add orbit rendering for bodies

1 files changed, 61 insertions, 0 deletions

diff --git a/assets/shaders/tacmap/orbit.wgsl b/assets/shaders/tacmap/orbit.wgsl
new file mode 100644
index 0000000..d054a05
--- /dev/null
+++ b/assets/shaders/tacmap/orbit.wgsl
@@ -0,0 +1,61 @@
+struct VertexInput {
+    @builtin(vertex_index) index: u32,
+    @location(0) origin: u32,
+    @location(1) position: vec3<f32>,
+};
+
+struct VertexOutput {
+    @builtin(position) clip_position: vec4<f32>,
+};
+
+struct CameraUniform {
+    view: mat4x4<f32>,
+    proj: mat4x4<f32>,
+    pos: vec3<f32>,
+    scale: f32
+};
+
+@group(0) @binding(0)
+var<uniform> camera: CameraUniform;
+
+@group(1) @binding(0)
+var<storage> origins: array<array<f32,3>>;
+
+const POINT_NORMALS = array<vec2<f32>,4>(
+    vec2<f32>(0.0, -0.5),
+    vec2<f32>(0.0,  0.5),
+    vec2<f32>(0.5, -0.5),
+    vec2<f32>(0.5,  0.5)
+);
+
+@vertex
+fn vs_main(
+    model: VertexInput,
+) -> VertexOutput {
+    var out: VertexOutput;
+
+    let index = model.index % 4u;
+    let normal = POINT_NORMALS[index];
+    let origin = vec3<f32>(
+        origins[model.origin][0],
+        origins[model.origin][1],
+        origins[model.origin][2]);
+
+    let model_pos = (origin + model.position - camera.pos) * camera.scale;
+    let view_proj = camera.proj * camera.view;
+
+    //Scale the world around the camera scale and translate about the camera's
+    //absolute (/target) position
+
+    let point_view_pos = view_proj * vec4<f32>(model_pos, 1.0);
+    out.clip_position = point_view_pos;
+    out.clip_position += vec4<f32>(normal * 0.01, 0.0, 0.0) * point_view_pos.w;
+
+    return out;
+}
+
+@fragment
+fn fs_main(in: VertexOutput
+) -> @location(0) vec4<f32> {
+    return vec4<f32>(0.25, 1.0, 0.25, 1.0);
+}