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# Copyright 2020 The Tint Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import "GLSL.std.450" as std;
# vertex shader
[[location(0)]] var<in> a_particlePos : vec2<f32>;
[[location(1)]] var<in> a_particleVel : vec2<f32>;
[[location(2)]] var<in> a_pos : vec2<f32>;
[[builtin(position)]] var gl_Position : vec4<f32>;
[[stage(vertex)]]
fn main() -> void {
var angle : f32 = -std::atan2(a_particleVel.x, a_particleVel.y);
var pos : vec2<f32> = vec2<f32>(
(a_pos.x * std::cos(angle)) - (a_pos.y * std::sin(angle)),
(a_pos.x * std::sin(angle)) + (a_pos.y * std::cos(angle)));
gl_Position = vec4<f32>(pos + a_particlePos, 0.0, 1.0);
return;
}
# fragment shader
[[location(0)]] var<out> fragColor : vec4<f32>;
[[stage(fragment)]]
fn main() -> void {
fragColor = vec4<f32>(1.0, 1.0, 1.0, 1.0);
return;
}
# compute shader
type Particle = struct {
[[offset(0)]] pos : vec2<f32>;
[[offset(8)]] vel : vec2<f32>;
};
type SimParams = struct {
[[offset(0)]] deltaT : f32;
[[offset(4)]] rule1Distance : f32;
[[offset(8)]] rule2Distance : f32;
[[offset(12)]] rule3Distance : f32;
[[offset(16)]] rule1Scale : f32;
[[offset(20)]] rule2Scale : f32;
[[offset(24)]] rule3Scale : f32;
};
type Particles = struct {
[[offset(0)]] particles : [[stride 16]] array<Particle, 5>;
};
[[group(0), binding(0)]] var<uniform> params : SimParams;
[[group(0), binding(1)]] var<storage> particlesA : Particles;
[[group(0), binding(2)]] var<storage> particlesB : Particles;
[[builtin(global_invocation_id)]] var gl_GlobalInvocationID : vec3<u32>;
# https://github.com/austinEng/Project6-Vulkan-Flocking/blob/master/data/shaders/computeparticles/particle.comp
[[stage(compute), workgroup_size(1)]]
fn main() -> void {
var index : u32 = gl_GlobalInvocationID.x;
if (index >= u32(5)) {
return;
}
var vPos : vec2<f32> = particlesA.particles[index].pos;
var vVel : vec2<f32> = particlesA.particles[index].vel;
var cMass : vec2<f32> = vec2<f32>(0.0, 0.0);
var cVel : vec2<f32> = vec2<f32>(0.0, 0.0);
var colVel : vec2<f32> = vec2<f32>(0.0, 0.0);
var cMassCount : i32 = 0;
var cVelCount : i32 = 0;
var pos : vec2<f32>;
var vel : vec2<f32>;
var i : u32 = 0;
loop {
if (i >= u32(5)) {
break;
}
if (i == index) {
continue;
}
pos = particlesA.particles[i].pos.xy;
vel = particlesA.particles[i].vel.xy;
if (std::distance(pos, vPos) < params.rule1Distance) {
cMass = cMass + pos;
cMassCount = cMassCount + 1;
}
if (std::distance(pos, vPos) < params.rule2Distance) {
colVel = colVel - (pos - vPos);
}
if (std::distance(pos, vPos) < params.rule3Distance) {
cVel = cVel + vel;
cVelCount = cVelCount + 1;
}
continuing {
i = i + u32(1);
}
}
if (cMassCount > 0) {
cMass = (cMass / vec2<f32>(cMassCount, cMassCount)) + vPos;
}
if (cVelCount > 0) {
cVel = cVel / vec2<f32>(cVelCount, cVelCount);
}
vVel = vVel + (cMass * params.rule1Scale) + (colVel * params.rule2Scale) +
(cVel * params.rule3Scale);
# clamp velocity for a more pleasing simulation
vVel = std::normalize(vVel) * std::fclamp(std::length(vVel), 0.0, 0.1);
# kinematic update
vPos = vPos + (vVel * params.deltaT);
# Wrap around boundary
if (vPos.x < -1.0) {
vPos.x = 1.0;
}
if (vPos.x > 1.0) {
vPos.x = -1.0;
}
if (vPos.y < -1.0) {
vPos.y = 1.0;
}
if (vPos.y > 1.0) {
vPos.y = -1.0;
}
# Write back
particlesB.particles[index].pos = vPos;
particlesB.particles[index].vel = vVel;
return;
}
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