1 files changed, 165 insertions, 0 deletions
diff --git a/gfx/wr/webrender/res/ps_quad_mask.glsl b/gfx/wr/webrender/res/ps_quad_mask.glsl
new file mode 100644
index 0000000000..3c6f7f6713
--- /dev/null
+++ b/gfx/wr/webrender/res/ps_quad_mask.glsl
@@ -0,0 +1,165 @@
+/* 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/. */
+
+#include ps_quad,ellipse
+
+varying highp vec2 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;
+
+struct Clip {
+    RectWithEndpoint rect;
+#ifdef WR_FEATURE_FAST_PATH
+    vec4 radii;
+#else
+    vec4 radii_top;
+    vec4 radii_bottom;
+#endif
+    float mode;
+};
+
+Clip fetch_clip(int index) {
+    Clip clip;
+
+#ifdef WR_FEATURE_FAST_PATH
+    vec4 texels[3] = fetch_from_gpu_buffer_3(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_4(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);
+
+    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);
+
+    Transform clip_transform = fetch_transform(aClipData.x);
+
+    vClipLocalPos = (clip_transform.m * vec4(prim_info.local_pos, 0.0, 1.0)).xy;
+    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 -= (half_size + clip.rect.p0);
+    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) {
+    float aa_range = compute_aa_range(vClipLocalPos);
+
+#ifdef WR_FEATURE_FAST_PATH
+    float dist = sd_rounded_box(vClipLocalPos, v_clip_params.xy, v_clip_params.z);
+#else
+    float dist = distance_to_rounded_rect(
+        vClipLocalPos,
+        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