// r_light.c

#include "quakedef.h"

int	r_dlightframecount;


//==========================================================================
//
// R_AnimateLight
//
//==========================================================================

void R_AnimateLight(void)
{
	int i;
	int v;
	int c;
	int defaultLocus;
	int locusHz[3];

	defaultLocus = locusHz[0] = (int)(cl.time*10);
	locusHz[1] = (int)(cl.time*20);
	locusHz[2] = (int)(cl.time*30);
	for(i = 0; i < MAX_LIGHTSTYLES; i++)
	{
		if(!cl_lightstyle[i].length)
		{ // No style def
			d_lightstylevalue[i] = 256;
			continue;
		}
		c = cl_lightstyle[i].map[0];
		if(c == '1' || c == '2' || c == '3')
		{ // Explicit anim rate
			if(cl_lightstyle[i].length == 1)
			{ // Bad style def
				d_lightstylevalue[i] = 256;
				continue;
			}
			v = locusHz[c-'1']%(cl_lightstyle[i].length-1);
			d_lightstylevalue[i] = (cl_lightstyle[i].map[v+1]-'a')*22;
			continue;
		}
		// Default anim rate (10 Hz)
		v = defaultLocus%cl_lightstyle[i].length;
		d_lightstylevalue[i] = (cl_lightstyle[i].map[v]-'a')*22;
	}
}

/*
=============================================================================

DYNAMIC LIGHTS BLEND RENDERING

=============================================================================
*/

void AddLightBlend (float r, float g, float b, float a2)
{
	float	a;

	v_blend[3] = a = v_blend[3] + a2*(1-v_blend[3]);

	a2 = a2/a;

	v_blend[0] = v_blend[1]*(1-a2) + r*a2;
	v_blend[1] = v_blend[1]*(1-a2) + g*a2;
	v_blend[2] = v_blend[2]*(1-a2) + b*a2;
}

void R_RenderDlight (dlight_t *light)
{
	int		i, j;
	float	a;
	vec3_t	v;
	float	rad;
    vec3_t	vp2;    //dave - slight fix

	rad = light->radius * 0.35;

	VectorSubtract (light->origin, r_origin, v);
	if (Length (v) < rad)
	{	// view is inside the dlight
		AddLightBlend (1, 0.5, 0, light->radius * 0.0003);
		return;
	}

    VectorSubtract (light->origin, r_origin, vp2);
	VectorNormalize(vp2);

	glBegin (GL_TRIANGLE_FAN);
	
    // CDL - epca@powerup.com.au
    if (light->color[0] || light->color[1] || light->color[2])
        glColor3f (light->color[0], light->color[1], light->color[2]);
    else
        glColor3f (0.2,0.1,0.0);
    // CDL
     
	// for (i=0 ; i<3 ; i++)
	//	  v[i] = light->origin[i] - vpn[i]*rad;
    for (i=0 ; i<3 ; i++) 
        v[i]=light->origin[i] - vp2[i]*rad;

	glVertex3fv (v);
	glColor3f (0,0,0);
	for (i=16 ; i>=0 ; i--)
	{
		a = i/16.0 * M_PI*2;
		for (j=0 ; j<3 ; j++)
			v[j] = light->origin[j] + vright[j]*cos(a)*rad
				+ vup[j]*sin(a)*rad;
		glVertex3fv (v);
	}
	glEnd ();
}

/*
=============
R_RenderDlights
=============
*/
void R_RenderDlights (void)
{
	int		i;
	dlight_t	*l;

	if (!gl_flashblend.value)
		return;

	r_dlightframecount = r_framecount + 1;	// because the count hasn't
											//  advanced yet for this frame
	// NATAS - BramBo - Disable drawing fog on lights - looks better
    if (gl_fogenable.value == 1) 
        {
        glDisable(GL_FOG);
        }

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

	l = cl_dlights;
	for (i=0 ; i<MAX_DLIGHTS ; i++, l++)
	{
		if (l->die < cl.time || !l->radius)
			continue;
		R_RenderDlight (l);
	}

	glColor3f (1,1,1);
	glDisable (GL_BLEND);
	glEnable (GL_TEXTURE_2D);
	glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glDepthMask (1);
    
    // NATAS - BramBo - re-enable fog again
    if (gl_fogenable.value == 1) 
        {
        glEnable(GL_FOG);
        }
}


/*
=============================================================================

DYNAMIC LIGHTS

=============================================================================
*/

/*
=============
R_MarkLights
=============
*/

void R_MarkLights (dlight_t *light, int bit, mnode_t *node)
{
	mplane_t	*splitplane;
	float		dist;
	msurface_t	*surf;
	int			i;
	float		l, maxdist;
	int			j, s, t;
	vec3_t		impact;
loc0:
	
	if (node->contents <0) 
        return; 
    splitplane=node->plane; 
    
    
    if (splitplane->type <3) 
        dist=light->origin[splitplane->type] - splitplane->dist;
	else
		dist = DotProduct (light->origin, splitplane->normal) - splitplane->dist; 
    
	if (dist > light->radius)
	{
		node = node->children[0];
		goto loc0;
	}
	if (dist <-light->radius)
	{
		node = node->children[1];
		goto loc0;
	}

	maxdist = light->radius*light->radius; 
	surf = cl.worldmodel->surfaces + node->firstsurface;
	for (i=0 ; i<node->numsurfaces ; i++, surf++)
	    {
		/* LordHavoc: original code
		if (surf->dlightframe != r_dlightframecount)
		{
			surf->dlightbits = 0;
			surf->dlightframe = r_dlightframecount;
		}
		surf->dlightbits |= bit;
		*/
		// LordHavoc: MAJOR dynamic light speedup here, eliminates marking of surfaces that are too far away from light, thus preventing unnecessary renders and uploads
		
        for (j=0 ; j<3 ; j++) impact[j]=light->origin[j] - surf->plane->normal[j]*dist;
		// clamp center of light to corner and check brightness
		
        l = DotProduct (impact, surf->texinfo->vecs[0]) + surf->texinfo->vecs[0][3] - surf->texturemins[0];
		s = l+0.5;
        if (s <0) 
            s=0;
        else 
            if (s> surf->extents[0]) 
                s = surf->extents[0];
		s = l - s;
		
        l = DotProduct (impact, surf->texinfo->vecs[1]) + surf->texinfo->vecs[1][3] - surf->texturemins[1];
		t = l+0.5;
        if (t <0) 
            t=0;
        else 
            if (t> surf->extents[1]) 
                t = surf->extents[1];
		t = l - t;
		
        // compare to minimum light
		if ((s*s+t*t+dist*dist) <maxdist) 
            { 
            if (surf->dlightframe != r_dlightframecount) // not dynamic until now
			    {
				surf->dlightbits = bit;
				surf->dlightframe = r_dlightframecount;
			    }
			else 
                // already dynamic
				surf->dlightbits |= bit;
		    }
		
	    }

	if (node->children[0]->contents >= 0)
		R_MarkLights (light, bit, node->children[0]); // LordHavoc: original code
	if (node->children[1]->contents >= 0)
		R_MarkLights (light, bit, node->children[1]); // LordHavoc: original code
}

/*
=============
R_PushDlights
=============
*/
void R_PushDlights (void)
{
	int		i;
	dlight_t	*l;

	if (gl_flashblend.value)
		return;

	r_dlightframecount = r_framecount + 1;	// because the count hasn't
											//  advanced yet for this frame
	l = cl_dlights;

	for (i=0 ; i<MAX_DLIGHTS ; i++, l++)
	{
		if (l->die < cl.time || !l->radius)
			continue;
		R_MarkLights ( l, 1<<i, cl.worldmodel->nodes );
	}
}


/*
=============================================================================

LIGHT SAMPLING

=============================================================================
*/

mplane_t		*lightplane;
vec3_t			lightspot;

int RecursiveLightPoint (mnode_t *node, vec3_t start, vec3_t end)
{
	int			r;
	float		front, back, frac;
	int			side;
	mplane_t	*plane;
	vec3_t		mid;
	msurface_t	*surf;
	int			s, t, ds, dt;
	int			i;
	mtexinfo_t	*tex;
	byte		*lightmap;
	unsigned	scale;
	int			maps;

	if (node->contents < 0)
		return -1;		// didn't hit anything
	
// calculate mid point

// FIXME: optimize for axial
	plane = node->plane;
	front = DotProduct (start, plane->normal) - plane->dist;
	back = DotProduct (end, plane->normal) - plane->dist;
	side = front < 0;
	
	if ( (back < 0) == side)
		return RecursiveLightPoint (node->children[side], start, end);
	
	frac = front / (front-back);
	mid[0] = start[0] + (end[0] - start[0])*frac;
	mid[1] = start[1] + (end[1] - start[1])*frac;
	mid[2] = start[2] + (end[2] - start[2])*frac;
	
// go down front side	
	r = RecursiveLightPoint (node->children[side], start, mid);
	if (r >= 0)
		return r;		// hit something
		
	if ( (back < 0) == side )
		return -1;		// didn't hit anuthing
		
// check for impact on this node
	VectorCopy (mid, lightspot);
	lightplane = plane;

	surf = cl.worldmodel->surfaces + node->firstsurface;
	for (i=0 ; i<node->numsurfaces ; i++, surf++)
	{
		if (surf->flags & SURF_DRAWTILED)
			continue;	// no lightmaps

		tex = surf->texinfo;
		
		s = DotProduct (mid, tex->vecs[0]) + tex->vecs[0][3];
		t = DotProduct (mid, tex->vecs[1]) + tex->vecs[1][3];;

		if (s < surf->texturemins[0] ||
		t < surf->texturemins[1])
			continue;
		
		ds = s - surf->texturemins[0];
		dt = t - surf->texturemins[1];
		
		if ( ds > surf->extents[0] || dt > surf->extents[1] )
			continue;

		if (!surf->samples)
			return 0;

		ds >>= 4;
		dt >>= 4;

		lightmap = surf->samples;
		r = 0;
		if (lightmap)
		{

			lightmap += dt * ((surf->extents[0]>>4)+1) + ds;

			for (maps = 0 ; maps < MAXLIGHTMAPS && surf->styles[maps] != 255 ;maps++)
			{
				scale = d_lightstylevalue[surf->styles[maps]];
				r += *lightmap * scale;
				lightmap += ((surf->extents[0]>>4)+1) *
						((surf->extents[1]>>4)+1);
			}
			
			r >>= 8;
		}
		
		return r;
	}

// go down back side
	return RecursiveLightPoint (node->children[!side], mid, end);
}

int R_LightPoint (vec3_t p)
{
	vec3_t		end;
	int			r;
	
	if (!cl.worldmodel->lightdata)
		return 255;
	
	end[0] = p[0];
	end[1] = p[1];
	end[2] = p[2] - 2048;
	
	r = RecursiveLightPoint (cl.worldmodel->nodes, p, end);
	
	if (r == -1)
		r = 0;

	return r;
}

// rgba lightmaps
static int      myr[4];

int *RecursiveLightPointColour (mnode_t *node, vec3_t start, vec3_t end)
{
    int         *r = myr;
    float       front, back, frac;
    int         side;
    mplane_t    *plane;
    vec3_t      mid;
    msurface_t  *surf;
    int         s, t, ds, dt;
    int         i;
    mtexinfo_t  *tex;
    byte        *lightmap;
    int         maps;
    int         smax,tmax;    

    r[0] = 0; r[1] = 0; r[2] = 0; r[3] = 0;
 
    if (node->contents < 0)
    {
        // didn't hit anything
        r[3] = -1;
        return r;
    }
 
    // calculate mid point
    // FIXME: optimize for axial
    plane = node->plane;
    front = DotProduct (start, plane->normal) - plane->dist;
    back = DotProduct (end, plane->normal) - plane->dist;
    side = front < 0;
    
    if ( (back < 0) == side)
        return RecursiveLightPointColour (node->children[side], start, end);
    
    frac = front / (front-back);
    mid[0] = start[0] + (end[0] - start[0])*frac;
    mid[1] = start[1] + (end[1] - start[1])*frac;
    mid[2] = start[2] + (end[2] - start[2])*frac;
 
    // go down front side   
    r = RecursiveLightPointColour (node->children[side], start, mid);

    if (r[3] >= 0)
        return r;       // hit something
 
    if ( (back < 0) == side )
    {
        // didn't hit anything
        r[3] = -1;
        return r;
    }
 
    // check for impact on this node
    VectorCopy (mid, lightspot);
    lightplane = plane;
 
    surf = cl.worldmodel->surfaces + node->firstsurface;

    smax = (surf->extents[0]>>4)+1;
	tmax = (surf->extents[1]>>4)+1;

    for (i=0 ; i<node->numsurfaces ; i++, surf++)
    {
        if (surf->flags & SURF_DRAWTILED)
            continue;   // no lightmaps
 
        tex = surf->texinfo;
        
        s = DotProduct (mid, tex->vecs[0]) + tex->vecs[0][3];
        t = DotProduct (mid, tex->vecs[1]) + tex->vecs[1][3];;
 
        if (s < surf->texturemins[0] || t < surf->texturemins[1])
            continue;
        
        ds = s - surf->texturemins[0];
        dt = t - surf->texturemins[1];
        
        if ( ds > surf->extents[0] || dt > surf->extents[1] )
            continue;
 
        if (!surf->samples)
            return r;
 
        lightmap = surf->samples;
        
        if (lightmap)
			{
				// LordHavoc: enhanced to interpolate lighting
				int line3, 
                dsfrac = ds & 15, 
                dtfrac = dt & 15, 
                r00 = 0, 
                g00 = 0, 
                b00 = 0,
                r01 = 0, g01 = 0, b01 = 0, r10 = 0, g10 = 0, b10 = 0, r11 = 0, g11 = 0, b11 = 0;
				float scale;
				line3 = smax*3;
				
                ds >>= 4;
                dt >>= 4;

                lightmap += (dt * smax + ds)*3; // LordHavoc: *3 for color
				
                for (maps = 0;maps < MAXLIGHTMAPS && surf->styles[maps] != 255;maps++)
				{
					scale = (float) d_lightstylevalue[surf->styles[maps]] * 1.0 / 256.0;
					r00 += (float) lightmap[0] * scale;
                    g00 += (float) lightmap[1] * scale;
                    b00 += (float) lightmap[2] * scale;

					r01 += (float) lightmap[3] * scale;
                    g01 += (float) lightmap[4] * scale;
                    b01 += (float) lightmap[5] * scale;

					r10 += (float) lightmap[line3+0] * scale;
                    g10 += (float) lightmap[line3+1] * scale;
                    b10 += (float) lightmap[line3+2] * scale;
					
                    r11 += (float) lightmap[line3+3] * scale;
                    g11 += (float) lightmap[line3+4] * scale;
                    b11 += (float) lightmap[line3+5] * scale;
					
                    lightmap += smax * tmax *3; // LordHavoc: *3 for colored lighting
				}
				r[0] +=  ((int) ((((((((r11-r10) * dsfrac) >> 4) + r10)-((((r01-r00) * dsfrac) >> 4) + r00)) * dtfrac) >> 4) + ((((r01-r00) * dsfrac) >> 4) + r00)));
				r[1] +=  ((int) ((((((((g11-g10) * dsfrac) >> 4) + g10)-((((g01-g00) * dsfrac) >> 4) + g00)) * dtfrac) >> 4) + ((((g01-g00) * dsfrac) >> 4) + g00)));
				r[2] +=  ((int) ((((((((b11-b10) * dsfrac) >> 4) + b10)-((((b01-b00) * dsfrac) >> 4) + b00)) * dtfrac) >> 4) + ((((b01-b00) * dsfrac) >> 4) + b00)));
			    r[3] = 255; 
            }
		return r; // success
    }
    // go down back side
    return RecursiveLightPointColour (node->children[!side], mid, end);
}


int* R_LightPointColour (vec3_t p)
{
    vec3_t      end;
    int         *r = myr;
    
    if (!cl.worldmodel->lightdata)
    {
        r[0] = 255; r[1] = 255; r[2] = 255; r[3] = 0;
        return r;
    }
 
    end[0] = p[0];
    end[1] = p[1];
    end[2] = p[2] - 2048;
 
    r = RecursiveLightPointColour (cl.worldmodel->nodes, p, end);
 
    if (r[3] == -1)
        r[3] = 0;
 
    return r;
}
 