@@ -32,6 +32,30 @@ struct Hsla {
float a;
};
+struct LinearColorStop {
+ Hsla color;
+ float percentage;
+};
+
+struct Background {
+ // 0u is Solid
+ // 1u is LinearGradient
+ uint tag;
+ // 0u is sRGB linear color
+ // 1u is Oklab color
+ uint color_space;
+ Hsla solid;
+ float angle;
+ LinearColorStop colors[2];
+ uint pad;
+};
+
+struct GradientColor {
+ float4 solid;
+ float4 color0;
+ float4 color1;
+};
+
struct AtlasTextureId {
uint index;
uint kind;
@@ -71,6 +95,17 @@ float4 distance_from_clip_rect(float2 unit_vertex, Bounds bounds, Bounds clip_bo
clip_bounds.origin.y + clip_bounds.size.y - position.y);
}
+// Convert linear RGB to sRGB
+float3 linear_to_srgb(float3 color) {
+ return pow(color, float3(2.2));
+}
+
+// Convert sRGB to linear RGB
+float3 srgb_to_linear(float3 color) {
+ return pow(color, float3(1.0 / 2.2));
+}
+
+/// Hsla to linear RGBA conversion.
float4 hsla_to_rgba(Hsla hsla) {
float h = hsla.h * 6.0; // Now, it's an angle but scaled in [0, 6) range
float s = hsla.s;
@@ -119,6 +154,48 @@ float4 hsla_to_rgba(Hsla hsla) {
return rgba;
}
+// Converts a sRGB color to the Oklab color space.
+// Reference: https://bottosson.github.io/posts/oklab/#converting-from-linear-srgb-to-oklab
+float4 srgb_to_oklab(float4 color) {
+ // Convert non-linear sRGB to linear sRGB
+ color = float4(srgb_to_linear(color.rgb), color.a);
+
+ float l = 0.4122214708 * color.r + 0.5363325363 * color.g + 0.0514459929 * color.b;
+ float m = 0.2119034982 * color.r + 0.6806995451 * color.g + 0.1073969566 * color.b;
+ float s = 0.0883024619 * color.r + 0.2817188376 * color.g + 0.6299787005 * color.b;
+
+ float l_ = pow(l, 1.0/3.0);
+ float m_ = pow(m, 1.0/3.0);
+ float s_ = pow(s, 1.0/3.0);
+
+ return float4(
+ 0.2104542553 * l_ + 0.7936177850 * m_ - 0.0040720468 * s_,
+ 1.9779984951 * l_ - 2.4285922050 * m_ + 0.4505937099 * s_,
+ 0.0259040371 * l_ + 0.7827717662 * m_ - 0.8086757660 * s_,
+ color.a
+ );
+}
+
+// Converts an Oklab color to the sRGB color space.
+float4 oklab_to_srgb(float4 color) {
+ float l_ = color.r + 0.3963377774 * color.g + 0.2158037573 * color.b;
+ float m_ = color.r - 0.1055613458 * color.g - 0.0638541728 * color.b;
+ float s_ = color.r - 0.0894841775 * color.g - 1.2914855480 * color.b;
+
+ float l = l_ * l_ * l_;
+ float m = m_ * m_ * m_;
+ float s = s_ * s_ * s_;
+
+ float3 linear_rgb = float3(
+ 4.0767416621 * l - 3.3077115913 * m + 0.2309699292 * s,
+ -1.2684380046 * l + 2.6097574011 * m - 0.3413193965 * s,
+ -0.0041960863 * l - 0.7034186147 * m + 1.7076147010 * s
+ );
+
+ // Convert linear sRGB to non-linear sRGB
+ return float4(linear_to_srgb(linear_rgb), color.a);
+}
+
// This approximates the error function, needed for the gaussian integral
float2 erf(float2 x) {
float2 s = sign(x);
@@ -190,6 +267,83 @@ float quad_sdf(float2 pt, Bounds bounds, Corners corner_radii) {
return distance;
}
+GradientColor prepare_gradient_color(uint tag, uint color_space, Hsla solid, Hsla color0, Hsla color1) {
+ GradientColor res;
+ if (tag == 0) {
+ res.solid = hsla_to_rgba(solid);
+ } else if (tag == 1) {
+ res.color0 = hsla_to_rgba(color0);
+ res.color1 = hsla_to_rgba(color1);
+
+ // Prepare color space in vertex for avoid conversion
+ // in fragment shader for performance reasons
+ if (color_space == 1) {
+ // Oklab
+ res.color0 = srgb_to_oklab(res.color0);
+ res.color1 = srgb_to_oklab(res.color1);
+ }
+ }
+
+ return res;
+}
+
+float4 gradient_color(Background background,
+ float2 position,
+ Bounds bounds,
+ float4 solid_color, float4 color0, float4 color1) {
+ float4 color;
+
+ switch (background.tag) {
+ case 0:
+ color = solid_color;
+ break;
+ case 1: {
+ // -90 degrees to match the CSS gradient angle.
+ float radians = (fmod(background.angle, 360.0) - 90.0) * (M_PI_F / 180.0);
+ float2 direction = float2(cos(radians), sin(radians));
+
+ // Expand the short side to be the same as the long side
+ if (bounds.size.x > bounds.size.y) {
+ direction.y *= bounds.size.y / bounds.size.x;
+ } else {
+ direction.x *= bounds.size.x / bounds.size.y;
+ }
+
+ // Get the t value for the linear gradient with the color stop percentages.
+ float2 half_size = float2(bounds.size.x, bounds.size.y) / 2.;
+ float2 center = float2(bounds.origin.x, bounds.origin.y) + half_size;
+ float2 center_to_point = position - center;
+ float t = dot(center_to_point, direction) / length(direction);
+ // Check the direct to determine the use x or y
+ if (abs(direction.x) > abs(direction.y)) {
+ t = (t + half_size.x) / bounds.size.x;
+ } else {
+ t = (t + half_size.y) / bounds.size.y;
+ }
+
+ // Adjust t based on the stop percentages
+ t = (t - background.colors[0].percentage)
+ / (background.colors[1].percentage
+ - background.colors[0].percentage);
+ t = clamp(t, 0.0, 1.0);
+
+ switch (background.color_space) {
+ case 0:
+ color = lerp(color0, color1, t);
+ break;
+ case 1: {
+ float4 oklab_color = lerp(color0, color1, t);
+ color = oklab_to_srgb(oklab_color);
+ break;
+ }
+ }
+ break;
+ }
+ }
+
+ return color;
+}
+
/*
**
** Shadows
@@ -294,7 +448,7 @@ struct Quad {
uint pad;
Bounds bounds;
Bounds content_mask;
- Hsla background;
+ Background background;
Hsla border_color;
Corners corner_radii;
Edges border_widths;
@@ -302,17 +456,22 @@ struct Quad {
struct QuadVertexOutput {
float4 position: SV_Position;
- float4 background_color: COLOR0;
- float4 border_color: COLOR1;
+ // float4 border_color: COLOR0;
+ float4 border_color: FLAT;
uint quad_id: FLAT;
+ float4 background_solid: FLAT;
+ float4 background_color0: FLAT;
+ float4 background_color1: FLAT;
float4 clip_distance: SV_ClipDistance;
};
struct QuadFragmentInput {
- float4 position: SV_Position;
- float4 background_color: COLOR0;
- float4 border_color: COLOR1;
uint quad_id: FLAT;
+ float4 position: SV_Position;
+ float4 border_color: FLAT;
+ float4 background_solid: FLAT;
+ float4 background_color0: FLAT;
+ float4 background_color1: FLAT;
};
StructuredBuffer<Quad> quads: register(t1);
@@ -322,20 +481,34 @@ QuadVertexOutput quad_vertex(uint vertex_id: SV_VertexID, uint quad_id: SV_Insta
Quad quad = quads[quad_id];
float4 device_position = to_device_position(unit_vertex, quad.bounds);
float4 clip_distance = distance_from_clip_rect(unit_vertex, quad.bounds, quad.content_mask);
- float4 background_color = hsla_to_rgba(quad.background);
float4 border_color = hsla_to_rgba(quad.border_color);
+ GradientColor gradient = prepare_gradient_color(
+ quad.background.tag,
+ quad.background.color_space,
+ quad.background.solid,
+ quad.background.colors[0].color,
+ quad.background.colors[1].color
+ );
+
QuadVertexOutput output;
output.position = device_position;
- output.background_color = background_color;
output.border_color = border_color;
output.quad_id = quad_id;
+ output.background_solid = gradient.solid;
+ output.background_color0 = gradient.color0;
+ output.background_color1 = gradient.color1;
output.clip_distance = clip_distance;
return output;
}
float4 quad_fragment(QuadFragmentInput input): SV_Target {
Quad quad = quads[input.quad_id];
+ float2 half_size = quad.bounds.size / 2.;
+ float2 center = quad.bounds.origin + half_size;
+ float2 center_to_point = input.position.xy - center;
+ float4 color = gradient_color(quad.background, input.position.xy, quad.bounds,
+ input.background_solid, input.background_color0, input.background_color1);
// Fast path when the quad is not rounded and doesn't have any border.
if (quad.corner_radii.top_left == 0. && quad.corner_radii.bottom_left == 0. &&
@@ -343,12 +516,9 @@ float4 quad_fragment(QuadFragmentInput input): SV_Target {
quad.corner_radii.bottom_right == 0. && quad.border_widths.top == 0. &&
quad.border_widths.left == 0. && quad.border_widths.right == 0. &&
quad.border_widths.bottom == 0.) {
- return input.background_color;
+ return color;
}
- float2 half_size = quad.bounds.size / 2.;
- float2 center = quad.bounds.origin + half_size;
- float2 center_to_point = input.position.xy - center;
float corner_radius;
if (center_to_point.x < 0.) {
if (center_to_point.y < 0.) {
@@ -385,16 +555,12 @@ float4 quad_fragment(QuadFragmentInput input): SV_Target {
border_width = vertical_border;
}
- float4 color;
- if (border_width == 0.) {
- color = input.background_color;
- } else {
+ if (border_width != 0.) {
float inset_distance = distance + border_width;
// Blend the border on top of the background and then linearly interpolate
// between the two as we slide inside the background.
- float4 blended_border = over(input.background_color, input.border_color);
- color = lerp(blended_border, input.background_color,
- saturate(0.5 - inset_distance));
+ float4 blended_border = over(color, input.border_color);
+ color = lerp(blended_border, color, saturate(0.5 - inset_distance));
}
return color * float4(1., 1., 1., saturate(0.5 - distance));
@@ -457,14 +623,17 @@ float4 path_rasterization_fragment(PathRasterizationInput input): SV_Target {
struct PathSprite {
Bounds bounds;
- Hsla color;
+ Background color;
AtlasTile tile;
};
struct PathVertexOutput {
float4 position: SV_Position;
float2 tile_position: POSITION1;
- float4 color: COLOR;
+ uint sprite_id: FLAT;
+ float4 solid_color: FLAT;
+ float4 color0: FLAT;
+ float4 color1: FLAT;
};
StructuredBuffer<PathSprite> path_sprites: register(t1);
@@ -473,18 +642,32 @@ PathVertexOutput paths_vertex(uint vertex_id: SV_VertexID, uint instance_id: SV_
float2 unit_vertex = float2(float(vertex_id & 1u), 0.5 * float(vertex_id & 2u));
PathSprite sprite = path_sprites[instance_id];
// Don't apply content mask because it was already accounted for when rasterizing the path.
-
PathVertexOutput output;
output.position = to_device_position(unit_vertex, sprite.bounds);
output.tile_position = to_tile_position(unit_vertex, sprite.tile);
- output.color = hsla_to_rgba(sprite.color);
+ output.sprite_id = instance_id;
+
+ GradientColor gradient = prepare_gradient_color(
+ sprite.color.tag,
+ sprite.color.color_space,
+ sprite.color.solid,
+ sprite.color.colors[0].color,
+ sprite.color.colors[1].color
+ );
+
+ output.solid_color = gradient.solid;
+ output.color0 = gradient.color0;
+ output.color1 = gradient.color1;
return output;
}
float4 paths_fragment(PathVertexOutput input): SV_Target {
float sample = t_sprite.Sample(s_sprite, input.tile_position).r;
float mask = 1.0 - abs(1.0 - sample % 2.0);
- float4 color = input.color;
+ PathSprite sprite = path_sprites[input.sprite_id];
+ Background background = sprite.color;
+ float4 color = gradient_color(background, input.position.xy, sprite.bounds,
+ input.solid_color, input.color0, input.color1);
color.a *= mask;
return color;
}