Galactica/crates/render/shaders/ui.wgsl

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// INCLUDE: global uniform header
struct InstanceInput {
@location(2) position: vec2<f32>,
@location(3) angle: f32,
@location(4) dim: vec2<f32>,
@location(5) color_transform: vec4<f32>,
@location(6) texture_index: vec2<u32>,
@location(7) texture_fade: f32,
@location(8) mask_index: vec2<u32>,
};
struct VertexInput {
@location(0) position: vec3<f32>,
@location(1) texture_coords: vec2<f32>,
}
struct VertexOutput {
@builtin(position) position: vec4<f32>,
@location(0) tween: f32,
@location(1) texture_index_a: u32,
@location(2) texture_coords_a: vec2<f32>,
@location(3) texture_index_b: u32,
@location(4) texture_coords_b: vec2<f32>,
@location(5) color: vec4<f32>,
@location(6) mask_coords: vec2<f32>,
@location(7) mask_index: vec2<u32>,
}
@group(0) @binding(0)
var texture_array: binding_array<texture_2d<f32>>;
@group(0) @binding(1)
var sampler_array: binding_array<sampler>;
fn transform_vertex(
instance: InstanceInput,
vertex_position: vec3<f32>,
texture_index: u32,
) -> vec4<f32> {
// Window size in logical pixels
let window_dim = (
vec2(global_data.window_size_w, global_data.window_size_h)
/ global_data.window_scale
);
let scale = instance.dim.y / window_dim.y;
var pos: vec2<f32> = vec2(
vertex_position.x * scale * (instance.dim.x / instance.dim.y),
vertex_position.y * scale
);
// Apply rotation (and adjust sprite angle, since sprites point north)
pos = mat2x2(
vec2(cos(instance.angle - 1.5708), sin(instance.angle - 1.5708)),
vec2(-sin(instance.angle - 1.5708), cos(instance.angle - 1.5708))
) * pos;
// Correct for screen aspect, preserving height
pos = vec2(
pos.x / global_data.window_aspect,
pos.y
);
pos = pos + (instance.position / window_dim) * 2.0;
return vec4<f32>(pos, 0.0, 1.0);
}
@vertex
fn vertex_main(
vertex: VertexInput,
instance: InstanceInput,
) -> VertexOutput {
var out: VertexOutput;
// Pick texture size by the size of the visible texture
// (texture index 0 is special, it's the "hidden" texture)
if instance.texture_index.x == 0u && instance.texture_index.y == 0u {
out.position = vec4<f32>(0.0, 0.0, 0.0, 1.0);
} else if instance.texture_index.x == 0u {
out.position = transform_vertex(
instance,
vertex.position,
instance.texture_index.y,
);
} else if instance.texture_index.y == 0u {
out.position = transform_vertex(
instance,
vertex.position,
instance.texture_index.x,
);
} else {
out.position = transform_vertex(
instance,
vertex.position,
instance.texture_index.x,
);
}
out.color = instance.color_transform;
out.tween = instance.texture_fade;
// Texture 0 is special, it's the empty texture
if instance.texture_index.x == 0u {
out.texture_index_a = 0u;
out.texture_coords_a = vec2(0.0, 0.0);
} else {
let t = global_atlas[instance.texture_index.x];
out.texture_index_a = t.atlas_texture;
out.texture_coords_a = vec2(t.xpos, t.ypos);
if vertex.texture_coords.x == 1.0 {
out.texture_coords_a = out.texture_coords_a + vec2(t.width, 0.0);
}
if vertex.texture_coords.y == 1.0 {
out.texture_coords_a = out.texture_coords_a + vec2(0.0, t.height);
}
}
if instance.texture_index.y == 0u {
out.texture_index_b = u32(0u);
out.texture_coords_b = vec2(0.0, 0.0);
} else {
let b = global_atlas[instance.texture_index.y];
out.texture_index_b = u32(b.atlas_texture);
out.texture_coords_b = vec2(b.xpos, b.ypos);
if vertex.texture_coords.x == 1.0 {
out.texture_coords_b = out.texture_coords_b + vec2(b.width, 0.0);
}
if vertex.texture_coords.y == 1.0 {
out.texture_coords_b = out.texture_coords_b + vec2(0.0, b.height);
}
}
// Pick mask image if mask is enabled
// x coordinate of mask index is either 0 or 1, telling us whether or not to use a mask.
// y coordinate is mask sprite index
if instance.mask_index.x == 1u {
let m = global_atlas[instance.mask_index.y];
out.mask_index = vec2(1u, u32(m.atlas_texture));
out.mask_coords = vec2(m.xpos, m.ypos);
if vertex.texture_coords.x == 1.0 {
out.mask_coords = vec2(out.mask_coords.x + m.width, out.mask_coords.y);
}
if vertex.texture_coords.y == 1.0 {
out.mask_coords = vec2(out.mask_coords.x, out.mask_coords.y + m.height);
}
} else {
out.mask_coords = vec2(0.0, 0.0);
out.mask_index = vec2(0u, 0u);
}
return out;
}
@fragment
fn fragment_main(in: VertexOutput) -> @location(0) vec4<f32> {
var mask: f32 = 1.0;
if in.mask_index.x == 1u {
mask = textureSampleLevel(
texture_array[in.mask_index.y],
sampler_array[0],
in.mask_coords,
0.0
).a;
}
var texture_a: vec4<f32> = vec4(0.0, 0.0, 0.0, 0.0);
if !(
(in.texture_index_a == 0u) &&
(in.texture_coords_a.x == 0.0) &&
(in.texture_coords_a.y == 0.0)
) {
texture_a = textureSampleLevel(
texture_array[in.texture_index_a],
sampler_array[0],
in.texture_coords_a,
0.0
).rgba;
}
var texture_b: vec4<f32> = vec4(0.0, 0.0, 0.0, 0.0);
if !(
(in.texture_index_b == 0u) &&
(in.texture_coords_b.x == 0.0) &&
(in.texture_coords_b.y == 0.0)
) {
texture_b = textureSampleLevel(
texture_array[in.texture_index_b],
sampler_array[0],
in.texture_coords_b,
0.0
).rgba;
}
var color: vec4<f32> = mix(
texture_a,
texture_b,
in.tween
) * in.color;
// Apply mask and discard fully transparent pixels
color = vec4(color.rgb, color.a *mask);
if color.a == 0.0 {
discard;
}
return color;
}