Initial commit

shaders/particle-header.wgsl

@@ -0,0 +1,60 @@
+@group(0) @binding(0)
+var<storage, read> positions : array<vec4<f32>>;
+
+@group(0) @binding(1)
+var<storage, read> colors : array<vec4<f32>>;
+
+@group(0) @binding(2)
+var<uniform> viewProjectionMatrix : mat4x4<f32>;
+
+@group(0) @binding(3)
+var<uniform> aspectRatio : f32;
+
+@group(0) @binding(4)
+var<uniform> mousePos : vec2<f32>;
+
+@group(0) @binding(5)
+var<uniform> hoverRadius : f32;
+
+struct VertexOutput {
+  @builtin(position) Position : vec4<f32>,
+  @location(0) color : vec4<f32>,
+};
+
+fn smoothStep(edge0: f32, edge1: f32, x: f32) -> f32 {
+  let t = clamp((x - edge0) / (edge1 - edge0), 0.0, 1.0);
+  return t * t * (3.0 - 2.0 * t);
+}
+
+@vertex
+fn vertex_main(@builtin(vertex_index) vertexIndex : u32) -> VertexOutput {
+  var output : VertexOutput;
+
+  let pos = positions[vertexIndex];
+  var color = colors[vertexIndex];
+
+  let correctedPosition = vec4<f32>(
+    pos.x * aspectRatio,
+    pos.y,
+    pos.z,
+    pos.w
+  );
+
+  // Change color if near mousePos:
+  // mousePos is passed as uniform vec2<f32> in clip space (-aspectRatio..aspectRatio, -1..1)
+  let dist = distance(vec2<f32>(pos.x* aspectRatio, pos.y), mousePos);
+  if (dist < hoverRadius) {
+    color = vec4<f32>(1.0, 0.0, 0.0, 1.0); // Red highlight
+  }
+
+  output.Position = viewProjectionMatrix * correctedPosition;
+
+  output.color = color;
+
+  return output;
+}
+
+@fragment
+fn fragment_main(input : VertexOutput) -> @location(0) vec4<f32> {
+  return input.color;
+}