Frustrum culling for tilemap (#8935)

* Frustrum culling for tilemap.
defold · Jun 3, 2024 · 985b43d · 985b43d
1 parent cb0d7b8
commit 985b43d
Showing 1 changed file with 43 additions and 4 deletions.
diff --git a/engine/gamesys/src/gamesys/components/comp_tilegrid.cpp b/engine/gamesys/src/gamesys/components/comp_tilegrid.cpp
@@ -29,6 +29,7 @@
 #include <gameobject/gameobject.h>
 #include <gameobject/gameobject_ddf.h>
 #include <dmsdk/dlib/vmath.h>
+#include <dmsdk/dlib/intersection.h>
 
 #include "../gamesys_private.h"
 #include "../gamesys.h"
@@ -55,9 +56,9 @@ namespace dmGameSystem
     // where the the box spans TILEGRID_REGION_SIZE tiles in each direction
     struct TileGridRegion
     {
-        uint8_t m_Dirty:1;
-        uint8_t m_Occupied:1;
-        uint8_t :6;
+        uint8_t m_Dirty      : 1;
+        uint8_t m_Occupied   : 1;
+        uint8_t              : 6;
     };
 
     struct TileGridLayer
@@ -631,6 +632,44 @@ namespace dmGameSystem
         return where;
     }
 
+    static void RenderListFrustumCulling(dmRender::RenderListVisibilityParams const &params)
+    {
+        DM_PROFILE("TileGridFrustrumCulling");
+        TileGridWorld* tilegrid_world = (TileGridWorld*)params.m_UserData;
+        const dmIntersection::Frustum frustum = *params.m_Frustum;
+        uint32_t num_entries = params.m_NumEntries;
+        for (uint32_t i = 0; i < num_entries; ++i)
+        {
+            dmRender::RenderListEntry* entry = &params.m_Entries[i];
+            uint32_t index, layer, region_x, region_y;
+            //entry->m_UserData - encoded region info
+            DecodeGridAndLayer(entry->m_UserData, index, layer, region_x, region_y);
+            TileGridComponent* component = tilegrid_world->m_Components[index];
+
+            TileGridResource* resource = component->m_Resource;
+            TextureSetResource* texture_set = GetTextureSet(component);
+            int32_t tile_width = (int32_t)texture_set->m_TextureSet->m_TileWidth;
+            int32_t tile_height = (int32_t)texture_set->m_TextureSet->m_TileHeight;
+
+            int32_t column_count = (int32_t)resource->m_ColumnCount;
+            int32_t row_count = (int32_t)resource->m_RowCount;
+            int32_t min_x = resource->m_MinCellX + region_x * TILEGRID_REGION_SIZE;
+            int32_t min_y = resource->m_MinCellY + region_y * TILEGRID_REGION_SIZE;
+
+            int32_t region_max_x = min_x + TILEGRID_REGION_SIZE;
+            int32_t tilemap_max_x = resource->m_MinCellX + column_count;
+            int32_t region_max_y = min_y + TILEGRID_REGION_SIZE;
+            int32_t tilemap_max_y = resource->m_MinCellY + row_count;
+            int32_t max_x = dmMath::Min(region_max_x, tilemap_max_x);
+            int32_t max_y = dmMath::Min(region_max_y, tilemap_max_y);
+
+            dmVMath::Vector3 min_corner = dmVMath::Vector3((float)(min_x * tile_width), (float)(min_y * tile_height), 0.f);
+            dmVMath::Vector3 max_corner = dmVMath::Vector3((float)(max_x * tile_width), (float)(max_y * tile_height), 0.f);
+            bool intersect = dmIntersection::TestFrustumOBB(frustum, component->m_World, min_corner, max_corner);
+            entry->m_Visibility = intersect ? dmRender::VISIBILITY_FULL : dmRender::VISIBILITY_NONE;
+        }
+    }
+
     static void RenderBatch(TileGridWorld* world, dmRender::HRenderContext render_context, dmRender::RenderListEntry *buf, uint32_t* begin, uint32_t* end)
     {
         DM_PROFILE("TileGridRenderBatch");
@@ -779,7 +818,7 @@ namespace dmGameSystem
 
         dmRender::HRenderContext render_context = context->m_RenderContext;
         dmRender::RenderListEntry* render_list = dmRender::RenderListAlloc(render_context, num_render_entries);
-        dmRender::HRenderListDispatch dispatch = dmRender::RenderListMakeDispatch(render_context, &RenderListDispatch, world);
+        dmRender::HRenderListDispatch dispatch = dmRender::RenderListMakeDispatch(render_context, &RenderListDispatch, &RenderListFrustumCulling, world);
         dmRender::RenderListEntry* write_ptr = render_list;
 
         for (uint32_t i = 0; i < n; ++i)