Implement Physical Light Units as an optional setting.

This allows light sources to be specified in physical light units in addition to the regular energy multiplier. In order to avoid loss of precision at high values, brightness values are premultiplied by an exposure normalization value.

In support of Physical Light Units this PR also renames CameraEffects to CameraAttributes.

3 files changed, 8 insertions, 2 deletions

diff --git a/modules/lightmapper_rd/lightmapper_rd.cpp b/modules/lightmapper_rd/lightmapper_rd.cpp
index 2dcf644a06..5b039e65c0 100644
--- a/modules/lightmapper_rd/lightmapper_rd.cpp
+++ b/modules/lightmapper_rd/lightmapper_rd.cpp
@@ -670,7 +670,7 @@ LightmapperRD::BakeError LightmapperRD::_dilate(RenderingDevice *rd, Ref<RDShade
 	return BAKE_OK;
 }
 
-LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_denoiser, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function, void *p_bake_userdata) {
+LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_denoiser, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function, void *p_bake_userdata, float p_exposure_normalization) {
 	if (p_step_function) {
 		p_step_function(0.0, RTR("Begin Bake"), p_bake_userdata, true);
 	}
@@ -1165,6 +1165,8 @@ LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_d
 		rd->compute_list_bind_uniform_set(compute_list, compute_base_uniform_set, 0);
 		rd->compute_list_bind_uniform_set(compute_list, light_uniform_set, 1);
 
+		push_constant.environment_xform[11] = p_exposure_normalization;
+
 		for (int i = 0; i < atlas_slices; i++) {
 			push_constant.atlas_slice = i;
 			rd->compute_list_set_push_constant(compute_list, &push_constant, sizeof(PushConstant));
@@ -1172,6 +1174,8 @@ LightmapperRD::BakeError LightmapperRD::bake(BakeQuality p_quality, bool p_use_d
 			//no barrier, let them run all together
 		}
 		rd->compute_list_end(); //done
+
+		push_constant.environment_xform[11] = 0.0;
 	}
 
 #ifdef DEBUG_TEXTURES
diff --git a/modules/lightmapper_rd/lightmapper_rd.h b/modules/lightmapper_rd/lightmapper_rd.h
index bf6b4399ca..b33a475dbc 100644
--- a/modules/lightmapper_rd/lightmapper_rd.h
+++ b/modules/lightmapper_rd/lightmapper_rd.h
@@ -241,7 +241,7 @@ public:
 	virtual void add_omni_light(bool p_static, const Vector3 &p_position, const Color &p_color, float p_energy, float p_range, float p_attenuation, float p_size, float p_shadow_blur) override;
 	virtual void add_spot_light(bool p_static, const Vector3 &p_position, const Vector3 p_direction, const Color &p_color, float p_energy, float p_range, float p_attenuation, float p_spot_angle, float p_spot_attenuation, float p_size, float p_shadow_blur) override;
 	virtual void add_probe(const Vector3 &p_position) override;
-	virtual BakeError bake(BakeQuality p_quality, bool p_use_denoiser, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function = nullptr, void *p_bake_userdata = nullptr) override;
+	virtual BakeError bake(BakeQuality p_quality, bool p_use_denoiser, int p_bounces, float p_bias, int p_max_texture_size, bool p_bake_sh, GenerateProbes p_generate_probes, const Ref<Image> &p_environment_panorama, const Basis &p_environment_transform, BakeStepFunc p_step_function = nullptr, void *p_bake_userdata = nullptr, float p_exposure_normalization = 1.0) override;
 
 	int get_bake_texture_count() const override;
 	Ref<Image> get_bake_texture(int p_index) const override;
diff --git a/modules/lightmapper_rd/lm_compute.glsl b/modules/lightmapper_rd/lm_compute.glsl
index efa6cd50b4..c2557dfed3 100644
--- a/modules/lightmapper_rd/lm_compute.glsl
+++ b/modules/lightmapper_rd/lm_compute.glsl
@@ -434,6 +434,7 @@ void main() {
 	imageStore(primary_dynamic, ivec3(atlas_pos, params.atlas_slice), vec4(dynamic_light, 1.0));
 
 	dynamic_light += static_light * albedo; //send for bounces
+	dynamic_light *= params.env_transform[2][3]; // exposure_normalization
 	imageStore(dest_light, ivec3(atlas_pos, params.atlas_slice), vec4(dynamic_light, 1.0));
 
 #ifdef USE_SH_LIGHTMAPS
@@ -444,6 +445,7 @@ void main() {
 	imageStore(accum_light, ivec3(atlas_pos, params.atlas_slice * 4 + 3), sh_accum[3]);
 
 #else
+	static_light *= params.env_transform[2][3]; // exposure_normalization
 	imageStore(accum_light, ivec3(atlas_pos, params.atlas_slice), vec4(static_light, 1.0));
 #endif