Files
LNXSDK/lib/haxejolt/JoltPhysics/Jolt/Shaders/HairGridAccumulate.hlsl
2026-03-04 00:50:15 -08:00

51 lines
2.2 KiB
HLSL

// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
// SPDX-FileCopyrightText: 2026 Jorrit Rouwe
// SPDX-License-Identifier: MIT
#include "HairGridAccumulateBindings.h"
#include "HairCommon.h"
void AtomicAddVelocityAndDensity(uint inIndex, int4 inValue)
{
JPH_AtomicAdd(gVelocityAndDensity[inIndex].x, inValue.x);
JPH_AtomicAdd(gVelocityAndDensity[inIndex].y, inValue.y);
JPH_AtomicAdd(gVelocityAndDensity[inIndex].z, inValue.z);
JPH_AtomicAdd(gVelocityAndDensity[inIndex].w, inValue.w);
}
JPH_SHADER_FUNCTION_BEGIN(void, main, cHairPerVertexBatch, 1, 1)
JPH_SHADER_PARAM_THREAD_ID(tid)
JPH_SHADER_FUNCTION_END
{
// Check that we are processing a valid vertex
uint vtx = tid.x + cNumStrands; // Skip the root of each strand, it's fixed
if (vtx >= cNumVertices)
return;
if (IsVertexFixed(gVerticesFixed, vtx))
return;
// Convert position to grid index and fraction
uint3 index;
float3 ma;
GridPositionToIndexAndFraction(gPositions[vtx].mPosition, index, ma);
float3 a = float3(1, 1, 1) - ma;
// Get velocity
float4 velocity_and_density = float4(gVelocities[vtx].mVelocity, 1) * cFloatToFixed;
// Calculate contribution of density and velocity for each cell
uint3 stride = cGridStride;
uint adr_000 = GridIndexToBufferIndex(index);
uint adr_100 = adr_000 + 1;
uint adr_010 = adr_000 + stride.y;
uint adr_110 = adr_010 + 1;
AtomicAddVelocityAndDensity(adr_000, (int4)round( a.x * a.y * a.z * velocity_and_density));
AtomicAddVelocityAndDensity(adr_100, (int4)round(ma.x * a.y * a.z * velocity_and_density));
AtomicAddVelocityAndDensity(adr_010, (int4)round( a.x * ma.y * a.z * velocity_and_density));
AtomicAddVelocityAndDensity(adr_110, (int4)round(ma.x * ma.y * a.z * velocity_and_density));
AtomicAddVelocityAndDensity(adr_000 + stride.z, (int4)round( a.x * a.y * ma.z * velocity_and_density));
AtomicAddVelocityAndDensity(adr_100 + stride.z, (int4)round(ma.x * a.y * ma.z * velocity_and_density));
AtomicAddVelocityAndDensity(adr_010 + stride.z, (int4)round( a.x * ma.y * ma.z * velocity_and_density));
AtomicAddVelocityAndDensity(adr_110 + stride.z, (int4)round(ma.x * ma.y * ma.z * velocity_and_density));
}