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

   1 MSTRINGIFY(\r
   2 \r
   3 cbuffer VSolveLinksCB : register( b0 )\r
   4 {\r
   5         int startLink;\r
   6         int numLinks;\r
   7         float kst;\r
   8         int padding;\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_linksLengthRatio : register( t1 );\r
  15 StructuredBuffer<float4> g_linksCurrentLength : register( t2 );\r
  16 StructuredBuffer<float> g_vertexInverseMass : register( t3 );\r
  17 \r
  18 RWStructuredBuffer<float4> g_vertexVelocity : register( u0 );\r
  19 \r
  20 [numthreads(128, 1, 1)]\r
  21 void \r
  22 VSolveLinksKernel( 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                 int2 nodeIndices = g_linksVertexIndices[linkID];\r
  28                 int node0 = nodeIndices.x;\r
  29                 int node1 = nodeIndices.y;\r
  30                 \r
  31                 float linkLengthRatio = g_linksLengthRatio[linkID];\r
  32                 float3 linkCurrentLength = g_linksCurrentLength[linkID].xyz;\r
  33                 \r
  34                 float3 vertexVelocity0 = g_vertexVelocity[node0].xyz;\r
  35                 float3 vertexVelocity1 = g_vertexVelocity[node1].xyz;\r
  36 \r
  37                 float vertexInverseMass0 = g_vertexInverseMass[node0];\r
  38                 float vertexInverseMass1 = g_vertexInverseMass[node1]; \r
  39 \r
  40                 float3 nodeDifference = vertexVelocity0 - vertexVelocity1;\r
  41                 float dotResult = dot(linkCurrentLength, nodeDifference);\r
  42                 float j = -dotResult*linkLengthRatio*kst;\r
  43                 \r
  44                 float3 velocityChange0 = linkCurrentLength*(j*vertexInverseMass0);\r
  45                 float3 velocityChange1 = linkCurrentLength*(j*vertexInverseMass1);\r
  46                 \r
  47                 vertexVelocity0 += velocityChange0;\r
  48                 vertexVelocity1 -= velocityChange1;\r
  49 \r
  50                 g_vertexVelocity[node0] = float4(vertexVelocity0, 0.f);\r
  51                 g_vertexVelocity[node1] = float4(vertexVelocity1, 0.f);\r
  52         }\r
  53 }\r
  54 \r
  55 );