T2-CPP/Mod Sources/Bullet/include/bullet/BulletMultiThreaded/GpuSoftBodySolvers/DX11/HLSL/SolvePositions.hlsl

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1.5 KiB
HLSL

MSTRINGIFY(
cbuffer SolvePositionsFromLinksKernelCB : register( b0 )
{
int startLink;
int numLinks;
float kst;
float ti;
};
// Node indices for each link
StructuredBuffer<int2> g_linksVertexIndices : register( t0 );
StructuredBuffer<float> g_linksMassLSC : register( t1 );
StructuredBuffer<float> g_linksRestLengthSquared : register( t2 );
StructuredBuffer<float> g_verticesInverseMass : register( t3 );
RWStructuredBuffer<float4> g_vertexPositions : register( u0 );
[numthreads(128, 1, 1)]
void
SolvePositionsFromLinksKernel( uint3 Gid : SV_GroupID, uint3 DTid : SV_DispatchThreadID, uint3 GTid : SV_GroupThreadID, uint GI : SV_GroupIndex )
{
int linkID = DTid.x + startLink;
if( DTid.x < numLinks )
{
float massLSC = g_linksMassLSC[linkID];
float restLengthSquared = g_linksRestLengthSquared[linkID];
if( massLSC > 0.0f )
{
int2 nodeIndices = g_linksVertexIndices[linkID];
int node0 = nodeIndices.x;
int node1 = nodeIndices.y;
float3 position0 = g_vertexPositions[node0].xyz;
float3 position1 = g_vertexPositions[node1].xyz;
float inverseMass0 = g_verticesInverseMass[node0];
float inverseMass1 = g_verticesInverseMass[node1];
float3 del = position1 - position0;
float len = dot(del, del);
float k = ((restLengthSquared - len)/(massLSC*(restLengthSquared+len)))*kst;
position0 = position0 - del*(k*inverseMass0);
position1 = position1 + del*(k*inverseMass1);
g_vertexPositions[node0] = float4(position0, 0.f);
g_vertexPositions[node1] = float4(position1, 0.f);
}
}
}
);