Assorted fixes to UV unwrapping and GPU lightmapper

Various fixes to UV2 unwrapping and the GPU lightmapper. Listed here for
context in case of git blame/bisect:

* Fix UV2 unwrapping on import, also cleaned up the unwrap cache code.
* Fix saving of RGBA images in EXR format.
* Fixes to the GPU lightmapper:
	- Added padding between atlas elements, avoids bleeding.
	- Remove old SDF generation code.
	- Fix baked attenuation for Omni/Spot lights.
	- Fix baking of material properties onto UV2 (wireframe was
	  wrongly used before).
	- Disable statically baked lights for objects that have a
	  lightmap texture to avoid applying the same light twice.
	- Fix lightmap pairing in RendererSceneCull.
	- Fix UV2 array generated from `RenderingServer::mesh_surface_get_arrays()`.
	- Port autoexposure fix for OIDN from 3.x.
	- Save debug textures as EXR when using floating point format.

2 files changed, 18 insertions, 2 deletions

diff --git a/servers/rendering/renderer_rd/shaders/light_data_inc.glsl b/servers/rendering/renderer_rd/shaders/light_data_inc.glsl
index 46b571a5f5..2fce258cff 100644
--- a/servers/rendering/renderer_rd/shaders/light_data_inc.glsl
+++ b/servers/rendering/renderer_rd/shaders/light_data_inc.glsl
@@ -1,3 +1,6 @@
+#define LIGHT_BAKE_DISABLED 0
+#define LIGHT_BAKE_DYNAMIC 1
+#define LIGHT_BAKE_STATIC 2
 
 struct LightData { //this structure needs to be as packed as possible
 	vec3 position;
@@ -23,7 +26,7 @@ struct LightData { //this structure needs to be as packed as possible
 	float soft_shadow_scale; // scales the shadow kernel for blurrier shadows
 	uint mask;
 	float shadow_volumetric_fog_fade;
-	uint pad;
+	uint bake_mode;
 	vec4 projector_rect; //projector rect in srgb decal atlas
 };
 
@@ -60,7 +63,8 @@ struct DirectionalLightData {
 	bool shadow_enabled;
 	float fade_from;
 	float fade_to;
-	uvec3 pad;
+	uvec2 pad;
+	uint bake_mode;
 	float shadow_volumetric_fog_fade;
 	vec4 shadow_bias;
 	vec4 shadow_normal_bias;
diff --git a/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl b/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
index 0bb16a8b29..1d67a3f1df 100644
--- a/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
+++ b/servers/rendering/renderer_rd/shaders/scene_forward_clustered.glsl
@@ -1227,6 +1227,10 @@ void main() {
 				continue; //not masked
 			}
 
+			if (directional_lights.data[i].bake_mode == LIGHT_BAKE_STATIC && bool(instances.data[instance_index].flags & INSTANCE_FLAGS_USE_LIGHTMAP)) {
+				continue; // Statically baked light and object uses lightmap, skip
+			}
+
 			float shadow = 1.0;
 
 #ifdef USE_SOFT_SHADOWS
@@ -1676,6 +1680,10 @@ void main() {
 						continue; //not masked
 					}
 
+					if (omni_lights.data[light_index].bake_mode == LIGHT_BAKE_STATIC && bool(instances.data[instance_index].flags & INSTANCE_FLAGS_USE_LIGHTMAP)) {
+						continue; // Statically baked light and object uses lightmap, skip
+					}
+
 					float shadow = light_process_omni_shadow(light_index, vertex, view);
 
 					shadow = blur_shadow(shadow);
@@ -1749,6 +1757,10 @@ void main() {
 						continue; //not masked
 					}
 
+					if (spot_lights.data[light_index].bake_mode == LIGHT_BAKE_STATIC && bool(instances.data[instance_index].flags & INSTANCE_FLAGS_USE_LIGHTMAP)) {
+						continue; // Statically baked light and object uses lightmap, skip
+					}
+
 					float shadow = light_process_spot_shadow(light_index, vertex, view);
 
 					shadow = blur_shadow(shadow);