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update default sph parameters

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This commit is contained in:
turanszkij
2018-05-07 16:10:30 +01:00
parent 0bd3ada39e
commit 2c59503ff9
2 changed files with 76 additions and 69 deletions
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WickedEngine/emittedparticle_nbodyCS.hlsl
+73 -66
View File
@@ -1,6 +1,14 @@
#include "globals.hlsli"
#include "ShaderInterop_EmittedParticle.h"
// enable pressure visualizer debug colors:
// green - under reference pressure
// red - above reference pressure
//#define DEBUG_PRESSURE
#define FLOOR_COLLISION
#define BOX_COLLISION
RWSTRUCTUREDBUFFER(particleBuffer, Particle, 0);
RWSTRUCTUREDBUFFER(aliveBuffer_CURRENT, uint, 1);
RWSTRUCTUREDBUFFER(aliveBuffer_NEW, uint, 2);
@@ -42,7 +50,7 @@ void main( uint3 DTid : SV_DispatchThreadID, uint groupIndex : SV_GroupIndex, ui
GroupMemoryBarrierWithGroupSync();
const uint LDSParticleCount = /*clamp(aliveCount - Gid.x * THREADCOUNT_SIMULATION, 0, THREADCOUNT_SIMULATION)*/ 256;
const uint LDSParticleCount = clamp(aliveCount - Gid.x * THREADCOUNT_SIMULATION, 0, THREADCOUNT_SIMULATION);
uint particleIndexA = groupIndex;
@@ -87,15 +95,13 @@ void main( uint3 DTid : SV_DispatchThreadID, uint groupIndex : SV_GroupIndex, ui
}
}
int asd = 0;
if (particleA.p > p0) asd = 1;
if (particleA.p < p0) asd = -1;
bool pressure_debug = particleA.p > p0 ? true : false;
// Can't be lower than reference density to avoid negative pressure!
//particleA.p = max(p0, particleA.p);
particleA.p = max(p0, particleA.p);
// Compute particle pressure:
particleA.P = K * (max(p0, particleA.p) - p0);
particleA.P = K * (particleA.p - p0);
// Store the results:
LDSParticles[particleIndexA].p = particleA.p;
@@ -106,86 +112,93 @@ void main( uint3 DTid : SV_DispatchThreadID, uint groupIndex : SV_GroupIndex, ui
GroupMemoryBarrierWithGroupSync();
if (particleA.p > 0)
// Compute acceleration:
float3 a = 0; // pressure force
float3 av = 0; // viscosity force
for (i = 0; i < LDSParticleCount; ++i)
{
// Compute acceleration:
float3 a = 0; // pressure force
float3 av = 0; // viscosity force
for (i = 0; i < LDSParticleCount; ++i)
if (i != particleIndexA)
{
if (i != particleIndexA)
uint particleIndexB = i;
LDSParticle particleB = LDSParticles[particleIndexB];
float3 diff = particleA.position - particleB.position;
float r2 = dot(diff, diff); // distance squared
float r = sqrt(r2);
//float range = particleA.size + particleB.size; // range of affection
if (r < h)
{
uint particleIndexB = i;
LDSParticle particleB = LDSParticles[particleIndexB];
float3 rNorm = normalize(diff);
float W = (-45 / (PI * h6)) * pow(h - r, 2); // spiky kernel smoothing function
float3 diff = particleA.position - particleB.position;
float r2 = dot(diff, diff); // distance squared
float r = sqrt(r2);
//float range = particleA.size + particleB.size; // range of affection
if (r < h)
{
float3 rNorm = normalize(diff);
float W = (-45 / (PI * h6)) * pow(h - r, 2); // spiky kernel smoothing function
a += (particleB.m / particleA.m) * ((particleA.P + particleB.P) / (2 * particleA.p * particleB.p)) * W * rNorm;
float r3 = r2 * r;
W = -(r3 / (2 * h3)) + (r2 / h2) + (h / (2 * r)) - 1;
av += (particleB.m / particleA.m) * (1.0f / particleB.p) * (particleB.v - particleA.v) * W * rNorm;
}
a += (particleB.m / particleA.m) * ((particleA.P + particleB.P) / (2 * particleA.p * particleB.p)) * W * rNorm;
float r3 = r2 * r;
W = -(r3 / (2 * h3)) + (r2 / h2) + (h / (2 * r)) - 1;
av += (particleB.m / particleA.m) * (1.0f / particleB.p) * (particleB.v - particleA.v) * W * rNorm;
}
}
a *= -1;
av *= e;
float3 force = a + av;
const float dt = g_xFrame_DeltaTime;
particleA.v += dt * force / particleA.p;
particleA.position += dt * particleA.v;
}
a *= -1;
av *= e;
// gravity:
const float3 G = float3(0, -9.8f, 0);
float3 gravity = G * particleA.p;
// apply all forces:
float3 force = a + av + gravity;
// integrate:
const float dt = g_xFrame_DeltaTime;
particleA.v += dt * force / particleA.p;
particleA.position += dt * particleA.v;
// drag:
particleA.v *= 0.98f;
float elastic = 0.9;
#ifdef FLOOR_COLLISION
// floor collision:
if (particleA.position.y - particleA.size < 0)
{
particleA.position.y = particleA.size;
particleA.v.y *= -elastic;
}
#endif // FLOOR_COLLISION
#ifdef BOX_COLLISION
// box collision:
float extent = 2;
if (particleA.position.x + particleA.size > extent)
float3 extent = float3(2, 0, 3);
if (particleA.position.x + particleA.size > extent.x)
{
particleA.position.x = extent - particleA.size;
particleA.position.x = extent.x - particleA.size;
particleA.v.x *= -elastic;
}
if (particleA.position.x - particleA.size < -extent)
if (particleA.position.x - particleA.size < -extent.x)
{
particleA.position.x = -extent + particleA.size;
particleA.position.x = -extent.x + particleA.size;
particleA.v.x *= -elastic;
}
if (particleA.position.z + particleA.size > extent)
if (particleA.position.z + particleA.size > extent.z)
{
particleA.position.z = extent - particleA.size;
particleA.position.z = extent.z - particleA.size;
particleA.v.z *= -elastic;
}
if (particleA.position.z - particleA.size < -extent)
if (particleA.position.z - particleA.size < -extent.z)
{
particleA.position.z = -extent + particleA.size;
particleA.position.z = -extent.z + particleA.size;
particleA.v.z *= -elastic;
}
particleA.v *= 0.99f;
particleA.v.y -= 0.8f;
#endif // BOX_COLLISION
if (DTid.x < aliveCount)
@@ -194,17 +207,11 @@ void main( uint3 DTid : SV_DispatchThreadID, uint groupIndex : SV_GroupIndex, ui
particleBuffer[writeIndex].position = particleA.position;
particleBuffer[writeIndex].velocity = particleA.v;
particleBuffer[writeIndex].color_mirror = 0x00FFFFFF;
//particleBuffer[writeIndex].color_mirror |= ((uint)particleA.p) & 0xFF;
if (asd > 0)
{
particleBuffer[writeIndex].color_mirror = 0xFF;
}
if (asd < 0)
{
particleBuffer[writeIndex].color_mirror = 0xFF00;
}
#ifdef DEBUG_PRESSURE
// debug pressure:
particleBuffer[writeIndex].color_mirror = pressure_debug ? 0xFF : 0xFF00;
#endif // DEBUG_PRESSURE
}
WickedEngine/wiEmittedParticle.h
+3 -3
View File
@@ -96,9 +96,9 @@ public:
float motionBlurAmount;
float mass = 1.0f;
float SPH_h = 0.2f; // smoothing radius
float SPH_K = 20.0f; // pressure constant
float SPH_p0 = 20.0f; // reference density
float SPH_h = 1.0f; // smoothing radius
float SPH_K = 250.0f; // pressure constant
float SPH_p0 = 1.0f; // reference density
float SPH_e = 0.018f; // viscosity constant
void SetMaxParticleCount(uint32_t value);