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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/// This shader applies a (rounded) rectangle mask to the content of the framebuffer.
#include ps_quad,ellipse
varying highp vec4 vClipLocalPos;
#ifdef WR_FEATURE_FAST_PATH
flat varying highp vec3 v_clip_params; // xy = box size, z = radius
#else
flat varying highp vec4 vClipCenter_Radius_TL;
flat varying highp vec4 vClipCenter_Radius_TR;
flat varying highp vec4 vClipCenter_Radius_BR;
flat varying highp vec4 vClipCenter_Radius_BL;
flat varying highp vec3 vClipPlane_TL;
flat varying highp vec3 vClipPlane_TR;
flat varying highp vec3 vClipPlane_BL;
flat varying highp vec3 vClipPlane_BR;
#endif
flat varying highp vec2 vClipMode;
#ifdef WR_VERTEX_SHADER
PER_INSTANCE in ivec4 aClipData;
#define CLIP_SPACE_RASTER 0
#define CLIP_SPACE_PRIMITIVE 1
struct Clip {
RectWithEndpoint rect;
#ifdef WR_FEATURE_FAST_PATH
vec4 radii;
#else
vec4 radii_top;
vec4 radii_bottom;
#endif
float mode;
int space;
};
Clip fetch_clip(int index) {
Clip clip;
clip.space = aClipData.z;
#ifdef WR_FEATURE_FAST_PATH
vec4 texels[3] = fetch_from_gpu_buffer_3f(index);
clip.rect = RectWithEndpoint(texels[0].xy, texels[0].zw);
clip.radii = texels[1];
clip.mode = texels[2].x;
#else
vec4 texels[4] = fetch_from_gpu_buffer_4f(index);
clip.rect = RectWithEndpoint(texels[0].xy, texels[0].zw);
clip.radii_top = texels[1];
clip.radii_bottom = texels[2];
clip.mode = texels[3].x;
#endif
return clip;
}
void main(void) {
PrimitiveInfo prim_info = ps_quad_main();
Clip clip = fetch_clip(aClipData.y);
Transform clip_transform = fetch_transform(aClipData.x);
vClipLocalPos = clip_transform.m * vec4(prim_info.local_pos, 0.0, 1.0);
#ifndef WR_FEATURE_FAST_PATH
if (clip.space == CLIP_SPACE_RASTER) {
vTransformBounds = vec4(clip.rect.p0, clip.rect.p1);
} else {
RectWithEndpoint xf_bounds = RectWithEndpoint(
max(clip.rect.p0, prim_info.local_clip_rect.p0),
min(clip.rect.p1, prim_info.local_clip_rect.p1)
);
vTransformBounds = vec4(xf_bounds.p0, xf_bounds.p1);
}
#endif
vClipMode.x = clip.mode;
#ifdef WR_FEATURE_FAST_PATH
// If the radii are all uniform, we can use a much simpler 2d
// signed distance function to get a rounded rect clip.
vec2 half_size = 0.5 * (clip.rect.p1 - clip.rect.p0);
float radius = clip.radii.x;
vClipLocalPos.xy -= (half_size + clip.rect.p0) * vClipLocalPos.w;
v_clip_params = vec3(half_size - vec2(radius), radius);
#else
vec2 r_tl = clip.radii_top.xy;
vec2 r_tr = clip.radii_top.zw;
vec2 r_br = clip.radii_bottom.zw;
vec2 r_bl = clip.radii_bottom.xy;
vClipCenter_Radius_TL = vec4(clip.rect.p0 + r_tl,
inverse_radii_squared(r_tl));
vClipCenter_Radius_TR = vec4(clip.rect.p1.x - r_tr.x,
clip.rect.p0.y + r_tr.y,
inverse_radii_squared(r_tr));
vClipCenter_Radius_BR = vec4(clip.rect.p1 - r_br,
inverse_radii_squared(r_br));
vClipCenter_Radius_BL = vec4(clip.rect.p0.x + r_bl.x,
clip.rect.p1.y - r_bl.y,
inverse_radii_squared(r_bl));
// We need to know the half-spaces of the corners separate from the center
// and radius. We compute a point that falls on the diagonal (which is just
// an inner vertex pushed out along one axis, but not on both) to get the
// plane offset of the half-space. We also compute the direction vector of
// the half-space, which is a perpendicular vertex (-y,x) of the vector of
// the diagonal. We leave the scales of the vectors unchanged.
vec2 n_tl = -r_tl.yx;
vec2 n_tr = vec2(r_tr.y, -r_tr.x);
vec2 n_br = r_br.yx;
vec2 n_bl = vec2(-r_bl.y, r_bl.x);
vClipPlane_TL = vec3(n_tl,
dot(n_tl, vec2(clip.rect.p0.x, clip.rect.p0.y + r_tl.y)));
vClipPlane_TR = vec3(n_tr,
dot(n_tr, vec2(clip.rect.p1.x - r_tr.x, clip.rect.p0.y)));
vClipPlane_BR = vec3(n_br,
dot(n_br, vec2(clip.rect.p1.x, clip.rect.p1.y - r_br.y)));
vClipPlane_BL = vec3(n_bl,
dot(n_bl, vec2(clip.rect.p0.x + r_bl.x, clip.rect.p1.y)));
#endif
}
#endif
#ifdef WR_FRAGMENT_SHADER
#ifdef WR_FEATURE_FAST_PATH
// See http://www.iquilezles.org/www/articles/distfunctions2d/distfunctions2d.htm
float sd_box(in vec2 pos, in vec2 box_size) {
vec2 d = abs(pos) - box_size;
return length(max(d, vec2(0.0))) + min(max(d.x,d.y), 0.0);
}
float sd_rounded_box(in vec2 pos, in vec2 box_size, in float radius) {
return sd_box(pos, box_size) - radius;
}
#endif
void main(void) {
vec2 clip_local_pos = vClipLocalPos.xy / vClipLocalPos.w;
float aa_range = compute_aa_range(clip_local_pos);
#ifdef WR_FEATURE_FAST_PATH
float dist = sd_rounded_box(clip_local_pos, v_clip_params.xy, v_clip_params.z);
#else
float dist = distance_to_rounded_rect(
clip_local_pos,
vClipPlane_TL,
vClipCenter_Radius_TL,
vClipPlane_TR,
vClipCenter_Radius_TR,
vClipPlane_BR,
vClipCenter_Radius_BR,
vClipPlane_BL,
vClipCenter_Radius_BL,
vTransformBounds
);
#endif
// Compute AA for the given dist and range.
float alpha = distance_aa(aa_range, dist);
// Select alpha or inverse alpha depending on clip in/out.
float final_alpha = mix(alpha, 1.0 - alpha, vClipMode.x);
oFragColor = vec4(final_alpha);
}
#endif
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