+ static f32 densities[] = {
+ [k_surface_prop_concrete] = 2.0f,
+ [k_surface_prop_grass] = 0.8f,
+ [k_surface_prop_metal] = 1.0f,
+ [k_surface_prop_wood] = 2.5f,
+ [k_surface_prop_tiles] = 4.0f
+ };
+
+ /* calculate total area */
+ f64 total_area = 0.0f;
+ for( u32 i=0; i<world->scene_geo.indice_count/3; i++ ){
+ u32 *tri = &world->scene_geo.arrindices[i*3];
+ struct world_surface *surf = world_tri_index_surface( world, tri[0] );
+
+ if( surf->info.shader == k_shader_boundary ||
+ surf->info.shader == k_shader_invisible ) continue;
+
+ if( !(surf->info.flags & k_material_flag_preview_visibile) ) continue;
+
+ scene_vert *va = &world->scene_geo.arrvertices[tri[0]],
+ *vb = &world->scene_geo.arrvertices[tri[1]],
+ *vc = &world->scene_geo.arrvertices[tri[2]];
+
+ v3f v0, v1, vn;
+ v3_sub( vb->co, va->co, v0 );
+ v3_sub( vc->co, va->co, v1 );
+ v3_cross( v0, v1, vn );
+ if( vn[1] < 0.0f ) continue;
+
+ f32 density = 1.0f;
+ if( surf->info.surface_prop < vg_list_size(densities) )
+ density = densities[surf->info.surface_prop];
+ total_area += v3_length(vn)*0.5f*density;
+ }
+
+ f32 accum = 0.0f;
+
+ u8 colour[] = { 80,80,80,255 };
+ v3f light_dir = {0.3f,0.8f,0.1f};
+ v3_normalize( light_dir );
+
+ v3f inv_ext;
+ v3_sub( pcbuf->boundary[1], pcbuf->boundary[0], inv_ext );
+ v3_div( (v3f){1.0f,1.0f,1.0f}, inv_ext, inv_ext );
+
+ for( u32 i=0; i<world->scene_geo.indice_count/3; i++ ){
+ u32 *tri = &world->scene_geo.arrindices[i*3];
+ struct world_surface *surf = world_tri_index_surface( world, tri[0] );
+
+ if( surf->info.shader == k_shader_boundary ||
+ surf->info.shader == k_shader_invisible ) continue;
+
+ if( !(surf->info.flags & k_material_flag_preview_visibile) ) continue;
+
+ scene_vert *va = &world->scene_geo.arrvertices[tri[0]],
+ *vb = &world->scene_geo.arrvertices[tri[1]],
+ *vc = &world->scene_geo.arrvertices[tri[2]];
+
+ v3f v0, v1, vn;
+ v3_sub( vb->co, va->co, v0 );
+ v3_sub( vc->co, va->co, v1 );
+ v3_cross( v0, v1, vn );
+ if( vn[1] < 0.0f ) continue;
+
+ f32 density = 1.0f;
+ if( surf->info.surface_prop < vg_list_size(densities) )
+ density = densities[surf->info.surface_prop];
+
+ f32 area = v3_length(vn)*0.5f*density;
+ accum += area;
+
+ v3_normalize( vn );