progs/tests/blendminmax.c

   1 /*
   2  * (C) Copyright IBM Corporation 2004
   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  * on the rights to use, copy, modify, merge, publish, distribute, sub
   9  * license, and/or sell copies of the Software, and to permit persons to whom
  10  * the 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 NON-INFRINGEMENT.  IN NO EVENT SHALL
  19  * VA LINUX SYSTEM, IBM AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
  20  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  21  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  22  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 /**
  26  * \file blendminmax.c
  27  *
  28  * Simple test of GL_EXT_blend_minmax functionality.  Four squares are drawn
  29  * with different blending modes, but all should be rendered with the same
  30  * final color.
  31  *
  32  * \author Ian Romanick <idr@us.ibm.com>
  33  */
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <GL/glew.h>
  38 #include <GL/glut.h>
  39
  40 static int Width = 400;
  41 static int Height = 200;
  42 static const GLfloat Near = 5.0, Far = 25.0;
  43
  44
  45 static void Display( void )
  46 {
  47    glClearColor(0.2, 0.2, 0.8, 0);
  48    glClear( GL_COLOR_BUFFER_BIT );
  49
  50    glPushMatrix();
  51
  52    /* This is the "reference" square.
  53     */
  54
  55    glTranslatef(-4.5, 0, 0);
  56    glBlendEquation( GL_FUNC_ADD );
  57    glBlendFunc( GL_ONE, GL_ZERO );
  58    glBegin(GL_QUADS);
  59    glColor3f( 0.5, 0.5, 0.5 );
  60    glVertex2f(-1, -1);
  61    glVertex2f( 1, -1);
  62    glVertex2f( 1,  1);
  63    glVertex2f(-1,  1);
  64    glEnd();
  65
  66
  67    /* GL_MIN and GL_MAX are supposed to ignore the blend function setting.
  68     * To test that, we set the blend function to GL_ZERO for both color and
  69     * alpha each time GL_MIN or GL_MAX is used.
  70     *
  71     * Apple ships an extension called GL_ATI_blend_weighted_minmax (supported
  72     * on Mac OS X 10.2 and later).  I believe the difference with that
  73     * extension is that it uses the blend function.  However, I have no idea
  74     * what the enums are for it.  The extension is listed at Apple's developer
  75     * site, but there is no documentation.
  76     *
  77     * http://developer.apple.com/opengl/extensions.html
  78     */
  79
  80    glTranslatef(3.0, 0, 0);
  81    glBlendEquation( GL_FUNC_ADD );
  82    glBlendFunc( GL_ONE, GL_ZERO );
  83    glBegin(GL_QUADS);
  84    glColor3f( 0.5, 0.5, 0.5 );
  85    glVertex2f(-1, -1);
  86    glVertex2f( 1, -1);
  87    glVertex2f( 1,  1);
  88    glVertex2f(-1,  1);
  89    glEnd();
  90
  91    glBlendEquation( GL_MAX );
  92    glBlendFunc( GL_ZERO, GL_ZERO );
  93    glBegin(GL_QUADS);
  94    glColor3f( 0.2, 0.2, 0.2 );
  95    glVertex2f(-1, -1);
  96    glVertex2f( 1, -1);
  97    glVertex2f( 1,  1);
  98    glVertex2f(-1,  1);
  99    glEnd();
 100
 101
 102    glTranslatef(3.0, 0, 0);
 103    glBlendEquation( GL_FUNC_ADD );
 104    glBlendFunc( GL_ONE, GL_ZERO );
 105    glBegin(GL_QUADS);
 106    glColor3f( 0.5, 0.5, 0.5 );
 107    glVertex2f(-1, -1);
 108    glVertex2f( 1, -1);
 109    glVertex2f( 1,  1);
 110    glVertex2f(-1,  1);
 111    glEnd();
 112
 113    glBlendEquation( GL_MIN );
 114    glBlendFunc( GL_ZERO, GL_ZERO );
 115    glBegin(GL_QUADS);
 116    glColor3f( 0.8, 0.8, 0.8 );
 117    glVertex2f(-1, -1);
 118    glVertex2f( 1, -1);
 119    glVertex2f( 1,  1);
 120    glVertex2f(-1,  1);
 121    glEnd();
 122
 123
 124    glTranslatef(3.0, 0, 0);
 125    glBlendEquation( GL_FUNC_ADD );
 126    glBlendFunc( GL_ONE, GL_ZERO );
 127    glBegin(GL_QUADS);
 128    glColor3f( 0.8, 0.8, 0.8 );
 129    glVertex2f(-1, -1);
 130    glVertex2f( 1, -1);
 131    glVertex2f( 1,  1);
 132    glVertex2f(-1,  1);
 133    glEnd();
 134
 135    glBlendEquation( GL_MIN );
 136    glBlendFunc( GL_ZERO, GL_ZERO );
 137    glBegin(GL_QUADS);
 138    glColor3f( 0.5, 0.5, 0.5 );
 139    glVertex2f(-1, -1);
 140    glVertex2f( 1, -1);
 141    glVertex2f( 1,  1);
 142    glVertex2f(-1,  1);
 143    glEnd();
 144
 145    glPopMatrix();
 146
 147    glutSwapBuffers();
 148 }
 149
 150
 151 static void Reshape( int width, int height )
 152 {
 153    GLfloat ar = (float) width / (float) height;
 154    Width = width;
 155    Height = height;
 156    glViewport( 0, 0, width, height );
 157    glMatrixMode( GL_PROJECTION );
 158    glLoadIdentity();
 159    glFrustum( -ar, ar, -1.0, 1.0, Near, Far );
 160    glMatrixMode( GL_MODELVIEW );
 161    glLoadIdentity();
 162    glTranslatef( 0.0, 0.0, -15.0 );
 163 }
 164
 165
 166 static void Key( unsigned char key, int x, int y )
 167 {
 168    (void) x;
 169    (void) y;
 170    switch (key) {
 171       case 27:
 172          exit(0);
 173          break;
 174    }
 175    glutPostRedisplay();
 176 }
 177
 178
 179 static void Init( void )
 180 {
 181    const char * const ver_string = (const char * const)
 182        glGetString( GL_VERSION );
 183
 184    printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
 185    printf("GL_VERSION = %s\n", ver_string);
 186
 187    if ( !glutExtensionSupported("GL_ARB_imaging") && !glutExtensionSupported("GL_EXT_blend_minmax")) {
 188       printf("Sorry, this program requires either GL_ARB_imaging or GL_EXT_blend_minmax.\n");
 189       exit(1);
 190    }
 191
 192    printf("\nAll 4 squares should be the same color.\n");
 193    glEnable( GL_BLEND );
 194 }
 195
 196
 197 int main( int argc, char *argv[] )
 198 {
 199    glutInit( &argc, argv );
 200    glutInitWindowPosition( 0, 0 );
 201    glutInitWindowSize( Width, Height );
 202    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 203    glutCreateWindow( "GL_EXT_blend_minmax test" );
 204    glewInit();
 205    glutReshapeFunc( Reshape );
 206    glutKeyboardFunc( Key );
 207    glutDisplayFunc( Display );
 208    Init();
 209    glutMainLoop();
 210    return 0;
 211 }