
        mipmapImage4[i][j][2] = 0; 
    } 
    } 
    for (i = 0; i < 2; i++) { 
    for (j = 0; j < 2; j++) { 
        mipmapImage2[i][j][0] = 0; 
        mipmapImage2[i][j][1] = 0; 
        mipmapImage2[i][j][2] = 255; 
    } 
    } 
    mipmapImage1[0][0][0] = 255; 
    mipmapImage1[0][0][1] = 255; 
    mipmapImage1[0][0][2] = 255; 
} 
 
void myinit(void) 
{     
    glEnable(GL_DEPTH_TEST); 
    glDepthFunc(GL_LESS); 
    glShadeModel(GL_FLAT); 
 
    glTranslatef(0.0, 0.0, -3.6); 
    makeImages(); 
    glPixelStorei(GL_UNPACK_ALIGNMENT, 1); 
    glTexImage2D(GL_TEXTURE_2D, 0, 3, 32, 32, 0, 
         GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage32[0][0][0]); 
    glTexImage2D(GL_TEXTURE_2D, 1, 3, 16, 16, 0, 
         GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage16[0][0][0]); 
    glTexImage2D(GL_TEXTURE_2D, 2, 3, 8, 8, 0, 
         GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage8[0][0][0]); 
    glTexImage2D(GL_TEXTURE_2D, 3, 3, 4, 4, 0, 
         GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage4[0][0][0]); 
    glTexImage2D(GL_TEXTURE_2D, 4, 3, 2, 2, 0, 
         GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage2[0][0][0]); 
    glTexImage2D(GL_TEXTURE_2D, 5, 3, 1, 1, 0, 
         GL_RGB, GL_UNSIGNED_BYTE, &mipmapImage1[0][0][0]); 
    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_MIPMAP_NEAREST); 
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL); 
    glEnable(GL_TEXTURE_2D); 
} 
 
void CALLBACK display(void) 
{ 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    glBegin(GL_QUADS); 
    glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0); 
    glTexCoord2f(0.0, 8.0); glVertex3f(-2.0, 1.0, 0.0); 
    glTexCoord2f(8.0, 8.0); glVertex3f(2000.0, 1.0, -6000.0); 
    glTexCoord2f(8.0, 0.0); glVertex3f(2000.0, -1.0, -6000.0); 
    glEnd(); 
    glFlush(); 
} 
 
void CALLBACK myReshape(GLsizei w, GLsizei h) 
{ 
    if (!h) return; 
    glViewport(0, 0, w, h); 
    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    gluPerspective(60.0, 1.0*(GLfloat)w/(GLfloat)h, 1.0, 30000.0); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
} 
 
int main(int argc, char** argv) 
{ 
    auxInitDisplayMode (AUX_SINGLE | AUX_RGB | AUX_DEPTH16); 
    auxInitPosition (0, 0, 500, 500); 
    auxInitWindow ("Texture Map Using Mipmap"); 
    myinit(); 
    auxReshapeFunc (myReshape); 
    auxMainLoop(display); 
    return(0); 
}