Galactica/crates/render/shaders/particle.wgsl

101 lines
2.4 KiB
Plaintext

// INCLUDE: global uniform header
struct InstanceInput {
@location(2) position: vec2<f32>,
@location(3) velocity: vec2<f32>,
@location(4) rotation_0: vec2<f32>,
@location(5) rotation_1: vec2<f32>,
@location(6) size: f32,
@location(7) created: f32,
@location(8) expires: f32,
@location(9) texture_index: u32,
};
struct VertexInput {
@location(0) position: vec3<f32>,
@location(1) texture_coords: vec2<f32>,
}
struct VertexOutput {
@builtin(position) position: vec4<f32>,
@location(0) texture_coords: vec2<f32>,
@location(1) texture_index: u32,
}
@group(0) @binding(0)
var texture_array: binding_array<texture_2d<f32>>;
@group(0) @binding(1)
var sampler_array: binding_array<sampler>;
// INCLUDE: animate.wgsl
@vertex
fn vertex_main(
vertex: VertexInput,
instance: InstanceInput,
) -> VertexOutput {
var out: VertexOutput;
out.texture_coords = vertex.texture_coords;
// Skip expired particles
if instance.expires < global.current_time.x {
out.texture_index = u32(0);
// Draw off screen
out.position = vec4<f32>(2.0, 2.0, 0.0, 1.0);
return out;
}
let age = global.current_time.x - instance.created;
// Apply transformations
let rotation = mat2x2(instance.rotation_0, instance.rotation_1);
var scale: f32 = instance.size / global.camera_zoom.x;
var pos: vec2<f32> = vec2(vertex.position.x, vertex.position.y);
pos = pos * vec2<f32>(
sprites.data[instance.texture_index].aspect * scale / global.window_aspect.x,
scale
);
pos = rotation * pos;
var ipos: vec2<f32> = (
vec2(instance.position.x, instance.position.y)
+ (instance.velocity * age)
- global.camera_position
);
pos = pos + vec2<f32>(
ipos.x / (global.camera_zoom.x/2.0) / global.window_aspect.x,
ipos.y / (global.camera_zoom.x/2.0)
);
out.position = vec4<f32>(pos, 0.0, 1.0);
// Compute texture coordinates
let t = atlas.data[animate(instance, age)];
out.texture_index = u32(0);
out.texture_coords = vec2(t.xpos, t.ypos);
if vertex.texture_coords.x == 1.0 {
out.texture_coords = vec2(out.texture_coords.x + t.width, out.texture_coords.y);
}
if vertex.texture_coords.y == 1.0 {
out.texture_coords = vec2(out.texture_coords.x, out.texture_coords.y + t.height);
}
return out;
}
@fragment
fn fragment_main(in: VertexOutput) -> @location(0) vec4<f32> {
return textureSampleLevel(
texture_array[in.texture_index],
sampler_array[0],
in.texture_coords,
0.0
).rgba;
}