Skip rendering sky if viewport is set to transparent background

drivers/gles3/rasterizer_scene_gles3.cpp

@@ -2394,6 +2394,7 @@ void RasterizerSceneGLES3::render_scene(const Ref<RenderSceneBuffers> &p_render_
 		RS::EnvironmentBG bg_mode = environment_get_background(render_data.environment);
 		float bg_energy_multiplier = environment_get_bg_energy_multiplier(render_data.environment);
 		bg_energy_multiplier *= environment_get_bg_intensity(render_data.environment);
+		RS::EnvironmentReflectionSource reflection_source = environment_get_reflection_source(render_data.environment);
 
 		if (render_data.camera_attributes.is_valid()) {
 			bg_energy_multiplier *= RSG::camera_attributes->camera_attributes_get_exposure_normalization_factor(render_data.camera_attributes);
@@ -2404,7 +2405,7 @@ void RasterizerSceneGLES3::render_scene(const Ref<RenderSceneBuffers> &p_render_
 				clear_color.r *= bg_energy_multiplier;
 				clear_color.g *= bg_energy_multiplier;
 				clear_color.b *= bg_energy_multiplier;
-				if (environment_get_fog_enabled(render_data.environment)) {
+				if (!render_data.transparent_bg && environment_get_fog_enabled(render_data.environment)) {
 					draw_sky_fog_only = true;
 					GLES3::MaterialStorage::get_singleton()->material_set_param(sky_globals.fog_material, "clear_color", Variant(clear_color));
 				}
@@ -2414,13 +2415,13 @@ void RasterizerSceneGLES3::render_scene(const Ref<RenderSceneBuffers> &p_render_
 				clear_color.r *= bg_energy_multiplier;
 				clear_color.g *= bg_energy_multiplier;
 				clear_color.b *= bg_energy_multiplier;
-				if (environment_get_fog_enabled(render_data.environment)) {
+				if (!render_data.transparent_bg && environment_get_fog_enabled(render_data.environment)) {
 					draw_sky_fog_only = true;
 					GLES3::MaterialStorage::get_singleton()->material_set_param(sky_globals.fog_material, "clear_color", Variant(clear_color));
 				}
 			} break;
 			case RS::ENV_BG_SKY: {
-				draw_sky = true;
+				draw_sky = !render_data.transparent_bg;
 			} break;
 			case RS::ENV_BG_CANVAS: {
 				keep_color = true;
@@ -2433,8 +2434,9 @@ void RasterizerSceneGLES3::render_scene(const Ref<RenderSceneBuffers> &p_render_
 			default: {
 			}
 		}
+
 		// setup sky if used for ambient, reflections, or background
-		if (draw_sky || draw_sky_fog_only || environment_get_reflection_source(render_data.environment) == RS::ENV_REFLECTION_SOURCE_SKY || environment_get_ambient_source(render_data.environment) == RS::ENV_AMBIENT_SOURCE_SKY) {
+		if (draw_sky || draw_sky_fog_only || (reflection_source == RS::ENV_REFLECTION_SOURCE_BG && bg_mode == RS::ENV_BG_SKY) || reflection_source == RS::ENV_REFLECTION_SOURCE_SKY || environment_get_ambient_source(render_data.environment) == RS::ENV_AMBIENT_SOURCE_SKY) {
 			RENDER_TIMESTAMP("Setup Sky");
 			Projection projection = render_data.cam_projection;
 			if (is_reflection_probe) {

servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.cpp

@@ -1812,6 +1812,7 @@ void RenderForwardClustered::_render_scene(RenderDataRD *p_render_data, const Co
 		RS::EnvironmentBG bg_mode = environment_get_background(p_render_data->environment);
 		float bg_energy_multiplier = environment_get_bg_energy_multiplier(p_render_data->environment);
 		bg_energy_multiplier *= environment_get_bg_intensity(p_render_data->environment);
+		RS::EnvironmentReflectionSource reflection_source = environment_get_reflection_source(p_render_data->environment);
 
 		if (p_render_data->camera_attributes.is_valid()) {
 			bg_energy_multiplier *= RSG::camera_attributes->camera_attributes_get_exposure_normalization_factor(p_render_data->camera_attributes);
@@ -1823,7 +1824,7 @@ void RenderForwardClustered::_render_scene(RenderDataRD *p_render_data, const Co
 				clear_color.r *= bg_energy_multiplier;
 				clear_color.g *= bg_energy_multiplier;
 				clear_color.b *= bg_energy_multiplier;
-				if ((rb->has_custom_data(RB_SCOPE_FOG)) || environment_get_fog_enabled(p_render_data->environment)) {
+				if (!p_render_data->transparent_bg && rb->has_custom_data(RB_SCOPE_FOG) && environment_get_fog_enabled(p_render_data->environment)) {
 					draw_sky_fog_only = true;
 					RendererRD::MaterialStorage::get_singleton()->material_set_param(sky.sky_scene_state.fog_material, "clear_color", Variant(clear_color.srgb_to_linear()));
 				}
@@ -1833,13 +1834,13 @@ void RenderForwardClustered::_render_scene(RenderDataRD *p_render_data, const Co
 				clear_color.r *= bg_energy_multiplier;
 				clear_color.g *= bg_energy_multiplier;
 				clear_color.b *= bg_energy_multiplier;
-				if ((rb->has_custom_data(RB_SCOPE_FOG)) || environment_get_fog_enabled(p_render_data->environment)) {
+				if (!p_render_data->transparent_bg && rb->has_custom_data(RB_SCOPE_FOG) && environment_get_fog_enabled(p_render_data->environment)) {
 					draw_sky_fog_only = true;
 					RendererRD::MaterialStorage::get_singleton()->material_set_param(sky.sky_scene_state.fog_material, "clear_color", Variant(clear_color.srgb_to_linear()));
 				}
 			} break;
 			case RS::ENV_BG_SKY: {
-				draw_sky = true;
+				draw_sky = !p_render_data->transparent_bg;
 			} break;
 			case RS::ENV_BG_CANVAS: {
 				if (!is_reflection_probe) {
@@ -1859,7 +1860,7 @@ void RenderForwardClustered::_render_scene(RenderDataRD *p_render_data, const Co
 		}
 
 		// setup sky if used for ambient, reflections, or background
-		if (draw_sky || draw_sky_fog_only || environment_get_reflection_source(p_render_data->environment) == RS::ENV_REFLECTION_SOURCE_SKY || environment_get_ambient_source(p_render_data->environment) == RS::ENV_AMBIENT_SOURCE_SKY) {
+		if (draw_sky || draw_sky_fog_only || (reflection_source == RS::ENV_REFLECTION_SOURCE_BG && bg_mode == RS::ENV_BG_SKY) || reflection_source == RS::ENV_REFLECTION_SOURCE_SKY || environment_get_ambient_source(p_render_data->environment) == RS::ENV_AMBIENT_SOURCE_SKY) {
 			RENDER_TIMESTAMP("Setup Sky");
 			RD::get_singleton()->draw_command_begin_label("Setup Sky");
 

servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.cpp

@@ -830,6 +830,7 @@ void RenderForwardMobile::_render_scene(RenderDataRD *p_render_data, const Color
 		RS::EnvironmentBG bg_mode = environment_get_background(p_render_data->environment);
 		float bg_energy_multiplier = environment_get_bg_energy_multiplier(p_render_data->environment);
 		bg_energy_multiplier *= environment_get_bg_intensity(p_render_data->environment);
+		RS::EnvironmentReflectionSource reflection_source = environment_get_reflection_source(p_render_data->environment);
 
 		if (p_render_data->camera_attributes.is_valid()) {
 			bg_energy_multiplier *= RSG::camera_attributes->camera_attributes_get_exposure_normalization_factor(p_render_data->camera_attributes);
@@ -841,7 +842,7 @@ void RenderForwardMobile::_render_scene(RenderDataRD *p_render_data, const Color
 				clear_color.r *= bg_energy_multiplier;
 				clear_color.g *= bg_energy_multiplier;
 				clear_color.b *= bg_energy_multiplier;
-				if (environment_get_fog_enabled(p_render_data->environment)) {
+				if (!p_render_data->transparent_bg && environment_get_fog_enabled(p_render_data->environment)) {
 					draw_sky_fog_only = true;
 					RendererRD::MaterialStorage::get_singleton()->material_set_param(sky.sky_scene_state.fog_material, "clear_color", Variant(clear_color.srgb_to_linear()));
 				}
@@ -851,13 +852,13 @@ void RenderForwardMobile::_render_scene(RenderDataRD *p_render_data, const Color
 				clear_color.r *= bg_energy_multiplier;
 				clear_color.g *= bg_energy_multiplier;
 				clear_color.b *= bg_energy_multiplier;
-				if (environment_get_fog_enabled(p_render_data->environment)) {
+				if (!p_render_data->transparent_bg && environment_get_fog_enabled(p_render_data->environment)) {
 					draw_sky_fog_only = true;
 					RendererRD::MaterialStorage::get_singleton()->material_set_param(sky.sky_scene_state.fog_material, "clear_color", Variant(clear_color.srgb_to_linear()));
 				}
 			} break;
 			case RS::ENV_BG_SKY: {
-				draw_sky = true;
+				draw_sky = !p_render_data->transparent_bg;
 			} break;
 			case RS::ENV_BG_CANVAS: {
 				if (rb_data.is_valid()) {
@@ -874,7 +875,7 @@ void RenderForwardMobile::_render_scene(RenderDataRD *p_render_data, const Color
 		}
 
 		// setup sky if used for ambient, reflections, or background
-		if (draw_sky || draw_sky_fog_only || environment_get_reflection_source(p_render_data->environment) == RS::ENV_REFLECTION_SOURCE_SKY || environment_get_ambient_source(p_render_data->environment) == RS::ENV_AMBIENT_SOURCE_SKY) {
+		if (draw_sky || draw_sky_fog_only || (reflection_source == RS::ENV_REFLECTION_SOURCE_BG && bg_mode == RS::ENV_BG_SKY) || reflection_source == RS::ENV_REFLECTION_SOURCE_SKY || environment_get_ambient_source(p_render_data->environment) == RS::ENV_AMBIENT_SOURCE_SKY) {
 			RENDER_TIMESTAMP("Setup Sky");
 			RD::get_singleton()->draw_command_begin_label("Setup Sky");
 

servers/rendering/renderer_rd/renderer_scene_render_rd.cpp

@@ -1149,6 +1149,10 @@ void RendererSceneRenderRD::render_scene(const Ref<RenderSceneBuffers> &p_render
 		render_data.sdfgi_update_data = p_sdfgi_update_data;
 
 		render_data.render_info = r_render_info;
+
+		if (p_render_buffers.is_valid() && p_reflection_probe.is_null()) {
+			render_data.transparent_bg = texture_storage->render_target_get_transparent(rb->get_render_target());
+		}
 	}
 
 	PagedArray<RID> empty;

servers/rendering/renderer_rd/storage_rd/render_data_rd.h

@@ -78,6 +78,9 @@ public:
 
 	RenderingMethod::RenderInfo *render_info = nullptr;
 
+	/* Viewport data */
+	bool transparent_bg = false;
+
 	/* Shadow data */
 	const RendererSceneRender::RenderShadowData *render_shadows = nullptr;
 	int render_shadow_count = 0;