78 lines
2.2 KiB
Plaintext
78 lines
2.2 KiB
Plaintext
#pragma kernel Project
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#pragma kernel Apply
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#include "MathUtils.cginc"
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#include "AtomicDeltas.cginc"
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StructuredBuffer<int> orientationIndices;
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StructuredBuffer<float3> stiffnesses;
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StructuredBuffer<float2> plasticity;
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RWStructuredBuffer<quaternion> restDarboux;
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RWStructuredBuffer<float3> lambdas;
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RWStructuredBuffer<quaternion> orientations;
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StructuredBuffer<float> invRotationalMasses;
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// Variables set from the CPU
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uint activeConstraintCount;
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float deltaTime;
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float sorFactor;
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[numthreads(128, 1, 1)]
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void Project (uint3 id : SV_DispatchThreadID)
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{
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unsigned int i = id.x;
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if (i >= activeConstraintCount) return;
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int q1 = orientationIndices[i * 2];
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int q2 = orientationIndices[i * 2 + 1];
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float w1 = invRotationalMasses[q1];
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float w2 = invRotationalMasses[q2];
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// calculate time adjusted compliance
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float3 compliances = stiffnesses[i] / (deltaTime * deltaTime);
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// rest and current darboux vectors
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quaternion rest = restDarboux[i];
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quaternion omega = qmul(q_conj(orientations[q1]), orientations[q2]);
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quaternion omega_plus;
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omega_plus = omega + rest; //delta Omega with - omega_0
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omega -= rest; //delta Omega with + omega_0
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if (dot(omega.xyz,omega.xyz) > dot(omega_plus.xyz,omega_plus.xyz))
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omega = omega_plus;
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// plasticity
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if (dot(omega.xyz, omega.xyz) > plasticity[i].x * plasticity[i].x)
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{
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rest += omega * plasticity[i].y * deltaTime;
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restDarboux[i] = rest;
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}
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float3 dlambda = (omega.xyz - compliances * lambdas[i]) / (compliances + w1 + w2 + EPSILON);
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//discrete Darboux vector does not have vanishing scalar part
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quaternion dlambdaQ = quaternion(dlambda[0], dlambda[1], dlambda[2],0);
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AddOrientationDelta(q1, qmul(orientations[q2], dlambdaQ) * w1);
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AddOrientationDelta(q2,-qmul(orientations[q1], dlambdaQ) * w2);
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lambdas[i] += dlambda;
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}
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[numthreads(128, 1, 1)]
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void Apply (uint3 id : SV_DispatchThreadID)
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{
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unsigned int i = id.x;
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if (i >= activeConstraintCount) return;
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int q1 = orientationIndices[i * 2];
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int q2 = orientationIndices[i * 2 + 1];
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ApplyOrientationDelta(orientations, q1, sorFactor);
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ApplyOrientationDelta(orientations, q2, sorFactor);
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} |