revision 2

[carveJwlIkooP6JGAAIwe30JlM.git] / world_gen.c

/*
 * Copyright (C) 2021-2023 Mt.ZERO Software, Harry Godden - All Rights Reserved
 *
 * World generation/population. Different to regular loading, since it needs to
 * create geometry, apply procedural stuff and save that image to files etc.
 */
#include "world.h"
#include "world_gen.h"
#include "world_load.h"
#include "world_volumes.h"
#include "world_gate.h"

/*
 * Add all triangles from the model, which match the material ID
 * applies affine transform to the model
 */
static void world_add_all_if_material( m4x3f transform, scene_context *scene, 
                                          mdl_context *mdl, u32 id )
{
   for( u32 i=0; i<mdl_arrcount(&mdl->meshs); i++ ){
      mdl_mesh *mesh = mdl_arritm( &mdl->meshs, i );

      for( u32 j=0; j<mesh->submesh_count; j++ ){
         mdl_submesh *sm = mdl_arritm( &mdl->submeshs, mesh->submesh_start+j );
         if( sm->material_id == id ){
            m4x3f transform2;
            mdl_transform_m4x3( &mesh->transform, transform2 );
            m4x3_mul( transform, transform2, transform2 );

            scene_add_mdl_submesh( scene, mdl, sm, transform2 );
         }
      }
   }
}

/*
 * Adds a small blob shape to the world at a raycast location. This is for the
 * grass sprites
 *
 *   /''''\
 *  /      \
 * |        |
 * |________|
 */
static void world_gen_add_blob( vg_rand *rand, world_instance *world,
                                   scene_context *scene, ray_hit *hit )
{
   m4x3f transform;
   v4f qsurface, qrandom;
   v3f axis;

   v3_cross( (v3f){0.0f,1.0f,0.0f}, hit->normal, axis );

   float angle = v3_dot(hit->normal,(v3f){0.0f,1.0f,0.0f});
   q_axis_angle( qsurface, axis, angle );
   q_axis_angle( qrandom, (v3f){0.0f,1.0f,0.0f}, vg_randf64(rand)*VG_TAUf );
   q_mul( qsurface, qrandom, qsurface );
   q_m3x3( qsurface, transform );
   v3_copy( hit->pos, transform[3] );

   scene_vert verts[] = 
   {
      { .co = { -1.00f, 0.0f, 0.0f } },
      { .co = {  1.00f, 0.0f, 0.0f } },
      { .co = { -1.00f, 1.2f, 0.0f } },
      { .co = {  1.00f, 1.2f, 0.0f } },
      { .co = { -0.25f, 2.0f, 0.0f } },
      { .co = {  0.25f, 2.0f, 0.0f } }
   };

   const u32 indices[] = { 0,1,3, 0,3,2, 2,3,5, 2,5,4 };

   if( scene->vertex_count + vg_list_size(verts) > scene->max_vertices )
      vg_fatal_error( "Scene vertex buffer overflow" );

   if( scene->indice_count + vg_list_size(indices) > scene->max_indices )
      vg_fatal_error( "Scene index buffer overflow" );

   scene_vert *dst_verts = &scene->arrvertices[ scene->vertex_count ];
   u32 *dst_indices      = &scene->arrindices [ scene->indice_count ];

   scene_vert *ref       = &world->scene_geo.arrvertices[ hit->tri[0] ];

   for( u32 i=0; i<vg_list_size(verts); i++ ){
      scene_vert *pvert = &dst_verts[ i ],
                 *src   = &verts[ i ];

      m4x3_mulv( transform, src->co, pvert->co );
      scene_vert_pack_norm( pvert, transform[1], 0.0f );

      v2_copy( ref->uv, pvert->uv );
   }

   for( u32 i=0; i<vg_list_size(indices); i++ )
      dst_indices[i] = indices[i] + scene->vertex_count;

   scene->vertex_count += vg_list_size(verts);
   scene->indice_count += vg_list_size(indices);
}

/* 
 * Sprinkle foliage models over the map on terrain material 
 */
static void world_apply_procedural_foliage( world_instance *world,
                                               scene_context *scene,
                                               struct world_surface *mat )
{
   if( (vg.quality_profile == k_quality_profile_low) ||
       (vg.quality_profile == k_quality_profile_min) )
      return;

   vg_info( "Applying foliage (%u)\n", mat->info.pstr_name );

   v3f volume;
   v3_sub( world->scene_geo.bbx[1], world->scene_geo.bbx[0], volume );
   volume[1] = 1.0f;

   int count = 0;

   float area = volume[0]*volume[2];
   u32 particles = 0.08f * area;

   vg_info( "Map area: %f. Max particles: %u\n", area, particles );

   u64 t0 = SDL_GetPerformanceCounter();
#if 0
   for( u32 i=0; i<particles; i++ ){
      v3f pos;
      v3_mul( volume, (v3f){ vg_randf64(), 1000.0f, vg_randf64() }, pos );
      pos[1] = 1000.0f;
      v3_add( pos, world->scene_geo.bbx[0], pos );
      
      ray_hit hit;
      hit.dist = INFINITY;

      if( ray_world( world, pos, (v3f){0.0f,-1.0f,0.0f}, &hit, 
                     k_material_flag_ghosts )){
         struct world_surface *m1 = ray_hit_surface( world, &hit );
         if((hit.normal[1] > 0.8f) && (m1 == mat) && (hit.pos[1] > 0.0f+10.0f)){
            world_gen_add_blob( world, scene, &hit );
            count ++;
         }
      }
   }
#else

   vg_rand rand;
   vg_rand_seed( &rand, 3030 );
   
   const f32 tile_scale = 16.0f;
   v2i tiles = { volume[0]/tile_scale, volume[2]/tile_scale };

   u32 per_tile = particles/(tiles[0]*tiles[1]);

   for( i32 x=0; x<tiles[0]; x ++ ){
      for( i32 z=0; z<tiles[1]; z ++ ){
         for( u32 i=0; i<per_tile; i ++ ){
            v3f co = { (f32)x+vg_randf64(&rand), 0, (f32)z+vg_randf64(&rand) };
            v3_muls( co, tile_scale, co );
            co[1] = 1000.0f;
            v3_add( co, world->scene_geo.bbx[0], co );

            ray_hit hit;
            hit.dist = INFINITY;

            if( ray_world( world, co, (v3f){0.0f,-1.0f,0.0f}, &hit, 
                           k_material_flag_ghosts )){
               struct world_surface *m1 = ray_hit_surface( world, &hit );
               if((hit.normal[1] > 0.8f) && (m1 == mat) &&
                  (hit.pos[1] > 0.0f+10.0f)){
                  world_gen_add_blob( &rand, world, scene, &hit );
                  count ++;
               }
            }

         }
      }
   }

#endif



   u64 t1 = SDL_GetPerformanceCounter(),
       utime_blobs = t1-t0,
       ufreq = SDL_GetPerformanceFrequency();
   f64 ftime_blobs = ((f64)utime_blobs / (f64)ufreq)*1000.0;

   vg_info( "%d foliage models added. %f%% (%fms)\n", count, 
            100.0*((f64)count/(f64)particles), ftime_blobs);
}

static 
void world_unpack_submesh_dynamic( world_instance *world,
                                   scene_context *scene, mdl_submesh *sm ){
   if( sm->flags & k_submesh_flag_consumed ) return;

   m4x3f identity;
   m4x3_identity( identity );
   scene_add_mdl_submesh( scene, &world->meta, sm, identity );

   scene_copy_slice( scene, sm );
   sm->flags |= k_submesh_flag_consumed;
}

/*
 * Create the main meshes for the world
 */
static void world_gen_generate_meshes( world_instance *world ){
   /* 
    * Compile meshes into the world scenes
    */
   scene_init( &world->scene_geo, 320000, 1200000 );
   u32 buf_size = scene_mem_required( &world->scene_geo );
   u8 *buffer = vg_linear_alloc( world->heap, buf_size );
   scene_supply_buffer( &world->scene_geo, buffer );

   m4x3f midentity;
   m4x3_identity( midentity );

   /*
    * Generate scene: collidable geometry
    * ----------------------------------------------------------------
    */

   vg_info( "Generating collidable geometry\n" );
   
   for( u32 i=0; i<world->surface_count; i++ ){
      struct world_surface *surf = &world->surfaces[ i ];

      if( surf->info.flags & k_material_flag_collision )
         world_add_all_if_material( midentity, &world->scene_geo, 
                                    &world->meta, i );

      scene_copy_slice( &world->scene_geo, &surf->sm_geo );
      scene_set_vertex_flags( &world->scene_geo, 
                              surf->sm_geo.vertex_start,
                              surf->sm_geo.vertex_count, 
                              (u16)(surf->info.flags & 0xffff) );
   }

   /* compress that bad boy */
   u32 new_vert_max = world->scene_geo.vertex_count,
       new_vert_size = vg_align8(new_vert_max*sizeof(scene_vert)),
       new_indice_len = world->scene_geo.indice_count*sizeof(u32);

   u32 *src_indices = world->scene_geo.arrindices,
       *dst_indices = (u32 *)(buffer + new_vert_size);

   memmove( dst_indices, src_indices, new_indice_len );

   world->scene_geo.max_indices = world->scene_geo.indice_count;
   world->scene_geo.max_vertices = world->scene_geo.vertex_count;
   buf_size = scene_mem_required( &world->scene_geo );

   buffer = vg_linear_resize( world->heap, buffer, buf_size );

   world->scene_geo.arrvertices = (scene_vert *)(buffer);
   world->scene_geo.arrindices = (u32 *)(buffer + new_vert_size);

   scene_upload_async( &world->scene_geo, &world->mesh_geo );

   /* need send off the memory to the gpu before we can create the bvh. */
   vg_async_stall();
   vg_info( "creating bvh\n" );
   world->geo_bh = scene_bh_create( world->heap, &world->scene_geo );

   /*
    * Generate scene: non-collidable geometry
    * ----------------------------------------------------------------
    */
   vg_info( "Generating non-collidable geometry\n" );

   vg_async_item *call = scene_alloc_async( &world->scene_no_collide,
                                            &world->mesh_no_collide,
                                            250000, 500000 );

   for( u32 i=0; i<world->surface_count; i++ ){
      struct world_surface *surf = &world->surfaces[ i ];

      if( !(surf->info.flags & k_material_flag_collision) ){
         world_add_all_if_material( midentity, 
                                    &world->scene_no_collide, &world->meta, i );
      }

      if( surf->info.flags & k_material_flag_grow_grass ){
         world_apply_procedural_foliage( world, &world->scene_no_collide, 
                                         surf );
      }

      scene_copy_slice( &world->scene_no_collide, &surf->sm_no_collide );
   }

   /* unpack traffic models.. TODO: should we just put all these submeshes in a
    * dynamic models list? and then the actual entitities point to the 
    * models. we only have 2 types at the moment which need dynamic models but
    * would make sense to do this when/if we have more.
    */
   for( u32 i=0; i<mdl_arrcount( &world->ent_traffic ); i++ ){
      ent_traffic *vehc = mdl_arritm( &world->ent_traffic, i );

      for( u32 j=0; j<vehc->submesh_count; j++ ){
         mdl_submesh *sm = mdl_arritm( &world->meta.submeshs, 
                                       vehc->submesh_start+j );
         world_unpack_submesh_dynamic( world, &world->scene_no_collide, sm );
         world->surfaces[ sm->material_id ].flags |= WORLD_SURFACE_HAS_TRAFFIC;
      }
   }

   /* unpack challenge models */
   for( u32 i=0; i<mdl_arrcount( &world->ent_objective ); i++ ){
      ent_objective *objective = mdl_arritm( &world->ent_objective, i );

      for( u32 j=0; j<objective->submesh_count; j ++ ){
         mdl_submesh *sm = mdl_arritm( &world->meta.submeshs, 
                                       objective->submesh_start+j );
         world_unpack_submesh_dynamic( world, &world->scene_no_collide, sm );
      }
   }

   /* unpack region models */
   for( u32 i=0; i<mdl_arrcount( &world->ent_region ); i++ ){
      ent_region *region = mdl_arritm( &world->ent_region, i );

      for( u32 j=0; j<region->submesh_count; j ++ ){
         mdl_submesh *sm = mdl_arritm( &world->meta.submeshs, 
                                       region->submesh_start+j );
         world_unpack_submesh_dynamic( world, &world->scene_no_collide, sm );
      }
   }

   /* unpack gate models */
   for( u32 i=0; i<mdl_arrcount( &world->ent_gate ); i++ ){
      ent_gate *gate = mdl_arritm( &world->ent_gate, i );

      if( !(gate->flags & k_ent_gate_custom_mesh) ) continue;

      for( u32 j=0; j<gate->submesh_count; j ++ ){
         mdl_submesh *sm = mdl_arritm( &world->meta.submeshs, 
                                       gate->submesh_start+j );
         world_unpack_submesh_dynamic( world, &world->scene_no_collide, sm );
      }
   }

   /* unpack prop models */
   for( u32 i=0; i<mdl_arrcount( &world->ent_prop ); i++ ){
      ent_prop *prop = mdl_arritm( &world->ent_prop, i );

      for( u32 j=0; j<prop->submesh_count; j ++ ){
         mdl_submesh *sm = mdl_arritm( &world->meta.submeshs, 
                                       prop->submesh_start+j );
         world->surfaces[ sm->material_id ].flags |= WORLD_SURFACE_HAS_PROPS;
         world_unpack_submesh_dynamic( world, &world->scene_no_collide, sm );
      }
   }

   vg_async_dispatch( call, async_scene_upload );
}

/* signed distance function for cone */
static f32 fsd_cone_infinite( v3f p, v2f c ){
   v2f q = { v2_length( (v2f){ p[0], p[2] } ), -p[1] };
   float s = vg_maxf( 0.0f, v2_dot( q, c ) );

   v2f v0;
   v2_muls( c, s, v0 );
   v2_sub( q, v0, v0 );

   float d = v2_length( v0 );
   return d * ((q[0]*c[1]-q[1]*c[0]<0.0f)?-1.0f:1.0f);
}

struct light_indices_upload_info{
   world_instance *world;
   v3i count;

   void *data;
};

/*
 * Async reciever to buffer light index data 
 */
static void async_upload_light_indices( void *payload, u32 size ){
   struct light_indices_upload_info *info = payload;

   glGenTextures( 1, &info->world->tex_light_cubes );
   glBindTexture( GL_TEXTURE_3D, info->world->tex_light_cubes );
   glTexImage3D( GL_TEXTURE_3D, 0, GL_RG32UI,
                 info->count[0], info->count[1], info->count[2],
                 0, GL_RG_INTEGER, GL_UNSIGNED_INT, info->data );
   glTexParameteri( GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
   glTexParameteri( GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
}

/*
 * Computes light indices for world
 */
static void world_gen_compute_light_indices( world_instance *world ){
   /* light cubes */
   v3f cubes_min, cubes_max;
   v3_muls( world->scene_geo.bbx[0], 1.0f/k_world_light_cube_size, cubes_min );
   v3_muls( world->scene_geo.bbx[1], 1.0f/k_world_light_cube_size, cubes_max );

   v3_sub( cubes_min, (v3f){ 0.5f, 0.5f, 0.5f }, cubes_min );
   v3_add( cubes_max, (v3f){ 0.5f, 0.5f, 0.5f }, cubes_max );

   v3_floor( cubes_min, cubes_min );
   v3_floor( cubes_max, cubes_max );

   v3i icubes_min, icubes_max;

   for( int i=0; i<3; i++ ){
      icubes_min[i] = cubes_min[i];
      icubes_max[i] = cubes_max[i];
   }

   v3f cube_size;

   v3i icubes_count;
   v3i_sub( icubes_max, icubes_min, icubes_count );
   
   for( int i=0; i<3; i++ ){
      int clamped_count = VG_MIN( 128, icubes_count[i]+1 );
      float clamped_max = icubes_min[i] + clamped_count,
                    max = icubes_min[i] + icubes_count[i]+1;

      icubes_count[i] = clamped_count;
      cube_size[i] = (max / clamped_max) * k_world_light_cube_size;
      cubes_max[i] = clamped_max;
   }

   v3_mul( cubes_min, cube_size, cubes_min );
   v3_mul( cubes_max, cube_size, cubes_max );

   for( int i=0; i<3; i++ ){
      float range = cubes_max[i]-cubes_min[i];
      world->ub_lighting.g_cube_inv_range[i] = 1.0f / range;
      world->ub_lighting.g_cube_inv_range[i] *= (float)icubes_count[i];

      vg_info( "cubes[%d]: %d\n", i, icubes_count[i] );
   }

   int total_cubes = icubes_count[0]*icubes_count[1]*icubes_count[2];

   u32 data_size = vg_align8(total_cubes*sizeof(u32)*2),
       hdr_size  = vg_align8(sizeof(struct light_indices_upload_info));

   vg_async_item *call = vg_async_alloc( data_size + hdr_size );
   struct light_indices_upload_info *info = call->payload;
   info->data = ((u8*)call->payload) + hdr_size;
   info->world = world;
   u32 *cubes_index = info->data;

   for( int i=0; i<3; i++ )
      info->count[i] = icubes_count[i];
                                       
   vg_info( "Computing light cubes (%d) [%f %f %f] -> [%f %f %f]\n", 
             total_cubes, cubes_min[0], -cubes_min[2], cubes_min[1],
                          cubes_max[0], -cubes_max[2], cubes_max[1] );
   v3_copy( cubes_min, world->ub_lighting.g_cube_min );

   float bound_radius = v3_length( cube_size );

   for( int iz = 0; iz<icubes_count[2]; iz ++ ){
      for( int iy = 0; iy<icubes_count[1]; iy++ ){
         for( int ix = 0; ix<icubes_count[0]; ix++ ){
            boxf bbx;
            v3_div( (v3f){ ix, iy, iz }, world->ub_lighting.g_cube_inv_range, 
                  bbx[0] );
            v3_div( (v3f){ ix+1, iy+1, iz+1 }, 
                  world->ub_lighting.g_cube_inv_range, 
                  bbx[1] );

            v3_add( bbx[0], world->ub_lighting.g_cube_min, bbx[0] );
            v3_add( bbx[1], world->ub_lighting.g_cube_min, bbx[1] );

            v3f center;
            v3_add( bbx[0], bbx[1], center );
            v3_muls( center, 0.5f, center );
            
            u32 indices[6] = { 0, 0, 0, 0, 0, 0 };
            u32 count = 0;

            float influences[6] = { 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
            const int N = vg_list_size( influences );

            for( u32 j=0; j<mdl_arrcount(&world->ent_light); j ++ ){
               ent_light *light = mdl_arritm( &world->ent_light, j );
               v3f closest;
               closest_point_aabb( light->transform.co, bbx, closest );

               f32 dist2 = v3_dist2( closest, light->transform.co );

               if( dist2 > light->range*light->range )
                  continue;

               f32 dist = sqrtf(dist2),
                   influence = 1.0f/(dist+1.0f);

               if( light->type == k_light_type_spot){
                  v3f local;
                  m4x3_mulv( light->inverse_world, center, local );

                  float r = fsd_cone_infinite( local, light->angle_sin_cos );

                  if( r > bound_radius )
                     continue;
               }

               int best_pos = N;
               for( int k=best_pos-1; k>=0; k -- )
                  if( influence > influences[k] )
                     best_pos = k;

               if( best_pos < N ){
                  for( int k=N-1; k>best_pos; k -- ){
                     influences[k] = influences[k-1];
                     indices[k] = indices[k-1];
                  }

                  influences[best_pos] = influence;
                  indices[best_pos] = j;
               }
            }

            for( int j=0; j<N; j++ )
               if( influences[j] > 0.0f )
                  count ++;

            int base_index = iz * (icubes_count[0]*icubes_count[1]) +
                             iy * (icubes_count[0]) +
                             ix;

            int lower_count = VG_MIN( 3, count );
            u32 packed_index_lower = lower_count;
            packed_index_lower |= indices[0]<<2;
            packed_index_lower |= indices[1]<<12;
            packed_index_lower |= indices[2]<<22;

            int upper_count = VG_MAX( 0, count - lower_count );
            u32 packed_index_upper = upper_count;
            packed_index_upper |= indices[3]<<2;
            packed_index_upper |= indices[4]<<12;
            packed_index_upper |= indices[5]<<22;

            cubes_index[ base_index*2 + 0 ] = packed_index_lower;
            cubes_index[ base_index*2 + 1 ] = packed_index_upper;
         }
      }
   }

   vg_async_dispatch( call, async_upload_light_indices );
}

/*
 * Rendering pass needed to complete the world
 */
static void async_world_postprocess( void *payload, u32 _size ){
   /* create scene lighting buffer */
   world_instance *world = payload;

   u32 size = VG_MAX(mdl_arrcount(&world->ent_light),1) * sizeof(float)*12;
   vg_info( "Upload %ubytes (lighting)\n", size );

   glGenBuffers( 1, &world->tbo_light_entities );
   glBindBuffer( GL_TEXTURE_BUFFER, world->tbo_light_entities );
   glBufferData( GL_TEXTURE_BUFFER, size, NULL, GL_DYNAMIC_DRAW );
   
   /* buffer layout
    *  
    *  colour               position                direction (spots)
    * | .   .   .   .     | .   .   .   .         | .   .   .   .  |
    * | Re  Ge  Be  Night | Xco Yco Zco Range     | Dx  Dy  Dz  Da |
    *
    */

   v4f *light_dst = glMapBuffer( GL_TEXTURE_BUFFER, GL_WRITE_ONLY );
   for( u32 i=0; i<mdl_arrcount(&world->ent_light); i++ ){
      ent_light *light = mdl_arritm( &world->ent_light, i );

      /* colour  + night */
      v3_muls( light->colour, light->colour[3] * 2.0f, light_dst[i*3+0] );
      light_dst[i*3+0][3] = 2.0f;

      if( !light->daytime ){
         u32 hash = (i * 29986577u) & 0xffu;
         float switch_on = hash;
               switch_on *= (1.0f/255.0f);

         light_dst[i*3+0][3] = 0.44f + switch_on * 0.015f;
      }
      
      /* position + 1/range^2 */
      v3_copy( light->transform.co, light_dst[i*3+1] );
      light_dst[i*3+1][3] = 1.0f/(light->range*light->range);

      /* direction + angle */
      q_mulv( light->transform.q, (v3f){0.0f,-1.0f,0.0f}, light_dst[i*3+2]);
      light_dst[i*3+2][3] = cosf( light->angle );
   }

   glUnmapBuffer( GL_TEXTURE_BUFFER );

   glGenTextures( 1, &world->tex_light_entities );
   glBindTexture( GL_TEXTURE_BUFFER, world->tex_light_entities );
   glTexBuffer( GL_TEXTURE_BUFFER, GL_RGBA32F, world->tbo_light_entities );

   /* Upload lighting uniform buffer */
   if( world->water.enabled )
      v4_copy( world->water.plane, world->ub_lighting.g_water_plane );

   v4f info_vec;
   v3f *bounds = world->scene_geo.bbx;

   info_vec[0] = bounds[0][0];
   info_vec[1] = bounds[0][2];
   info_vec[2] = 1.0f/ (bounds[1][0]-bounds[0][0]);
   info_vec[3] = 1.0f/ (bounds[1][2]-bounds[0][2]);
   v4_copy( info_vec, world->ub_lighting.g_depth_bounds );

   /* 
    * Rendering the depth map
    */
   vg_camera ortho;

   v3f extent;
   v3_sub( world->scene_geo.bbx[1], world->scene_geo.bbx[0], extent );

   float fl = world->scene_geo.bbx[0][0],
         fr = world->scene_geo.bbx[1][0],
         fb = world->scene_geo.bbx[0][2],
         ft = world->scene_geo.bbx[1][2],
         rl = 1.0f / (fr-fl),
         tb = 1.0f / (ft-fb);

   m4x4_zero( ortho.mtx.p );
   ortho.mtx.p[0][0] = 2.0f * rl;
   ortho.mtx.p[2][1] = 2.0f * tb;
   ortho.mtx.p[3][0] = (fr + fl) * -rl;
   ortho.mtx.p[3][1] = (ft + fb) * -tb;
   ortho.mtx.p[3][3] = 1.0f;
   m4x3_identity( ortho.transform );
   vg_camera_update_view( &ortho );
   vg_camera_finalize( &ortho );

   glDisable(GL_DEPTH_TEST);
   glDisable(GL_BLEND);
   glDisable(GL_CULL_FACE);
   render_fb_bind( &world->heightmap, 0 );
   shader_blitcolour_use();
   shader_blitcolour_uColour( (v4f){-9999.0f,-9999.0f,-9999.0f,-9999.0f} );
   render_fsquad();

   glEnable(GL_BLEND);
   glBlendFunc(GL_ONE, GL_ONE);
   glBlendEquation(GL_MAX);

   render_world_position( world, &ortho );
   glDisable(GL_BLEND);
   glEnable(GL_DEPTH_TEST);
   glBindFramebuffer( GL_FRAMEBUFFER, 0 );

   /* upload full buffer */
   glBindBuffer( GL_UNIFORM_BUFFER, world->ubo_lighting );
   glBufferSubData( GL_UNIFORM_BUFFER, 0, 
                    sizeof(struct ub_world_lighting), &world->ub_lighting );

   /*
    * Allocate cubemaps
    */
   for( u32 i=0; i<mdl_arrcount(&world->ent_cubemap); i++ ){
      ent_cubemap *cm = mdl_arritm(&world->ent_cubemap,i);

      glGenTextures( 1, &cm->texture_id );
      glBindTexture( GL_TEXTURE_CUBE_MAP, cm->texture_id );
      glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
                glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
                glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
                glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
                glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

                for( u32 j=0; j<6; j ++ ) {
                        glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_X + j, 0, GL_RGB, 
                        WORLD_CUBEMAP_RES, WORLD_CUBEMAP_RES, 
                        0, GL_RGB, GL_UNSIGNED_BYTE, NULL );
                }

                glGenFramebuffers( 1, &cm->framebuffer_id );
                glBindFramebuffer( GL_FRAMEBUFFER, cm->framebuffer_id );
                glGenRenderbuffers(1, &cm->renderbuffer_id );
                glBindRenderbuffer( GL_RENDERBUFFER, cm->renderbuffer_id );
                glRenderbufferStorage( GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, 
                              WORLD_CUBEMAP_RES, WORLD_CUBEMAP_RES );

                glFramebufferTexture2D( GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                        GL_TEXTURE_CUBE_MAP_POSITIVE_X, cm->texture_id, 0 );
                glFramebufferRenderbuffer( GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, 
                                 GL_RENDERBUFFER, cm->renderbuffer_id );

                glFramebufferTexture2D( GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, 
         GL_TEXTURE_CUBE_MAP_POSITIVE_X, cm->texture_id, 0 );

                if( glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE ){
         vg_error( "Cubemap framebuffer incomplete.\n" );
      }
   }

   glBindFramebuffer( GL_FRAMEBUFFER, 0 );
}

/* Loads textures from the pack file */
static void world_gen_load_surfaces( world_instance *world ){
   vg_info( "Loading textures\n" );
   world->texture_count = 0;

   world->texture_count = world->meta.textures.count+1;
   world->textures = vg_linear_alloc( world->heap,
                              vg_align8(sizeof(GLuint)*world->texture_count) );
   world->textures[0] = vg.tex_missing;

   for( u32 i=0; i<mdl_arrcount(&world->meta.textures); i++ ){
      mdl_texture *tex = mdl_arritm( &world->meta.textures, i );

      if( !tex->file.pack_size ){
         vg_fatal_error( "World models must have packed textures!" );
      }

      vg_linear_clear( vg_mem.scratch );
      void *src_data = vg_linear_alloc( vg_mem.scratch, 
                                        tex->file.pack_size );
      mdl_fread_pack_file( &world->meta, &tex->file, src_data );

      vg_tex2d_load_qoi_async( src_data, tex->file.pack_size,
                               VG_TEX2D_NEAREST|VG_TEX2D_REPEAT,
                               &world->textures[i+1] );
   }

   vg_info( "Loading materials\n" );

   world->surface_count = world->meta.materials.count+1;
   world->surfaces = vg_linear_alloc( world->heap,
               vg_align8(sizeof(struct world_surface)*world->surface_count) );

   /* error material */
   struct world_surface *errmat = &world->surfaces[0];
   memset( errmat, 0, sizeof(struct world_surface) );
                       
   for( u32 i=0; i<mdl_arrcount(&world->meta.materials); i++ ){
      struct world_surface *surf = &world->surfaces[i+1];
      surf->info = *(mdl_material *)mdl_arritm( &world->meta.materials, i );
      surf->flags = 0;
   }
}