8x block meshes (#13133)

Reduce the number of drawcalls by generating a mesh per 8 blocks (2x2x2). Only blocks with even coordinates (lowest bit set to 0) will get a mesh.

Note: This also removes the old 'loops' algorithm for building the draw list, because it produces visual artifacts and cannot be made compatible with the approach of having a mesh for every 8th block without hurting performance.

Co-authored-by: Jude Melton-Houghton <jwmhjwmh@gmail.com>
Co-authored-by: Lars <larsh@apache.org>
Co-authored-by: sfan5 <sfan5@live.de>

1 files changed, 30 insertions, 7 deletions

diff --git a/src/client/clientmap.cpp b/src/client/clientmap.cpp
index 34d99e07d..146531d8b 100644
--- a/src/client/clientmap.cpp
+++ b/src/client/clientmap.cpp
@@ -298,6 +298,8 @@ void ClientMap::updateDrawList()
 	blocks_to_consider.push(camera_block);
 	blocks_seen.getChunk(camera_block).getBits(camera_block) = 0x07; // mark all sides as visible
 
+	std::set<v3s16> shortlist;
+
 	// Recursively walk the space and pick mapblocks for drawing
 	while (blocks_to_consider.size() > 0) {
 
@@ -369,11 +371,13 @@ void ClientMap::updateDrawList()
 			continue;
 		}
 
-		// The block is visible, add to the draw list
-		if (mesh) {
-			// Add to set
+		// Block meshes are stored in blocks where all coordinates are even (lowest bit set to 0)
+		// Add them to the de-dup set.
+		shortlist.emplace(block_coord.X & ~1, block_coord.Y & ~1, block_coord.Z & ~1);
+		// All other blocks we can grab and add to the drawlist right away.
+		if (block && m_drawlist.emplace(block_coord, block).second) {
+			// only grab the ref if the block exists and was not in the list
 			block->refGrab();
-			m_drawlist[block_coord] = block;
 		}
 
 		// Decide which sides to traverse next or to block away
@@ -474,6 +478,16 @@ void ClientMap::updateDrawList()
 		}
 	}
 
+	g_profiler->avg("MapBlocks shortlist [#]", shortlist.size());
+
+	for (auto pos : shortlist) {
+		MapBlock * block = getBlockNoCreateNoEx(pos);
+		if (block && m_drawlist.emplace(pos, block).second) {
+			// only grab the ref if the block exists and was not in the list
+			block->refGrab();
+		}
+	}
+
 	g_profiler->avg("MapBlocks occlusion culled [#]", blocks_occlusion_culled);
 	g_profiler->avg("MapBlocks sides skipped [#]", sides_skipped);
 	g_profiler->avg("MapBlocks examined [#]", blocks_visited);
@@ -597,7 +611,11 @@ void ClientMap::renderMap(video::IVideoDriver* driver, s32 pass)
 		MapBlock *block = i.second;
 		MapBlockMesh *block_mesh = block->mesh;
 
-		// If the mesh of the block happened to get deleted, ignore it
+		// Meshes are only stored every 8-th block (where all coordinates are even),
+		// but we keep all the visible blocks in the draw list to prevent client
+		// from dropping them.
+		// On top of that, in some cases block mesh can be removed
+		// before the block is removed from the draw list.
 		if (!block_mesh)
 			continue;
 
@@ -720,7 +738,7 @@ void ClientMap::renderMap(video::IVideoDriver* driver, s32 pass)
 			material.TextureLayer[ShadowRenderer::TEXTURE_LAYER_SHADOW].Texture = nullptr;
 		}
 
-		v3f block_wpos = intToFloat(descriptor.m_pos * MAP_BLOCKSIZE, BS);
+		v3f block_wpos = intToFloat(descriptor.m_pos / 8 * 8 * MAP_BLOCKSIZE, BS);
 		m.setTranslation(block_wpos - offset);
 
 		driver->setTransform(video::ETS_WORLD, m);
@@ -1046,7 +1064,7 @@ void ClientMap::renderMapShadows(video::IVideoDriver *driver,
 			++material_swaps;
 		}
 
-		v3f block_wpos = intToFloat(descriptor.m_pos * MAP_BLOCKSIZE, BS);
+		v3f block_wpos = intToFloat(descriptor.m_pos / 8 * 8 * MAP_BLOCKSIZE, BS);
 		m.setTranslation(block_wpos - offset);
 
 		driver->setTransform(video::ETS_WORLD, m);
@@ -1133,6 +1151,11 @@ void ClientMap::updateDrawListShadow(v3f shadow_light_pos, v3f shadow_light_dir,
 	g_profiler->avg("SHADOW MapBlocks loaded [#]", blocks_loaded);
 }
 
+void ClientMap::reportMetrics(u64 save_time_us, u32 saved_blocks, u32 all_blocks)
+{
+	g_profiler->avg("CM::reportMetrics loaded blocks [#]", all_blocks);
+}
+
 void ClientMap::updateTransparentMeshBuffers()
 {
 	ScopeProfiler sp(g_profiler, "CM::updateTransparentMeshBuffers", SPT_AVG);