From 67cdbde243f3d7588994d790dcd30c28e6fcde0d Mon Sep 17 00:00:00 2001
From: Tobias Frisch <tfrisch@uni-koblenz.de>
Date: Thu, 3 Feb 2022 04:35:01 +0100
Subject: [PATCH] Using MLS MPM to combine shaders and reduce sources of errors
Signed-off-by: Tobias Frisch <tfrisch@uni-koblenz.de>
---
projects/wobble_bobble/shaders/particle.inc | 1 +
.../shaders/transform_particles_to_grid.comp | 6 ++
.../shaders/update_grid_forces.comp | 58 +-------------
.../shaders/update_particle_deformation.comp | 64 ---------------
.../shaders/update_particle_positions.comp | 51 ------------
.../shaders/update_particle_velocities.comp | 65 +++++++++++----
projects/wobble_bobble/src/main.cpp | 80 ++-----------------
7 files changed, 66 insertions(+), 259 deletions(-)
delete mode 100644 projects/wobble_bobble/shaders/update_particle_deformation.comp
delete mode 100644 projects/wobble_bobble/shaders/update_particle_positions.comp
diff --git a/projects/wobble_bobble/shaders/particle.inc b/projects/wobble_bobble/shaders/particle.inc
index 595db9ab..77d2691e 100644
--- a/projects/wobble_bobble/shaders/particle.inc
+++ b/projects/wobble_bobble/shaders/particle.inc
@@ -14,6 +14,7 @@ struct ParticleMinimal {
struct Particle {
ParticleMinimal minimal;
mat4 deformation;
+ mat4 mls;
};
const float PI = 3.1415926535897932384626433832795;
diff --git a/projects/wobble_bobble/shaders/transform_particles_to_grid.comp b/projects/wobble_bobble/shaders/transform_particles_to_grid.comp
index 9bae58ef..69154658 100644
--- a/projects/wobble_bobble/shaders/transform_particles_to_grid.comp
+++ b/projects/wobble_bobble/shaders/transform_particles_to_grid.comp
@@ -27,6 +27,12 @@ void main() {
if (localOffset < particles.length()) {
shared_particles[gl_LocalInvocationIndex] = particles[localOffset].minimal;
+
+ vec3 distance = (position - shared_particles[gl_LocalInvocationIndex].position);
+
+ shared_particles[gl_LocalInvocationIndex].velocity += (
+ mat3(particles[localOffset].mls) * distance
+ );
} else {
shared_particles[gl_LocalInvocationIndex].position = vec3(0.0f);
shared_particles[gl_LocalInvocationIndex].size = 0.0f;
diff --git a/projects/wobble_bobble/shaders/update_grid_forces.comp b/projects/wobble_bobble/shaders/update_grid_forces.comp
index 7db54625..9c0d0c07 100644
--- a/projects/wobble_bobble/shaders/update_grid_forces.comp
+++ b/projects/wobble_bobble/shaders/update_grid_forces.comp
@@ -14,6 +14,8 @@ layout(set=0, binding=2, std430) readonly buffer particleBuffer {
layout( push_constant ) uniform constants {
float lame1;
float lame2;
+ float alpha;
+ float beta;
float t;
float dt;
};
@@ -41,63 +43,11 @@ void main() {
vec3 velocity = gridSample.xyz;
float mass = gridSample.w;
- vec3 force = vec3(0.0f);
- uint offset = 0;
-
barrier();
memoryBarrierBuffer();
- for (offset = 0; offset < particles.length(); offset += SHARED_PARTICLES_BATCH_SIZE) {
- uint localOffset = offset + gl_LocalInvocationIndex;
-
- if (localOffset < particles.length()) {
- shared_particles[gl_LocalInvocationIndex] = particles[localOffset];
- } else {
- shared_particles[gl_LocalInvocationIndex].minimal.position = vec3(0.0f);
- shared_particles[gl_LocalInvocationIndex].minimal.size = 0.0f;
- shared_particles[gl_LocalInvocationIndex].minimal.velocity = vec3(0.0f);
- shared_particles[gl_LocalInvocationIndex].minimal.mass = 0.0f;
- shared_particles[gl_LocalInvocationIndex].deformation = mat4(0.0f);
- }
-
- barrier();
- memoryBarrierShared();
-
- for (uint i = 0; i < SHARED_PARTICLES_BATCH_SIZE; i++) {
- float volume = sphere_volume(shared_particles[i].minimal.size);
- mat3 F = mat3(shared_particles[i].deformation);
-
- float J = determinant(F);
-
- if ((J > 0.0f) && (volume > 0.0f)) {
- mat3 F_invT = inverse(transpose(F));
-
- vec3 v = shared_particles[i].minimal.velocity;
- float m = shared_particles[i].minimal.mass;
-
- mat3 delta = lame2 * (F - F_invT) + lame1 * log(J) * F_invT;
-
- vec3 weight_gradient = voxel_particle_grad_weight(
- position,
- shared_particles[i].minimal
- );
-
- force -= (
- volume *
- delta * transpose(F) *
- weight_gradient
- );
- }
- }
-
- barrier();
- memoryBarrierShared();
- }
-
- if (dt > 0.0f) {
- if (mass > 0.0f) {
- velocity += force * dt / mass;
- }
+ if (mass > 0.0f) {
+ velocity += vec3(0.0f, -9.81f * dt * 0.0f, 0.0f);
}
bvec3 lowerID = lessThanEqual(gl_GlobalInvocationID, ivec3(0));
diff --git a/projects/wobble_bobble/shaders/update_particle_deformation.comp b/projects/wobble_bobble/shaders/update_particle_deformation.comp
deleted file mode 100644
index a8a89bc5..00000000
--- a/projects/wobble_bobble/shaders/update_particle_deformation.comp
+++ /dev/null
@@ -1,64 +0,0 @@
-#version 450
-#extension GL_GOOGLE_include_directive : enable
-
-layout(local_size_x = 64, local_size_y = 1, local_size_z = 1) in;
-
-#include "particle.inc"
-
-layout(set=0, binding=0, std430) restrict buffer particleBuffer {
- Particle particles [];
-};
-
-layout(set=0, binding=1) uniform texture3D gridImage;
-layout(set=0, binding=2) uniform sampler gridSampler;
-
-layout( push_constant ) uniform constants {
- float K;
- float E;
- float t;
- float dt;
-};
-
-void main() {
- if (gl_GlobalInvocationID.x < particles.length()) {
- ParticleMinimal minimal = particles[gl_GlobalInvocationID.x].minimal;
- mat3 deformation = mat3(particles[gl_GlobalInvocationID.x].deformation);
-
- ivec3 gridResolution = textureSize(sampler3D(gridImage, gridSampler), 0);
- ivec3 gridWindow = ivec3(minimal.size * 2.0f * gridResolution);
-
- mat3 velocity_gradient = mat3(0.0f);
-
- int i, j, k;
-
- for (i = -gridWindow.x; i <= gridWindow.x; i++) {
- for (j = -gridWindow.y; j <= gridWindow.y; j++) {
- for (k = -gridWindow.z; k <= gridWindow.z; k++) {
- vec3 offset = vec3(i, j, k) / gridResolution;
- vec3 voxel = minimal.position + offset;
-
- vec4 gridSample = texture(sampler3D(gridImage, gridSampler), voxel);
-
- velocity_gradient += outerProduct(
- gridSample.xyz,
- voxel_particle_grad_weight(voxel, minimal)
- );
- }
- }
- }
-
- barrier();
- memoryBarrierBuffer();
-
- mat3 deformation_elastic = deformation;
-
- if (dt > 0.0f) {
- deformation_elastic = (mat3(1.0f) + dt * velocity_gradient) * deformation;
- }
-
- barrier();
- memoryBarrierBuffer();
-
- particles[gl_GlobalInvocationID.x].deformation = mat4(deformation_elastic);
- }
-}
\ No newline at end of file
diff --git a/projects/wobble_bobble/shaders/update_particle_positions.comp b/projects/wobble_bobble/shaders/update_particle_positions.comp
deleted file mode 100644
index 5e012f40..00000000
--- a/projects/wobble_bobble/shaders/update_particle_positions.comp
+++ /dev/null
@@ -1,51 +0,0 @@
-#version 450
-#extension GL_GOOGLE_include_directive : enable
-
-layout(local_size_x = 64, local_size_y = 1, local_size_z = 1) in;
-
-#include "particle.inc"
-
-layout(set=0, binding=0, std430) restrict buffer particleBuffer {
- Particle particles [];
-};
-
-layout( push_constant ) uniform constants {
- float K;
- float E;
- float t;
- float dt;
-};
-
-void main() {
- memoryBarrierBuffer();
-
- if (gl_GlobalInvocationID.x < particles.length()) {
- vec3 position = particles[gl_GlobalInvocationID.x].minimal.position;
- float size = particles[gl_GlobalInvocationID.x].minimal.size;
- vec3 velocity = particles[gl_GlobalInvocationID.x].minimal.velocity;
-
- if (dt > 0.0f) {
- position = position + velocity * dt;
- }
-
- for (uint i = 0; i < 3; i++) {
- if (position[i] - size < 0.0f) {
- position[i] = -position[i] + 2.0f * size;
- velocity[i] *= -1.0f;
- } else
- if (position[i] + size > 1.0f) {
- position[i] = 2.0f * (1.0f - size) - position[i];
- velocity[i] *= -1.0f;
- }
- }
-
- barrier();
- memoryBarrierBuffer();
-
- particles[gl_GlobalInvocationID.x].minimal.position = position;
- particles[gl_GlobalInvocationID.x].minimal.velocity = velocity;
- }
-
- barrier();
- memoryBarrierBuffer();
-}
\ No newline at end of file
diff --git a/projects/wobble_bobble/shaders/update_particle_velocities.comp b/projects/wobble_bobble/shaders/update_particle_velocities.comp
index d29b22e1..e8d671e5 100644
--- a/projects/wobble_bobble/shaders/update_particle_velocities.comp
+++ b/projects/wobble_bobble/shaders/update_particle_velocities.comp
@@ -15,8 +15,12 @@ layout(set=0, binding=2) uniform texture3D gridOldImage;
layout(set=0, binding=3) uniform sampler gridSampler;
layout( push_constant ) uniform constants {
+ float lame1;
+ float lame2;
float alpha;
float beta;
+ float t;
+ float dt;
};
void main() {
@@ -24,16 +28,21 @@ void main() {
memoryBarrierImage();
if (gl_GlobalInvocationID.x < particles.length()) {
- ParticleMinimal minimal = particles[gl_GlobalInvocationID.x].minimal;
+ Particle particle = particles[gl_GlobalInvocationID.x];
+
+ vec3 position = particle.minimal.position;
+ float size = particle.minimal.size;
+ float volume = sphere_volume(size);
+ float mass = particle.minimal.mass;
ivec3 gridResolution = textureSize(sampler3D(gridImage, gridSampler), 0);
- ivec3 gridWindow = ivec3(minimal.size * 2.0f * gridResolution);
+ ivec3 gridWindow = ivec3(size * 2.0f * gridResolution);
mat3 affine_D = mat3(0.0f);
mat3 affine_B = mat3(0.0f);
vec3 velocity_pic = vec3(0.0f);
- vec3 velocity_flip = vec3(minimal.velocity);
+ vec3 velocity_flip = vec3(particle.minimal.velocity);
int i, j, k;
@@ -41,12 +50,12 @@ void main() {
for (j = -gridWindow.y; j <= gridWindow.y; j++) {
for (k = -gridWindow.z; k <= gridWindow.z; k++) {
vec3 offset = vec3(i, j, k) / gridResolution;
- vec3 voxel = minimal.position + offset;
+ vec3 voxel = position + offset;
vec4 gridSample = texture(sampler3D(gridImage, gridSampler), voxel);
vec4 gridOldSample = texture(sampler3D(gridOldImage, gridSampler), voxel);
- float weight = voxel_particle_weight(voxel, minimal);
+ float weight = voxel_particle_weight(voxel, particle.minimal);
vec3 velocity = gridSample.xyz * weight;
affine_D += outerProduct(weight * offset, offset);
@@ -61,30 +70,52 @@ void main() {
barrier();
memoryBarrierBuffer();
+ mat3 mls_Q = mat3(0.0f);
mat3 affine_C = mat3(0.0f);
- vec3 velocity_apic = vec3(0.0f);
+
+ mat3 F = mat3(particle.deformation);
if (abs(determinant(affine_D)) > 0.0f) {
- affine_C = affine_B * inverse(affine_D);
+ mat3 D_inv = inverse(affine_D);
+ float J = determinant(F);
+
+ if ((J > 0.0f) && (mass > 0.0f)) {
+ mat3 F_T = transpose(F);
+ mat3 F_invT = inverse(F_T);
+
+ mat3 delta = lame2 * (F - F_invT) + lame1 * log(J) * F_invT;
+
+ //mls_Q += beta * dt * volume * particle.minimal.weight_sum * delta * F_T * D_inv / mass;
+ }
+
+ affine_C = affine_B * D_inv;
+ mls_Q += beta * affine_C;
}
- for (i = -gridWindow.x; i <= gridWindow.x; i++) {
- for (j = -gridWindow.y; j <= gridWindow.y; j++) {
- for (k = -gridWindow.z; k <= gridWindow.z; k++) {
- vec3 offset = vec3(i, j, k) / gridResolution;
+ F = (mat3(1.0f) + dt * affine_C) * F;
- velocity_apic += affine_C * offset;
- }
+ vec3 velocity = mix(velocity_pic, velocity_flip, alpha);
+
+ position = position + velocity * dt;
+
+ for (uint i = 0; i < 3; i++) {
+ if (position[i] - size < 0.0f) {
+ position[i] = -position[i] + 2.0f * size;
+ velocity[i] *= -1.0f;
+ } else
+ if (position[i] + size > 1.0f) {
+ position[i] = 2.0f * (1.0f - size) - position[i];
+ velocity[i] *= -1.0f;
}
}
barrier();
memoryBarrierBuffer();
- vec3 velocity_alpha = mix(velocity_pic, velocity_flip, alpha);
- vec3 velocity_beta = mix(velocity_alpha, velocity_apic, beta);
-
- particles[gl_GlobalInvocationID.x].minimal.velocity = velocity_beta;
+ particles[gl_GlobalInvocationID.x].minimal.position = position;
+ particles[gl_GlobalInvocationID.x].minimal.velocity = velocity;
+ particles[gl_GlobalInvocationID.x].deformation = mat4(F);
+ particles[gl_GlobalInvocationID.x].mls = mat4(mls_Q);
}
barrier();
diff --git a/projects/wobble_bobble/src/main.cpp b/projects/wobble_bobble/src/main.cpp
index fab2ae31..9f41267a 100644
--- a/projects/wobble_bobble/src/main.cpp
+++ b/projects/wobble_bobble/src/main.cpp
@@ -17,18 +17,16 @@ struct Particle {
float weight_sum;
glm::mat4 deformation;
+ glm::mat4 mls;
};
struct Physics {
float lame1;
float lame2;
- float t;
- float dt;
-};
-
-struct Tweaks {
float alpha;
float beta;
+ float t;
+ float dt;
};
float sphere_volume(float radius) {
@@ -80,6 +78,8 @@ void distributeParticles(Particle *particles, size_t count, const glm::vec3& cen
particles[i].pad = glm::vec3(0.0f);
particles[i].weight_sum = 1.0f;
+
+ particles[i].mls = glm::mat4(0.0f);
}
}
@@ -268,21 +268,6 @@ int main(int argc, const char **argv) {
core.writeDescriptorSet(updateGridForcesSets[0], writes);
}
- std::vector<vkcv::DescriptorSetHandle> updateParticleDeformationSets;
- vkcv::ComputePipelineHandle updateParticleDeformationPipeline = createComputePipeline(
- core, compiler,
- "shaders/update_particle_deformation.comp",
- updateParticleDeformationSets
- );
-
- {
- vkcv::DescriptorWrites writes;
- writes.storageBufferWrites.push_back(vkcv::BufferDescriptorWrite(0, particles.getHandle()));
- writes.sampledImageWrites.push_back(vkcv::SampledImageDescriptorWrite(1, grid.getHandle()));
- writes.samplerWrites.push_back(vkcv::SamplerDescriptorWrite(2, gridSampler));
- core.writeDescriptorSet(updateParticleDeformationSets[0], writes);
- }
-
std::vector<vkcv::DescriptorSetHandle> updateParticleVelocitiesSets;
vkcv::ComputePipelineHandle updateParticleVelocitiesPipeline = createComputePipeline(
core, compiler,
@@ -299,19 +284,6 @@ int main(int argc, const char **argv) {
core.writeDescriptorSet(updateParticleVelocitiesSets[0], writes);
}
- std::vector<vkcv::DescriptorSetHandle> updateParticlePositionsSets;
- vkcv::ComputePipelineHandle updateParticlePositionsPipeline = createComputePipeline(
- core, compiler,
- "shaders/update_particle_positions.comp",
- updateParticlePositionsSets
- );
-
- {
- vkcv::DescriptorWrites writes;
- writes.storageBufferWrites.push_back(vkcv::BufferDescriptorWrite(0, particles.getHandle()));
- core.writeDescriptorSet(updateParticlePositionsSets[0], writes);
- }
-
vkcv::ShaderProgram gfxProgramGrid;
compiler.compile(
@@ -600,19 +572,14 @@ int main(int argc, const char **argv) {
Physics physics;
physics.lame1 = material.m_lame1;
physics.lame2 = material.m_lame2;
+ physics.alpha = alpha;
+ physics.beta = beta;
physics.t = static_cast<float>(0.000001 * static_cast<double>(time.count()));
physics.dt = static_cast<float>(0.000001 * static_cast<double>(deltatime.count()));
vkcv::PushConstants physicsPushConstants (sizeof(physics));
physicsPushConstants.appendDrawcall(physics);
- Tweaks tweaks;
- tweaks.alpha = alpha;
- tweaks.beta = beta;
-
- vkcv::PushConstants tweakPushConstants (sizeof(tweaks));
- tweakPushConstants.appendDrawcall(tweaks);
-
cameraManager.update(physics.dt);
glm::mat4 mvp = cameraManager.getActiveCamera().getMVP();
@@ -676,23 +643,6 @@ int main(int argc, const char **argv) {
core.recordImageMemoryBarrier(cmdStream, grid.getHandle());
core.recordEndDebugLabel(cmdStream);
- core.recordBeginDebugLabel(cmdStream, "UPDATE PARTICLE DEFORMATION", { 0.78f, 0.89f, 0.94f, 1.0f });
- core.recordBufferMemoryBarrier(cmdStream, particles.getHandle());
- core.prepareImageForSampling(cmdStream, grid.getHandle());
-
- core.recordComputeDispatchToCmdStream(
- cmdStream,
- updateParticleDeformationPipeline,
- dispatchSizeParticles,
- { vkcv::DescriptorSetUsage(
- 0, core.getDescriptorSet(updateParticleDeformationSets[0]).vulkanHandle
- ) },
- physicsPushConstants
- );
-
- core.recordBufferMemoryBarrier(cmdStream, particles.getHandle());
- core.recordEndDebugLabel(cmdStream);
-
core.recordBeginDebugLabel(cmdStream, "UPDATE PARTICLE VELOCITIES", { 0.78f, 0.89f, 0.94f, 1.0f });
core.recordBufferMemoryBarrier(cmdStream, particles.getHandle());
core.prepareImageForSampling(cmdStream, grid.getHandle());
@@ -705,22 +655,6 @@ int main(int argc, const char **argv) {
{ vkcv::DescriptorSetUsage(
0, core.getDescriptorSet(updateParticleVelocitiesSets[0]).vulkanHandle
) },
- tweakPushConstants
- );
-
- core.recordBufferMemoryBarrier(cmdStream, particles.getHandle());
- core.recordEndDebugLabel(cmdStream);
-
- core.recordBeginDebugLabel(cmdStream, "UPDATE PARTICLE POSITIONS", { 0.78f, 0.89f, 0.94f, 1.0f });
- core.recordBufferMemoryBarrier(cmdStream, particles.getHandle());
-
- core.recordComputeDispatchToCmdStream(
- cmdStream,
- updateParticlePositionsPipeline,
- dispatchSizeParticles,
- { vkcv::DescriptorSetUsage(
- 0, core.getDescriptorSet(updateParticlePositionsSets[0]).vulkanHandle
- ) },
physicsPushConstants
);
--
GitLab