Initial commit

shaders/gravity.wgsl

@@ -0,0 +1,69 @@
+@group(0) @binding(0)
+var<storage, read_write> positions: array<vec3<f32>>;
+
+@group(0) @binding(1)
+var<storage, read_write> velocities: array<vec3<f32>>;
+
+@group(0) @binding(2)
+var<storage, read_write> distances: array<f32>;
+
+@group(0) @binding(3)
+var<storage, read_write> indices: array<u32>;
+
+@group(0) @binding(4)
+var<uniform> deltaTimeSeconds: f32;
+
+@group(0) @binding(5)
+var<uniform> cameraPosition: vec3<f32>;
+
+@group(0) @binding(6)
+var<uniform> updateDistancesAndIndices: u32;  
+
+@group(0) @binding(7)
+var<uniform> cellCount: u32;
+
+@group(0) @binding(8)
+var<uniform> gravity: f32;
+
+@compute @workgroup_size(64)
+fn computeMain(@builtin(global_invocation_id) globalInvocationId: vec3<u32>) {
+	let particleIndex = globalInvocationId.x;
+
+	if (particleIndex >= arrayLength(&positions)) {
+		return;
+	}
+
+	let gravityAcceleration = vec3<f32>(0.0, gravity, 0.0);
+
+	var currentPosition 	= positions[particleIndex];
+	var currentVelocity 	= velocities[particleIndex];
+
+	let deltaTimeClamped 	= min(deltaTimeSeconds, 0.01);
+
+	currentVelocity += gravityAcceleration * deltaTimeClamped;
+
+	currentPosition += currentVelocity * deltaTimeClamped;
+
+	let friction = 0.98;
+
+	currentVelocity *= friction;
+
+
+	positions[particleIndex] 	= currentPosition;
+	
+	velocities[particleIndex] 	= currentVelocity;
+
+	if ( updateDistancesAndIndices == 1u ) {
+
+		let diff 					= currentPosition - cameraPosition;
+
+		let dist 					= length(diff);
+
+		distances[ particleIndex ] 	= dist;
+
+		indices[ particleIndex ] 	= particleIndex;
+
+		positions[ particleIndex ] 	= currentPosition;
+
+	}
+}