--- /dev/null
+/*
+ * (C) Copyright IBM Corporation 2004
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * on the rights to use, copy, modify, merge, publish, distribute, sub
+ * license, and/or sell copies of the Software, and to permit persons to whom
+ * the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * VA LINUX SYSTEM, IBM AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * \file blendminmax.c
+ *
+ * Simple test of GL_EXT_blend_minmax functionality. Four squares are drawn
+ * with different blending modes, but all should be rendered with the same
+ * final color.
+ *
+ * \author Ian Romanick <idr@us.ibm.com>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <GL/glut.h>
+
+static int Width = 400;
+static int Height = 200;
+static const GLfloat Near = 5.0, Far = 25.0;
+
+
+static void Display( void )
+{
+ glClearColor(0.2, 0.2, 0.8, 0);
+ glClear( GL_COLOR_BUFFER_BIT );
+
+ glPushMatrix();
+
+ /* This is the "reference" square.
+ */
+
+ glTranslatef(-4.5, 0, 0);
+ glBlendEquation( GL_FUNC_ADD );
+ glBlendFunc( GL_ONE, GL_ZERO );
+ glBegin(GL_QUADS);
+ glColor3f( 0.5, 0.5, 0.5 );
+ glVertex2f(-1, -1);
+ glVertex2f( 1, -1);
+ glVertex2f( 1, 1);
+ glVertex2f(-1, 1);
+ glEnd();
+
+
+ /* GL_MIN and GL_MAX are supposed to ignore the blend function setting.
+ * To test that, we set the blend function to GL_ZERO for both color and
+ * alpha each time GL_MIN or GL_MAX is used.
+ *
+ * Apple ships an extension called GL_ATI_blend_weighted_minmax (supported
+ * on Mac OS X 10.2 and later). I believe the difference with that
+ * extension is that it uses the blend function. However, I have no idea
+ * what the enums are for it. The extension is listed at Apple's developer
+ * site, but there is no documentation.
+ *
+ * http://developer.apple.com/opengl/extensions.html
+ */
+
+ glTranslatef(3.0, 0, 0);
+ glBlendEquation( GL_FUNC_ADD );
+ glBlendFunc( GL_ONE, GL_ZERO );
+ glBegin(GL_QUADS);
+ glColor3f( 0.5, 0.5, 0.5 );
+ glVertex2f(-1, -1);
+ glVertex2f( 1, -1);
+ glVertex2f( 1, 1);
+ glVertex2f(-1, 1);
+ glEnd();
+
+ glBlendEquation( GL_MAX );
+ glBlendFunc( GL_ZERO, GL_ZERO );
+ glBegin(GL_QUADS);
+ glColor3f( 0.2, 0.2, 0.2 );
+ glVertex2f(-1, -1);
+ glVertex2f( 1, -1);
+ glVertex2f( 1, 1);
+ glVertex2f(-1, 1);
+ glEnd();
+
+
+ glTranslatef(3.0, 0, 0);
+ glBlendEquation( GL_FUNC_ADD );
+ glBlendFunc( GL_ONE, GL_ZERO );
+ glBegin(GL_QUADS);
+ glColor3f( 0.5, 0.5, 0.5 );
+ glVertex2f(-1, -1);
+ glVertex2f( 1, -1);
+ glVertex2f( 1, 1);
+ glVertex2f(-1, 1);
+ glEnd();
+
+ glBlendEquation( GL_MIN );
+ glBlendFunc( GL_ZERO, GL_ZERO );
+ glBegin(GL_QUADS);
+ glColor3f( 0.8, 0.8, 0.8 );
+ glVertex2f(-1, -1);
+ glVertex2f( 1, -1);
+ glVertex2f( 1, 1);
+ glVertex2f(-1, 1);
+ glEnd();
+
+
+ glTranslatef(3.0, 0, 0);
+ glBlendEquation( GL_FUNC_ADD );
+ glBlendFunc( GL_ONE, GL_ZERO );
+ glBegin(GL_QUADS);
+ glColor3f( 0.8, 0.8, 0.8 );
+ glVertex2f(-1, -1);
+ glVertex2f( 1, -1);
+ glVertex2f( 1, 1);
+ glVertex2f(-1, 1);
+ glEnd();
+
+ glBlendEquation( GL_MIN );
+ glBlendFunc( GL_ZERO, GL_ZERO );
+ glBegin(GL_QUADS);
+ glColor3f( 0.5, 0.5, 0.5 );
+ 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 )
+{
+ const char * const ver_string = (const char * const)
+ glGetString( GL_VERSION );
+
+ printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
+ printf("GL_VERSION = %s\n", ver_string);
+
+ if ( !glutExtensionSupported("GL_ARB_imaging") && !glutExtensionSupported("GL_EXT_blend_minmax")) {
+ printf("Sorry, this program requires either GL_ARB_imaging or GL_EXT_blend_minmax.\n");
+ exit(1);
+ }
+
+ printf("\nAll 4 squares should be the same color.\n");
+ glEnable( GL_BLEND );
+}
+
+
+int main( int argc, char *argv[] )
+{
+ glutInit( &argc, argv );
+ glutInitWindowPosition( 0, 0 );
+ glutInitWindowSize( Width, Height );
+ glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
+ glutCreateWindow( "GL_EXT_blend_minmax test" );
+ glutReshapeFunc( Reshape );
+ glutKeyboardFunc( Key );
+ glutDisplayFunc( Display );
+ Init();
+ glutMainLoop();
+ return 0;
+}