Galactica/crates/render/shaders/ui.wgsl

// INCLUDE: global uniform header

struct InstanceInput {
	@location(2) transform_matrix_0: vec4<f32>,
	@location(3) transform_matrix_1: vec4<f32>,
	@location(4) transform_matrix_2: vec4<f32>,
	@location(5) transform_matrix_3: vec4<f32>,
	@location(6) color_transform: vec4<f32>,
	@location(7) 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,
	@location(2) color_transform: vec4<f32>,
}

@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 {

	let transform = mat4x4<f32>(
		instance.transform_matrix_0,
		instance.transform_matrix_1,
		instance.transform_matrix_2,
		instance.transform_matrix_3,
	);

	var out: VertexOutput;
	out.position = transform * vec4<f32>(vertex.position, 1.0);
	out.color_transform = instance.color_transform;

	// Pick texture frame
	let t = atlas[animate(instance, global.current_time.x)];
	out.texture_index = u32(t.atlas_texture);
	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 * in.color_transform;
}