+VG_STATIC
+struct world_surface *world_tri_index_surface( world_instance *world,
+ u32 index );
+
+VG_STATIC f64 world_routes_scatter_surface_points( world_instance *world,
+ pointcloud_buffer *pcbuf,
+ f32 rate )
+{
+ 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 );
+
+ while( accum > rate ){
+ accum -= rate;
+
+ if( pcbuf->count >= pcbuf->max ) return total_area;
+
+ v2f co = { vg_randf64(), vg_randf64() };
+ if( v2_length2(co) > 0.5f ){
+ co[0] = 1.0f-co[0];
+ co[1] = 1.0f-co[1];
+ }
+
+ v3f pt;
+ v3_muls( v0, co[0], pt );
+ v3_muladds( pt, v1, co[1], pt );
+ v3_add( va->co, pt, pt );
+
+ if( pt[1] < world->water.height ) continue;
+ pointcloud_vert *vert = &pcbuf->buf[ pcbuf->count ++ ];
+
+ v3f pos;
+ v3_sub( pt, pcbuf->boundary[0], pos );
+ v3_mul( pos, inv_ext, pos );
+
+ for( u32 i=0; i<3; i++ ){
+ vert->pos[i] = (pos[i]-0.5f) * 32767.0f;
+ }
+
+ static v4f colours[] = {
+ [k_surface_prop_concrete] = { 0.13, 0.15, 0.17, 1.0 },
+ [k_surface_prop_grass] = { 0.07, 0.1, 0.14, 1.0 },
+ [k_surface_prop_metal] = { 0.15, 0.19, 0.22, 1.0 },
+ [k_surface_prop_wood] = { 0.1, 0.13, 0.17, 1.0 },
+ [k_surface_prop_tiles] = { 0.05, 0.06, 0.07, 1.0 },
+ };
+
+ v4f col = {0.0f,0.0f,0.0f,0.0f};
+ if( surf->info.surface_prop < vg_list_size(colours) ){
+ v4_copy( colours[surf->info.surface_prop], col );
+ }
+
+ f32 brightness = v3_dot(vn,light_dir)*0.5f+0.5f;
+ v3_muls( col, brightness, col );
+
+ for( u32 j=0; j<4; j++ ){
+ vert->colour[j] = col[j] * 255.0f;
+ }
+ }
+ }
+
+ return total_area;
+}
+
+VG_STATIC void world_routes_surface_grid( world_instance *world,
+ pointcloud_buffer *pcbuf )
+{
+ i32 const k_gridlines = 32,
+ k_gridres = 255;
+
+ 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 );
+ v4f colour = {0.2f,0.2f,0.2f,1.0f};
+ v3f dir = {0.0f,-1.0f,0.0f};
+
+ for( u32 k=0; k<2; k++ ){
+ u32 a = k*2,
+ b = (k^0x1)*2;
+
+ for( i32 x=0; x<=k_gridlines; x++ ){
+ f32 t = (float)x / (float)k_gridlines,
+ px = vg_lerpf( pcbuf->boundary[0][a], pcbuf->boundary[1][a], t );
+
+ for( i32 z=0; z<=k_gridres; z++ ){
+ f32 tz = (float)z / (float)k_gridres,
+ pz = vg_lerpf(pcbuf->boundary[0][b],pcbuf->boundary[1][b], tz);
+
+ v3f ro, hit;
+ ro[a] = px;
+ ro[1] = 1000.0f;
+ ro[b] = pz;
+
+ bh_iter it;
+ bh_iter_init_ray( 0, &it, ro, dir, INFINITY );
+ i32 idx;
+
+ while( bh_next( world->geo_bh, &it, &idx ) ){
+ u32 *tri = &world->scene_geo.arrindices[ idx*3 ];
+ v3f vs[3];
+
+ for( u32 i=0; i<3; i++ ){
+ v3_copy( world->scene_geo.arrvertices[tri[i]].co, vs[i] );
+ }
+
+ f32 t;
+ if( ray_tri( vs, ro, dir, &t ) ){
+ v3_muladds( ro, dir, t, hit );
+ struct world_surface *m1 =
+ world_tri_index_surface( world, tri[0] );
+
+ if( !(m1->info.flags & k_material_flag_preview_visibile) )
+ continue;
+
+ if( world->water.enabled )
+ if( hit[1] < world->water.height )
+ continue;
+
+ if( pcbuf->count >= pcbuf->max ) return;
+
+ pointcloud_vert *vert = &pcbuf->buf[ pcbuf->count ++ ];
+
+ v3f co;
+ v3_sub( hit, pcbuf->boundary[0], co );
+ v3_mul( co, inv_ext, co );
+
+ for( u32 i=0; i<3; i++ ){
+ vert->pos[i] = (co[i]-0.5f) * 32767.0f;
+ }
+
+ for( u32 i=0; i<4; i++ ){
+ vert->colour[i] = colour[i] * 255.0f;
+ }
+ }
+ }
+ }
+ }
+ }
+}
+