wehub-resource-sync
61 lines
1.6 KiB
HLSL
61 lines
1.6 KiB
HLSL
#include "shared/hash-functions.hlsl"
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#include "shared/point.hlsl"
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#include "shared/quat-functions.hlsl"
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cbuffer Params : register(b0)
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{
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float3 Center;
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float Radius;
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float StartAngle;
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float Scatter;
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}
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RWStructuredBuffer<Point> ResultPoints : u0; // output
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static float precision = 0.0001;
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static float phi = PI * (3. - sqrt(5.)); // golden angle in radians
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static float modPi = 2*PI * precision;
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static float toRad = PI/180;
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// Fix orientation so z aligns with sphere normal
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static float4 rot4 = qFromAngleAxis( -PI/2 , float3(1,0,0));
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static float4 rot5 = qMul(rot4, qFromAngleAxis( PI/2 , float3(0,0,1)));
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[numthreads(256,4,1)]
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void main(uint3 dtID : SV_DispatchThreadID)
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{
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uint count, stride;
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ResultPoints.GetDimensions(count, stride);
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int i = dtID.x;
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if(i >= count)
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return;
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float t = i / float(count - 1);
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float y = 1 - t * 2; // y goes from 1 to -1
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float radius = sqrt(1 - y * y); // radius at y
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float theta = i * precision;
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theta *= phi;
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theta %= modPi;
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theta /= precision;
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theta += StartAngle * toRad;
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theta += (hash11(i/123.71) -0.5) * Scatter;
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float x = cos(theta) * radius;
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float z = sin(theta) * radius;
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float3 position = float3(x,y,z);
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ResultPoints[i].Position = position * Radius + Center;
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ResultPoints[i].FX1 = 1;
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ResultPoints[i].FX2 = 1;
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float4 rot = qFromAngleAxis( theta, float3(0,-1,0));
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float angle4 = atan2( y, radius) - PI/2;
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float4 rot2 = qFromAngleAxis( angle4 , float3(0,0,1));
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ResultPoints[i].Rotation = qMul( qMul(rot,rot2) , rot5);
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ResultPoints[i].Color = 1;
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ResultPoints[i].Scale = 1;
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}
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