rounded border: remove dead code in shader (#12602)

# Objective

- #12500 added dead code to the ui shader

## Solution

- Remove it

Author: mockersf

crates/bevy_ui/src/render/ui.wgsl

@@ -62,10 +62,6 @@ fn vertex(
 @group(1) @binding(0) var sprite_texture: texture_2d<f32>;
 @group(1) @binding(1) var sprite_sampler: sampler;
 
-fn sigmoid(t: f32) -> f32 {
-    return 1.0 / (1.0 + exp(-t));
-}
-
 // The returned value is the shortest distance from the given point to the boundary of the rounded 
 // box.
 // 
@@ -124,143 +120,6 @@ fn sd_inset_rounded_box(point: vec2<f32>, size: vec2<f32>, radius: vec4<f32>, in
     return sd_rounded_box(inner_point, inner_size, r);
 }
 
-#ifdef CLAMP_INNER_CURVES
-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;
-
-    if 0. < min(inset.x, inset.y) || inset.x + inset.y <= 0. {
-        // Top left corner.
-        r.x = r.x - max(inset.x, inset.y);
-    } else {
-        r.x = 0.;
-    }
-
-    if 0. < min(inset.z, inset.y) || inset.z + inset.y <= 0. {
-        // Top right corner.
-        r.y = r.y - max(inset.z, inset.y);
-    } else {
-        r.y = 0.;
-    }
-
-    if 0. < min(inset.z, inset.w) || inset.z + inset.w <= 0. {
-        // Bottom right corner.
-        r.z = r.z - max(inset.z, inset.w);
-    } else {
-        r.z = 0.;
-    }
-
-    if 0. < min(inset.x, inset.w) || inset.x + inset.w <= 0. {
-        // Bottom left corner.
-        r.w = r.w - max(inset.x, inset.w);
-    } else {
-        r.w = 0.;
-    }
-
-    let half_size = inner_size * 0.5;
-    let min = min(half_size.x, half_size.y);
-
-    r = min(max(r, vec4<f32>(0.0)), vec4<f32>(min));
-
-    return sd_rounded_box(inner_point, inner_size, r);
-}
-#endif
-
-const RED: vec4<f32> = vec4<f32>(1., 0., 0., 1.);
-const GREEN: vec4<f32> = vec4<f32>(0., 1., 0., 1.);
-const BLUE: vec4<f32> = vec4<f32>(0., 0., 1., 1.);
-const WHITE = vec4<f32>(1., 1., 1., 1.);
-const BLACK = vec4<f32>(0., 0., 0., 1.);
-
-// Draw the border in white, rest of the rect black.
-fn draw_border(in: VertexOutput) -> vec4<f32> {
-    // Distance from external border. Positive values outside.
-    let external_distance = sd_rounded_box(in.point, in.size, in.radius);
-
-    // Distance from internal border. Positive values inside.
-    let internal_distance = sd_inset_rounded_box(in.point, in.size, in.radius, in.border);
-
-    // Distance from border, positive values inside border.
-    let border = max(-internal_distance, external_distance);
-
-    if border < 0.0 {
-        return WHITE;
-    } else {
-        return BLACK;
-    }
-}
-
-// Draw just the interior in white, rest of the rect black.
-fn draw_interior(in: VertexOutput) -> vec4<f32> {
-    // Distance from external border. Positive values outside.
-    let external_distance = sd_rounded_box(in.point, in.size, in.radius);
-
-    if external_distance < 0.0 {
-        return WHITE;
-    } else {
-        return BLACK;
-    }
-}
-
-// Draw all the geometry.
-fn draw_test(in: VertexOutput) -> vec4<f32> {
-    // Distance from external border. Negative inside
-    let external_distance = sd_rounded_box(in.point, in.size, in.radius);
-
-    // Distance from internal border.
-    let internal_distance = sd_inset_rounded_box(in.point, in.size, in.radius, in.border);
-
-    // Distance from border.
-    let border = max(-internal_distance, external_distance);
-
-    // Draw the area outside the border in green.
-    if 0.0 < external_distance {
-        return GREEN;
-    }
-
-    // Draw the area inside the border in white.
-    if border < 0.0 {
-        return WHITE;
-    }
-
-    // Draw the interior in blue.
-    if internal_distance < 0.0 {
-        return BLUE;
-    }
-
-    // Fill anything else with red (the presence of any red is a bug).
-    return RED;
-}
-
-fn draw_no_aa(in: VertexOutput) -> vec4<f32> {
-    let texture_color = textureSample(sprite_texture, sprite_sampler, in.uv);
-    let color = select(in.color, in.color * texture_color, enabled(in.flags, TEXTURED));
-
-    // Negative value => point inside external border.
-    let external_distance = sd_rounded_box(in.point, in.size, in.radius);
-    // Negative value => point inside internal border.
-    let internal_distance = sd_inset_rounded_box(in.point, in.size, in.radius, in.border);
-    // Negative value => point inside border.
-    let border = max(external_distance, -internal_distance);
-
-    if enabled(in.flags, BORDER) {
-        if border < 0.0 {
-            return color;
-        } else {
-            return vec4(0.0);
-        }
-    }
-
-    if external_distance < 0.0 {
-        return color;
-    }
-
-    return vec4(0.0);
-}
-
 fn draw(in: VertexOutput) -> vec4<f32> {
     let texture_color = textureSample(sprite_texture, sprite_sampler, in.uv);