glparticlesystem/main.cpp

/*
 * A particle system using triangles and textured particles
 * you can also switch between textured triangles and colored points
 * and you can change the emitter's position/direction.
 *
 * The actual action goes on in particle.h, but I figured main.cpp is where
 * most folks would start reading. This isn't a complete system; I had intended
 * to implement textured particles, but I didn't get that implemented by my 6 am deadline.
 * I'm going to go ahead and leave in the code for textured polys/quads (which
 * does nothing right now) because I intend to implement that in the future.
 *
 * I also haven't profiled this code, so I have no idea how efficient it is. However,
 * since this is my *first ever* attempt at a particle system, I don't think it's
 * too bad considering I churned it out in 6 hours without anyone else's code to guide me.
 * So take this as you will. :)
 *
 * Written with openGL and SDL (http://www.libsdl.org).
 *
 * Andrew Kesterson, Feb. 2005.
 *
 * NOTE: Textured polys are currently not implemented, but now that I have the particles
 * distributing around the emitter properly and fading correctly, it is *definitely* next
 * on the list.
 */
 
 
#include <stdio.h>
#include <stdlib.h>

#include "common.h"

int main( int argc, char **argv )
{
    /* Flags and stuff for the state machine and SDL */
    int videoFlags;
    int done = FALSE;
    SDL_Event event;
    const SDL_VideoInfo *videoInfo;
    int isActive = TRUE;
    GLfloat emitterColors[2][3] = {
        //{1.0, 1.0, 1.0},
		{0.0, 0.0, 0.0},
        {0.0, 0.5, 1.0}};
    Vector emitterSpeeds[2] = {
        {0.00f, 0.0001f, 0.0f},
        {0.00f, 0.005f, 0.0f}};
    Vector emitterGravities[2] = {
        {0.002f, -0.0f, 0.0f},
        {0.00f, -0.00001f, 0.00f}};
    Vector emitterPositions[2] = {
        {0.0f, 0.0f, -50.0f},
        {0.0f, -2.0f, -50.0f}};
    Vector randPositions[2] = {
        {5.7f, 5.7f, 0.0f},
        {.5f, 3.5f, .5f}
    };
    Vector randSpeeds[2] = {
        {0.001f, 0.001f, 0.0f},
        {0.000f, 0.00f, 0.000f}
    };
    Vector randGravities[2] = {
        {0.0f, 0.0f, 0.0f},
        {0.000005f, 0.0f, 0.000005f},
    };
    
    srand((long)time(NULL));
    
    PopulateEmitter(&theEmitter[0], 
                    GL_TRUE, 
                    emitterColors[0],
                    0.0001F,
                    1000, 
                    &emitterGravities[0], 
                    &emitterPositions[0], 
                    &emitterSpeeds[0],
                    &randGravities[0],
                    &randPositions[0], 
                    &randSpeeds[0], 
                    500,
                    GL_POINTS, 
                    0);
    PopulateEmitter(&theEmitter[1], 
                    GL_TRUE, 
                    emitterColors[1],
                    0.0002F,
                    5000, 
                    &emitterGravities[1], 
                    &emitterPositions[1], 
                    &emitterSpeeds[1],
                    &randGravities[1],
                    &randPositions[1], 
                    &randSpeeds[1], 
                    1400,
                    GL_POINTS, 
                    0);

    
    /* initialize SDL */
    if ( SDL_Init( SDL_INIT_VIDEO ) < 0 )
	{
	    fprintf( stderr, "Video initialization failed: %s\n",
		     SDL_GetError( ) );
	    Quit( 1 );
	}

    /* Fetch the video info */
    videoInfo = SDL_GetVideoInfo( );

    if ( !videoInfo )
	{
	    fprintf( stderr, "Video query failed: %s\n",
		     SDL_GetError( ) );
	    Quit( 1 );
	}

    /* Ask SDL for a OpenGL double buffered context with various flags. */
    videoFlags  = SDL_OPENGL;          
    videoFlags |= SDL_GL_DOUBLEBUFFER; 
    videoFlags |= SDL_HWPALETTE;       
    videoFlags |= SDL_RESIZABLE;       

    /* Can we have hardware surfaces? */
    if ( videoInfo->hw_available )
	videoFlags |= SDL_HWSURFACE;
    else
	videoFlags |= SDL_SWSURFACE;

    /* Hardware blits? */
    if ( videoInfo->blit_hw )
	videoFlags |= SDL_HWACCEL;

    SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 );

    /* get the main SDL surface */
    surface = SDL_SetVideoMode( SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP,
				videoFlags );

    if ( !surface )
	{
	    fprintf( stderr,  "Video mode set failed: %s\n", SDL_GetError( ) );
	    Quit( 1 );
	}

    if ( initGL( ) == FALSE )
	{
	    fprintf( stderr, "Could not initialize OpenGL.\n" );
	    Quit( 1 );
	}

    resizeWindow( SCREEN_WIDTH, SCREEN_HEIGHT );

    /* wait for events */
    while ( !done )
	{
	    /* handle the events in the queue, pumped by the SDL event machine */

	    while ( SDL_PollEvent( &event ) )
		{
		    switch( event.type )
			{
			case SDL_ACTIVEEVENT:
			    /* Gained or lost window focus. */
			    if ( event.active.gain == 0 )
				isActive = FALSE;
			    else
				isActive = TRUE;
			    break;
			case SDL_VIDEORESIZE:
			    /* handle resize event */
			    surface = SDL_SetVideoMode( event.resize.w,
							event.resize.h,
							16, videoFlags );
			    if ( !surface )
				{
				    fprintf( stderr, "Could not get a surface after resize: %s\n", SDL_GetError( ) );
				    Quit( 1 );
				}
			    resizeWindow( event.resize.w, event.resize.h );
			    break;
			case SDL_KEYDOWN:
			    /* handle key presses */
			    handleKeyPress( &event.key.keysym );
			    break;
			case SDL_QUIT:
			    /* handle quit requests */
			    done = TRUE;
			    break;
			default:
			    break;
			}
		}

	    /* draw the scene */
	    if ( isActive ) {
            drawGLScene( );
        }
    }

    /* clean ourselves up and exit */
    Quit( 0 );

    /* Should never even get here */
    return( 0 );
}