1 files changed, 40 insertions, 0 deletions
diff --git a/gfx/wr/webrender/res/rect.glsl b/gfx/wr/webrender/res/rect.glsl
new file mode 100644
index 0000000000..2a080ee393
--- /dev/null
+++ b/gfx/wr/webrender/res/rect.glsl
@@ -0,0 +1,40 @@
+/* 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/. */
+
+struct RectWithSize {
+    vec2 p0;
+    vec2 size;
+};
+
+struct RectWithEndpoint {
+    vec2 p0;
+    vec2 p1;
+};
+
+float point_inside_rect(vec2 p, vec2 p0, vec2 p1) {
+    vec2 s = step(p0, p) - step(p1, p);
+    return s.x * s.y;
+}
+
+vec2 signed_distance_rect_xy(vec2 pos, vec2 p0, vec2 p1) {
+    // Instead of using a true signed distance to rect here, we just use the
+    // simpler approximation of the maximum distance on either axis from the
+    // outside of the rectangle. This avoids expensive use of length() and only
+    // causes mostly imperceptible differences at corner pixels.
+    return max(p0 - pos, pos - p1);
+}
+
+float signed_distance_rect(vec2 pos, vec2 p0, vec2 p1) {
+    // Collapse the per-axis distances to edges to a single approximate value.
+    vec2 d = signed_distance_rect_xy(pos, p0, p1);
+    return max(d.x, d.y);
+}
+
+vec2 rect_clamp(RectWithEndpoint rect, vec2 pt) {
+    return clamp(pt, rect.p0, rect.p1);
+}
+
+vec2 rect_size(RectWithEndpoint rect) {
+    return rect.p1 - rect.p0;
+}