Use radial distance for making LOD decisions.

Previously, only forward basis distance from the camera was used.
This means that unnecessarily high LOD levels were used for objects located to the side of the camera.
The distance from the camera origin is now used, independently of direction.

2 files changed, 11 insertions, 13 deletions

diff --git a/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.cpp b/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.cpp
index 039a2d2bf4..59a8cdf30a 100644
--- a/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.cpp
+++ b/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.cpp
@@ -940,12 +940,13 @@ void RenderForwardClustered::_fill_render_list(RenderListType p_render_list, con
 			// LOD
 
 			if (p_render_data->scene_data->screen_mesh_lod_threshold > 0.0 && mesh_storage->mesh_surface_has_lod(surf->surface)) {
-				//lod
-				Vector3 lod_support_min = inst->transformed_aabb.get_support(-p_render_data->scene_data->lod_camera_plane.normal);
-				Vector3 lod_support_max = inst->transformed_aabb.get_support(p_render_data->scene_data->lod_camera_plane.normal);
+				// Get the LOD support points on the mesh AABB.
+				Vector3 lod_support_min = inst->transformed_aabb.get_support(p_render_data->scene_data->cam_transform.basis.get_column(Vector3::AXIS_Z));
+				Vector3 lod_support_max = inst->transformed_aabb.get_support(-p_render_data->scene_data->cam_transform.basis.get_column(Vector3::AXIS_Z));
 
-				float distance_min = p_render_data->scene_data->lod_camera_plane.distance_to(lod_support_min);
-				float distance_max = p_render_data->scene_data->lod_camera_plane.distance_to(lod_support_max);
+				// Get the distances to those points on the AABB from the camera origin.
+				float distance_min = (float)p_render_data->scene_data->cam_transform.origin.distance_to(lod_support_min);
+				float distance_max = (float)p_render_data->scene_data->cam_transform.origin.distance_to(lod_support_max);
 
 				float distance = 0.0;
 
@@ -1830,7 +1831,7 @@ void RenderForwardClustered::_render_scene(RenderDataRD *p_render_data, const Co
 		RID rp_uniform_set = _setup_render_pass_uniform_set(RENDER_LIST_OPAQUE, nullptr, RID());
 
 		bool finish_depth = using_ssao || using_sdfgi || using_voxelgi;
-		RenderListParameters render_list_params(render_list[RENDER_LIST_OPAQUE].elements.ptr(), render_list[RENDER_LIST_OPAQUE].element_info.ptr(), render_list[RENDER_LIST_OPAQUE].elements.size(), reverse_cull, depth_pass_mode, 0, rb_data.is_null(), p_render_data->directional_light_soft_shadows, rp_uniform_set, get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_WIREFRAME, Vector2(), p_render_data->scene_data->lod_camera_plane, p_render_data->scene_data->lod_distance_multiplier, p_render_data->scene_data->screen_mesh_lod_threshold, p_render_data->scene_data->view_count);
+		RenderListParameters render_list_params(render_list[RENDER_LIST_OPAQUE].elements.ptr(), render_list[RENDER_LIST_OPAQUE].element_info.ptr(), render_list[RENDER_LIST_OPAQUE].elements.size(), reverse_cull, depth_pass_mode, 0, rb_data.is_null(), p_render_data->directional_light_soft_shadows, rp_uniform_set, get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_WIREFRAME, Vector2(), p_render_data->scene_data->lod_distance_multiplier, p_render_data->scene_data->screen_mesh_lod_threshold, p_render_data->scene_data->view_count);
 		_render_list_with_threads(&render_list_params, depth_framebuffer, needs_pre_resolve ? RD::INITIAL_ACTION_CONTINUE : RD::INITIAL_ACTION_CLEAR, RD::FINAL_ACTION_READ, needs_pre_resolve ? RD::INITIAL_ACTION_CONTINUE : RD::INITIAL_ACTION_CLEAR, finish_depth ? RD::FINAL_ACTION_READ : RD::FINAL_ACTION_CONTINUE, needs_pre_resolve ? Vector<Color>() : depth_pass_clear);
 
 		RD::get_singleton()->draw_command_end_label();
@@ -1900,7 +1901,7 @@ void RenderForwardClustered::_render_scene(RenderDataRD *p_render_data, const Co
 			}
 		}
 
-		RenderListParameters render_list_params(render_list[RENDER_LIST_OPAQUE].elements.ptr(), render_list[RENDER_LIST_OPAQUE].element_info.ptr(), render_list[RENDER_LIST_OPAQUE].elements.size(), reverse_cull, PASS_MODE_COLOR, color_pass_flags, rb_data.is_null(), p_render_data->directional_light_soft_shadows, rp_uniform_set, get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_WIREFRAME, Vector2(), p_render_data->scene_data->lod_camera_plane, p_render_data->scene_data->lod_distance_multiplier, p_render_data->scene_data->screen_mesh_lod_threshold, p_render_data->scene_data->view_count);
+		RenderListParameters render_list_params(render_list[RENDER_LIST_OPAQUE].elements.ptr(), render_list[RENDER_LIST_OPAQUE].element_info.ptr(), render_list[RENDER_LIST_OPAQUE].elements.size(), reverse_cull, PASS_MODE_COLOR, color_pass_flags, rb_data.is_null(), p_render_data->directional_light_soft_shadows, rp_uniform_set, get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_WIREFRAME, Vector2(), p_render_data->scene_data->lod_distance_multiplier, p_render_data->scene_data->screen_mesh_lod_threshold, p_render_data->scene_data->view_count);
 		_render_list_with_threads(&render_list_params, color_framebuffer, keep_color ? RD::INITIAL_ACTION_KEEP : RD::INITIAL_ACTION_CLEAR, will_continue_color ? RD::FINAL_ACTION_CONTINUE : RD::FINAL_ACTION_READ, depth_pre_pass ? (continue_depth ? RD::INITIAL_ACTION_CONTINUE : RD::INITIAL_ACTION_KEEP) : RD::INITIAL_ACTION_CLEAR, will_continue_depth ? RD::FINAL_ACTION_CONTINUE : RD::FINAL_ACTION_READ, c, 1.0, 0);
 		if (will_continue_color && using_separate_specular) {
 			// close the specular framebuffer, as it's no longer used
@@ -2021,7 +2022,7 @@ void RenderForwardClustered::_render_scene(RenderDataRD *p_render_data, const Co
 	{
 		uint32_t transparent_color_pass_flags = (color_pass_flags | COLOR_PASS_FLAG_TRANSPARENT) & ~(COLOR_PASS_FLAG_SEPARATE_SPECULAR);
 		RID alpha_framebuffer = rb_data.is_valid() ? rb_data->get_color_pass_fb(transparent_color_pass_flags) : color_only_framebuffer;
-		RenderListParameters render_list_params(render_list[RENDER_LIST_ALPHA].elements.ptr(), render_list[RENDER_LIST_ALPHA].element_info.ptr(), render_list[RENDER_LIST_ALPHA].elements.size(), false, PASS_MODE_COLOR, transparent_color_pass_flags, rb_data.is_null(), p_render_data->directional_light_soft_shadows, rp_uniform_set, get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_WIREFRAME, Vector2(), p_render_data->scene_data->lod_camera_plane, p_render_data->scene_data->lod_distance_multiplier, p_render_data->scene_data->screen_mesh_lod_threshold, p_render_data->scene_data->view_count);
+		RenderListParameters render_list_params(render_list[RENDER_LIST_ALPHA].elements.ptr(), render_list[RENDER_LIST_ALPHA].element_info.ptr(), render_list[RENDER_LIST_ALPHA].elements.size(), false, PASS_MODE_COLOR, transparent_color_pass_flags, rb_data.is_null(), p_render_data->directional_light_soft_shadows, rp_uniform_set, get_debug_draw_mode() == RS::VIEWPORT_DEBUG_DRAW_WIREFRAME, Vector2(), p_render_data->scene_data->lod_distance_multiplier, p_render_data->scene_data->screen_mesh_lod_threshold, p_render_data->scene_data->view_count);
 		_render_list_with_threads(&render_list_params, alpha_framebuffer, can_continue_color ? RD::INITIAL_ACTION_CONTINUE : RD::INITIAL_ACTION_KEEP, RD::FINAL_ACTION_READ, can_continue_depth ? RD::INITIAL_ACTION_CONTINUE : RD::INITIAL_ACTION_KEEP, RD::FINAL_ACTION_READ);
 	}
 
@@ -2307,7 +2308,6 @@ void RenderForwardClustered::_render_shadow_append(RID p_framebuffer, const Page
 	scene_data.view_projection[0] = p_projection;
 	scene_data.z_far = p_zfar;
 	scene_data.z_near = 0.0;
-	scene_data.lod_camera_plane = p_camera_plane;
 	scene_data.lod_distance_multiplier = p_lod_distance_multiplier;
 	scene_data.dual_paraboloid_side = p_use_dp_flip ? -1 : 1;
 	scene_data.opaque_prepass_threshold = 0.1f;
@@ -2378,7 +2378,7 @@ void RenderForwardClustered::_render_shadow_end(uint32_t p_barrier) {
 
 	for (uint32_t i = 0; i < scene_state.shadow_passes.size(); i++) {
 		SceneState::ShadowPass &shadow_pass = scene_state.shadow_passes[i];
-		RenderListParameters render_list_parameters(render_list[RENDER_LIST_SECONDARY].elements.ptr() + shadow_pass.element_from, render_list[RENDER_LIST_SECONDARY].element_info.ptr() + shadow_pass.element_from, shadow_pass.element_count, shadow_pass.flip_cull, shadow_pass.pass_mode, 0, true, false, shadow_pass.rp_uniform_set, false, Vector2(), shadow_pass.camera_plane, shadow_pass.lod_distance_multiplier, shadow_pass.screen_mesh_lod_threshold, 1, shadow_pass.element_from, RD::BARRIER_MASK_NO_BARRIER);
+		RenderListParameters render_list_parameters(render_list[RENDER_LIST_SECONDARY].elements.ptr() + shadow_pass.element_from, render_list[RENDER_LIST_SECONDARY].element_info.ptr() + shadow_pass.element_from, shadow_pass.element_count, shadow_pass.flip_cull, shadow_pass.pass_mode, 0, true, false, shadow_pass.rp_uniform_set, false, Vector2(), shadow_pass.lod_distance_multiplier, shadow_pass.screen_mesh_lod_threshold, 1, shadow_pass.element_from, RD::BARRIER_MASK_NO_BARRIER);
 		_render_list_with_threads(&render_list_parameters, shadow_pass.framebuffer, RD::INITIAL_ACTION_DROP, RD::FINAL_ACTION_DISCARD, shadow_pass.initial_depth_action, shadow_pass.final_depth_action, Vector<Color>(), 1.0, 0, shadow_pass.rect);
 	}
 
diff --git a/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.h b/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.h
index 55f1ef01af..670eb93e20 100644
--- a/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.h
+++ b/servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.h
@@ -206,7 +206,6 @@ class RenderForwardClustered : public RendererSceneRenderRD {
 		RID render_pass_uniform_set;
 		bool force_wireframe = false;
 		Vector2 uv_offset;
-		Plane lod_plane;
 		float lod_distance_multiplier = 0.0;
 		float screen_mesh_lod_threshold = 0.0;
 		RD::FramebufferFormatID framebuffer_format = 0;
@@ -214,7 +213,7 @@ class RenderForwardClustered : public RendererSceneRenderRD {
 		uint32_t barrier = RD::BARRIER_MASK_ALL;
 		bool use_directional_soft_shadow = false;
 
-		RenderListParameters(GeometryInstanceSurfaceDataCache **p_elements, RenderElementInfo *p_element_info, int p_element_count, bool p_reverse_cull, PassMode p_pass_mode, uint32_t p_color_pass_flags, bool p_no_gi, bool p_use_directional_soft_shadows, RID p_render_pass_uniform_set, bool p_force_wireframe = false, const Vector2 &p_uv_offset = Vector2(), const Plane &p_lod_plane = Plane(), float p_lod_distance_multiplier = 0.0, float p_screen_mesh_lod_threshold = 0.0, uint32_t p_view_count = 1, uint32_t p_element_offset = 0, uint32_t p_barrier = RD::BARRIER_MASK_ALL) {
+		RenderListParameters(GeometryInstanceSurfaceDataCache **p_elements, RenderElementInfo *p_element_info, int p_element_count, bool p_reverse_cull, PassMode p_pass_mode, uint32_t p_color_pass_flags, bool p_no_gi, bool p_use_directional_soft_shadows, RID p_render_pass_uniform_set, bool p_force_wireframe = false, const Vector2 &p_uv_offset = Vector2(), float p_lod_distance_multiplier = 0.0, float p_screen_mesh_lod_threshold = 0.0, uint32_t p_view_count = 1, uint32_t p_element_offset = 0, uint32_t p_barrier = RD::BARRIER_MASK_ALL) {
 			elements = p_elements;
 			element_info = p_element_info;
 			element_count = p_element_count;
@@ -226,7 +225,6 @@ class RenderForwardClustered : public RendererSceneRenderRD {
 			render_pass_uniform_set = p_render_pass_uniform_set;
 			force_wireframe = p_force_wireframe;
 			uv_offset = p_uv_offset;
-			lod_plane = p_lod_plane;
 			lod_distance_multiplier = p_lod_distance_multiplier;
 			screen_mesh_lod_threshold = p_screen_mesh_lod_threshold;
 			element_offset = p_element_offset;