From 1407c30f51fc645ea8a42543d51f0d7a17f2548e Mon Sep 17 00:00:00 2001
From: Oriol Ferrer Mesia <oriol@uri.cat>
Date: Thu, 22 Oct 2020 01:50:50 +0200
Subject: [PATCH] add crt-blurPi slang shader variants

---
 crt/crt-blurPi-sharp.slangp  | 11 +++++
 crt/crt-blurPi-soft.slangp   |  7 +++
 crt/shaders/crt-blurPi.slang | 84 ++++++++++++++++++++++++++++++++++++
 3 files changed, 102 insertions(+)
 create mode 100644 crt/crt-blurPi-sharp.slangp
 create mode 100644 crt/crt-blurPi-soft.slangp
 create mode 100644 crt/shaders/crt-blurPi.slang

diff --git a/crt/crt-blurPi-sharp.slangp b/crt/crt-blurPi-sharp.slangp
new file mode 100644
index 0000000..ff6c67a
--- /dev/null
+++ b/crt/crt-blurPi-sharp.slangp
@@ -0,0 +1,11 @@
+shaders = 1
+
+shader0 = shaders/crt-blurPi.slang
+filter_linear0 = false
+scale_type0 = viewport
+scale0 = 1.0
+alias0 = "PASS0"
+
+parameters = "blurGain;blurRadius"
+blurGain = "0.5"
+blurRadius = "1.5"
diff --git a/crt/crt-blurPi-soft.slangp b/crt/crt-blurPi-soft.slangp
new file mode 100644
index 0000000..e1ec12b
--- /dev/null
+++ b/crt/crt-blurPi-soft.slangp
@@ -0,0 +1,7 @@
+shaders = 1
+
+shader0 = shaders/crt-blurPi.slang
+filter_linear0 = true
+scale_type0 = viewport
+scale0 = 1.0
+alias0 = "PASS0"
\ No newline at end of file
diff --git a/crt/shaders/crt-blurPi.slang b/crt/shaders/crt-blurPi.slang
new file mode 100644
index 0000000..8976bd8
--- /dev/null
+++ b/crt/shaders/crt-blurPi.slang
@@ -0,0 +1,84 @@
+#version 450
+
+/*
+
+- crt-blurPi slang shader -
+
+Looks good on low res screens (640 x 480 or less), providing screen space scanlines.
+Developed on and for the Raspberry Pi.
+
+Made by Oriol Ferrer Mesià (armadillu)
+http://uri.cat
+
+MIT license
+*/
+
+
+layout(push_constant) uniform Push{
+	vec4 SourceSize;
+	vec4 OriginalSize;
+	vec4 OutputSize;
+	uint FrameCount;
+	//params....
+	float scanlineGain;
+	float rgbExtraGain;
+	float blurGain;	
+	float blurRadius;
+}params;
+
+
+#pragma name crt-blurPi
+#pragma parameter scanlineGain "scanlineGain" 	0.30 	0.0 	1.0 	0.05
+#pragma parameter rgbExtraGain "rgbExtraGain" 	0.10 	0.0 	1.0 	0.05
+#pragma parameter blurGain "blurGain" 			0.15 	0.0 	1.0 	0.05
+#pragma parameter blurRadius "blurRadius" 		1.5 	0.1 	3.0 	0.1
+
+layout(std140, set = 0, binding = 0) uniform UBO{
+	mat4 MVP;
+}global;
+
+
+
+/////////////////////////////////////////////////////////////////////////////////////////
+#pragma stage vertex
+/////////////////////////////////////////////////////////////////////////////////////////
+
+layout(location = 0) in vec4 Position;
+layout(location = 1) in vec2 TexCoord;
+layout(location = 0) out vec2 vTexCoord;
+layout(location = 1) out vec2 dot_size;
+
+void main(){
+	gl_Position = global.MVP * Position;
+	vTexCoord = TexCoord;
+	dot_size = params.SourceSize.zw;
+}
+
+
+/////////////////////////////////////////////////////////////////////////////////////////
+#pragma stage fragment
+/////////////////////////////////////////////////////////////////////////////////////////
+
+layout(location = 0) in vec2 vTexCoord;
+layout(location = 1) in vec2 dot_size;
+layout(location = 0) out vec4 FragColor;
+layout(set = 0, binding = 2) uniform sampler2D Source;
+
+void main(){
+
+	float time = mod(params.FrameCount / 60.0, params.OutputSize.y);
+
+	const vec2 off = params.blurRadius * dot_size;
+	float srcGain = 1.0f - 0.75f * params.blurGain;
+
+	vec4 blurred = srcGain * (1.0f + params.rgbExtraGain) * texture(Source, vTexCoord) + 
+   				0.25f * params.blurGain * texture(Source, vTexCoord + vec2(-off.x ,0.0f)) +
+   				0.25f * params.blurGain * texture(Source, vTexCoord + vec2(off.x, 0.0f)) +
+   				0.25f * params.blurGain * texture(Source, vTexCoord + vec2(0.0f, off.y))
+   				;
+
+	float scanLine = mod(int(vTexCoord.y * params.OutputSize.y), 2.0f);
+
+	FragColor = mix(1.0f, scanLine * scanLine, params.scanlineGain) * blurred;
+
+}
\ No newline at end of file