builtin shape sdfs

Author: Erfan-Ahmadi

include/nbl/builtin/hlsl/shapes/circle.hlsl

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+namespace nbl
+{
+namespace hlsl
+{
+namespace shapes
+{
+	struct Circle_t
+	{
+		float2 center;
+		float radius;
+
+		Circle_t(float2 center, float radius) :
+			center(center),
+			radius(radius)
+		{}
+
+		float getSignedDistance(float2 p)
+		{
+			return distance(p, center) - radius;
+		}
+	};
+}
+}
+}

include/nbl/builtin/hlsl/shapes/line.hlsl

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+namespace nbl
+{
+namespace hlsl
+{
+namespace shapes
+{
+	struct Line_t
+	{
+		float2 start, end;
+
+		// https://www.shadertoy.com/view/stcfzn with modifications
+		float getSignedDistance(float2 p, float thickness)
+		{
+			const float l = length(end - start);
+			const float2  d = (end - start) / l;
+			float2  q = p - (start + end) * 0.5;
+			q = mul(float2x2(d.x, d.y, -d.y, d.x), q);
+			q = abs(q) - float2(l * 0.5, thickness);
+			return length(max(q, 0.0)) + min(max(q.x, q.y), 0.0);
+		}
+	};
+}
+}
+}

include/nbl/builtin/hlsl/shapes/rounded_line.hlsl

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+#include <nbl/builtin/hlsl/shapes/line.hlsl>
+#include <nbl/builtin/hlsl/shapes/circle.hlsl>
+
+namespace nbl
+{
+namespace hlsl
+{
+namespace shapes
+{
+	struct RoundedLine_t
+	{
+		float2 start, end;
+
+		float getSignedDistance(float2 p, float thickness)
+		{
+			Circle_t startCircle = {start, thickness};
+			Circle_t endCircle = {end, thickness};
+			Line_t mainLine = {start, end};
+			const float startCircleSD = startCircle.getSignedDistance(p);
+			const float endCircleSD = endCircle.getSignedDistance(p);
+			const float lineSD = mainLine.getSignedDistance(p, thickness);
+			return min(lineSD, min(startCircleSD, endCircleSD));
+		}
+	};
+}
+}
+}