86 lines
2.8 KiB
Plaintext
86 lines
2.8 KiB
Plaintext
// Inspired by https://github.com/keijiro/Boids
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#include "../../../Resources/Compute/Include/PlatformDefines.hlsl"
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#pragma kernel CSGPUIBoids
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RWStructuredBuffer<float4x4> boidsData;
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uniform uint bufferSize;
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uniform Texture2D<float4> noiseTexture;
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uniform SamplerState samplernoiseTexture;
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uniform float4x4 controllerTransform;
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uniform float controllerVelocity;
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uniform float controllerVelocityVariation;
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uniform float controllerRotationCoeff;
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uniform float controllerNeighborDist;
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uniform float time;
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uniform float deltaTime;
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#include "../../../Resources/Compute/Include/DataModel.hlsl"
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#include "../../../Resources/Compute/Include/Matrix.hlsl"
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float3 GetSeparationVector(float3 pos, float3 targetPos)
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{
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float3 diff = pos - targetPos;
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float diffLen = length(diff);
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float scaler = clamp(1.0f - diffLen / controllerNeighborDist, 0, 1);
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return diff * (scaler / diffLen);
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}
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[numthreads(GPUI_THREADS, 1, 1)]
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void CSGPUIBoids(uint3 id : SV_DispatchThreadID)
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{
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if (id.x >= bufferSize)
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return;
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float4x4 boid = boidsData[id.x];
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float3 currentPosition = boid._14_24_34;
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float3 currentDirection = boid._13_23_33;
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// Current velocity randomized with noise.
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float4 noiseTxt = noiseTexture.SampleLevel(samplernoiseTexture, float2(time / 100.0, (float(id.x) / float(bufferSize))), 0);
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float velocity = controllerVelocity * (1.0 + lerp(0, lerp(-1, 1, noiseTxt.r), controllerVelocityVariation));
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// Initializes the vectors.
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float3 separation = float3(0, 0, 0);
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float3 alignment = float3(0, 0, 0);
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float3 cohesion = controllerTransform._14_24_34;
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uint nearbyCount = 1;
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// Accumulates the vectors.
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for (uint i = 0; i < bufferSize; i++)
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{
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if (i == id.x)
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continue;
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float4x4 checkBoid = boidsData[i];
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float3 checkPos = checkBoid._14_24_34;
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if (distance(currentPosition, checkPos) <= controllerNeighborDist)
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{
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separation += GetSeparationVector(currentPosition, checkPos);
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alignment += checkBoid._13_23_33;
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cohesion += checkPos;
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nearbyCount++;
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}
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}
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float avg = 1.0f / nearbyCount;
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alignment *= avg;
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cohesion *= avg;
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cohesion = normalize(cohesion - currentPosition);
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// Calculates a rotation from the vectors.
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float3 direction = normalize(separation + alignment + cohesion);
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// Applys the rotation with interpolation.
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float ip = frac(exp(-controllerRotationCoeff * deltaTime) * controllerRotationCoeff / 100);
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float4x4 newRotation = SetMatrixRotationWithQuaternion(identityMatrix, FromToRotation(float3(0, 0, 1), lerp(currentDirection, direction, ip)));
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// Moves forward.
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currentPosition = currentPosition + newRotation._13_23_33 * (velocity * deltaTime);
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boidsData[id.x] = TRS(currentPosition, newRotation, vector3One);
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}
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