| /* |
| * Exercise GL_EXT_fog_coord |
| */ |
| |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <math.h> |
| #include <GL/glew.h> |
| #include <GL/glut.h> |
| |
| static int Width = 600; |
| static int Height = 200; |
| static GLfloat Near = 5.0, Far = 25.0; |
| |
| |
| static void Display( void ) |
| { |
| GLfloat t; |
| |
| glClearColor(0.2, 0.2, 0.8, 0); |
| glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT ); |
| |
| for (t = 0.0; t <= 1.0; t += 0.25) { |
| GLfloat f = Near + t * (Far - Near); |
| printf("glFogCoord(%4.1f)\n", f); |
| glFogCoordfEXT(f); |
| |
| glPushMatrix(); |
| glTranslatef(t * 10.0 - 5.0, 0, 0); |
| glBegin(GL_POLYGON); |
| glVertex2f(-1, -1); |
| glVertex2f( 1, -1); |
| glVertex2f( 1, 1); |
| glVertex2f(-1, 1); |
| glEnd(); |
| glPopMatrix(); |
| } |
| glutSwapBuffers(); |
| } |
| |
| |
| static void Reshape( int width, int height ) |
| { |
| GLfloat ar = (float) width / (float) height; |
| Width = width; |
| Height = height; |
| glViewport( 0, 0, width, height ); |
| glMatrixMode( GL_PROJECTION ); |
| glLoadIdentity(); |
| glFrustum( -ar, ar, -1.0, 1.0, Near, Far ); |
| glMatrixMode( GL_MODELVIEW ); |
| glLoadIdentity(); |
| glTranslatef( 0.0, 0.0, -15.0 ); |
| } |
| |
| |
| static void Key( unsigned char key, int x, int y ) |
| { |
| (void) x; |
| (void) y; |
| switch (key) { |
| case 27: |
| exit(0); |
| break; |
| } |
| glutPostRedisplay(); |
| } |
| |
| |
| static void Init( void ) |
| { |
| printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER)); |
| printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION)); |
| /* setup lighting, etc */ |
| if (!glutExtensionSupported("GL_EXT_fog_coord")) { |
| printf("Sorry, this program requires GL_EXT_fog_coord\n"); |
| exit(1); |
| } |
| glFogi(GL_FOG_COORDINATE_SOURCE_EXT, GL_FOG_COORDINATE_EXT); |
| glFogi(GL_FOG_MODE, GL_LINEAR); |
| glFogf(GL_FOG_START, Near); |
| glFogf(GL_FOG_END, Far); |
| glEnable(GL_FOG); |
| printf("Squares should be colored from white -> gray -> black.\n"); |
| } |
| |
| |
| int main( int argc, char *argv[] ) |
| { |
| glutInit( &argc, argv ); |
| glutInitWindowPosition( 0, 0 ); |
| glutInitWindowSize( Width, Height ); |
| glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH ); |
| glutCreateWindow(argv[0]); |
| glewInit(); |
| glutReshapeFunc( Reshape ); |
| glutKeyboardFunc( Key ); |
| glutDisplayFunc( Display ); |
| Init(); |
| glutMainLoop(); |
| return 0; |
| } |