examples: Add 'Vignette' Filter Shader

data/examples/shaders/filter/vignette.effect

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+// Copyright 2021 Michael Fabian Dirks <info@xaymar.com>
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice,
+//    this list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+//    this list of conditions and the following disclaimer in the documentation
+//    and/or other materials provided with the distribution.
+// 3. Neither the name of the copyright holder nor the names of its contributors
+//    may be used to endorse or promote products derived from this software
+//    without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+
+// Always provided by OBS
+uniform float4x4 ViewProj<
+	bool automatic = true;
+	string name = "View Projection Matrix";
+>;
+
+// Provided by Stream Effects
+uniform texture2d InputA<
+	bool automatic = true;
+>;
+
+uniform float _00_vignette_area<
+	string name = "Vignetting Area";
+	string field_type = "slider";
+	float minimum = 0.;
+	float maximum = 100.;
+	float step = 0.01;
+	float scale = 0.01;
+> = 50.0;
+
+uniform float4 _01_vignette_color<
+	string name = "Vignette Color";
+	string field_type = "slider";
+	float4 minimum = {0., 0., 0., 0.};
+	float4 maximum = {100., 100., 100., 100.};
+	float4 step = {0.01, 0.01, 0.01, 0.01};
+	float4 scale = {0.01, 0.01, 0.01, 0.01};
+> = {0., 0., 0., 0.};
+
+uniform float _02_vignette_strength<
+	string name = "Vignette Strength";
+	string field_type = "slider";
+	float minimum = 0.;
+	float maximum = 100.;
+	float step = 0.01;
+	float scale = 0.01;
+> = 100.0;
+
+#define PI		3.1415926f
+#define TwoPI	6.2831853f
+#define HalfPI	1.5707963f
+
+// ---------- Shader Code
+sampler_state def_sampler {
+	AddressU  = Clamp;
+	AddressV  = Clamp;
+	Filter    = Linear;
+};
+
+struct VertData {
+	float4 pos : POSITION;
+	float2 uv  : TEXCOORD0;
+};
+
+VertData VSDefault(VertData v_in) {
+	VertData vert_out;
+	vert_out.pos = mul(float4(v_in.pos.xyz, 1.0), ViewProj);
+	vert_out.uv  = v_in.uv;
+	return vert_out;
+}
+
+float4 PSDefault(VertData v_in) : TARGET {
+    static const float2 center = float2(.5, .5);
+    float4 smp = InputA.Sample(def_sampler, v_in.uv);
+	float borderFade = clamp(((1. - distance(v_in.uv, center)) - (_00_vignette_area - .5)), 0., 1.);
+
+    float4 vignette_color = _01_vignette_color;
+	return lerp(smp, vignette_color, (1. - borderFade) / max(1. - _02_vignette_strength, 0.0001));
+}
+
+technique Draw
+{
+	pass
+	{
+		vertex_shader = VSDefault(v_in);
+		pixel_shader  = PSDefault(v_in);
+	}
+}
+
+float4 PSRectangle(VertData v_in) : TARGET {
+    static const float2 center = float2(.5, .5);
+    float4 smp = InputA.Sample(def_sampler, v_in.uv);
+
+    if (_00_vignette_area < 0.01)
+        return smp;
+
+	float2 borderArea = center * _00_vignette_area;
+	float2 borderDistance = center;
+    borderDistance -= abs(v_in.uv - center);
+    borderDistance /= center;
+    borderDistance -= center * _00_vignette_area;
+    borderDistance = min(borderDistance, 0);
+    borderDistance += borderArea;
+    borderDistance /= borderArea;
+
+	// Now apply a modifier so that we only get the border area.
+	float borderFade = sin(borderDistance.x * HalfPI) * sin(borderDistance.y * HalfPI);
+
+	return lerp(smp, _01_vignette_color, (1. - borderFade) * _02_vignette_strength);
+}
+
+technique Rectangle
+{
+	pass
+	{
+		vertex_shader = VSDefault(v_in);
+		pixel_shader  = PSRectangle(v_in);
+	}
+}