/*
 * Test GL_NV_conditional_render
 *
 * Brian Paul
 * 30 Dec 2009
 *
 * Copyright (C) 2009  VMware, Inc.  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
 * THE AUTHORS 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 TEST_DISPLAY_LISTS 0

static GLboolean Anim = GL_TRUE;
static GLfloat Xpos = 0;
static GLuint OccQuery;
static GLint Win = 0;


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 )
{
   glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

   glEnable(GL_DEPTH_TEST);

   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);

#if TEST_DISPLAY_LISTS
   glNewList(10, GL_COMPILE);
   glBeginQueryARB(GL_SAMPLES_PASSED_ARB, OccQuery);
   glEndList();
   glCallList(10);
#else
   glBeginQueryARB(GL_SAMPLES_PASSED_ARB, OccQuery);
#endif

   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();

#if TEST_DISPLAY_LISTS
   glNewList(11, GL_COMPILE);
   glEndQueryARB(GL_SAMPLES_PASSED_ARB);
   glEndList();
   glCallList(11);
#else
   glEndQueryARB(GL_SAMPLES_PASSED_ARB);
#endif

   glColorMask(1, 1, 1, 1);
   glDepthMask(GL_TRUE);

   /* Note: disable depth test here so that we'll always see the orange
    * box, except when it's totally culled.
    */
   glDisable(GL_DEPTH_TEST);

   glBeginConditionalRenderNV(OccQuery, GL_QUERY_WAIT_NV);
      /* 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();
   glEndConditionalRenderNV();

   /* always draw white outline around orange box */
   glColor3f(1.0, 1.0, 1.0);
   glBegin(GL_LINE_LOOP);
      glVertex3f(-1, -1, 0);
      glVertex3f( 1, -1, 0);
      glVertex3f( 1,  1, 0);
       glVertex3f(-1,  1, 0);
   glEnd();

   glPopMatrix();

   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:
      glDeleteQueriesARB(1, &OccQuery);
      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;
   (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 )
{
   if (!glutExtensionSupported("GL_ARB_occlusion_query") ||
       !glutExtensionSupported("GL_NV_conditional_render")) {
      printf("Sorry, this demo requires the extensions:\n");
      printf("  GL_ARB_occlusion_query\n");
      printf("  GL_NV_conditional_render\n");
      exit(-1);
   }

   glGenQueriesARB(1, &OccQuery);
   assert(OccQuery > 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 );
   glutIdleFunc( Idle );
   glutDisplayFunc( Display );
   Init();
   glutMainLoop();
   return 0;
}