Panda3D

td_light.cxx

00001 #include "zgl.h"
00002 #include <math.h>
00003 
00004 static inline PN_stdfloat clampf(PN_stdfloat a,PN_stdfloat min,PN_stdfloat max)
00005 {
00006   if (a<min) return min;
00007   else if (a>max) return max;
00008   else return a;
00009 }
00010 
00011 /* non optimized lighting model */
00012 void gl_shade_vertex(GLContext *c,GLVertex *v)
00013 {
00014   PN_stdfloat R,G,B,A;
00015   GLMaterial *m;
00016   GLLight *l;
00017   V3 n,s,d;
00018   PN_stdfloat dist,tmp,att,dot,dot_spot,dot_spec;
00019   int twoside = c->light_model_two_side;
00020 
00021   m=&c->materials[0];
00022 
00023   n.v[0]=v->normal.v[0];
00024   n.v[1]=v->normal.v[1];
00025   n.v[2]=v->normal.v[2];
00026 
00027   R=m->emission.v[0]+m->ambient.v[0]*c->ambient_light_model.v[0];
00028   G=m->emission.v[1]+m->ambient.v[1]*c->ambient_light_model.v[1];
00029   B=m->emission.v[2]+m->ambient.v[2]*c->ambient_light_model.v[2];
00030   A=clampf(m->diffuse.v[3],0,1);
00031 
00032   for(l=c->first_light;l!=NULL;l=l->next) {
00033     PN_stdfloat lR,lB,lG;
00034     
00035     /* ambient */
00036     lR=l->ambient.v[0] * m->ambient.v[0];
00037     lG=l->ambient.v[1] * m->ambient.v[1];
00038     lB=l->ambient.v[2] * m->ambient.v[2];
00039 
00040     if (l->position.v[3] == 0) {
00041       /* light at infinity */
00042       d.v[0]=l->position.v[0];
00043       d.v[1]=l->position.v[1];
00044       d.v[2]=l->position.v[2];
00045       att=1;
00046     } else {
00047       /* distance attenuation */
00048       d.v[0]=l->position.v[0]-v->ec.v[0];
00049       d.v[1]=l->position.v[1]-v->ec.v[1];
00050       d.v[2]=l->position.v[2]-v->ec.v[2];
00051       dist = sqrtf(d.v[0]*d.v[0]+d.v[1]*d.v[1]+d.v[2]*d.v[2]);
00052       if (dist>1E-3) {
00053         tmp=1/dist;
00054         d.v[0]*=tmp;
00055         d.v[1]*=tmp;
00056         d.v[2]*=tmp;
00057       }
00058       att=1.0f/(l->attenuation[0]+dist*(l->attenuation[1]+
00059                                         dist*l->attenuation[2]));
00060     }
00061     dot=d.v[0]*n.v[0]+d.v[1]*n.v[1]+d.v[2]*n.v[2];
00062     if (twoside && dot < 0) dot = -dot;
00063     if (dot>0) {
00064       /* diffuse light */
00065       lR+=dot * l->diffuse.v[0] * m->diffuse.v[0];
00066       lG+=dot * l->diffuse.v[1] * m->diffuse.v[1];
00067       lB+=dot * l->diffuse.v[2] * m->diffuse.v[2];
00068 
00069       /* spot light */
00070       if (l->spot_cutoff != 180) {
00071         dot_spot=-(d.v[0]*l->norm_spot_direction.v[0]+
00072                    d.v[1]*l->norm_spot_direction.v[1]+
00073                    d.v[2]*l->norm_spot_direction.v[2]);
00074         if (twoside && dot_spot < 0) dot_spot = -dot_spot;
00075         if (dot_spot < l->cos_spot_cutoff) {
00076           /* no contribution */
00077           continue;
00078         } else {
00079           /* TODO: optimize */
00080           if (l->spot_exponent > 0) {
00081             att=att*pow(dot_spot,l->spot_exponent);
00082           }
00083         }
00084       }
00085 
00086       /* specular light */
00087       
00088       if (c->local_light_model) {
00089         V3 vcoord;
00090         vcoord.v[0]=v->ec.v[0];
00091         vcoord.v[1]=v->ec.v[1];
00092         vcoord.v[2]=v->ec.v[2];
00093         gl_V3_Norm(&vcoord);
00094         s.v[0]=d.v[0]-vcoord.v[0];
00095         s.v[1]=d.v[1]-vcoord.v[0];
00096         s.v[2]=d.v[2]-vcoord.v[0];
00097       } else {
00098         s.v[0]=d.v[0];
00099         s.v[1]=d.v[1];
00100         s.v[2]=d.v[2]+1.0f;
00101       }
00102       dot_spec=n.v[0]*s.v[0]+n.v[1]*s.v[1]+n.v[2]*s.v[2];
00103       if (twoside && dot_spec < 0) dot_spec = -dot_spec;
00104       if (dot_spec>0) {
00105         GLSpecBuf *specbuf;
00106         int idx;
00107         tmp=sqrt(s.v[0]*s.v[0]+s.v[1]*s.v[1]+s.v[2]*s.v[2]);
00108         if (tmp > 1E-3) {
00109           dot_spec=dot_spec / tmp;
00110         }
00111       
00112         /* TODO: optimize */
00113         /* testing specular buffer code */
00114         /* dot_spec= pow(dot_spec,m->shininess);*/
00115         specbuf = specbuf_get_buffer(c, m->shininess_i, m->shininess);
00116         idx = (int)(dot_spec*SPECULAR_BUFFER_SIZE);
00117         if (idx > SPECULAR_BUFFER_SIZE) idx = SPECULAR_BUFFER_SIZE;
00118         dot_spec = specbuf->buf[idx];
00119         lR+=dot_spec * l->specular.v[0] * m->specular.v[0];
00120         lG+=dot_spec * l->specular.v[1] * m->specular.v[1];
00121         lB+=dot_spec * l->specular.v[2] * m->specular.v[2];
00122       }
00123     }
00124 
00125     R+=att * lR;
00126     G+=att * lG;
00127     B+=att * lB;
00128   }
00129 
00130   v->color.v[0]=clampf(R,0,1);
00131   v->color.v[1]=clampf(G,0,1);
00132   v->color.v[2]=clampf(B,0,1);
00133   v->color.v[3]=A;
00134 }
00135 
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