84     extvol *xvol;  in newextvol()  local
89     xvol = (extvol *)rt_getmem(sizeof(extvol));  in newextvol()
90     memset(xvol, 0, sizeof(extvol));  in newextvol()
92     xvol->methods = &extvol_methods;  in newextvol()
94     xvol->min = min;  in newextvol()
95     xvol->max = max;  in newextvol()
96     xvol->evaluator = evaluator;  in newextvol()
97     xvol->ambient = tex->ambient;  in newextvol()
98     xvol->diffuse = tex->diffuse;  in newextvol()
99     xvol->opacity = tex->opacity;  in newextvol()
100     xvol->samples = samples;  in newextvol()
102     xvol->tex = (texture *)rt_getmem(sizeof(texture));  in newextvol()
103     memset(xvol->tex, 0, sizeof(texture));  in newextvol()
105     xvol->tex->ctr.x = 0.0;  in newextvol()
106     xvol->tex->ctr.y = 0.0;  in newextvol()
107     xvol->tex->ctr.z = 0.0;  in newextvol()
108     xvol->tex->rot = xvol->tex->ctr;  in newextvol()
109     xvol->tex->scale = xvol->tex->ctr;  in newextvol()
110     xvol->tex->uaxs = xvol->tex->ctr;  in newextvol()
111     xvol->tex->vaxs = xvol->tex->ctr;  in newextvol()
112     xvol->tex->islight = 0;  in newextvol()
113     xvol->tex->shadowcast = 0;  in newextvol()
115     xvol->tex->col = tex->col;  in newextvol()
116     xvol->tex->ambient = 1.0;  in newextvol()
117     xvol->tex->diffuse = 0.0;  in newextvol()
118     xvol->tex->specular = 0.0;  in newextvol()
119     xvol->tex->opacity = 1.0;  in newextvol()
120     xvol->tex->img = nullptr;  in newextvol()
121     xvol->tex->texfunc = (color(*)(void *, void *, void *))(ext_volume_texture);  in newextvol()
122     xvol->tex->obj = (void *)xvol; /* XXX hack! */  in newextvol()
124     return xvol;  in newextvol()
152     extvol *xvol;  in ext_volume_texture()  local
169     xvol = (extvol *)tex->obj;  in ext_volume_texture()
243     tdist = xvol->samples;  in ext_volume_texture()
245     tt = (xvol->opacity / tdist);  in ext_volume_texture()
262             scalar = xvol->evaluator(pnt.x, pnt.y, pnt.z);  in ext_volume_texture()
269             col.r += transval * col2.r * xvol->ambient;  in ext_volume_texture()
270             col.g += transval * col2.g * xvol->ambient;  in ext_volume_texture()
271             col.b += transval * col2.b * xvol->ambient;  in ext_volume_texture()
276             if (xvol->diffuse > 0.0) {  in ext_volume_texture()
278                 N.x = (xvol->evaluator(pnt.x - ddt, pnt.y, pnt.z) -  in ext_volume_texture()
279                        xvol->evaluator(pnt.x + ddt, pnt.y, pnt.z)) *  in ext_volume_texture()
282                 N.y = (xvol->evaluator(pnt.x, pnt.y - ddt, pnt.z) -  in ext_volume_texture()
283                        xvol->evaluator(pnt.x, pnt.y + ddt, pnt.z)) *  in ext_volume_texture()
286                 N.z = (xvol->evaluator(pnt.x, pnt.y, pnt.z - ddt) -  in ext_volume_texture()
287                        xvol->evaluator(pnt.x, pnt.y, pnt.z + ddt)) *  in ext_volume_texture()
311                     col.r += col2.r * diffint.r * xvol->diffuse;  in ext_volume_texture()
312                     col.g += col2.g * diffint.g * xvol->diffuse;  in ext_volume_texture()
313                     col.b += col2.b * diffint.b * xvol->diffuse;  in ext_volume_texture()