add bead by request :)

misc/bead.slang

@@ -0,0 +1,72 @@
+#version 450
+
+layout(push_constant) uniform Push
+{
+	vec4 SourceSize;
+	vec4 OriginalSize;
+	vec4 OutputSize;
+	uint FrameCount;
+   float BEAD_HIGH, BEAD_LOW;
+} params;
+
+#pragma parameter BEAD_HIGH "Bead High" 0.35 0.0 1.0 0.01
+#define BEAD_HIGH params.BEAD_HIGH
+#pragma parameter BEAD_LOW  "Bead Low"  0.2  0.0 1.0 0.01
+#define BEAD_LOW params.BEAD_LOW
+
+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 pixel_no;
+
+void main()
+{
+   gl_Position = global.MVP * Position;
+   vTexCoord = TexCoord;
+   pixel_no = vTexCoord * params.SourceSize.xy;
+}
+
+#pragma stage fragment
+layout(location = 0) in vec2 vTexCoord;
+layout(location = 1) in vec2 pixel_no;
+layout(location = 0) out vec4 FragColor;
+layout(set = 0, binding = 2) uniform sampler2D Source;
+
+float dist(vec2 coord, vec2 source)
+{
+   vec2 delta = coord - source;
+   return sqrt(dot(delta, delta));
+}
+
+float rolloff(float len)
+{
+   return exp(-6.0 * len);
+}
+
+vec3 lookup(vec2 pixel_no, vec3 color)
+{
+   float delta = dist(fract(pixel_no), vec2(0.5, 0.5));
+
+   if (delta > BEAD_LOW && delta < BEAD_HIGH)
+      return color;
+   else if (delta >= BEAD_HIGH)
+      return color * rolloff(delta - BEAD_HIGH);
+   else if (delta <= BEAD_LOW)
+      return color * rolloff(BEAD_LOW - delta);
+   else
+      return vec3(0.0, 0.0, 0.0);
+}
+
+#define TEX(coord) texture(Source, coord).rgb
+
+void main()
+{
+   vec3 mid_color = lookup(pixel_no, TEX(vTexCoord));
+   FragColor = vec4(mid_color, 1.0);
+}