3 files changed, 19 insertions, 6 deletions

diff --git a/src/client/client.cpp b/src/client/client.cpp
index 8ab96b7d1..e078dc530 100644
--- a/src/client/client.cpp
+++ b/src/client/client.cpp
@@ -530,6 +530,7 @@ void Client::step(float dtime)
 	{
 		int num_processed_meshes = 0;
 		std::vector<v3s16> blocks_to_ack;
+		bool force_update_shadows = false;
 		while (!m_mesh_update_thread.m_queue_out.empty())
 		{
 			num_processed_meshes++;
@@ -556,9 +557,11 @@ void Client::step(float dtime)
 
 					if (is_empty)
 						delete r.mesh;
-					else
+					else {
 						// Replace with the new mesh
 						block->mesh = r.mesh;
+						force_update_shadows = true;
+					}
 				}
 			} else {
 				delete r.mesh;
@@ -583,6 +586,10 @@ void Client::step(float dtime)
 
 		if (num_processed_meshes > 0)
 			g_profiler->graphAdd("num_processed_meshes", num_processed_meshes);
+
+		auto shadow_renderer = RenderingEngine::get_shadow_renderer();
+		if (shadow_renderer && force_update_shadows)
+			shadow_renderer->setForceUpdateShadowMap();
 	}
 
 	/*
diff --git a/src/client/shadows/dynamicshadowsrender.cpp b/src/client/shadows/dynamicshadowsrender.cpp
index c13cfe252..b8ceeb623 100644
--- a/src/client/shadows/dynamicshadowsrender.cpp
+++ b/src/client/shadows/dynamicshadowsrender.cpp
@@ -242,7 +242,7 @@ void ShadowRenderer::updateSMTextures()
 
 		// detect if SM should be regenerated
 		for (DirectionalLight &light : m_light_list) {
-			if (light.should_update_map_shadow) {
+			if (light.should_update_map_shadow || m_force_update_shadow_map) {
 				light.should_update_map_shadow = false;
 				m_current_frame = 0;
 				reset_sm_texture = true;
@@ -271,14 +271,14 @@ void ShadowRenderer::updateSMTextures()
 			// should put some gl* fn here
 
 
-			if (m_current_frame < m_map_shadow_update_frames) {
+			if (m_current_frame < m_map_shadow_update_frames || m_force_update_shadow_map) {
 				m_driver->setRenderTarget(shadowMapTargetTexture, reset_sm_texture, true,
 						video::SColor(255, 255, 255, 255));
 				renderShadowMap(shadowMapTargetTexture, light);
 
 				// Render transparent part in one pass.
 				// This is also handled in ClientMap.
-				if (m_current_frame == m_map_shadow_update_frames - 1) {
+				if (m_current_frame == m_map_shadow_update_frames - 1 || m_force_update_shadow_map) {
 					if (m_shadow_map_colored) {
 						m_driver->setRenderTarget(0, false, false);
 						m_driver->setRenderTarget(shadowMapTextureColors,
@@ -298,7 +298,7 @@ void ShadowRenderer::updateSMTextures()
 			++m_current_frame;
 
 		// pass finished, swap textures and commit light changes
-		if (m_current_frame == m_map_shadow_update_frames) {
+		if (m_current_frame == m_map_shadow_update_frames || m_force_update_shadow_map) {
 			if (shadowMapClientMapFuture != nullptr)
 				std::swap(shadowMapClientMapFuture, shadowMapClientMap);
 
@@ -306,6 +306,7 @@ void ShadowRenderer::updateSMTextures()
 			for (DirectionalLight &light : m_light_list)
 				light.commitFrustum();
 		}
+		m_force_update_shadow_map = false;
 	}
 }
 
@@ -432,7 +433,10 @@ void ShadowRenderer::renderShadowMap(video::ITexture *target,
 		m_driver->setTransform(video::ETS_WORLD,
 				map_node->getAbsoluteTransformation());
 
-		map_node->renderMapShadows(m_driver, material, pass, m_current_frame, m_map_shadow_update_frames);
+		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);
 		break;
 	}
 }
diff --git a/src/client/shadows/dynamicshadowsrender.h b/src/client/shadows/dynamicshadowsrender.h
index 0e4ef6b70..2e3b58f6f 100644
--- a/src/client/shadows/dynamicshadowsrender.h
+++ b/src/client/shadows/dynamicshadowsrender.h
@@ -74,6 +74,7 @@ public:
 	void removeNodeFromShadowList(scene::ISceneNode *node);
 
 	void update(video::ITexture *outputTarget = nullptr);
+	void setForceUpdateShadowMap() { m_force_update_shadow_map = true; }
 	void drawDebug();
 
 	video::ITexture *get_texture()
@@ -131,6 +132,7 @@ private:
 	bool m_shadows_enabled;
 	bool m_shadows_supported;
 	bool m_shadow_map_colored;
+	bool m_force_update_shadow_map;
 	u8 m_map_shadow_update_frames; /* Use this number of frames to update map shaodw */
 	u8 m_current_frame{0}; /* Current frame */
 	f32 m_perspective_bias_xy;