#define_import_path bevy_ui::ui_node
#import bevy_render::view::View
const TEXTURED = 1u;
const RIGHT_VERTEX = 2u;
const BOTTOM_VERTEX = 4u;
// must align with BORDER_* shader_flags from bevy_ui/render/mod.rs
const BORDER_LEFT: u32 = 256u;
const BORDER_TOP: u32 = 512u;
const BORDER_RIGHT: u32 = 1024u;
const BORDER_BOTTOM: u32 = 2048u;
const BORDER_ANY: u32 = BORDER_LEFT + BORDER_TOP + BORDER_RIGHT + BORDER_BOTTOM;
fn enabled(flags: u32, mask: u32) -> bool {
return (flags & mask) != 0u;
}
@group(0) @binding(0) var<uniform> view: View;
struct VertexOutput {
@location(0) uv: vec2<f32>,
@location(1) color: vec4<f32>,
@location(2) @interpolate(flat) size: vec2<f32>,
@location(3) @interpolate(flat) flags: u32,
@location(4) @interpolate(flat) radius: vec4<f32>,
@location(5) @interpolate(flat) border: vec4<f32>,
// Position relative to the center of the rectangle.
@location(6) point: vec2<f32>,
@builtin(position) position: vec4<f32>,
};
@vertex
fn vertex(
@location(0) vertex_position: vec3<f32>,
@location(1) vertex_uv: vec2<f32>,
@location(2) vertex_color: vec4<f32>,
@location(3) flags: u32,
// x: top left, y: top right, z: bottom right, w: bottom left.
@location(4) radius: vec4<f32>,
// x: left, y: top, z: right, w: bottom.
@location(5) border: vec4<f32>,
@location(6) size: vec2<f32>,
@location(7) point: vec2<f32>,
) -> VertexOutput {
var out: VertexOutput;
out.uv = vertex_uv;
out.position = view.clip_from_world * vec4(vertex_position, 1.0);
out.color = vertex_color;
out.flags = flags;
out.radius = radius;
out.size = size;
out.border = border;
out.point = point;
return out;
}
@group(1) @binding(0) var sprite_texture: texture_2d<f32>;
@group(1) @binding(1) var sprite_sampler: sampler;
// The returned value is the shortest distance from the given point to the boundary of the rounded
// box.
//
// Negative values indicate that the point is inside the rounded box, positive values that the point
// is outside, and zero is exactly on the boundary.
//
// Arguments:
// - `point` -> The function will return the distance from this point to the closest point on
// the boundary.
// - `size` -> The maximum width and height of the box.
// - `corner_radii` -> The radius of each rounded corner. Ordered counter clockwise starting
// top left:
// x: top left, y: top right, z: bottom right, w: bottom left.
fn sd_rounded_box(point: vec2<f32>, size: vec2<f32>, corner_radii: vec4<f32>) -> f32 {
// If 0.0 < y then select bottom left (w) and bottom right corner radius (z).
// Else select top left (x) and top right corner radius (y).
let rs = select(corner_radii.xy, corner_radii.wz, 0.0 < point.y);
// w and z are swapped above so that both pairs are in left to right order, otherwise this second
// select statement would return the incorrect value for the bottom pair.
let radius = select(rs.x, rs.y, 0.0 < point.x);
// Vector from the corner closest to the point, to the point.
let corner_to_point = abs(point) - 0.5 * size;
// Vector from the center of the radius circle to the point.
let q = corner_to_point + radius;
// Length from center of the radius circle to the point, zeros a component if the point is not
// within the quadrant of the radius circle that is part of the curved corner.
let l = length(max(q, vec2(0.0)));
let m = min(max(q.x, q.y), 0.0);
return l + m - radius;
}
fn sd_inset_rounded_box(point: vec2<f32>, size: vec2<f32>, radius: vec4<f32>, inset: vec4<f32>) -> f32 {
let inner_size = size - inset.xy - inset.zw;
let inner_center = inset.xy + 0.5 * inner_size - 0.5 * size;
let inner_point = point - inner_center;
var r = radius;
// Top left corner.
r.x = r.x - max(inset.x, inset.y);
// Top right corner.
r.y = r.y - max(inset.z, inset.y);
// Bottom right corner.
r.z = r.z - max(inset.z, inset.w);
// Bottom left corner.
r.w = r.w - max(inset.x, inset.w);
let half_size = inner_size * 0.5;
let min_size = min(half_size.x, half_size.y);
r = min(max(r, vec4(0.0)), vec4<f32>(min_size));
return sd_rounded_box(inner_point, inner_size, r);
}
fn nearest_border_active(point_vs_mid: vec2<f32>, size: vec2<f32>, width: vec4<f32>, flags: u32) -> bool {
if (flags & BORDER_ANY) == BORDER_ANY {
return true;
}
// get point vs top left
let point = clamp(point_vs_mid + size * 0.49999, vec2(0.0), size);
let left = point.x / width.x;
let top = point.y / width.y;
let right = (size.x - point.x) / width.z;
let bottom = (size.y - point.y) / width.w;
let min_dist = min(min(left, top), min(right, bottom));
return (enabled(flags, BORDER_LEFT) && min_dist == left) ||
(enabled(flags, BORDER_TOP) && min_dist == top) ||
(enabled(flags, BORDER_RIGHT) && min_dist == right) ||
(enabled(flags, BORDER_BOTTOM) && min_dist == bottom);
}
// get alpha for antialiasing for sdf
fn antialias(distance: f32) -> f32 {
// Using the fwidth(distance) was causing artifacts, so just use the distance.
return saturate(0.5 - distance);
}
fn draw_uinode_border(
color: vec4<f32>,
point: vec2<f32>,
size: vec2<f32>,
radius: vec4<f32>,
border: vec4<f32>,
flags: u32,
) -> vec4<f32> {
// Signed distances. The magnitude is the distance of the point from the edge of the shape.
// * Negative values indicate that the point is inside the shape.
// * Zero values indicate the point is on the edge of the shape.
// * Positive values indicate the point is outside the shape.
// Signed distance from the exterior boundary.
let external_distance = sd_rounded_box(point, size, radius);
// Signed distance from the border's internal edge (the signed distance is negative if the point
// is inside the rect but not on the border).
// If the border size is set to zero, this is the same as the external distance.
let internal_distance = sd_inset_rounded_box(point, size, radius, border);
// Signed distance from the border (the intersection of the rect with its border).
// Points inside the border have negative signed distance. Any point outside the border, whether
// outside the outside edge, or inside the inner edge have positive signed distance.
let border_distance = max(external_distance, -internal_distance);
// check if this node should apply color for the nearest border
let nearest_border = select(0.0, 1.0, nearest_border_active(point, size, border, flags));
#ifdef ANTI_ALIAS
// At external edges with no border, `border_distance` is equal to zero.
// This select statement ensures we only perform anti-aliasing where a non-zero width border
// is present, otherwise an outline about the external boundary would be drawn even without
// a border.
let t = select(1.0 - step(0.0, border_distance), antialias(border_distance), external_distance < internal_distance);
#else
let t = 1.0 - step(0.0, border_distance);
#endif
// Blend mode ALPHA_BLENDING is used for UI elements, so we don't premultiply alpha here.
return vec4(color.rgb, saturate(color.a * t * nearest_border));
}
fn draw_uinode_background(
color: vec4<f32>,
point: vec2<f32>,
size: vec2<f32>,
radius: vec4<f32>,
border: vec4<f32>,
) -> vec4<f32> {
// When drawing the background only draw the internal area and not the border.
let internal_distance = sd_inset_rounded_box(point, size, radius, border);
#ifdef ANTI_ALIAS
let t = antialias(internal_distance);
#else
let t = 1.0 - step(0.0, internal_distance);
#endif
return vec4(color.rgb, saturate(color.a * t));
}
@fragment
fn fragment(in: VertexOutput) -> @location(0) vec4<f32> {
let texture_color = textureSample(sprite_texture, sprite_sampler, in.uv);
// Only use the color sampled from the texture if the `TEXTURED` flag is enabled.
// This allows us to draw both textured and untextured shapes together in the same batch.
let color = select(in.color, in.color * texture_color, enabled(in.flags, TEXTURED));
if enabled(in.flags, BORDER_ANY) {
return draw_uinode_border(color, in.point, in.size, in.radius, in.border, in.flags);
} else {
return draw_uinode_background(color, in.point, in.size, in.radius, in.border);
}
}
