/*
	gl_part.c

	OpenGL particle rendering

	Copyright (C) 1996-1997  Id Software, Inc.

	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:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include "r_shared.h"
#include "r_local.h"
#include "glquake.h"
#include "server.h"
#include "console.h"

#define MAX_FIRES	128	// rocket flames
fire_t		r_fires[MAX_FIRES];

/*
===============
R_DrawParticles
===============
*/

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;

	unsigned char	*at;
	unsigned char	theAlpha;
	qboolean		alphaTestEnabled;
	qboolean		blendEnabled;

	glBindTexture (GL_TEXTURE_2D, particletexture);
	// LordHavoc: particles should not affect zbuffer
	glDepthMask (0);

	if (!(blendEnabled = glIsEnabled (GL_BLEND))) {
		glEnable (GL_BLEND);
	}
	if ((alphaTestEnabled = glIsEnabled (GL_ALPHA_TEST))) {
		glDisable (GL_ALPHA_TEST);
	}
	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 = frametime * 4;
	
	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;
		at = (byte *)&d_8to24table[(int)p->color];
		if (p->type==pt_fire)
			theAlpha = 255*(6-p->ramp)/6;
		else
			theAlpha = 255;
		if (lighthalf)
			glColor4ub((byte) ((int) at[0] >> 1), (byte) ((int) at[1] >> 1), (byte) ((int) at[2] >> 1), theAlpha);
		else
			glColor4ub(at[0], at[1], at[2], theAlpha);
		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 ();
	if (alphaTestEnabled) {
		glEnable (GL_ALPHA_TEST);
	}
	if (!blendEnabled) {
		glDisable (GL_BLEND);
	}
	glDepthMask (1);
}

/*
	R_AddFire

	Nifty ball of fire GL effect.  Kinda a meshing of the dlight and
	particle engine code.
*/
float r_firecolor_flame[3]={0.9,0.7,0.3};
float r_firecolor_light[3]={0.9,0.7,0.3};

void
R_AddFire (vec3_t start, vec3_t end, entity_t *ent)
{
	float		len;
	fire_t		*f;
	dlight_t	*dl;
	vec3_t		vec;
	int			key;

	if (!gl_fires->int_val)
		return;

	VectorSubtract (end, start, vec);
	len = VectorNormalize (vec);
	key = ent-cl_entities+1;

	if (len)
	{
		f = R_AllocFire (key);
		VectorCopy (end, f->origin);
		VectorCopy (start, f->owner);
		f->size = 20;
		f->die = cl.time + 0.5;
		f->decay = -1;
		f->color=r_firecolor_flame;

		dl = CL_AllocDlight (key);
		VectorCopy (end, dl->origin);
		dl->radius = 200;
		dl->die = cl.time + 0.5;
		dl->color=r_firecolor_light;
	}
}

/*
	R_AllocFire

	Clears out and returns a new fireball
*/
fire_t *
R_AllocFire (int key)
{
	int		i;
	fire_t		*f;
	if (key)	// first try to find/reuse a keyed spot
	{
		f = r_fires;
		for (i = 0; i < MAX_FIRES; i++, f++)
			if (f->key == key)
			{
				memset (f, 0, sizeof(*f));
				f->key = key;
				f->color = f->_color;
				return f;
			}
	}

	f = r_fires;	// no match, look for a free spot
	for (i = 0; i < MAX_FIRES; i++, f++)
	{
		if (f->die < cl.time)
		{
			memset (f, 0, sizeof(*f));
			f->key = key;
			f->color = f->_color;
			return f;
		}
	}

	f = &r_fires[0];
	memset (f, 0, sizeof(*f));
	f->key = key;
	f->color = f->_color;
	return f;	
}

/*
	R_DrawFire

	draws one fireball - probably never need to call this directly
*/
void
R_DrawFire (fire_t *f)
{
	int		i, j;
	vec3_t		vec,vec2;
	float		radius;
	float		*b_sin, *b_cos;

	b_sin = bubble_sintable;
	b_cos = bubble_costable;

	radius = f->size + 0.35;

	// figure out if we're inside the area of effect
	VectorSubtract (f->origin, r_origin, vec);
	if (Length (vec) < radius)
	{
		AddLightBlend (1, 0.5, 0, f->size * 0.0003);	// we are
		return;
	}

	// we're not - draw it
	glBegin (GL_TRIANGLE_FAN);
	if (lighthalf)
		glColor3f(f->color[0]*0.5,f->color[1]*0.5,f->color[2]*0.5);
	else
		glColor3fv(f->color);
	for (i=0 ; i<3 ; i++)
		vec[i] = f->origin[i] - vpn[i] * radius;
	glVertex3fv (vec);
	glColor3f (0.0, 0.0, 0.0);

	// don't panic, this just draws a bubble...
	for (i=16 ; i>=0 ; i--)
	{
		for (j=0 ; j<3 ; j++) {
			vec[j] = f->origin[j] + (*b_cos * vright[j]
				+ vup[j]*(*b_sin)) * radius;
			vec2[j] = f->owner[j] + (*b_cos * vright[j]
				+ vup[j]*(*b_sin)) * radius;
		}
		glVertex3fv (vec);
		glVertex3fv (vec2);

		b_sin+=2;
		b_cos+=2;
	}
	glEnd ();
}

/*
	R_UpdateFires

	Draws each fireball in sequence
*/
void
R_UpdateFires (void)
{
	int		i;
	fire_t	*f;

	if (!gl_fires->int_val)
		return;

	glDepthMask (0);
	glDisable (GL_TEXTURE_2D);
	glShadeModel (GL_SMOOTH);
	glEnable (GL_BLEND);
	glBlendFunc (GL_ONE, GL_ONE);

	f = r_fires;
	for (i = 0; i < MAX_FIRES; i++, f++)
	{
		if (f->die < cl.time || !f->size)
			continue;
		f->size += f->decay;
		R_DrawFire (f);
	}

	glColor3f (1.0, 1.0, 1.0);
	glDisable (GL_BLEND);
	glEnable (GL_TEXTURE_2D);
	glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glDepthMask (1);
}

void
R_FireColor_f (void)
{
	int i;

	if (Cmd_Argc() == 1) {
		Con_Printf ("r_firecolor %f %f %f\n",
					r_firecolor_flame[0],
					r_firecolor_flame[1],
					r_firecolor_flame[2]);
		return;
	}
	if (Cmd_Argc() == 5 || Cmd_Argc() == 6) {
		Con_Printf ("Warning: obsolete 4th and 5th parameters to r_firecolor ignored\n");
	} else if (Cmd_Argc() !=4) {
		Con_Printf ("Usage r_firecolor R G B\n");
		return;
	}
	for (i=0; i<4; i++) {
		r_firecolor_flame[i]=atof(Cmd_Argv(i+1));
		r_firecolor_light[i]=r_firecolor_flame[i];
	}
}