/*
Copyright (C) 1996-1997 Id Software, Inc.
Portions Copyright (C) 1999,2000  Nelson Rush.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "quakedef.h"
#include "glquake.h"
#include "r_local.h"
#include <mathlib.h>

extern particle_t	*active_particles, *free_particles;
extern int			ramp1[8], ramp2[8], ramp3[8];

/*
===============
R_DrawParticles
===============
*/
extern	cvar_t	sv_gravity;

void R_DrawParticles (void)
{
	particle_t		*p, *kill;
	float			grav;
	int				i;
	float			time2, time3;
	float			time1;
	float			dvel;
	float			frametime;
	
	vec3_t			up, right;
	float			scale;

    GL_Bind(particletexture);
	glEnable (GL_BLEND);
	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
	glBegin (GL_TRIANGLES);

	VectorScale (vup, 1.5, up);
	VectorScale (vright, 1.5, right);
	frametime = cl.time - cl.oldtime;
	time3 = frametime * 15;
	time2 = frametime * 10; // 15;
	time1 = frametime * 5;
	grav = frametime * sv_gravity.value * 0.05;
	dvel = 4*frametime;
	
	for ( ;; ) 
	{
		kill = active_particles;
		if (kill && kill->die < cl.time)
		{
			active_particles = kill->next;
			kill->next = free_particles;
			free_particles = kill;
			continue;
		}
		break;
	}

	for (p=active_particles ; p ; p=p->next)
	{
		for ( ;; )
		{
			kill = p->next;
			if (kill && kill->die < cl.time)
			{
				p->next = kill->next;
				kill->next = free_particles;
				free_particles = kill;
				continue;
			}
			break;
		}

		// hack a scale up to keep particles from disapearing
		scale = (p->org[0] - r_origin[0])*vpn[0] + (p->org[1] - r_origin[1])*vpn[1]
			+ (p->org[2] - r_origin[2])*vpn[2];
		if (scale < 20)
			scale = 1;
		else
			scale = 1 + scale * 0.004;
		glColor3ubv ((byte *)&d_8to24table[(int)p->color]);
		glTexCoord2f (0,0);
		glVertex3fv (p->org);
		glTexCoord2f (1,0);
		glVertex3f (p->org[0] + up[0]*scale, p->org[1] + up[1]*scale, p->org[2] + up[2]*scale);
		glTexCoord2f (0,1);
		glVertex3f (p->org[0] + right[0]*scale, p->org[1] + right[1]*scale, p->org[2] + right[2]*scale);
		p->org[0] += p->vel[0]*frametime;
		p->org[1] += p->vel[1]*frametime;
		p->org[2] += p->vel[2]*frametime;
		
		switch (p->type)
		{
		case pt_static:
			break;
		case pt_fire:
			p->ramp += time1;
			if (p->ramp >= 6)
				p->die = -1;
			else
				p->color = ramp3[(int)p->ramp];
			p->vel[2] += grav;
			break;

		case pt_explode:
			p->ramp += time2;
			if (p->ramp >=8)
				p->die = -1;
			else
				p->color = ramp1[(int)p->ramp];
			for (i=0 ; i<3 ; i++)
				p->vel[i] += p->vel[i]*dvel;
			p->vel[2] -= grav;
			break;

		case pt_explode2:
			p->ramp += time3;
			if (p->ramp >=8)
				p->die = -1;
			else
				p->color = ramp2[(int)p->ramp];
			for (i=0 ; i<3 ; i++)
				p->vel[i] -= p->vel[i]*frametime;
			p->vel[2] -= grav;
			break;

		case pt_blob:
			for (i=0 ; i<3 ; i++)
				p->vel[i] += p->vel[i]*dvel;
			p->vel[2] -= grav;
			break;

		case pt_blob2:
			for (i=0 ; i<2 ; i++)
				p->vel[i] -= p->vel[i]*dvel;
			p->vel[2] -= grav;
			break;

		case pt_grav:
#ifdef QUAKE2
			p->vel[2] -= grav * 20;
			break;
#endif
		case pt_slowgrav:
			p->vel[2] -= grav;
			break;
		}
	}

	glEnd ();
	glDisable (GL_BLEND);
	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
}