Commit 86258034 authored by Brian Paul's avatar Brian Paul

GL_ARB_occlusion_query demo.

parent b17a722c
......@@ -15,6 +15,7 @@ LIB_DEP = $(LIBDIR)/$(GL_LIB) $(LIBDIR)/$(GLU_LIB) $(LIBDIR)/$(GLUT_LIB)
PROGS = \
arbfplight \
arbocclude \
bounce \
clearspd \
cubemap \
......
/*
* GL_ARB_occlustion_query demo
*
* Brian Paul
* 12 June 2003
*
* Copyright (C) 2003 Brian Paul 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
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* 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 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 NONINFRINGEMENT. IN NO EVENT SHALL
* BRIAN PAUL 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.
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define GL_GLEXT_PROTOTYPES
#include <GL/glut.h>
static GLfloat Xpos = 0;
static GLuint OccQuery;
static void
PrintString(const char *s)
{
while (*s) {
glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
s++;
}
}
static void Idle(void)
{
static int lastTime = 0;
static int sign = +1;
int time = glutGet(GLUT_ELAPSED_TIME);
float step;
if (lastTime == 0)
lastTime = time;
else if (time - lastTime < 20) /* 50Hz update */
return;
step = (time - lastTime) / 1000.0 * sign;
lastTime = time;
Xpos += step;
if (Xpos > 2.5) {
Xpos = 2.5;
sign = -1;
}
else if (Xpos < -2.5) {
Xpos = -2.5;
sign = +1;
}
glutPostRedisplay();
}
static void Display( void )
{
GLuint passed;
GLint ready;
char s[100];
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glTranslatef( 0.0, 0.0, -15.0 );
/* draw the occluding polygons */
glColor3f(0, 0.6, 0.8);
glBegin(GL_QUADS);
glVertex2f(-1.6, -1.5);
glVertex2f(-0.4, -1.5);
glVertex2f(-0.4, 1.5);
glVertex2f(-1.6, 1.5);
glVertex2f( 0.4, -1.5);
glVertex2f( 1.6, -1.5);
glVertex2f( 1.6, 1.5);
glVertex2f( 0.4, 1.5);
glEnd();
/* draw the test polygon with occlusion testing */
glPushMatrix();
glTranslatef(Xpos, 0, -0.5);
glScalef(0.3, 0.3, 1.0);
glRotatef(-90.0 * Xpos, 0, 0, 1);
glBeginQueryARB(GL_SAMPLES_PASSED_ARB, OccQuery);
glColorMask(0, 0, 0, 0);
glDepthMask(GL_FALSE);
glBegin(GL_POLYGON);
glVertex3f(-1, -1, 0);
glVertex3f( 1, -1, 0);
glVertex3f( 1, 1, 0);
glVertex3f(-1, 1, 0);
glEnd();
glEndQueryARB(GL_SAMPLES_PASSED_ARB);
do {
/* do useful work here, if any */
glGetQueryObjectivARB(OccQuery, GL_QUERY_RESULT_AVAILABLE_ARB, &ready);
} while (!ready);
glGetQueryObjectuivARB(OccQuery, GL_QUERY_RESULT_ARB, &passed);
/* turn off occlusion testing */
glColorMask(1, 1, 1, 1);
glDepthMask(GL_TRUE);
/* draw the orange rect, so we can see what's going on */
glColor3f(0.8, 0.5, 0);
glBegin(GL_POLYGON);
glVertex3f(-1, -1, 0);
glVertex3f( 1, -1, 0);
glVertex3f( 1, 1, 0);
glVertex3f(-1, 1, 0);
glEnd();
glPopMatrix();
/* Print result message */
glMatrixMode( GL_PROJECTION );
glLoadIdentity();
glOrtho( -1.0, 1.0, -1.0, 1.0, -1.0, 1.0 );
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
glColor3f(1, 1, 1);
sprintf(s, " %4d Fragments Visible", passed);
glRasterPos3f(-0.50, -0.7, 0);
PrintString(s);
if (!passed) {
glRasterPos3f(-0.25, -0.8, 0);
PrintString("Fully Occluded");
}
glutSwapBuffers();
}
static void Reshape( int width, int height )
{
glViewport( 0, 0, width, height );
}
static void Key( unsigned char key, int x, int y )
{
(void) x;
(void) y;
switch (key) {
case 27:
exit(0);
break;
}
glutPostRedisplay();
}
static void SpecialKey( int key, int x, int y )
{
const GLfloat step = 0.1;
(void) x;
(void) y;
switch (key) {
case GLUT_KEY_LEFT:
Xpos -= step;
break;
case GLUT_KEY_RIGHT:
Xpos += step;
break;
}
glutPostRedisplay();
}
static void Init( void )
{
const char *ext = (const char *) glGetString(GL_EXTENSIONS);
GLint bits;
if (!strstr(ext, "GL_ARB_occlusion_query")) {
printf("Sorry, this demo requires the GL_ARB_occlusion_query extension\n");
exit(-1);
}
glGetQueryivARB(GL_SAMPLES_PASSED_ARB, GL_QUERY_COUNTER_BITS_ARB, &bits);
if (!bits) {
printf("Hmmm, GL_QUERY_COUNTER_BITS_ARB is zero!\n");
exit(-1);
}
glGenQueriesARB(1, &OccQuery);
assert( glIsQueryARB(OccQuery) );
glEnable(GL_DEPTH_TEST);
}
int main( int argc, char *argv[] )
{
glutInit( &argc, argv );
glutInitWindowPosition( 0, 0 );
glutInitWindowSize( 400, 400 );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
glutCreateWindow(argv[0]);
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutSpecialFunc( SpecialKey );
glutIdleFunc( Idle );
glutDisplayFunc( Display );
Init();
glutMainLoop();
return 0;
}
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