Allow using between 1 and 8 cascades for SDFGI

This provides more flexibility between performance and quality
adjustments, especially when using SDFGI for small-scale levels
(which can be useful for procedurally generated scenes).

6 files changed, 13 insertions, 11 deletions

diff --git a/servers/rendering/renderer_rd/renderer_scene_environment_rd.cpp b/servers/rendering/renderer_rd/renderer_scene_environment_rd.cpp
index 7ea117ef33..0d0d7513d0 100644
--- a/servers/rendering/renderer_rd/renderer_scene_environment_rd.cpp
+++ b/servers/rendering/renderer_rd/renderer_scene_environment_rd.cpp
@@ -68,7 +68,7 @@ void RendererSceneEnvironmentRD::set_glow(bool p_enable, Vector<float> p_levels,
 	glow_hdr_luminance_cap = p_hdr_luminance_cap;
 }
 
-void RendererSceneEnvironmentRD::set_sdfgi(bool p_enable, RS::EnvironmentSDFGICascades p_cascades, float p_min_cell_size, RS::EnvironmentSDFGIYScale p_y_scale, bool p_use_occlusion, float p_bounce_feedback, bool p_read_sky, float p_energy, float p_normal_bias, float p_probe_bias) {
+void RendererSceneEnvironmentRD::set_sdfgi(bool p_enable, int p_cascades, float p_min_cell_size, RS::EnvironmentSDFGIYScale p_y_scale, bool p_use_occlusion, float p_bounce_feedback, bool p_read_sky, float p_energy, float p_normal_bias, float p_probe_bias) {
 	sdfgi_enabled = p_enable;
 	sdfgi_cascades = p_cascades;
 	sdfgi_min_cell_size = p_min_cell_size;
diff --git a/servers/rendering/renderer_rd/renderer_scene_environment_rd.h b/servers/rendering/renderer_rd/renderer_scene_environment_rd.h
index 9e36a61870..629d224b49 100644
--- a/servers/rendering/renderer_rd/renderer_scene_environment_rd.h
+++ b/servers/rendering/renderer_rd/renderer_scene_environment_rd.h
@@ -133,7 +133,7 @@ public:
 
 	/// SDFGI
 	bool sdfgi_enabled = false;
-	RS::EnvironmentSDFGICascades sdfgi_cascades;
+	int sdfgi_cascades = 6;
 	float sdfgi_min_cell_size = 0.2;
 	bool sdfgi_use_occlusion = false;
 	float sdfgi_bounce_feedback = 0.0;
@@ -155,7 +155,7 @@ public:
 	void set_ambient_light(const Color &p_color, RS::EnvironmentAmbientSource p_ambient, float p_energy, float p_sky_contribution, RS::EnvironmentReflectionSource p_reflection_source);
 	void set_tonemap(RS::EnvironmentToneMapper p_tone_mapper, float p_exposure, float p_white, bool p_auto_exposure, float p_min_luminance, float p_max_luminance, float p_auto_exp_speed, float p_auto_exp_scale);
 	void set_glow(bool p_enable, Vector<float> p_levels, float p_intensity, float p_strength, float p_mix, float p_bloom_threshold, RS::EnvironmentGlowBlendMode p_blend_mode, float p_hdr_bleed_threshold, float p_hdr_bleed_scale, float p_hdr_luminance_cap);
-	void set_sdfgi(bool p_enable, RS::EnvironmentSDFGICascades p_cascades, float p_min_cell_size, RS::EnvironmentSDFGIYScale p_y_scale, bool p_use_occlusion, float p_bounce_feedback, bool p_read_sky, float p_energy, float p_normal_bias, float p_probe_bias);
+	void set_sdfgi(bool p_enable, int p_cascades, float p_min_cell_size, RS::EnvironmentSDFGIYScale p_y_scale, bool p_use_occlusion, float p_bounce_feedback, bool p_read_sky, float p_energy, float p_normal_bias, float p_probe_bias);
 	void set_fog(bool p_enable, const Color &p_light_color, float p_light_energy, float p_sun_scatter, float p_density, float p_height, float p_height_density, float p_fog_aerial_perspective);
 	void set_volumetric_fog(bool p_enable, float p_density, const Color &p_scatterin, const Color &p_emission, float p_emission_energy, float p_anisotropy, float p_length, float p_detail_spread, float p_gi_inject, bool p_temporal_reprojection, float p_temporal_reprojection_amount, float p_ambient_inject);
 	void set_ssr(bool p_enable, int p_max_steps, float p_fade_int, float p_fade_out, float p_depth_tolerance);
diff --git a/servers/rendering/renderer_rd/renderer_scene_gi_rd.cpp b/servers/rendering/renderer_rd/renderer_scene_gi_rd.cpp
index 73cb088f6a..3069b1c379 100644
--- a/servers/rendering/renderer_rd/renderer_scene_gi_rd.cpp
+++ b/servers/rendering/renderer_rd/renderer_scene_gi_rd.cpp
@@ -42,14 +42,13 @@ const Vector3i RendererSceneGIRD::SDFGI::Cascade::DIRTY_ALL = Vector3i(0x7FFFFFF
 void RendererSceneGIRD::SDFGI::create(RendererSceneEnvironmentRD *p_env, const Vector3 &p_world_position, uint32_t p_requested_history_size, RendererSceneGIRD *p_gi) {
 	storage = p_gi->storage;
 	gi = p_gi;
-	cascade_mode = p_env->sdfgi_cascades;
+	num_cascades = p_env->sdfgi_cascades;
 	min_cell_size = p_env->sdfgi_min_cell_size;
 	uses_occlusion = p_env->sdfgi_use_occlusion;
 	y_scale_mode = p_env->sdfgi_y_scale;
 	static const float y_scale[3] = { 1.0, 1.5, 2.0 };
 	y_mult = y_scale[y_scale_mode];
-	static const int cascasde_size[3] = { 4, 6, 8 };
-	cascades.resize(cascasde_size[cascade_mode]);
+	cascades.resize(num_cascades);
 	probe_axis_count = SDFGI::PROBE_DIVISOR + 1;
 	solid_cell_ratio = gi->sdfgi_solid_cell_ratio;
 	solid_cell_count = uint32_t(float(cascade_size * cascade_size * cascade_size) * solid_cell_ratio);
@@ -716,7 +715,10 @@ void RendererSceneGIRD::SDFGI::create(RendererSceneEnvironmentRD *p_env, const V
 			u.uniform_type = RD::UNIFORM_TYPE_IMAGE;
 			u.binding = 13;
 			RID parent_average;
-			if (i < cascades.size() - 1) {
+			if (cascades.size() == 1) {
+				// If there is only one SDFGI cascade, we can't use the previous cascade for blending.
+				parent_average = cascades[i].lightprobe_average_tex;
+			} else if (i < cascades.size() - 1) {
 				parent_average = cascades[i + 1].lightprobe_average_tex;
 			} else {
 				parent_average = cascades[i - 1].lightprobe_average_tex; //to use something, but it won't be used
diff --git a/servers/rendering/renderer_rd/renderer_scene_gi_rd.h b/servers/rendering/renderer_rd/renderer_scene_gi_rd.h
index a407199d0a..5e55262798 100644
--- a/servers/rendering/renderer_rd/renderer_scene_gi_rd.h
+++ b/servers/rendering/renderer_rd/renderer_scene_gi_rd.h
@@ -495,7 +495,7 @@ public:
 		float solid_cell_ratio = 0;
 		uint32_t solid_cell_count = 0;
 
-		RS::EnvironmentSDFGICascades cascade_mode;
+		int num_cascades = 6;
 		float min_cell_size = 0;
 		uint32_t probe_axis_count = 0; //amount of probes per axis, this is an odd number because it encloses endpoints
 
diff --git a/servers/rendering/renderer_rd/renderer_scene_render_rd.cpp b/servers/rendering/renderer_rd/renderer_scene_render_rd.cpp
index a499cedd2c..76ef5461ac 100644
--- a/servers/rendering/renderer_rd/renderer_scene_render_rd.cpp
+++ b/servers/rendering/renderer_rd/renderer_scene_render_rd.cpp
@@ -65,7 +65,7 @@ void RendererSceneRenderRD::sdfgi_update(RID p_render_buffers, RID p_environment
 	static const uint32_t history_frames_to_converge[RS::ENV_SDFGI_CONVERGE_MAX] = { 5, 10, 15, 20, 25, 30 };
 	uint32_t requested_history_size = history_frames_to_converge[gi.sdfgi_frames_to_converge];
 
-	if (rb->sdfgi && (rb->sdfgi->cascade_mode != env->sdfgi_cascades || rb->sdfgi->min_cell_size != env->sdfgi_min_cell_size || requested_history_size != rb->sdfgi->history_size || rb->sdfgi->uses_occlusion != env->sdfgi_use_occlusion || rb->sdfgi->y_scale_mode != env->sdfgi_y_scale)) {
+	if (rb->sdfgi && (rb->sdfgi->num_cascades != env->sdfgi_cascades || rb->sdfgi->min_cell_size != env->sdfgi_min_cell_size || requested_history_size != rb->sdfgi->history_size || rb->sdfgi->uses_occlusion != env->sdfgi_use_occlusion || rb->sdfgi->y_scale_mode != env->sdfgi_y_scale)) {
 		//configuration changed, erase
 		rb->sdfgi->erase();
 		memdelete(rb->sdfgi);
@@ -303,7 +303,7 @@ void RendererSceneRenderRD::environment_glow_set_use_high_quality(bool p_enable)
 	glow_high_quality = p_enable;
 }
 
-void RendererSceneRenderRD::environment_set_sdfgi(RID p_env, bool p_enable, RS::EnvironmentSDFGICascades p_cascades, float p_min_cell_size, RS::EnvironmentSDFGIYScale p_y_scale, bool p_use_occlusion, float p_bounce_feedback, bool p_read_sky, float p_energy, float p_normal_bias, float p_probe_bias) {
+void RendererSceneRenderRD::environment_set_sdfgi(RID p_env, bool p_enable, int p_cascades, float p_min_cell_size, RS::EnvironmentSDFGIYScale p_y_scale, bool p_use_occlusion, float p_bounce_feedback, bool p_read_sky, float p_energy, float p_normal_bias, float p_probe_bias) {
 	RendererSceneEnvironmentRD *env = environment_owner.get_or_null(p_env);
 	ERR_FAIL_COND(!env);
 
diff --git a/servers/rendering/renderer_rd/renderer_scene_render_rd.h b/servers/rendering/renderer_rd/renderer_scene_render_rd.h
index 6432ca99f0..08e084f5cc 100644
--- a/servers/rendering/renderer_rd/renderer_scene_render_rd.h
+++ b/servers/rendering/renderer_rd/renderer_scene_render_rd.h
@@ -1093,7 +1093,7 @@ public:
 	bool environment_is_ssr_enabled(RID p_env) const;
 	bool environment_is_sdfgi_enabled(RID p_env) const;
 
-	virtual void environment_set_sdfgi(RID p_env, bool p_enable, RS::EnvironmentSDFGICascades p_cascades, float p_min_cell_size, RS::EnvironmentSDFGIYScale p_y_scale, bool p_use_occlusion, float p_bounce_feedback, bool p_read_sky, float p_energy, float p_normal_bias, float p_probe_bias) override;
+	virtual void environment_set_sdfgi(RID p_env, bool p_enable, int p_cascades, float p_min_cell_size, RS::EnvironmentSDFGIYScale p_y_scale, bool p_use_occlusion, float p_bounce_feedback, bool p_read_sky, float p_energy, float p_normal_bias, float p_probe_bias) override;
 	virtual void environment_set_sdfgi_ray_count(RS::EnvironmentSDFGIRayCount p_ray_count) override;
 	virtual void environment_set_sdfgi_frames_to_converge(RS::EnvironmentSDFGIFramesToConverge p_frames) override;
 	virtual void environment_set_sdfgi_frames_to_update_light(RS::EnvironmentSDFGIFramesToUpdateLight p_update) override;