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_mobile/render_forward_mobile.cpp b/servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.cpp
index 2b2090f8ed..2dfdb302dc 100644
--- a/servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.cpp
+++ b/servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.cpp
@@ -916,7 +916,7 @@ void RenderForwardMobile::_render_scene(RenderDataRD *p_render_data, const Color
 			}
 
 			RD::FramebufferFormatID fb_format = RD::get_singleton()->framebuffer_get_format(framebuffer);
-			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, rp_uniform_set, spec_constant_base_flags, 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, rp_uniform_set, spec_constant_base_flags, 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_params.framebuffer_format = fb_format;
 			if ((uint32_t)render_list_params.element_count > render_list_thread_threshold && false) {
 				// secondary command buffers need more testing at this time
@@ -983,7 +983,7 @@ void RenderForwardMobile::_render_scene(RenderDataRD *p_render_data, const Color
 
 		if (using_subpass_transparent) {
 			RD::FramebufferFormatID fb_format = RD::get_singleton()->framebuffer_get_format(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(), reverse_cull, PASS_MODE_COLOR_TRANSPARENT, rp_uniform_set, spec_constant_base_flags, 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(), reverse_cull, PASS_MODE_COLOR_TRANSPARENT, rp_uniform_set, spec_constant_base_flags, 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_params.framebuffer_format = fb_format;
 			if ((uint32_t)render_list_params.element_count > render_list_thread_threshold && false) {
 				// secondary command buffers need more testing at this time
@@ -1022,7 +1022,7 @@ void RenderForwardMobile::_render_scene(RenderDataRD *p_render_data, const Color
 			// _setup_environment(p_render_data, p_render_data->reflection_probe.is_valid(), screen_size, !p_render_data->reflection_probe.is_valid(), p_default_bg_color, false);
 
 			RD::FramebufferFormatID fb_format = RD::get_singleton()->framebuffer_get_format(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(), reverse_cull, PASS_MODE_COLOR, rp_uniform_set, spec_constant_base_flags, 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(), reverse_cull, PASS_MODE_COLOR, rp_uniform_set, spec_constant_base_flags, 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_params.framebuffer_format = fb_format;
 			if ((uint32_t)render_list_params.element_count > render_list_thread_threshold && false) {
 				// secondary command buffers need more testing at this time
@@ -1266,7 +1266,6 @@ void RenderForwardMobile::_render_shadow_append(RID p_framebuffer, const PagedAr
 	scene_data.view_projection[0] = p_projection;
 	scene_data.z_near = 0.0;
 	scene_data.z_far = p_zfar;
-	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 = 0.1;
@@ -1335,7 +1334,7 @@ void RenderForwardMobile::_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, shadow_pass.rp_uniform_set, 0, 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, shadow_pass.rp_uniform_set, 0, 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);
 	}
 
@@ -1808,12 +1807,13 @@ void RenderForwardMobile::_fill_render_list(RenderListType p_render_list, const
 			// 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;
 
diff --git a/servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.h b/servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.h
index 415bd79ad6..ce64d805b7 100644
--- a/servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.h
+++ b/servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.h
@@ -163,7 +163,6 @@ private:
 		RID render_pass_uniform_set;
 		bool force_wireframe = false;
 		Vector2 uv_offset;
-		Plane lod_plane;
 		uint32_t spec_constant_base_flags = 0;
 		float lod_distance_multiplier = 0.0;
 		float screen_mesh_lod_threshold = 0.0;
@@ -172,7 +171,7 @@ private:
 		uint32_t barrier = RD::BARRIER_MASK_ALL;
 		uint32_t subpass = 0;
 
-		RenderListParameters(GeometryInstanceSurfaceDataCache **p_elements, RenderElementInfo *p_element_info, int p_element_count, bool p_reverse_cull, PassMode p_pass_mode, RID p_render_pass_uniform_set, uint32_t p_spec_constant_base_flags = 0, 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, RID p_render_pass_uniform_set, uint32_t p_spec_constant_base_flags = 0, 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;
@@ -183,7 +182,6 @@ private:
 			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;