284 lines
6.5 KiB
C
284 lines
6.5 KiB
C
/*
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* GL_ARB_occlusion_query demo
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*
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* Brian Paul
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* 12 June 2003
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*
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* Copyright (C) 2003 Brian Paul All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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#define GL_GLEXT_PROTOTYPES
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#include <GL/glut.h>
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#define TEST_DISPLAY_LISTS 0
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static GLboolean Anim = GL_TRUE;
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static GLfloat Xpos = 0;
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static GLuint OccQuery;
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static void
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PrintString(const char *s)
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{
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while (*s) {
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glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
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s++;
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}
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}
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static void Idle(void)
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{
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static int lastTime = 0;
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static int sign = +1;
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int time = glutGet(GLUT_ELAPSED_TIME);
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float step;
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if (lastTime == 0)
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lastTime = time;
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else if (time - lastTime < 20) /* 50Hz update */
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return;
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step = (time - lastTime) / 1000.0 * sign;
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lastTime = time;
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Xpos += step;
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if (Xpos > 2.5) {
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Xpos = 2.5;
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sign = -1;
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}
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else if (Xpos < -2.5) {
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Xpos = -2.5;
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sign = +1;
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}
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glutPostRedisplay();
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}
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static void Display( void )
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{
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GLuint passed;
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GLint ready;
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char s[100];
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glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
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glMatrixMode( GL_PROJECTION );
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glLoadIdentity();
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glFrustum( -1.0, 1.0, -1.0, 1.0, 5.0, 25.0 );
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glMatrixMode( GL_MODELVIEW );
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glLoadIdentity();
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glTranslatef( 0.0, 0.0, -15.0 );
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/* draw the occluding polygons */
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glColor3f(0, 0.6, 0.8);
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glBegin(GL_QUADS);
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glVertex2f(-1.6, -1.5);
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glVertex2f(-0.4, -1.5);
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glVertex2f(-0.4, 1.5);
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glVertex2f(-1.6, 1.5);
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glVertex2f( 0.4, -1.5);
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glVertex2f( 1.6, -1.5);
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glVertex2f( 1.6, 1.5);
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glVertex2f( 0.4, 1.5);
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glEnd();
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/* draw the test polygon with occlusion testing */
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glPushMatrix();
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glTranslatef(Xpos, 0, -0.5);
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glScalef(0.3, 0.3, 1.0);
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glRotatef(-90.0 * Xpos, 0, 0, 1);
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#if defined(GL_ARB_occlusion_query)
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#if TEST_DISPLAY_LISTS
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glNewList(10, GL_COMPILE);
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glBeginQueryARB(GL_SAMPLES_PASSED_ARB, OccQuery);
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glEndList();
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glCallList(10);
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#else
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glBeginQueryARB(GL_SAMPLES_PASSED_ARB, OccQuery);
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#endif
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glColorMask(0, 0, 0, 0);
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glDepthMask(GL_FALSE);
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glBegin(GL_POLYGON);
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glVertex3f(-1, -1, 0);
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glVertex3f( 1, -1, 0);
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glVertex3f( 1, 1, 0);
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glVertex3f(-1, 1, 0);
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glEnd();
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#if TEST_DISPLAY_LISTS
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glNewList(11, GL_COMPILE);
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glEndQueryARB(GL_SAMPLES_PASSED_ARB);
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glEndList();
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glCallList(11);
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#else
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glEndQueryARB(GL_SAMPLES_PASSED_ARB);
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#endif
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do {
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/* do useful work here, if any */
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glGetQueryObjectivARB(OccQuery, GL_QUERY_RESULT_AVAILABLE_ARB, &ready);
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} while (!ready);
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glGetQueryObjectuivARB(OccQuery, GL_QUERY_RESULT_ARB, &passed);
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/* turn off occlusion testing */
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glColorMask(1, 1, 1, 1);
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glDepthMask(GL_TRUE);
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#endif /* GL_ARB_occlusion_query */
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/* draw the orange rect, so we can see what's going on */
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glColor3f(0.8, 0.5, 0);
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glBegin(GL_POLYGON);
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glVertex3f(-1, -1, 0);
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glVertex3f( 1, -1, 0);
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glVertex3f( 1, 1, 0);
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glVertex3f(-1, 1, 0);
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glEnd();
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glPopMatrix();
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/* Print result message */
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glMatrixMode( GL_PROJECTION );
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glLoadIdentity();
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glOrtho( -1.0, 1.0, -1.0, 1.0, -1.0, 1.0 );
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glMatrixMode( GL_MODELVIEW );
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glLoadIdentity();
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glColor3f(1, 1, 1);
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#if defined(GL_ARB_occlusion_query)
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sprintf(s, " %4d Fragments Visible", passed);
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glRasterPos3f(-0.50, -0.7, 0);
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PrintString(s);
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if (!passed) {
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glRasterPos3f(-0.25, -0.8, 0);
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PrintString("Fully Occluded");
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}
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#else
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glRasterPos3f(-0.25, -0.8, 0);
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PrintString("GL_ARB_occlusion_query not available at compile time");
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#endif /* GL_ARB_occlusion_query */
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glutSwapBuffers();
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}
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static void Reshape( int width, int height )
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{
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glViewport( 0, 0, width, height );
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}
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static void Key( unsigned char key, int x, int y )
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{
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(void) x;
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(void) y;
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switch (key) {
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case 27:
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exit(0);
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break;
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case ' ':
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Anim = !Anim;
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if (Anim)
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glutIdleFunc(Idle);
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else
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glutIdleFunc(NULL);
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break;
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}
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glutPostRedisplay();
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}
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static void SpecialKey( int key, int x, int y )
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{
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const GLfloat step = 0.1;
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(void) x;
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(void) y;
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switch (key) {
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case GLUT_KEY_LEFT:
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Xpos -= step;
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break;
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case GLUT_KEY_RIGHT:
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Xpos += step;
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break;
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}
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glutPostRedisplay();
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}
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static void Init( void )
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{
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const char *ext = (const char *) glGetString(GL_EXTENSIONS);
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GLint bits;
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if (!strstr(ext, "GL_ARB_occlusion_query")) {
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printf("Sorry, this demo requires the GL_ARB_occlusion_query extension\n");
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exit(-1);
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}
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#if defined(GL_ARB_occlusion_query)
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glGetQueryivARB(GL_SAMPLES_PASSED_ARB, GL_QUERY_COUNTER_BITS_ARB, &bits);
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if (!bits) {
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printf("Hmmm, GL_QUERY_COUNTER_BITS_ARB is zero!\n");
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exit(-1);
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}
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#endif /* GL_ARB_occlusion_query */
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glGetIntegerv(GL_DEPTH_BITS, &bits);
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printf("Depthbits: %d\n", bits);
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#if defined(GL_ARB_occlusion_query)
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glGenQueriesARB(1, &OccQuery);
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assert(OccQuery > 0);
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#endif /* GL_ARB_occlusion_query */
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glEnable(GL_DEPTH_TEST);
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}
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int main( int argc, char *argv[] )
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{
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glutInit( &argc, argv );
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glutInitWindowPosition( 0, 0 );
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glutInitWindowSize( 400, 400 );
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glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH );
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glutCreateWindow(argv[0]);
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glutReshapeFunc( Reshape );
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glutKeyboardFunc( Key );
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glutSpecialFunc( SpecialKey );
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glutIdleFunc( Idle );
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glutDisplayFunc( Display );
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Init();
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glutMainLoop();
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return 0;
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}
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