progs/tests/fog.c

   1 /*
   2  * Copyright 2005 Eric Anholt
   3  * All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice (including the next
  13  * paragraph) shall be included in all copies or substantial portions of the
  14  * Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  *
  24  * Authors:
  25  *    Eric Anholt <anholt@FreeBSD.org>
  26  *    Brian Paul (fogcoord.c used as a skeleton)
  27  */
  28
  29 /*
  30  * Test to exercise fog modes and for comparison with GL_EXT_fog_coord.
  31  */
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <math.h>
  36 #include <GL/glew.h>
  37 #include <GL/glut.h>
  38
  39 static int Width = 600;
  40 static int Height = 600;
  41 static GLfloat Near = 0.0, Far = 1.0;
  42 GLboolean has_fogcoord;
  43
  44 static void drawString( const char *string )
  45 {
  46    glRasterPos2f(0, .5);
  47    while ( *string ) {
  48       glutBitmapCharacter( GLUT_BITMAP_TIMES_ROMAN_10, *string );
  49       string++;
  50    }
  51 }
  52
  53 static void Display( void )
  54 {
  55    GLint i, depthi;
  56    GLfloat fogcolor[4] = {1, 1, 1, 1};
  57
  58    glEnable(GL_FOG);
  59    glFogfv(GL_FOG_COLOR, fogcolor);
  60
  61    glClearColor(0.2, 0.2, 0.8, 0);
  62    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
  63
  64    glPushMatrix();
  65    for (i = 0; i < 6; i++) {
  66       if (i >= 3 && !has_fogcoord)
  67          break;
  68
  69       glPushMatrix();
  70       for (depthi = 0; depthi < 5; depthi++) {
  71          GLfloat depth = Near + (Far - Near) * depthi / 4;
  72
  73          switch (i % 3) {
  74          case 0:
  75             glFogi(GL_FOG_MODE, GL_LINEAR);
  76             glFogf(GL_FOG_START, Near);
  77             glFogf(GL_FOG_END, Far);
  78             break;
  79          case 1:
  80             glFogi(GL_FOG_MODE, GL_EXP);
  81             glFogf(GL_FOG_DENSITY, 2);
  82             break;
  83          case 2:
  84             glFogi(GL_FOG_MODE, GL_EXP2);
  85             glFogf(GL_FOG_DENSITY, 2);
  86             break;
  87          }
  88
  89          glColor4f(0, 0, 0, 0);
  90          if (i < 3) {
  91             if (has_fogcoord)
  92                glFogi(GL_FOG_COORDINATE_SOURCE_EXT, GL_FRAGMENT_DEPTH_EXT);
  93
  94             glBegin(GL_POLYGON);
  95             glVertex3f(0, 0, depth);
  96             glVertex3f(1, 0, depth);
  97             glVertex3f(1, 1, depth);
  98             glVertex3f(0, 1, depth);
  99             glEnd();
 100          } else {
 101             glFogi(GL_FOG_COORDINATE_SOURCE_EXT, GL_FOG_COORDINATE_EXT);
 102             glFogCoordfEXT(depth);
 103
 104             glBegin(GL_POLYGON);
 105             glVertex3f(0, 0, (Near + Far) / 2);
 106             glVertex3f(1, 0, (Near + Far) / 2);
 107             glVertex3f(1, 1, (Near + Far) / 2);
 108             glVertex3f(0, 1, (Near + Far) / 2);
 109             glEnd();
 110          }
 111          glTranslatef(1.5, 0, 0);
 112       }
 113
 114       glTranslatef(.1, 0, 0);
 115       switch (i) {
 116       case 0:
 117          drawString("GL_LINEAR");
 118          break;
 119       case 1:
 120          drawString("GL_EXP");
 121          break;
 122       case 2:
 123          drawString("GL_EXP2");
 124          break;
 125       case 3:
 126          drawString("GL_FOGCOORD GL_LINEAR");
 127          break;
 128       case 4:
 129          drawString("GL_FOGCOORD GL_EXP");
 130          break;
 131       case 5:
 132          drawString("GL_FOGCOORD GL_EXP2");
 133          break;
 134       }
 135
 136       glPopMatrix();
 137       glTranslatef(0, 1.5, 0);
 138    }
 139    glPopMatrix();
 140
 141    glutSwapBuffers();
 142 }
 143
 144
 145 static void Reshape( int width, int height )
 146 {
 147    Width = width;
 148    Height = height;
 149    glViewport( 0, 0, width, height );
 150
 151    glMatrixMode( GL_PROJECTION );
 152    glLoadIdentity();
 153    glOrtho( 0, 11, 9, 0, -Near, -Far );
 154
 155    glMatrixMode( GL_MODELVIEW );
 156    glLoadIdentity();
 157    glTranslatef(.25, .25, 0);
 158 }
 159
 160
 161 static void Key( unsigned char key, int x, int y )
 162 {
 163    (void) x;
 164    (void) y;
 165    switch (key) {
 166       case 27:
 167          exit(0);
 168          break;
 169    }
 170    glutPostRedisplay();
 171 }
 172
 173
 174 static void Init( void )
 175 {
 176    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 177    printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
 178    /* setup lighting, etc */
 179    has_fogcoord = glutExtensionSupported("GL_EXT_fog_coord");
 180    if (!has_fogcoord) {
 181       printf("Some output of this program requires GL_EXT_fog_coord\n");
 182    }
 183 }
 184
 185
 186 int main( int argc, char *argv[] )
 187 {
 188    glutInit( &argc, argv );
 189    glutInitWindowPosition( 0, 0 );
 190    glutInitWindowSize( Width, Height );
 191    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
 192    glutCreateWindow(argv[0]);
 193    glewInit();
 194    glutReshapeFunc( Reshape );
 195    glutKeyboardFunc( Key );
 196    glutDisplayFunc( Display );
 197    Init();
 198    glutMainLoop();
 199    return 0;
 200 }