/*
* GL_ARB_occlusion_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>
#include <GL/glew.h>
#include <GL/glut.h>
#define NUM_OCC 10
static GLboolean Anim = GL_TRUE;
static GLfloat Xpos[NUM_OCC], Ypos[NUM_OCC];
static GLfloat Sign[NUM_OCC];
static GLuint OccQuery[NUM_OCC];
static GLint Win = 0;
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;
int time = glutGet(GLUT_ELAPSED_TIME);
float step;
int i;
if (lastTime == 0)
lastTime = time;
else if (time - lastTime < 20) /* 50Hz update */
return;
for (i = 0; i < NUM_OCC; i++) {
step = (time - lastTime) / 1000.0 * Sign[i];
Xpos[i] += step;
if (Xpos[i] > 2.5) {
Xpos[i] = 2.5;
Sign[i] = -1;
}
else if (Xpos[i] < -2.5) {
Xpos[i] = -2.5;
Sign[i] = +1;
}
}
lastTime = time;
glutPostRedisplay();
}
static void Display( void )
{
int i;
glClearColor(0.25, 0.25, 0.25, 0.0);
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, 0.4, 0.6);
glBegin(GL_QUADS);
glVertex2f(-1.6, -2.5);
glVertex2f(-0.4, -2.5);
glVertex2f(-0.4, 2.5);
glVertex2f(-1.6, 2.5);
glVertex2f( 0.4, -2.5);
glVertex2f( 1.6, -2.5);
glVertex2f( 1.6, 2.5);
glVertex2f( 0.4, 2.5);
glEnd();
glColorMask(0, 0, 0, 0);
glDepthMask(GL_FALSE);
/* draw the test polygons with occlusion testing */
for (i = 0; i < NUM_OCC; i++) {
glPushMatrix();
glTranslatef(Xpos[i], Ypos[i], -0.5);
glScalef(0.2, 0.2, 1.0);
glRotatef(-90.0 * Xpos[i], 0, 0, 1);
glBeginQueryARB(GL_SAMPLES_PASSED_ARB, OccQuery[i]);
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);
glPopMatrix();
}
glColorMask(1, 1, 1, 1);
glDepthMask(GL_TRUE);
/* Draw the rectangles now.
* Draw orange if result was ready
* Draw red if result was not ready.
*/
for (i = 0; i < NUM_OCC; i++) {
GLuint passed;
GLint ready;
glGetQueryObjectivARB(OccQuery[i], GL_QUERY_RESULT_AVAILABLE_ARB, &ready);
glGetQueryObjectuivARB(OccQuery[i], GL_QUERY_RESULT_ARB, &passed);
if (!ready)
glColor3f(1, 0, 0);
else
glColor3f(0.8, 0.5, 0);
if (!ready || passed) {
glPushMatrix();
glTranslatef(Xpos[i], Ypos[i], -0.5);
glScalef(0.2, 0.2, 1.0);
glRotatef(-90.0 * Xpos[i], 0, 0, 1);
glBegin(GL_POLYGON);
glVertex3f(-1, -1, 0);
glVertex3f( 1, -1, 0);
glVertex3f( 1, 1, 0);
glVertex3f(-1, 1, 0);
glEnd();
glPopMatrix();
}
{
char s[10];
glRasterPos3f(0.45, Ypos[i], 1.0);
sprintf(s, "%4d", passed);
PrintString(s);
}
}
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:
glutDestroyWindow(Win);
exit(0);
break;
case ' ':
Anim = !Anim;
if (Anim)
glutIdleFunc(Idle);
else
glutIdleFunc(NULL);
break;
}
glutPostRedisplay();
}
static void SpecialKey( int key, int x, int y )
{
const GLfloat step = 0.1;
int i;
(void) x;
(void) y;
switch (key) {
case GLUT_KEY_LEFT:
for (i = 0; i < NUM_OCC; i++)
Xpos[i] -= step;
break;
case GLUT_KEY_RIGHT:
for (i = 0; i < NUM_OCC; i++)
Xpos[i] += step;
break;
}
glutPostRedisplay();
}
static void Init( void )
{
const char *ext = (const char *) glGetString(GL_EXTENSIONS);
GLint bits;
int i;
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);
}
glGetIntegerv(GL_DEPTH_BITS, &bits);
printf("Depthbits: %d\n", bits);
glGenQueriesARB(NUM_OCC, OccQuery);
glEnable(GL_DEPTH_TEST);
for (i = 0; i < NUM_OCC; i++) {
float t = (float) i / (NUM_OCC - 1);
Xpos[i] = 2.5 * t;
Ypos[i] = 4.0 * (t - 0.5);
Sign[i] = 1.0;
}
}
int main( int argc, char *argv[] )
{
glutInitWindowSize( 400, 400 );
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
Win = glutCreateWindow(argv[0]);
glewInit();
glutReshapeFunc( Reshape );
glutKeyboardFunc( Key );
glutSpecialFunc( SpecialKey );
if (Anim)
glutIdleFunc(Idle);
else
glutIdleFunc(NULL);
glutDisplayFunc( Display );
Init();
glutMainLoop();
return 0;
}