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struct InstanceInput {
@location(0) position: vec3<f32>,
@location(1) origin: vec3<f32>,
@location(2) radius: f32
};
struct VertexOutput {
@builtin(position) clip_position: vec4<f32>,
@location(0) local_position: vec3<f32>
};
struct CameraUniform {
view: mat4x4<f32>,
proj: mat4x4<f32>,
pos: vec3<f32>,
scale: f32
};
@group(0) @binding(0)
var<uniform> camera: CameraUniform;
const QUAD_VERTICES = array<vec3<f32>,6>(
vec3<f32>(-1.0, -1.0, 0.0),
vec3<f32>(-1.0, 1.0 , 0.0),
vec3<f32>(1.0, 1.0 , 0.0),
vec3<f32>(1.0, 1.0 , 0.0),
vec3<f32>(1.0, -1.0, 0.0),
vec3<f32>(-1.0, -1.0, 0.0),
);
@vertex
fn vs_main(
@builtin(vertex_index) index: u32,
instance: InstanceInput
) -> VertexOutput {
var out: VertexOutput;
let model = QUAD_VERTICES[index];
var view = camera.view;
//Billboard the circle
let camera_right = vec3<f32>(view[0][0], view[1][0], view[2][0]);
let camera_up = vec3<f32>(view[0][1], view[1][1], view[2][1]);
let model_pos = camera_right * model.x +
camera_up * model.y;
let min_size = 0.025;
//Scale the world around the camera scale and translate about the camera's
//absolute (/target) position
let relative_pos = instance.position * camera.scale;
let origin_pos = (instance.origin - camera.pos) * camera.scale;
if all(relative_pos != origin_pos) {
if length(relative_pos) < 0.01 {
out.clip_position = vec4<f32>(0.0, 0.0, 0.0, 1.0);
return out;
}
}
let instance_pos = relative_pos + origin_pos;
let view_proj = camera.proj * view;
let center_view_pos = view_proj * vec4<f32>(instance_pos, 1.0);
let vertex_view_pos = view_proj * vec4<f32>(instance_pos + (model_pos * instance.radius * camera.scale), 1.0);
let vertex_dist = length(vertex_view_pos - center_view_pos) / center_view_pos.w;
if vertex_dist < min_size {
out.clip_position = center_view_pos / center_view_pos.w;
out.clip_position += camera.proj * vec4<f32>(model.xy * (min_size / 2.0), 0.0, 0.0);
}else{
out.clip_position = vertex_view_pos;
}
out.local_position = model;
return out;
}
@fragment
fn fs_main(in: VertexOutput
) -> @location(0) vec4<f32> {
let point_dist = length(in.local_position);
var alpha = 1.0;
if point_dist > 1.0 {
alpha = 0.0;
}
return vec4<f32>(1.0, 1.0, 1.0, alpha);
}
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