From 99d25b5ef615a23ef63645fea87596b3384b5ede Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 15 Jun 2019 15:23:02 +0300
Subject: [PATCH] Make ambient occlusion edge detection threshold adjustable

This may be necessary to avoid artifacts when running the postprocessor
at a reduced resolution.
---
 shaderlib/ambientocclusion.glsl         |  1 +
 shaderlib/ambientocclusion_combine.glsl |  2 +-
 source/ambientocclusion.cpp             | 11 ++++++++++-
 source/ambientocclusion.h               |  2 ++
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/shaderlib/ambientocclusion.glsl b/shaderlib/ambientocclusion.glsl
index 7f1e79a0..a9873b1d 100644
--- a/shaderlib/ambientocclusion.glsl
+++ b/shaderlib/ambientocclusion.glsl
@@ -12,6 +12,7 @@ uniform AmbientOcclusionParams
 	vec3 sample_points[max_samples];
 	int n_samples;
 	float occlusion_radius;
+	float edge_depth_threshold;
 };
 
 #pragma MSP stage(fragment)
diff --git a/shaderlib/ambientocclusion_combine.glsl b/shaderlib/ambientocclusion_combine.glsl
index 05aea60a..c1e7f272 100644
--- a/shaderlib/ambientocclusion_combine.glsl
+++ b/shaderlib/ambientocclusion_combine.glsl
@@ -15,7 +15,7 @@ void main()
 			vec2 sample_coord = texcoord+offset*tex_scale;
 			float occ = texture(occlusion, sample_coord).r;
 			float sample = texture(depth, sample_coord).r;
-			float z_range = occlusion_radius*length(offset)*0.1;
+			float z_range = occlusion_radius*length(offset)*edge_depth_threshold;
 			float min_depth = project(vec3(center.xy, center.z+z_range)).z;
 			float max_depth = project(vec3(center.xy, center.z-z_range)).z;
 			if(sample>=min_depth && sample<=max_depth)
diff --git a/source/ambientocclusion.cpp b/source/ambientocclusion.cpp
index 0079009b..ed7d1636 100644
--- a/source/ambientocclusion.cpp
+++ b/source/ambientocclusion.cpp
@@ -47,6 +47,7 @@ AmbientOcclusion::AmbientOcclusion(unsigned w, unsigned h, float):
 	set_n_samples(16);
 	set_occlusion_radius(0.5f);
 	set_darkness(1.0f);
+	set_edge_depth_threshold(0.1f);
 }
 
 float AmbientOcclusion::random(unsigned &seed)
@@ -87,6 +88,11 @@ void AmbientOcclusion::set_darkness(float darkness)
 	shdata.uniform("darkness", darkness);
 }
 
+void AmbientOcclusion::set_edge_depth_threshold(float edt)
+{
+	shdata.uniform("edge_depth_threshold", edt);
+}
+
 void AmbientOcclusion::render(Renderer &renderer, const Texture2D &color, const Texture2D &depth)
 {
 	texturing.attach(0, color);
@@ -112,7 +118,8 @@ void AmbientOcclusion::render(Renderer &renderer, const Texture2D &color, const
 AmbientOcclusion::Template::Template():
 	n_samples(16),
 	occlusion_radius(0.5f),
-	darkness(1.0f)
+	darkness(1.0f),
+	edge_depth_threshold(0.1f)
 { }
 
 AmbientOcclusion *AmbientOcclusion::Template::create(unsigned width, unsigned height) const
@@ -121,6 +128,7 @@ AmbientOcclusion *AmbientOcclusion::Template::create(unsigned width, unsigned he
 	ao->set_n_samples(n_samples);
 	ao->set_occlusion_radius(occlusion_radius);
 	ao->set_darkness(darkness);
+	ao->set_edge_depth_threshold(edge_depth_threshold);
 	return ao.release();
 }
 
@@ -129,6 +137,7 @@ AmbientOcclusion::Template::Loader::Loader(Template &t):
 	DataFile::DerivedObjectLoader<Template, PostProcessor::Template::Loader>(t)
 {
 	add("darkness", &Template::darkness);
+	add("edge_depth_threshold", &Template::edge_depth_threshold);
 	add("occlusion_radius", &Template::occlusion_radius);
 	add("samples", &Template::n_samples);
 }
diff --git a/source/ambientocclusion.h b/source/ambientocclusion.h
index e7829c18..41918994 100644
--- a/source/ambientocclusion.h
+++ b/source/ambientocclusion.h
@@ -32,6 +32,7 @@ public:
 		unsigned n_samples;
 		float occlusion_radius;
 		float darkness;
+		float edge_depth_threshold;
 
 		Template();
 
@@ -56,6 +57,7 @@ private:
 public:
 	void set_n_samples(unsigned);
 	void set_occlusion_radius(float);
+	void set_edge_depth_threshold(float);
 
 	// Deprecated
 	void set_depth_ratio(float);
-- 
2.43.0