gl_light.c

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/*
Copyright (C) 1997-2001 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 the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
*/
// r_light.c
 
#include "gl_local.h"
 
int r_dlightframecount;
 
#define DLIGHT_CUTOFF   64
 
/*
=============================================================================
 
DYNAMIC LIGHTS BLEND RENDERING
 
=============================================================================
*/
 
void R_RenderDlight (dlight_t *light)
{
    int     i, j;
    float   a;
    vec3_t  v;
    float   rad;
 
    rad = light->intensity * 0.35;
 
    VectorSubtract (light->origin, r_origin, v);
#if 0
    // FIXME?
    if (VectorLength (v) < rad)
    {   // view is inside the dlight
        V_AddBlend (light->color[0], light->color[1], light->color[2], light->intensity * 0.0003, v_blend);
        return;
    }
#endif
 
    qglBegin (GL_TRIANGLE_FAN);
    qglColor3f (light->color[0]*0.2, light->color[1]*0.2, light->color[2]*0.2);
    for (i=0 ; i<3 ; i++)
        v[i] = light->origin[i] - vpn[i]*rad;
    qglVertex3fv (v);
    qglColor3f (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;
        qglVertex3fv (v);
    }
    qglEnd ();
}
 
/*
=============
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
    qglDepthMask (0);
    qglDisable (GL_TEXTURE_2D);
    qglShadeModel (GL_SMOOTH);
    qglEnable (GL_BLEND);
    qglBlendFunc (GL_ONE, GL_ONE);
 
    l = r_newrefdef.dlights;
    for (i=0 ; i<r_newrefdef.num_dlights ; i++, l++)
        R_RenderDlight (l);
 
    qglColor3f (1,1,1);
    qglDisable (GL_BLEND);
    qglEnable (GL_TEXTURE_2D);
    qglBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    qglDepthMask (1);
}
 
 
/*
=============================================================================
 
DYNAMIC LIGHTS
 
=============================================================================
*/
 
/*
=============
R_MarkLights
=============
*/
void R_MarkLights (dlight_t *light, int bit, mnode_t *node)
{
    cplane_t    *splitplane;
    float       dist;
    msurface_t  *surf;
    int         i;
    
    if (node->contents != -1)
        return;
 
    splitplane = node->plane;
    dist = DotProduct (light->origin, splitplane->normal) - splitplane->dist;
    
    if (dist > light->intensity-DLIGHT_CUTOFF)
    {
        R_MarkLights (light, bit, node->children[0]);
        return;
    }
    if (dist < -light->intensity+DLIGHT_CUTOFF)
    {
        R_MarkLights (light, bit, node->children[1]);
        return;
    }
        
// mark the polygons
    surf = r_worldmodel->surfaces + node->firstsurface;
    for (i=0 ; i<node->numsurfaces ; i++, surf++)
    {
        if (surf->dlightframe != r_dlightframecount)
        {
            surf->dlightbits = 0;
            surf->dlightframe = r_dlightframecount;
        }
        surf->dlightbits |= bit;
    }
 
    R_MarkLights (light, bit, node->children[0]);
    R_MarkLights (light, bit, node->children[1]);
}
 
 
/*
=============
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 = r_newrefdef.dlights;
    for (i=0 ; i<r_newrefdef.num_dlights ; i++, l++)
        R_MarkLights ( l, 1<<i, r_worldmodel->nodes );
}
 
 
/*
=============================================================================
 
LIGHT SAMPLING
 
=============================================================================
*/
 
vec3_t          pointcolor;
cplane_t        *lightplane;        // used as shadow plane
vec3_t          lightspot;
 
int RecursiveLightPoint (mnode_t *node, vec3_t start, vec3_t end)
{
    float       front, back, frac;
    int         side;
    cplane_t    *plane;
    vec3_t      mid;
    msurface_t  *surf;
    int         s, t, ds, dt;
    int         i;
    mtexinfo_t  *tex;
    byte        *lightmap;
    int         maps;
    int         r;
 
    if (node->contents != -1)
        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 = r_worldmodel->surfaces + node->firstsurface;
    for (i=0 ; i<node->numsurfaces ; i++, surf++)
    {
        if (surf->flags&(SURF_DRAWTURB|SURF_DRAWSKY)) 
            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;
        VectorCopy (vec3_origin, pointcolor);
        if (lightmap)
        {
            vec3_t scale;
 
            lightmap += 3*(dt * ((surf->extents[0]>>4)+1) + ds);
 
            for (maps = 0 ; maps < MAXLIGHTMAPS && surf->styles[maps] != 255 ;
                    maps++)
            {
                for (i=0 ; i<3 ; i++)
                    scale[i] = gl_modulate->value*r_newrefdef.lightstyles[surf->styles[maps]].rgb[i];
 
                pointcolor[0] += lightmap[0] * scale[0] * (1.0/255);
                pointcolor[1] += lightmap[1] * scale[1] * (1.0/255);
                pointcolor[2] += lightmap[2] * scale[2] * (1.0/255);
                lightmap += 3*((surf->extents[0]>>4)+1) *
                        ((surf->extents[1]>>4)+1);
            }
        }
        
        return 1;
    }
 
// go down back side
    return RecursiveLightPoint (node->children[!side], mid, end);
}
 
/*
===============
R_LightPoint
===============
*/
void R_LightPoint (vec3_t p, vec3_t color)
{
    vec3_t      end;
    float       r;
    int         lnum;
    dlight_t    *dl;
    float       light;
    vec3_t      dist;
    float       add;
    
    if (!r_worldmodel->lightdata)
    {
        color[0] = color[1] = color[2] = 1.0;
        return;
    }
    
    end[0] = p[0];
    end[1] = p[1];
    end[2] = p[2] - 2048;
    
    r = RecursiveLightPoint (r_worldmodel->nodes, p, end);
    
    if (r == -1)
    {
        VectorCopy (vec3_origin, color);
    }
    else
    {
        VectorCopy (pointcolor, color);
    }
 
    //
    // add dynamic lights
    //
    light = 0;
    dl = r_newrefdef.dlights;
    for (lnum=0 ; lnum<r_newrefdef.num_dlights ; lnum++, dl++)
    {
        VectorSubtract (currententity->origin,
                        dl->origin,
                        dist);
        add = dl->intensity - VectorLength(dist);
        add *= (1.0/256);
        if (add > 0)
        {
            VectorMA (color, add, dl->color, color);
        }
    }
 
    VectorScale (color, gl_modulate->value, color);
}
 
 
//===================================================================
 
static float s_blocklights[34*34*3];
/*
===============
R_AddDynamicLights
===============
*/
void R_AddDynamicLights (msurface_t *surf)
{
    int         lnum;
    int         sd, td;
    float       fdist, frad, fminlight;
    vec3_t      impact, local;
    int         s, t;
    int         i;
    int         smax, tmax;
    mtexinfo_t  *tex;
    dlight_t    *dl;
    float       *pfBL;
    float       fsacc, ftacc;
 
    smax = (surf->extents[0]>>4)+1;
    tmax = (surf->extents[1]>>4)+1;
    tex = surf->texinfo;
 
    for (lnum=0 ; lnum<r_newrefdef.num_dlights ; lnum++)
    {
        if ( !(surf->dlightbits & (1<<lnum) ) )
            continue;       // not lit by this light
 
        dl = &r_newrefdef.dlights[lnum];
        frad = dl->intensity;
        fdist = DotProduct (dl->origin, surf->plane->normal) -
                surf->plane->dist;
        frad -= fabs(fdist);
        // rad is now the highest intensity on the plane
 
        fminlight = DLIGHT_CUTOFF;  // FIXME: make configurable?
        if (frad < fminlight)
            continue;
        fminlight = frad - fminlight;
 
        for (i=0 ; i<3 ; i++)
        {
            impact[i] = dl->origin[i] -
                    surf->plane->normal[i]*fdist;
        }
 
        local[0] = DotProduct (impact, tex->vecs[0]) + tex->vecs[0][3] - surf->texturemins[0];
        local[1] = DotProduct (impact, tex->vecs[1]) + tex->vecs[1][3] - surf->texturemins[1];
 
        pfBL = s_blocklights;
        for (t = 0, ftacc = 0 ; t<tmax ; t++, ftacc += 16)
        {
            td = local[1] - ftacc;
            if ( td < 0 )
                td = -td;
 
            for ( s=0, fsacc = 0 ; s<smax ; s++, fsacc += 16, pfBL += 3)
            {
                sd = Q_ftol( local[0] - fsacc );
 
                if ( sd < 0 )
                    sd = -sd;
 
                if (sd > td)
                    fdist = sd + (td>>1);
                else
                    fdist = td + (sd>>1);
 
                if ( fdist < fminlight )
                {
                    pfBL[0] += ( frad - fdist ) * dl->color[0];
                    pfBL[1] += ( frad - fdist ) * dl->color[1];
                    pfBL[2] += ( frad - fdist ) * dl->color[2];
                }
            }
        }
    }
}
 
 
/*
** R_SetCacheState
*/
void R_SetCacheState( msurface_t *surf )
{
    int maps;
 
    for (maps = 0 ; maps < MAXLIGHTMAPS && surf->styles[maps] != 255 ;
         maps++)
    {
        surf->cached_light[maps] = r_newrefdef.lightstyles[surf->styles[maps]].white;
    }
}
 
/*
===============
R_BuildLightMap
 
Combine and scale multiple lightmaps into the floating format in blocklights
===============
*/
void R_BuildLightMap (msurface_t *surf, byte *dest, int stride)
{
    int         smax, tmax;
    int         r, g, b, a, max;
    int         i, j, size;
    byte        *lightmap;
    float       scale[4];
    int         nummaps;
    float       *bl;
    lightstyle_t    *style;
    int monolightmap;
 
    if ( surf->texinfo->flags & (SURF_SKY|SURF_TRANS33|SURF_TRANS66|SURF_WARP) )
        ri.Sys_Error (ERR_DROP, "R_BuildLightMap called for non-lit surface");
 
    smax = (surf->extents[0]>>4)+1;
    tmax = (surf->extents[1]>>4)+1;
    size = smax*tmax;
    if (size > (sizeof(s_blocklights)>>4) )
        ri.Sys_Error (ERR_DROP, "Bad s_blocklights size");
 
// set to full bright if no light data
    if (!surf->samples)
    {
        int maps;
 
        for (i=0 ; i<size*3 ; i++)
            s_blocklights[i] = 255;
        for (maps = 0 ; maps < MAXLIGHTMAPS && surf->styles[maps] != 255 ;
             maps++)
        {
            style = &r_newrefdef.lightstyles[surf->styles[maps]];
        }
        goto store;
    }
 
    // count the # of maps
    for ( nummaps = 0 ; nummaps < MAXLIGHTMAPS && surf->styles[nummaps] != 255 ;
         nummaps++)
        ;
 
    lightmap = surf->samples;
 
    // add all the lightmaps
    if ( nummaps == 1 )
    {
        int maps;
 
        for (maps = 0 ; maps < MAXLIGHTMAPS && surf->styles[maps] != 255 ;
             maps++)
        {
            bl = s_blocklights;
 
            for (i=0 ; i<3 ; i++)
                scale[i] = gl_modulate->value*r_newrefdef.lightstyles[surf->styles[maps]].rgb[i];
 
            if ( scale[0] == 1.0F &&
                 scale[1] == 1.0F &&
                 scale[2] == 1.0F )
            {
                for (i=0 ; i<size ; i++, bl+=3)
                {
                    bl[0] = lightmap[i*3+0];
                    bl[1] = lightmap[i*3+1];
                    bl[2] = lightmap[i*3+2];
                }
            }
            else
            {
                for (i=0 ; i<size ; i++, bl+=3)
                {
                    bl[0] = lightmap[i*3+0] * scale[0];
                    bl[1] = lightmap[i*3+1] * scale[1];
                    bl[2] = lightmap[i*3+2] * scale[2];
                }
            }
            lightmap += size*3;     // skip to next lightmap
        }
    }
    else
    {
        int maps;
 
        memset( s_blocklights, 0, sizeof( s_blocklights[0] ) * size * 3 );
 
        for (maps = 0 ; maps < MAXLIGHTMAPS && surf->styles[maps] != 255 ;
             maps++)
        {
            bl = s_blocklights;
 
            for (i=0 ; i<3 ; i++)
                scale[i] = gl_modulate->value*r_newrefdef.lightstyles[surf->styles[maps]].rgb[i];
 
            if ( scale[0] == 1.0F &&
                 scale[1] == 1.0F &&
                 scale[2] == 1.0F )
            {
                for (i=0 ; i<size ; i++, bl+=3 )
                {
                    bl[0] += lightmap[i*3+0];
                    bl[1] += lightmap[i*3+1];
                    bl[2] += lightmap[i*3+2];
                }
            }
            else
            {
                for (i=0 ; i<size ; i++, bl+=3)
                {
                    bl[0] += lightmap[i*3+0] * scale[0];
                    bl[1] += lightmap[i*3+1] * scale[1];
                    bl[2] += lightmap[i*3+2] * scale[2];
                }
            }
            lightmap += size*3;     // skip to next lightmap
        }
    }
 
// add all the dynamic lights
    if (surf->dlightframe == r_framecount)
        R_AddDynamicLights (surf);
 
// put into texture format
store:
    stride -= (smax<<2);
    bl = s_blocklights;
 
    monolightmap = gl_monolightmap->string[0];
 
    if ( monolightmap == '0' )
    {
        for (i=0 ; i<tmax ; i++, dest += stride)
        {
            for (j=0 ; j<smax ; j++)
            {
                
                r = Q_ftol( bl[0] );
                g = Q_ftol( bl[1] );
                b = Q_ftol( bl[2] );
 
                // catch negative lights
                if (r < 0)
                    r = 0;
                if (g < 0)
                    g = 0;
                if (b < 0)
                    b = 0;
 
                /*
                ** determine the brightest of the three color components
                */
                if (r > g)
                    max = r;
                else
                    max = g;
                if (b > max)
                    max = b;
 
                /*
                ** alpha is ONLY used for the mono lightmap case.  For this reason
                ** we set it to the brightest of the color components so that 
                ** things don't get too dim.
                */
                a = max;
 
                /*
                ** rescale all the color components if the intensity of the greatest
                ** channel exceeds 1.0
                */
                if (max > 255)
                {
                    float t = 255.0F / max;
 
                    r = r*t;
                    g = g*t;
                    b = b*t;
                    a = a*t;
                }
 
                dest[0] = r;
                dest[1] = g;
                dest[2] = b;
                dest[3] = a;
 
                bl += 3;
                dest += 4;
            }
        }
    }
    else
    {
        for (i=0 ; i<tmax ; i++, dest += stride)
        {
            for (j=0 ; j<smax ; j++)
            {
                
                r = Q_ftol( bl[0] );
                g = Q_ftol( bl[1] );
                b = Q_ftol( bl[2] );
 
                // catch negative lights
                if (r < 0)
                    r = 0;
                if (g < 0)
                    g = 0;
                if (b < 0)
                    b = 0;
 
                /*
                ** determine the brightest of the three color components
                */
                if (r > g)
                    max = r;
                else
                    max = g;
                if (b > max)
                    max = b;
 
                /*
                ** alpha is ONLY used for the mono lightmap case.  For this reason
                ** we set it to the brightest of the color components so that 
                ** things don't get too dim.
                */
                a = max;
 
                /*
                ** rescale all the color components if the intensity of the greatest
                ** channel exceeds 1.0
                */
                if (max > 255)
                {
                    float t = 255.0F / max;
 
                    r = r*t;
                    g = g*t;
                    b = b*t;
                    a = a*t;
                }
 
                /*
                ** So if we are doing alpha lightmaps we need to set the R, G, and B
                ** components to 0 and we need to set alpha to 1-alpha.
                */
                switch ( monolightmap )
                {
                case 'L':
                case 'I':
                    r = a;
                    g = b = 0;
                    break;
                case 'C':
                    // try faking colored lighting
                    a = 255 - ((r+g+b)/3);
                    r *= a/255.0;
                    g *= a/255.0;
                    b *= a/255.0;
                    break;
                case 'A':
                default:
                    r = g = b = 0;
                    a = 255 - a;
                    break;
                }
 
                dest[0] = r;
                dest[1] = g;
                dest[2] = b;
                dest[3] = a;
 
                bl += 3;
                dest += 4;
            }
        }
    }
}