servo/resources/shaders/clip_shared.glsl
2016-10-23 13:20:36 +02:00

51 lines
2 KiB
GLSL

#line 1
/* 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/. */
flat varying vec4 vClipRect;
flat varying vec4 vClipRadius;
#ifdef WR_VERTEX_SHADER
void write_clip(Clip clip) {
vClipRect = vec4(clip.rect.rect.xy, clip.rect.rect.xy + clip.rect.rect.zw);
vClipRadius = vec4(clip.top_left.outer_inner_radius.x,
clip.top_right.outer_inner_radius.x,
clip.bottom_right.outer_inner_radius.x,
clip.bottom_left.outer_inner_radius.x);
}
#endif
#ifdef WR_FRAGMENT_SHADER
float do_clip(vec2 pos) {
vec2 ref_tl = vClipRect.xy + vec2( vClipRadius.x, vClipRadius.x);
vec2 ref_tr = vClipRect.zy + vec2(-vClipRadius.y, vClipRadius.y);
vec2 ref_br = vClipRect.zw + vec2(-vClipRadius.z, -vClipRadius.z);
vec2 ref_bl = vClipRect.xw + vec2( vClipRadius.w, -vClipRadius.w);
float d_tl = distance(pos, ref_tl);
float d_tr = distance(pos, ref_tr);
float d_br = distance(pos, ref_br);
float d_bl = distance(pos, ref_bl);
float pixels_per_fragment = length(fwidth(pos.xy));
// TODO: compute the `nudge` separately for X and Y
float nudge = 0.5 * pixels_per_fragment;
bool out0 = pos.x < ref_tl.x && pos.y < ref_tl.y && d_tl > vClipRadius.x - nudge;
bool out1 = pos.x > ref_tr.x && pos.y < ref_tr.y && d_tr > vClipRadius.y - nudge;
bool out2 = pos.x > ref_br.x && pos.y > ref_br.y && d_br > vClipRadius.z - nudge;
bool out3 = pos.x < ref_bl.x && pos.y > ref_bl.y && d_bl > vClipRadius.w - nudge;
vec4 distances = vec4(d_tl, d_tr, d_br, d_bl) - vClipRadius + nudge;
float distance_from_border = dot(vec4(out0, out1, out2, out3), distances);
// Move the distance back into pixels.
distance_from_border /= pixels_per_fragment;
// Apply a more gradual fade out to transparent.
//distance_from_border -= 0.5;
return 1.0 - smoothstep(0.0, 1.0, distance_from_border);
}
#endif