Refactor shadow map material override

src/client/clientmap.cpp

@@ -1414,7 +1414,7 @@ void ClientMap::PrintInfo(std::ostream &out)
 }
 
 void ClientMap::renderMapShadows(video::IVideoDriver *driver,
-		const video::SMaterial &material, s32 pass, int frame, int total_frames)
+		ModifyMaterialCallback cb, s32 pass, int frame, int total_frames)
 {
 	bool is_transparent_pass = pass != scene::ESNRP_SOLID;
 	std::string prefix;
@@ -1504,22 +1504,9 @@ void ClientMap::renderMapShadows(video::IVideoDriver *driver,
 
 	for (auto &descriptor : draw_order) {
 		if (!descriptor.m_reuse_material) {
-			// override some material properties
 			video::SMaterial local_material = descriptor.getMaterial();
-			// do not override culling if the original material renders both back
+			bool is_foliage = translucent_foliage && CONTAINS(leaves_material, local_material.MaterialType);
-			// and front faces in solid mode (e.g. plantlike)
+			cb(local_material, is_foliage);
-			// Transparent plants would still render shadows only from one side,
-			// but this conflicts with water which occurs much more frequently
-			if (is_transparent_pass || local_material.BackfaceCulling || local_material.FrontfaceCulling) {
-				local_material.BackfaceCulling = material.BackfaceCulling;
-				local_material.FrontfaceCulling = material.FrontfaceCulling;
-			}
-			if (translucent_foliage && CONTAINS(leaves_material, local_material.MaterialType)) {
-				local_material.BackfaceCulling = true;
-				local_material.FrontfaceCulling = false;
-			}
-			local_material.MaterialType = material.MaterialType;
-			local_material.BlendOperation = material.BlendOperation;
 			driver->setMaterial(local_material);
 			++material_swaps;
 		}
@@ -1533,9 +1520,9 @@ void ClientMap::renderMapShadows(video::IVideoDriver *driver,
 	// restore the driver material state
 	video::SMaterial clean;
 	clean.BlendOperation = video::EBO_ADD;
-	driver->setMaterial(clean); // reset material to defaults
+	driver->setMaterial(clean);
 	// This is somehow needed to fully reset the rendering state, or later operations
-	// will be broken.
+	// will be broken. (TODO why?)
 	driver->draw3DLine(v3f(), v3f(), video::SColor(0));
 
 	g_profiler->avg(prefix + "draw meshes [ms]", draw.stop(true));

src/client/clientmap.h

@@ -9,6 +9,7 @@
 #include <ISceneNode.h>
 #include <set>
 #include <map>
+#include <functional>
 
 struct MapDrawControl
 {
@@ -46,6 +47,7 @@ struct CachedMeshBuffer {
 
 using CachedMeshBuffers = std::unordered_map<std::string, CachedMeshBuffer>;
 
+using ModifyMaterialCallback = std::function<void(video::SMaterial& /* material */, bool /* is_foliage */)>;
 
 /*
 	ClientMap
@@ -107,7 +109,7 @@ public:
 	void renderMap(video::IVideoDriver* driver, s32 pass);
 
 	void renderMapShadows(video::IVideoDriver *driver,
-			const video::SMaterial &material, s32 pass, int frame, int total_frames);
+			ModifyMaterialCallback cb, s32 pass, int frame, int total_frames);
 
 	int getBackgroundBrightness(float max_d, u32 daylight_factor,
 			int oldvalue, bool *sunlight_seen_result);

src/client/shadows/dynamicshadowsrender.cpp

@@ -415,34 +415,40 @@ video::ITexture *ShadowRenderer::getSMTexture(const std::string &shadow_map_name
 void ShadowRenderer::renderShadowMap(video::ITexture *target,
 		DirectionalLight &light, scene::E_SCENE_NODE_RENDER_PASS pass)
 {
+	bool is_transparent_pass = pass != scene::ESNRP_SOLID;
+
 	m_driver->setTransform(video::ETS_VIEW, light.getFutureViewMatrix());
 	m_driver->setTransform(video::ETS_PROJECTION, light.getFutureProjectionMatrix());
 
+	// ClientMap will call this for every material it renders
+	ModifyMaterialCallback cb = [&] (video::SMaterial &mat, bool foliage) {
+		// Do not override culling if the original material renders both back
+		// and front faces in solid mode (e.g. plantlike)
+		// Transparent plants would still render shadows only from one side,
+		// but this conflicts with water which occurs much more frequently
+		if (is_transparent_pass || mat.BackfaceCulling || mat.FrontfaceCulling) {
+			mat.BackfaceCulling = false;
+			mat.FrontfaceCulling = true;
+		}
+		if (foliage) {
+			mat.BackfaceCulling = true;
+			mat.FrontfaceCulling = false;
+		}
+
+		if (m_shadow_map_colored && is_transparent_pass) {
+			mat.MaterialType = depth_shader_trans;
+		} else {
+			mat.MaterialType = depth_shader;
+			mat.BlendOperation = video::EBO_MIN;
+		}
+	};
+
 	ClientMap &map_node = static_cast<ClientMap &>(m_client->getEnv().getMap());
 
-	video::SMaterial material;
-	if (map_node.getMaterialCount() > 0) {
-		// we only want the first material, which is the one with the albedo info
-		material = map_node.getMaterial(0);
-	}
-
-	material.BackfaceCulling = false;
-	material.FrontfaceCulling = true;
-
-	if (m_shadow_map_colored && pass != scene::ESNRP_SOLID) {
-		material.MaterialType = depth_shader_trans;
-	} else {
-		material.MaterialType = depth_shader;
-		material.BlendOperation = video::EBO_MIN;
-	}
-
-	m_driver->setTransform(video::ETS_WORLD,
-			map_node.getAbsoluteTransformation());
-
 	int frame = m_force_update_shadow_map ? 0 : m_current_frame;
 	int total_frames = m_force_update_shadow_map ? 1 : m_map_shadow_update_frames;
 
-	map_node.renderMapShadows(m_driver, material, pass, frame, total_frames);
+	map_node.renderMapShadows(m_driver, cb, pass, frame, total_frames);
 }
 
 void ShadowRenderer::renderShadowObjects(
@@ -480,6 +486,7 @@ void ShadowRenderer::renderShadowObjects(
 			current_mat.FrontfaceCulling = false;
 
 			BufferBlendOperationList.push_back(current_mat.BlendOperation);
+			// shouldn't we be setting EBO_MIN here?
 		}
 
 		m_driver->setTransform(video::ETS_WORLD,