src/BulletMultiThreaded/GpuSoftBodySolvers/DX11/HLSL/SolvePositions.hlsl

   1 MSTRINGIFY(\r
   2 \r
   3 cbuffer SolvePositionsFromLinksKernelCB : register( b0 )\r
   4 {\r
   5         int startLink;\r
   6         int numLinks;\r
   7         float kst;\r
   8         float ti;\r
   9 };\r
  10 \r
  11 // Node indices for each link\r
  12 StructuredBuffer<int2> g_linksVertexIndices : register( t0 );\r
  13 \r
  14 StructuredBuffer<float> g_linksMassLSC : register( t1 );\r
  15 StructuredBuffer<float> g_linksRestLengthSquared : register( t2 );\r
  16 StructuredBuffer<float> g_verticesInverseMass : register( t3 );\r
  17 \r
  18 RWStructuredBuffer<float4> g_vertexPositions : register( u0 );\r
  19 \r
  20 [numthreads(128, 1, 1)]\r
  21 void \r
  22 SolvePositionsFromLinksKernel( uint3 Gid : SV_GroupID, uint3 DTid : SV_DispatchThreadID, uint3 GTid : SV_GroupThreadID, uint GI : SV_GroupIndex )\r
  23 {\r
  24         int linkID = DTid.x + startLink;\r
  25         if( DTid.x < numLinks )\r
  26         {       \r
  27                 float massLSC = g_linksMassLSC[linkID];\r
  28                 float restLengthSquared = g_linksRestLengthSquared[linkID];\r
  29                 \r
  30                 if( massLSC > 0.0f )\r
  31                 {               \r
  32                         int2 nodeIndices = g_linksVertexIndices[linkID];\r
  33                         int node0 = nodeIndices.x;\r
  34                         int node1 = nodeIndices.y;\r
  35                         \r
  36                         float3 position0 = g_vertexPositions[node0].xyz;\r
  37                         float3 position1 = g_vertexPositions[node1].xyz;\r
  38 \r
  39                         float inverseMass0 = g_verticesInverseMass[node0];\r
  40                         float inverseMass1 = g_verticesInverseMass[node1]; \r
  41 \r
  42                         float3 del = position1 - position0;\r
  43                         float len = dot(del, del);\r
  44                         float k = ((restLengthSquared - len)/(massLSC*(restLengthSquared+len)))*kst;\r
  45                         position0 = position0 - del*(k*inverseMass0);\r
  46                         position1 = position1 + del*(k*inverseMass1);\r
  47 \r
  48                         g_vertexPositions[node0] = float4(position0, 0.f);\r
  49                         g_vertexPositions[node1] = float4(position1, 0.f);\r
  50 \r
  51                 }\r
  52         }\r
  53 }\r
  54 \r
  55 );