Merge pull request #2055 from matze/perceptual-gradient

Compute gradients in Oklab color space

3 files changed, 304 insertions, 306 deletions

diff --git a/wgpu/src/shader/quad.wgsl b/wgpu/src/shader/quad.wgsl
index 023b5a6d..f919cfe2 100644
--- a/wgpu/src/shader/quad.wgsl
+++ b/wgpu/src/shader/quad.wgsl
@@ -37,309 +37,3 @@ fn select_border_radius(radi: vec4<f32>, position: vec2<f32>, center: vec2<f32>)
     rx = select(rx, ry, position.y > center.y);
     return rx;
 }
-
-fn unpack_u32(color: vec2<u32>) -> vec4<f32> {
-    let rg: vec2<f32> = unpack2x16float(color.x);
-    let ba: vec2<f32> = unpack2x16float(color.y);
-
-    return vec4<f32>(rg.y, rg.x, ba.y, ba.x);
-}
-
-struct SolidVertexInput {
-    @location(0) v_pos: vec2<f32>,
-    @location(1) color: vec4<f32>,
-    @location(2) pos: vec2<f32>,
-    @location(3) scale: vec2<f32>,
-    @location(4) border_color: vec4<f32>,
-    @location(5) border_radius: vec4<f32>,
-    @location(6) border_width: f32,
-}
-
-struct SolidVertexOutput {
-    @builtin(position) position: vec4<f32>,
-    @location(0) color: vec4<f32>,
-    @location(1) border_color: vec4<f32>,
-    @location(2) pos: vec2<f32>,
-    @location(3) scale: vec2<f32>,
-    @location(4) border_radius: vec4<f32>,
-    @location(5) border_width: f32,
-}
-
-@vertex
-fn solid_vs_main(input: SolidVertexInput) -> SolidVertexOutput {
-    var out: SolidVertexOutput;
-
-    var pos: vec2<f32> = input.pos * globals.scale;
-    var scale: vec2<f32> = input.scale * globals.scale;
-
-    var min_border_radius = min(input.scale.x, input.scale.y) * 0.5;
-    var border_radius: vec4<f32> = vec4<f32>(
-        min(input.border_radius.x, min_border_radius),
-        min(input.border_radius.y, min_border_radius),
-        min(input.border_radius.z, min_border_radius),
-        min(input.border_radius.w, min_border_radius)
-    );
-
-    var transform: mat4x4<f32> = mat4x4<f32>(
-        vec4<f32>(scale.x + 1.0, 0.0, 0.0, 0.0),
-        vec4<f32>(0.0, scale.y + 1.0, 0.0, 0.0),
-        vec4<f32>(0.0, 0.0, 1.0, 0.0),
-        vec4<f32>(pos - vec2<f32>(0.5, 0.5), 0.0, 1.0)
-    );
-
-    out.position = globals.transform * transform * vec4<f32>(input.v_pos, 0.0, 1.0);
-    out.color = input.color;
-    out.border_color = input.border_color;
-    out.pos = pos;
-    out.scale = scale;
-    out.border_radius = border_radius * globals.scale;
-    out.border_width = input.border_width * globals.scale;
-
-    return out;
-}
-
-@fragment
-fn solid_fs_main(
-    input: SolidVertexOutput
-) -> @location(0) vec4<f32> {
-    var mixed_color: vec4<f32> = input.color;
-
-    var border_radius = select_border_radius(
-        input.border_radius,
-        input.position.xy,
-        (input.pos + input.scale * 0.5).xy
-    );
-
-    if (input.border_width > 0.0) {
-        var internal_border: f32 = max(border_radius - input.border_width, 0.0);
-
-        var internal_distance: f32 = distance_alg(
-            input.position.xy,
-            input.pos + vec2<f32>(input.border_width, input.border_width),
-            input.scale - vec2<f32>(input.border_width * 2.0, input.border_width * 2.0),
-            internal_border
-        );
-
-        var border_mix: f32 = smoothstep(
-            max(internal_border - 0.5, 0.0),
-            internal_border + 0.5,
-            internal_distance
-        );
-
-        mixed_color = mix(input.color, input.border_color, vec4<f32>(border_mix, border_mix, border_mix, border_mix));
-    }
-
-    var dist: f32 = distance_alg(
-        vec2<f32>(input.position.x, input.position.y),
-        input.pos,
-        input.scale,
-        border_radius
-    );
-
-    var radius_alpha: f32 = 1.0 - smoothstep(
-        max(border_radius - 0.5, 0.0),
-        border_radius + 0.5,
-        dist
-    );
-
-    return vec4<f32>(mixed_color.x, mixed_color.y, mixed_color.z, mixed_color.w * radius_alpha);
-}
-
-struct GradientVertexInput {
-    @location(0) v_pos: vec2<f32>,
-    @location(1) @interpolate(flat) colors_1: vec4<u32>,
-    @location(2) @interpolate(flat) colors_2: vec4<u32>,
-    @location(3) @interpolate(flat) colors_3: vec4<u32>,
-    @location(4) @interpolate(flat) colors_4: vec4<u32>,
-    @location(5) @interpolate(flat) offsets: vec4<u32>,
-    @location(6) direction: vec4<f32>,
-    @location(7) position_and_scale: vec4<f32>,
-    @location(8) border_color: vec4<f32>,
-    @location(9) border_radius: vec4<f32>,
-    @location(10) border_width: f32,
-}
-
-struct GradientVertexOutput {
-    @builtin(position) position: vec4<f32>,
-    @location(1) @interpolate(flat) colors_1: vec4<u32>,
-    @location(2) @interpolate(flat) colors_2: vec4<u32>,
-    @location(3) @interpolate(flat) colors_3: vec4<u32>,
-    @location(4) @interpolate(flat) colors_4: vec4<u32>,
-    @location(5) @interpolate(flat) offsets: vec4<u32>,
-    @location(6) direction: vec4<f32>,
-    @location(7) position_and_scale: vec4<f32>,
-    @location(8) border_color: vec4<f32>,
-    @location(9) border_radius: vec4<f32>,
-    @location(10) border_width: f32,
-}
-
-@vertex
-fn gradient_vs_main(input: GradientVertexInput) -> GradientVertexOutput {
-    var out: GradientVertexOutput;
-
-    var pos: vec2<f32> = input.position_and_scale.xy * globals.scale;
-    var scale: vec2<f32> = input.position_and_scale.zw * globals.scale;
-
-    var min_border_radius = min(input.position_and_scale.z, input.position_and_scale.w) * 0.5;
-    var border_radius: vec4<f32> = vec4<f32>(
-        min(input.border_radius.x, min_border_radius),
-        min(input.border_radius.y, min_border_radius),
-        min(input.border_radius.z, min_border_radius),
-        min(input.border_radius.w, min_border_radius)
-    );
-
-    var transform: mat4x4<f32> = mat4x4<f32>(
-        vec4<f32>(scale.x + 1.0, 0.0, 0.0, 0.0),
-        vec4<f32>(0.0, scale.y + 1.0, 0.0, 0.0),
-        vec4<f32>(0.0, 0.0, 1.0, 0.0),
-        vec4<f32>(pos - vec2<f32>(0.5, 0.5), 0.0, 1.0)
-    );
-
-    out.position = globals.transform * transform * vec4<f32>(input.v_pos, 0.0, 1.0);
-    out.colors_1 = input.colors_1;
-    out.colors_2 = input.colors_2;
-    out.colors_3 = input.colors_3;
-    out.colors_4 = input.colors_4;
-    out.offsets = input.offsets;
-    out.direction = input.direction * globals.scale;
-    out.position_and_scale = vec4<f32>(pos, scale);
-    out.border_color = input.border_color;
-    out.border_radius = border_radius * globals.scale;
-    out.border_width = input.border_width * globals.scale;
-
-    return out;
-}
-
-fn random(coords: vec2<f32>) -> f32 {
-    return fract(sin(dot(coords, vec2(12.9898,78.233))) * 43758.5453);
-}
-
-/// Returns the current interpolated color with a max 8-stop gradient
-fn gradient(
-    raw_position: vec2<f32>,
-    direction: vec4<f32>,
-    colors: array<vec4<f32>, 8>,
-    offsets: array<f32, 8>,
-    last_index: i32
-) -> vec4<f32> {
-    let start = direction.xy;
-    let end = direction.zw;
-
-    let v1 = end - start;
-    let v2 = raw_position - start;
-    let unit = normalize(v1);
-    let coord_offset = dot(unit, v2) / length(v1);
-
-    //need to store these as a var to use dynamic indexing in a loop
-    //this is already added to wgsl spec but not in wgpu yet
-    var colors_arr = colors;
-    var offsets_arr = offsets;
-
-    var color: vec4<f32>;
-
-    let noise_granularity: f32 = 0.3/255.0;
-
-    for (var i: i32 = 0; i < last_index; i++) {
-        let curr_offset = offsets_arr[i];
-        let next_offset = offsets_arr[i+1];
-
-        if (coord_offset <= offsets_arr[0]) {
-            color = colors_arr[0];
-        }
-
-        if (curr_offset <= coord_offset && coord_offset <= next_offset) {
-            color = mix(colors_arr[i], colors_arr[i+1], smoothstep(
-                curr_offset,
-                next_offset,
-                coord_offset,
-            ));
-        }
-
-        if (coord_offset >= offsets_arr[last_index]) {
-            color = colors_arr[last_index];
-        }
-    }
-
-    return color + mix(-noise_granularity, noise_granularity, random(raw_position));
-}
-
-@fragment
-fn gradient_fs_main(input: GradientVertexOutput) -> @location(0) vec4<f32> {
-    let colors = array<vec4<f32>, 8>(
-        unpack_u32(input.colors_1.xy),
-        unpack_u32(input.colors_1.zw),
-        unpack_u32(input.colors_2.xy),
-        unpack_u32(input.colors_2.zw),
-        unpack_u32(input.colors_3.xy),
-        unpack_u32(input.colors_3.zw),
-        unpack_u32(input.colors_4.xy),
-        unpack_u32(input.colors_4.zw),
-    );
-
-    let offsets_1: vec4<f32> = unpack_u32(input.offsets.xy);
-    let offsets_2: vec4<f32> = unpack_u32(input.offsets.zw);
-
-    var offsets = array<f32, 8>(
-        offsets_1.x,
-        offsets_1.y,
-        offsets_1.z,
-        offsets_1.w,
-        offsets_2.x,
-        offsets_2.y,
-        offsets_2.z,
-        offsets_2.w,
-    );
-
-    //TODO could just pass this in to the shader but is probably more performant to just check it here
-    var last_index = 7;
-    for (var i: i32 = 0; i <= 7; i++) {
-        if (offsets[i] > 1.0) {
-            last_index = i - 1;
-            break;
-        }
-    }
-
-    var mixed_color: vec4<f32> = gradient(input.position.xy, input.direction, colors, offsets, last_index);
-
-    let pos = input.position_and_scale.xy;
-    let scale = input.position_and_scale.zw;
-
-    var border_radius = select_border_radius(
-        input.border_radius,
-        input.position.xy,
-        (pos + scale * 0.5).xy
-    );
-
-    if (input.border_width > 0.0) {
-        var internal_border: f32 = max(border_radius - input.border_width, 0.0);
-
-        var internal_distance: f32 = distance_alg(
-            input.position.xy,
-            pos + vec2<f32>(input.border_width, input.border_width),
-            scale - vec2<f32>(input.border_width * 2.0, input.border_width * 2.0),
-            internal_border
-        );
-
-        var border_mix: f32 = smoothstep(
-            max(internal_border - 0.5, 0.0),
-            internal_border + 0.5,
-            internal_distance
-        );
-
-        mixed_color = mix(mixed_color, input.border_color, vec4<f32>(border_mix, border_mix, border_mix, border_mix));
-    }
-
-    var dist: f32 = distance_alg(
-        input.position.xy,
-        pos,
-        scale,
-        border_radius
-    );
-
-    var radius_alpha: f32 = 1.0 - smoothstep(
-        max(border_radius - 0.5, 0.0),
-        border_radius + 0.5,
-        dist);
-
-    return vec4<f32>(mixed_color.x, mixed_color.y, mixed_color.z, mixed_color.w * radius_alpha);
-}
diff --git a/wgpu/src/shader/quad/gradient.wgsl b/wgpu/src/shader/quad/gradient.wgsl
new file mode 100644
index 00000000..0754e97f
--- /dev/null
+++ b/wgpu/src/shader/quad/gradient.wgsl
@@ -0,0 +1,205 @@
+struct GradientVertexInput {
+    @location(0) v_pos: vec2<f32>,
+    @location(1) @interpolate(flat) colors_1: vec4<u32>,
+    @location(2) @interpolate(flat) colors_2: vec4<u32>,
+    @location(3) @interpolate(flat) colors_3: vec4<u32>,
+    @location(4) @interpolate(flat) colors_4: vec4<u32>,
+    @location(5) @interpolate(flat) offsets: vec4<u32>,
+    @location(6) direction: vec4<f32>,
+    @location(7) position_and_scale: vec4<f32>,
+    @location(8) border_color: vec4<f32>,
+    @location(9) border_radius: vec4<f32>,
+    @location(10) border_width: f32,
+}
+
+struct GradientVertexOutput {
+    @builtin(position) position: vec4<f32>,
+    @location(1) @interpolate(flat) colors_1: vec4<u32>,
+    @location(2) @interpolate(flat) colors_2: vec4<u32>,
+    @location(3) @interpolate(flat) colors_3: vec4<u32>,
+    @location(4) @interpolate(flat) colors_4: vec4<u32>,
+    @location(5) @interpolate(flat) offsets: vec4<u32>,
+    @location(6) direction: vec4<f32>,
+    @location(7) position_and_scale: vec4<f32>,
+    @location(8) border_color: vec4<f32>,
+    @location(9) border_radius: vec4<f32>,
+    @location(10) border_width: f32,
+}
+
+@vertex
+fn gradient_vs_main(input: GradientVertexInput) -> GradientVertexOutput {
+    var out: GradientVertexOutput;
+
+    var pos: vec2<f32> = input.position_and_scale.xy * globals.scale;
+    var scale: vec2<f32> = input.position_and_scale.zw * globals.scale;
+
+    var min_border_radius = min(input.position_and_scale.z, input.position_and_scale.w) * 0.5;
+    var border_radius: vec4<f32> = vec4<f32>(
+        min(input.border_radius.x, min_border_radius),
+        min(input.border_radius.y, min_border_radius),
+        min(input.border_radius.z, min_border_radius),
+        min(input.border_radius.w, min_border_radius)
+    );
+
+    var transform: mat4x4<f32> = mat4x4<f32>(
+        vec4<f32>(scale.x + 1.0, 0.0, 0.0, 0.0),
+        vec4<f32>(0.0, scale.y + 1.0, 0.0, 0.0),
+        vec4<f32>(0.0, 0.0, 1.0, 0.0),
+        vec4<f32>(pos - vec2<f32>(0.5, 0.5), 0.0, 1.0)
+    );
+
+    out.position = globals.transform * transform * vec4<f32>(input.v_pos, 0.0, 1.0);
+    out.colors_1 = input.colors_1;
+    out.colors_2 = input.colors_2;
+    out.colors_3 = input.colors_3;
+    out.colors_4 = input.colors_4;
+    out.offsets = input.offsets;
+    out.direction = input.direction * globals.scale;
+    out.position_and_scale = vec4<f32>(pos, scale);
+    out.border_color = input.border_color;
+    out.border_radius = border_radius * globals.scale;
+    out.border_width = input.border_width * globals.scale;
+
+    return out;
+}
+
+fn random(coords: vec2<f32>) -> f32 {
+    return fract(sin(dot(coords, vec2(12.9898,78.233))) * 43758.5453);
+}
+
+/// Returns the current interpolated color with a max 8-stop gradient
+fn gradient(
+    raw_position: vec2<f32>,
+    direction: vec4<f32>,
+    colors: array<vec4<f32>, 8>,
+    offsets: array<f32, 8>,
+    last_index: i32
+) -> vec4<f32> {
+    let start = direction.xy;
+    let end = direction.zw;
+
+    let v1 = end - start;
+    let v2 = raw_position - start;
+    let unit = normalize(v1);
+    let coord_offset = dot(unit, v2) / length(v1);
+
+    //need to store these as a var to use dynamic indexing in a loop
+    //this is already added to wgsl spec but not in wgpu yet
+    var colors_arr = colors;
+    var offsets_arr = offsets;
+
+    var color: vec4<f32>;
+
+    let noise_granularity: f32 = 0.3/255.0;
+
+    for (var i: i32 = 0; i < last_index; i++) {
+        let curr_offset = offsets_arr[i];
+        let next_offset = offsets_arr[i+1];
+
+        if (coord_offset <= offsets_arr[0]) {
+            color = colors_arr[0];
+        }
+
+        if (curr_offset <= coord_offset && coord_offset <= next_offset) {
+            let from_ = colors_arr[i];
+            let to_ = colors_arr[i+1];
+            let factor = smoothstep(curr_offset, next_offset, coord_offset);
+
+            color = interpolate_color(from_, to_, factor);
+        }
+
+        if (coord_offset >= offsets_arr[last_index]) {
+            color = colors_arr[last_index];
+        }
+    }
+
+    return color + mix(-noise_granularity, noise_granularity, random(raw_position));
+}
+
+@fragment
+fn gradient_fs_main(input: GradientVertexOutput) -> @location(0) vec4<f32> {
+    let colors = array<vec4<f32>, 8>(
+        unpack_u32(input.colors_1.xy),
+        unpack_u32(input.colors_1.zw),
+        unpack_u32(input.colors_2.xy),
+        unpack_u32(input.colors_2.zw),
+        unpack_u32(input.colors_3.xy),
+        unpack_u32(input.colors_3.zw),
+        unpack_u32(input.colors_4.xy),
+        unpack_u32(input.colors_4.zw),
+    );
+
+    let offsets_1: vec4<f32> = unpack_u32(input.offsets.xy);
+    let offsets_2: vec4<f32> = unpack_u32(input.offsets.zw);
+
+    var offsets = array<f32, 8>(
+        offsets_1.x,
+        offsets_1.y,
+        offsets_1.z,
+        offsets_1.w,
+        offsets_2.x,
+        offsets_2.y,
+        offsets_2.z,
+        offsets_2.w,
+    );
+
+    //TODO could just pass this in to the shader but is probably more performant to just check it here
+    var last_index = 7;
+    for (var i: i32 = 0; i <= 7; i++) {
+        if (offsets[i] > 1.0) {
+            last_index = i - 1;
+            break;
+        }
+    }
+
+    var mixed_color: vec4<f32> = gradient(input.position.xy, input.direction, colors, offsets, last_index);
+
+    let pos = input.position_and_scale.xy;
+    let scale = input.position_and_scale.zw;
+
+    var border_radius = select_border_radius(
+        input.border_radius,
+        input.position.xy,
+        (pos + scale * 0.5).xy
+    );
+
+    if (input.border_width > 0.0) {
+        var internal_border: f32 = max(border_radius - input.border_width, 0.0);
+
+        var internal_distance: f32 = distance_alg(
+            input.position.xy,
+            pos + vec2<f32>(input.border_width, input.border_width),
+            scale - vec2<f32>(input.border_width * 2.0, input.border_width * 2.0),
+            internal_border
+        );
+
+        var border_mix: f32 = smoothstep(
+            max(internal_border - 0.5, 0.0),
+            internal_border + 0.5,
+            internal_distance
+        );
+
+        mixed_color = mix(mixed_color, input.border_color, vec4<f32>(border_mix, border_mix, border_mix, border_mix));
+    }
+
+    var dist: f32 = distance_alg(
+        input.position.xy,
+        pos,
+        scale,
+        border_radius
+    );
+
+    var radius_alpha: f32 = 1.0 - smoothstep(
+        max(border_radius - 0.5, 0.0),
+        border_radius + 0.5,
+        dist);
+
+    return vec4<f32>(mixed_color.x, mixed_color.y, mixed_color.z, mixed_color.w * radius_alpha);
+}
+
+fn unpack_u32(color: vec2<u32>) -> vec4<f32> {
+    let rg: vec2<f32> = unpack2x16float(color.x);
+    let ba: vec2<f32> = unpack2x16float(color.y);
+
+    return vec4<f32>(rg.y, rg.x, ba.y, ba.x);
+}
diff --git a/wgpu/src/shader/quad/solid.wgsl b/wgpu/src/shader/quad/solid.wgsl
new file mode 100644
index 00000000..ebd6d877
--- /dev/null
+++ b/wgpu/src/shader/quad/solid.wgsl
@@ -0,0 +1,99 @@
+struct SolidVertexInput {
+    @location(0) v_pos: vec2<f32>,
+    @location(1) color: vec4<f32>,
+    @location(2) pos: vec2<f32>,
+    @location(3) scale: vec2<f32>,
+    @location(4) border_color: vec4<f32>,
+    @location(5) border_radius: vec4<f32>,
+    @location(6) border_width: f32,
+}
+
+struct SolidVertexOutput {
+    @builtin(position) position: vec4<f32>,
+    @location(0) color: vec4<f32>,
+    @location(1) border_color: vec4<f32>,
+    @location(2) pos: vec2<f32>,
+    @location(3) scale: vec2<f32>,
+    @location(4) border_radius: vec4<f32>,
+    @location(5) border_width: f32,
+}
+
+@vertex
+fn solid_vs_main(input: SolidVertexInput) -> SolidVertexOutput {
+    var out: SolidVertexOutput;
+
+    var pos: vec2<f32> = input.pos * globals.scale;
+    var scale: vec2<f32> = input.scale * globals.scale;
+
+    var min_border_radius = min(input.scale.x, input.scale.y) * 0.5;
+    var border_radius: vec4<f32> = vec4<f32>(
+        min(input.border_radius.x, min_border_radius),
+        min(input.border_radius.y, min_border_radius),
+        min(input.border_radius.z, min_border_radius),
+        min(input.border_radius.w, min_border_radius)
+    );
+
+    var transform: mat4x4<f32> = mat4x4<f32>(
+        vec4<f32>(scale.x + 1.0, 0.0, 0.0, 0.0),
+        vec4<f32>(0.0, scale.y + 1.0, 0.0, 0.0),
+        vec4<f32>(0.0, 0.0, 1.0, 0.0),
+        vec4<f32>(pos - vec2<f32>(0.5, 0.5), 0.0, 1.0)
+    );
+
+    out.position = globals.transform * transform * vec4<f32>(input.v_pos, 0.0, 1.0);
+    out.color = input.color;
+    out.border_color = input.border_color;
+    out.pos = pos;
+    out.scale = scale;
+    out.border_radius = border_radius * globals.scale;
+    out.border_width = input.border_width * globals.scale;
+
+    return out;
+}
+
+@fragment
+fn solid_fs_main(
+    input: SolidVertexOutput
+) -> @location(0) vec4<f32> {
+    var mixed_color: vec4<f32> = input.color;
+
+    var border_radius = select_border_radius(
+        input.border_radius,
+        input.position.xy,
+        (input.pos + input.scale * 0.5).xy
+    );
+
+    if (input.border_width > 0.0) {
+        var internal_border: f32 = max(border_radius - input.border_width, 0.0);
+
+        var internal_distance: f32 = distance_alg(
+            input.position.xy,
+            input.pos + vec2<f32>(input.border_width, input.border_width),
+            input.scale - vec2<f32>(input.border_width * 2.0, input.border_width * 2.0),
+            internal_border
+        );
+
+        var border_mix: f32 = smoothstep(
+            max(internal_border - 0.5, 0.0),
+            internal_border + 0.5,
+            internal_distance
+        );
+
+        mixed_color = mix(input.color, input.border_color, vec4<f32>(border_mix, border_mix, border_mix, border_mix));
+    }
+
+    var dist: f32 = distance_alg(
+        vec2<f32>(input.position.x, input.position.y),
+        input.pos,
+        input.scale,
+        border_radius
+    );
+
+    var radius_alpha: f32 = 1.0 - smoothstep(
+        max(border_radius - 0.5, 0.0),
+        border_radius + 0.5,
+        dist
+    );
+
+    return vec4<f32>(mixed_color.x, mixed_color.y, mixed_color.z, mixed_color.w * radius_alpha);
+}