Adjust shadowmap distortion to use entire SM texture (#12166)

src/client/shadows/dynamicshadows.cpp

@@ -29,7 +29,6 @@ using m4f = core::matrix4;
 
 void DirectionalLight::createSplitMatrices(const Camera *cam)
 {
-	float radius;
 	v3f newCenter;
 	v3f look = cam->getDirection();
 
@@ -42,17 +41,16 @@ void DirectionalLight::createSplitMatrices(const Camera *cam)
 	float sfFar = adjustDist(future_frustum.zFar, cam->getFovY());
 
 	// adjusted camera positions
-	v3f camPos2 = cam->getPosition();
-	v3f camPos = v3f(camPos2.X - cam->getOffset().X * BS,
-			camPos2.Y - cam->getOffset().Y * BS,
-			camPos2.Z - cam->getOffset().Z * BS);
-	camPos += look * sfNear;
-	camPos2 += look * sfNear;
+	v3f cam_pos_world = cam->getPosition();
+	v3f cam_pos_scene = v3f(cam_pos_world.X - cam->getOffset().X * BS,
+			cam_pos_world.Y - cam->getOffset().Y * BS,
+			cam_pos_world.Z - cam->getOffset().Z * BS);
+	cam_pos_scene += look * sfNear;
+	cam_pos_world += look * sfNear;
 
 	// center point of light frustum
-	float end = sfNear + sfFar;
-	newCenter = camPos + look * (sfNear + 0.05f * end);
-	v3f world_center = camPos2 + look * (sfNear + 0.05f * end);
+	v3f center_scene = cam_pos_scene + look * 0.35 * (sfFar - sfNear);
+	v3f center_world = cam_pos_world + look * 0.35 * (sfFar - sfNear);
 
 	// Create a vector to the frustum far corner
 	const v3f &viewUp = cam->getCameraNode()->getUpVector();
@@ -60,22 +58,21 @@ void DirectionalLight::createSplitMatrices(const Camera *cam)
 
 	v3f farCorner = (look + viewRight * tanFovX + viewUp * tanFovY).normalize();
 	// Compute the frustumBoundingSphere radius
-	v3f boundVec = (camPos + farCorner * sfFar) - newCenter;
-	radius = boundVec.getLength();
-	// boundVec.getLength();
-	float vvolume = radius;
-	v3f frustumCenter = newCenter;
-	v3f eye_displacement = direction * vvolume;
+	v3f boundVec = (cam_pos_scene + farCorner * sfFar) - center_scene;
+	float radius = boundVec.getLength();
+	float length = radius * 3.0f;
+	v3f eye_displacement = direction * length;
 
 	// we must compute the viewmat with the position - the camera offset
 	// but the future_frustum position must be the actual world position
-	v3f eye = frustumCenter - eye_displacement;
-	future_frustum.position = world_center - eye_displacement;
-	future_frustum.length = vvolume;
-	future_frustum.ViewMat.buildCameraLookAtMatrixLH(eye, frustumCenter, v3f(0.0f, 1.0f, 0.0f));
-	future_frustum.ProjOrthMat.buildProjectionMatrixOrthoLH(future_frustum.length,
-			future_frustum.length, -future_frustum.length,
-			future_frustum.length,false);
+	v3f eye = center_scene - eye_displacement;
+	future_frustum.player = cam_pos_scene;
+	future_frustum.position = center_world - eye_displacement;
+	future_frustum.length = length;
+	future_frustum.radius = radius;
+	future_frustum.ViewMat.buildCameraLookAtMatrixLH(eye, center_scene, v3f(0.0f, 1.0f, 0.0f));
+	future_frustum.ProjOrthMat.buildProjectionMatrixOrthoLH(radius, radius, 
+			0.0f, length, false);
 	future_frustum.camera_offset = cam->getOffset();
 }
 
@@ -94,7 +91,7 @@ void DirectionalLight::update_frustum(const Camera *cam, Client *client, bool fo
 	float zNear = cam->getCameraNode()->getNearValue();
 	float zFar = getMaxFarValue();
 	if (!client->getEnv().getClientMap().getControl().range_all)
-		zFar = MYMIN(zFar, client->getEnv().getClientMap().getControl().wanted_range * BS * 1.5);
+		zFar = MYMIN(zFar, client->getEnv().getClientMap().getControl().wanted_range * BS);
 
 	///////////////////////////////////
 	// update splits near and fars
@@ -105,7 +102,7 @@ void DirectionalLight::update_frustum(const Camera *cam, Client *client, bool fo
 	createSplitMatrices(cam);
 	// get the draw list for shadows
 	client->getEnv().getClientMap().updateDrawListShadow(
-			getPosition(), getDirection(), future_frustum.length);
+			getPosition(), getDirection(), future_frustum.radius, future_frustum.length);
 	should_update_map_shadow = true;
 	dirty = true;
 
@@ -115,6 +112,7 @@ void DirectionalLight::update_frustum(const Camera *cam, Client *client, bool fo
 		v3f rotated_offset;
 		shadow_frustum.ViewMat.rotateVect(rotated_offset, intToFloat(cam_offset - shadow_frustum.camera_offset, BS));
 		shadow_frustum.ViewMat.setTranslation(shadow_frustum.ViewMat.getTranslation() + rotated_offset);
+		shadow_frustum.player += intToFloat(shadow_frustum.camera_offset - cam->getOffset(), BS);
 		shadow_frustum.camera_offset = cam_offset;
 	}
 }
@@ -139,6 +137,16 @@ v3f DirectionalLight::getPosition() const
 	return shadow_frustum.position;
 }
 
+v3f DirectionalLight::getPlayerPos() const
+{
+	return shadow_frustum.player;
+}
+
+v3f DirectionalLight::getFuturePlayerPos() const
+{
+	return future_frustum.player;
+}
+
 const m4f &DirectionalLight::getViewMatrix() const
 {
 	return shadow_frustum.ViewMat;

src/client/shadows/dynamicshadows.h

@@ -29,12 +29,14 @@ class Client;
 
 struct shadowFrustum
 {
-	float zNear{0.0f};
-	float zFar{0.0f};
-	float length{0.0f};
+	f32 zNear{0.0f};
+	f32 zFar{0.0f};
+	f32 length{0.0f};
+	f32 radius{0.0f};
 	core::matrix4 ProjOrthMat;
 	core::matrix4 ViewMat;
 	v3f position;
+	v3f player;
 	v3s16 camera_offset;
 };
 
@@ -57,6 +59,8 @@ public:
 		return direction;
 	};
 	v3f getPosition() const;
+	v3f getPlayerPos() const;
+	v3f getFuturePlayerPos() const;
 
 	/// Gets the light's matrices.
 	const core::matrix4 &getViewMatrix() const;

src/client/shadows/dynamicshadowsrender.cpp

@@ -158,7 +158,6 @@ void ShadowRenderer::setShadowIntensity(float shadow_intensity)
 		disable();
 }
 
-
 void ShadowRenderer::addNodeToShadowList(
 		scene::ISceneNode *node, E_SHADOW_MODE shadowMode)
 {
@@ -261,8 +260,9 @@ void ShadowRenderer::updateSMTextures()
 					cb->MaxFar = (f32)m_shadow_map_max_distance * BS;
 					cb->PerspectiveBiasXY = getPerspectiveBiasXY();
 					cb->PerspectiveBiasZ = getPerspectiveBiasZ();
+					cb->CameraPos = light.getFuturePlayerPos();
 				}
-
+			
 			// set the Render Target
 			// right now we can only render in usual RTT, not
 			// Depth texture is available in irrlicth maybe we
@@ -322,9 +322,10 @@ void ShadowRenderer::update(video::ITexture *outputTarget)
 	if (!m_shadow_node_array.empty() && !m_light_list.empty()) {
 
 		for (DirectionalLight &light : m_light_list) {
-			// Static shader values.
-			m_shadow_depth_cb->MapRes = (f32)m_shadow_map_texture_size;
-			m_shadow_depth_cb->MaxFar = (f32)m_shadow_map_max_distance * BS;
+			// Static shader values for entities are set in updateSMTextures
+			// SM texture for entities is not updated incrementally and 
+			// must by updated using current player position.
+			m_shadow_depth_entity_cb->CameraPos = light.getPlayerPos();
 
 			// render shadows for the n0n-map objects.
 			m_driver->setRenderTarget(shadowMapTextureDynamicObjects, true,

src/client/shadows/shadowsshadercallbacks.cpp

@@ -26,6 +26,10 @@ void ShadowDepthShaderCB::OnSetConstants(
 
 	core::matrix4 lightMVP = driver->getTransform(video::ETS_PROJECTION);
 	lightMVP *= driver->getTransform(video::ETS_VIEW);
+
+	f32 cam_pos[4];
+	lightMVP.transformVect(cam_pos, CameraPos);
+
 	lightMVP *= driver->getTransform(video::ETS_WORLD);
 
 	m_light_mvp_setting.set(lightMVP.pointer(), services);
@@ -39,4 +43,6 @@ void ShadowDepthShaderCB::OnSetConstants(
 	m_perspective_bias1.set(&bias1, services);
 	f32 zbias = PerspectiveBiasZ;
 	m_perspective_zbias.set(&zbias, services);
+
+	m_cam_pos_setting.set(cam_pos, services);
 }

src/client/shadows/shadowsshadercallbacks.h

@@ -33,7 +33,8 @@ public:
 			m_color_map_sampler_setting("ColorMapSampler"),
 			m_perspective_bias0("xyPerspectiveBias0"),
 			m_perspective_bias1("xyPerspectiveBias1"),
-			m_perspective_zbias("zPerspectiveBias")
+			m_perspective_zbias("zPerspectiveBias"),
+			m_cam_pos_setting("CameraPos")
 	{}
 
 	void OnSetMaterial(const video::SMaterial &material) override {}
@@ -43,6 +44,7 @@ public:
 
 	f32 MaxFar{2048.0f}, MapRes{1024.0f};
 	f32 PerspectiveBiasXY {0.9f}, PerspectiveBiasZ {0.5f};
+	v3f CameraPos;
 
 private:
 	CachedVertexShaderSetting<f32, 16> m_light_mvp_setting;
@@ -52,4 +54,5 @@ private:
 	CachedVertexShaderSetting<f32> m_perspective_bias0;
 	CachedVertexShaderSetting<f32> m_perspective_bias1;
 	CachedVertexShaderSetting<f32> m_perspective_zbias;
+	CachedVertexShaderSetting<f32, 4> m_cam_pos_setting;
 };