Revert avoiding air voxels contribution to texturing in Transvoxel

doc/source/changelog.md

@@ -15,6 +15,7 @@ Primarily developped with Godot 4.3.
 - Fixes
     - `VoxelInstanceLibrary`: Editor: reworked the way items are exposed as a Blender-style list. Now removing an item while the library is open as a sub-inspector is no longer problematic
     - `VoxelGeneratorGraph`: fix wrong values when using `OutputWeight` with optimized execution map enabled, when weights are determined to be locally constant
+    - `VoxelMesherTransvoxel`: revert texturing logic that attempted to prevent air voxels from contributing, but was lowering quality. It is now optional as an experimental property.
 
 - Breaking changes
     - `VoxelInstanceLibrary`: Items should no longer be accessed using generated properties (`item1`, `item2` etc). Use `get_item` instead.

meshers/transvoxel/transvoxel.cpp

@@ -186,9 +186,9 @@ struct CellTextureDatas {
 template <unsigned int NVoxels, typename WeightSampler_T>
 CellTextureDatas<NVoxels> select_textures_4_per_voxel(
 		const FixedArray<unsigned int, NVoxels> &voxel_indices,
-		Span<const uint16_t> indices_data,
+		const Span<const uint16_t> indices_data,
 		const WeightSampler_T &weights_sampler,
-		unsigned int case_code
+		const unsigned int case_code
 ) {
 	// TODO Optimization: this function takes almost half of the time when polygonizing non-empty cells.
 	// I wonder how it can be optimized further?
@@ -284,7 +284,8 @@ inline void get_cell_texture_data(
 		const TextureIndicesData &texture_indices_data,
 		const FixedArray<unsigned int, NVoxels> &voxel_indices,
 		const WeightSampler_T &weights_data,
-		unsigned int case_code
+		// Used for rejecting air voxels. Can be set to 0 so all corners are always used.
+		const unsigned int case_code
 ) {
 	if (texture_indices_data.buffer.size() == 0) {
 		// Indices are known for the whole block, just read weights directly
@@ -293,6 +294,9 @@ inline void get_cell_texture_data(
 		for (unsigned int ci = 0; ci < voxel_indices.size(); ++ci) {
 			if ((case_code & (1 << ci)) != 0) {
 				// Force air voxels to not contribute
+				// TODO This is not great, because every Transvoxel vertex interpolates between a matter and air corner.
+				// This approach means we would always interpolate towards 0 as a result.
+				// Maybe we'll have to use a different approach and remove this option in the future.
 				fill(cell_textures.weights[ci], uint8_t(0));
 			} else {
 				const unsigned int wi = voxel_indices[ci];
@@ -366,7 +370,8 @@ void build_regular_mesh(
 		MeshArrays &output,
 		const IDeepSDFSampler *deep_sdf_sampler,
 		StdVector<CellInfo> *cell_info,
-		const float edge_clamp_margin
+		const float edge_clamp_margin,
+		const bool textures_skip_air_voxels
 ) {
 	ZN_PROFILE_SCOPE();
 
@@ -492,7 +497,11 @@ void build_regular_mesh(
 				CellTextureDatas<8> cell_textures;
 				if (texturing_mode == TEXTURES_BLEND_4_OVER_16) {
 					get_cell_texture_data(
-							cell_textures, texture_indices_data, corner_data_indices, weights_sampler, case_code
+							cell_textures,
+							texture_indices_data,
+							corner_data_indices,
+							weights_sampler,
+							textures_skip_air_voxels ? case_code : 0
 					);
 					current_reuse_cell.packed_texture_indices = cell_textures.packed_indices;
 				}
@@ -919,7 +928,8 @@ void build_transition_mesh(
 		TexturingMode texturing_mode,
 		Cache &cache,
 		MeshArrays &output,
-		const float edge_clamp_margin
+		const float edge_clamp_margin,
+		const bool textures_skip_air_voxels
 ) {
 	// From this point, we expect the buffer to contain allocated data.
 	// This function has some comments as quotes from the Transvoxel paper.
@@ -1076,15 +1086,15 @@ void build_transition_mesh(
 			CellTextureDatas<13> cell_textures;
 			if (texturing_mode == TEXTURES_BLEND_4_OVER_16) {
 				// Re-making an ordered case code...
-				//                       |436785210|
-				const uint16_t alt_case_code = 0 //
-						| ((case_code & 0b000000111)) // 210
-						| ((case_code & 0b110000000) >> 4) // 43
-						| ((case_code & 0b000001000) << 2) // 5
-						| ((case_code & 0b001000000)) // 6
-						| ((case_code & 0b000100000) << 2) // 7
-						| ((case_code & 0b000010000) << 4) // 8
-						;
+				//                               |436785210|
+				const uint16_t alt_case_code = textures_skip_air_voxels ? 0 //
+								| ((case_code & 0b000000111)) // 210
+								| ((case_code & 0b110000000) >> 4) // 43
+								| ((case_code & 0b000001000) << 2) // 5
+								| ((case_code & 0b001000000)) // 6
+								| ((case_code & 0b000100000) << 2) // 7
+								| ((case_code & 0b000010000) << 4) // 8
+																		: 0;
 
 				// uint16_t alt_case_code = sign_f(cell_samples[0]);
 				// alt_case_code |= (sign_f(cell_samples[1]) << 1);
@@ -1493,7 +1503,8 @@ DefaultTextureIndicesData build_regular_mesh(
 		MeshArrays &output,
 		const IDeepSDFSampler *deep_sdf_sampler,
 		StdVector<CellInfo> *cell_infos,
-		const float edge_clamp_margin
+		const float edge_clamp_margin,
+		const bool textures_ignore_air_voxels
 ) {
 	ZN_PROFILE_SCOPE();
 	// From this point, we expect the buffer to contain allocated data in the relevant channels.
@@ -1550,7 +1561,8 @@ DefaultTextureIndicesData build_regular_mesh(
 					output,
 					deep_sdf_sampler,
 					cell_infos,
-					edge_clamp_margin
+					edge_clamp_margin,
+					textures_ignore_air_voxels
 			);
 		} break;
 
@@ -1567,7 +1579,8 @@ DefaultTextureIndicesData build_regular_mesh(
 					output,
 					deep_sdf_sampler,
 					cell_infos,
-					edge_clamp_margin
+					edge_clamp_margin,
+					textures_ignore_air_voxels
 			);
 		} break;
 
@@ -1587,7 +1600,8 @@ DefaultTextureIndicesData build_regular_mesh(
 					output,
 					deep_sdf_sampler,
 					cell_infos,
-					edge_clamp_margin
+					edge_clamp_margin,
+					textures_ignore_air_voxels
 			);
 		} break;
 
@@ -1613,7 +1627,8 @@ void build_transition_mesh(
 		Cache &cache,
 		MeshArrays &output,
 		DefaultTextureIndicesData default_texture_indices_data,
-		const float edge_clamp_margin
+		const float edge_clamp_margin,
+		const bool textures_ignore_air_voxels
 ) {
 	ZN_PROFILE_SCOPE();
 	// From this point, we expect the buffer to contain allocated data in the relevant channels.
@@ -1678,7 +1693,8 @@ void build_transition_mesh(
 					texturing_mode,
 					cache,
 					output,
-					edge_clamp_margin
+					edge_clamp_margin,
+					textures_ignore_air_voxels
 			);
 		} break;
 
@@ -1694,7 +1710,8 @@ void build_transition_mesh(
 					texturing_mode,
 					cache,
 					output,
-					edge_clamp_margin
+					edge_clamp_margin,
+					textures_ignore_air_voxels
 			);
 		} break;
 
@@ -1710,7 +1727,8 @@ void build_transition_mesh(
 					texturing_mode,
 					cache,
 					output,
-					edge_clamp_margin
+					edge_clamp_margin,
+					textures_ignore_air_voxels
 			);
 		} break;
 

meshers/transvoxel/transvoxel.h

@@ -173,7 +173,8 @@ DefaultTextureIndicesData build_regular_mesh(
 		MeshArrays &output,
 		const IDeepSDFSampler *deep_sdf_sampler,
 		StdVector<CellInfo> *cell_infos,
-		const float edge_clamp_margin
+		const float edge_clamp_margin,
+		const bool textures_ignore_air_voxels
 );
 
 void build_transition_mesh(
@@ -185,7 +186,8 @@ void build_transition_mesh(
 		Cache &cache,
 		MeshArrays &output,
 		DefaultTextureIndicesData default_texture_indices_data,
-		const float edge_clamp_margin
+		const float edge_clamp_margin,
+		const bool textures_ignore_air_voxels
 );
 
 } // namespace zylann::voxel::transvoxel

meshers/transvoxel/voxel_mesher_transvoxel.cpp

@@ -290,7 +290,8 @@ void VoxelMesherTransvoxel::build(VoxelMesher::Output &output, const VoxelMesher
 				mesh_arrays,
 				&ds,
 				cell_infos,
-				_edge_clamp_margin
+				_edge_clamp_margin,
+				_textures_ignore_air_voxels
 		);
 	} else {
 		default_texture_indices_data = transvoxel::build_regular_mesh(
@@ -302,7 +303,8 @@ void VoxelMesherTransvoxel::build(VoxelMesher::Output &output, const VoxelMesher
 				mesh_arrays,
 				nullptr,
 				cell_infos,
-				_edge_clamp_margin
+				_edge_clamp_margin,
+				_textures_ignore_air_voxels
 		);
 	}
 
@@ -350,7 +352,8 @@ void VoxelMesherTransvoxel::build(VoxelMesher::Output &output, const VoxelMesher
 					tls_cache,
 					*combined_mesh_arrays,
 					default_texture_indices_data,
-					_edge_clamp_margin
+					_edge_clamp_margin,
+					_textures_ignore_air_voxels
 			);
 		}
 	}
@@ -398,7 +401,8 @@ Ref<ArrayMesh> VoxelMesherTransvoxel::build_transition_mesh(Ref<godot::VoxelBuff
 			s_cache,
 			s_mesh_arrays,
 			default_texture_indices_data,
-			_edge_clamp_margin
+			_edge_clamp_margin,
+			_textures_ignore_air_voxels
 	);
 
 	Ref<ArrayMesh> mesh;
@@ -425,6 +429,14 @@ VoxelMesherTransvoxel::TexturingMode VoxelMesherTransvoxel::get_texturing_mode()
 	return _texture_mode;
 }
 
+void VoxelMesherTransvoxel::set_textures_ignore_air_voxels(const bool enable) {
+	_textures_ignore_air_voxels = enable;
+}
+
+bool VoxelMesherTransvoxel::get_textures_ignore_air_voxels() const {
+	return _textures_ignore_air_voxels;
+}
+
 void VoxelMesherTransvoxel::set_mesh_optimization_enabled(bool enabled) {
 	_mesh_optimization_params.enabled = enabled;
 }
@@ -485,6 +497,9 @@ void VoxelMesherTransvoxel::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_texturing_mode", "mode"), &Self::set_texturing_mode);
 	ClassDB::bind_method(D_METHOD("get_texturing_mode"), &Self::get_texturing_mode);
 
+	ClassDB::bind_method(D_METHOD("set_textures_ignore_air_voxels", "enabled"), &Self::set_textures_ignore_air_voxels);
+	ClassDB::bind_method(D_METHOD("get_textures_ignore_air_voxels"), &Self::get_textures_ignore_air_voxels);
+
 	ClassDB::bind_method(D_METHOD("set_mesh_optimization_enabled", "enabled"), &Self::set_mesh_optimization_enabled);
 	ClassDB::bind_method(D_METHOD("is_mesh_optimization_enabled"), &Self::is_mesh_optimization_enabled);
 
@@ -509,12 +524,20 @@ void VoxelMesherTransvoxel::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_edge_clamp_margin"), &Self::get_edge_clamp_margin);
 	ClassDB::bind_method(D_METHOD("set_edge_clamp_margin", "margin"), &Self::set_edge_clamp_margin);
 
+	ADD_GROUP("Materials", "");
+
 	ADD_PROPERTY(
 			PropertyInfo(Variant::INT, "texturing_mode", PROPERTY_HINT_ENUM, "None,4-blend over 16 textures (4 bits)"),
 			"set_texturing_mode",
 			"get_texturing_mode"
 	);
 
+	ADD_PROPERTY(
+			PropertyInfo(Variant::BOOL, "textures_ignore_air_voxels"),
+			"set_textures_ignore_air_voxels",
+			"get_textures_ignore_air_voxels"
+	);
+
 	ADD_GROUP("Mesh optimization", "mesh_optimization_");
 
 	ADD_PROPERTY(

meshers/transvoxel/voxel_mesher_transvoxel.h

@@ -36,6 +36,9 @@ class VoxelMesherTransvoxel : public VoxelMesher {
 	void set_texturing_mode(TexturingMode mode);
 	TexturingMode get_texturing_mode() const;
 
+	void set_textures_ignore_air_voxels(const bool enable);
+	bool get_textures_ignore_air_voxels() const;
+
 	void set_mesh_optimization_enabled(bool enabled);
 	bool is_mesh_optimization_enabled() const;
 
@@ -103,6 +106,8 @@ class VoxelMesherTransvoxel : public VoxelMesher {
 	float _edge_clamp_margin = 0.02f;
 
 	bool _transitions_enabled = true;
+
+	bool _textures_ignore_air_voxels = false;
 };
 
 } // namespace zylann::voxel