[gtk/ngl-cleanups] add forgotten file

[Matthias Clasen <matthiasc src gnome org>]

commit 9048a589f5854ec156c94119de164267b416f659
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Mar 14 12:07:50 2021 -0400

    add forgotten file

 gsk/ngl/resources/filled_border.glsl | 47 ++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
---
diff --git a/gsk/ngl/resources/filled_border.glsl b/gsk/ngl/resources/filled_border.glsl
new file mode 100644
index 0000000000..d503dd0500
--- /dev/null
+++ b/gsk/ngl/resources/filled_border.glsl
@@ -0,0 +1,47 @@
+// VERTEX_SHADER:
+// filled_border.glsl
+
+uniform vec4 u_widths;
+uniform vec4[3] u_outline_rect;
+
+_OUT_ vec4 outer_color;
+_OUT_ vec4 inner_color;
+_OUT_ _GSK_ROUNDED_RECT_UNIFORM_ transformed_outside_outline;
+_OUT_ _GSK_ROUNDED_RECT_UNIFORM_ transformed_inside_outline;
+
+void main() {
+  gl_Position = u_projection * u_modelview * vec4(aPosition, 0.0, 1.0);
+
+  outer_color = gsk_scaled_premultiply(aColor, u_alpha);
+  inner_color = gsk_scaled_premultiply(aColor2, u_alpha);
+
+  GskRoundedRect outside = gsk_create_rect(u_outline_rect);
+  GskRoundedRect inside = gsk_rounded_rect_shrink (outside, u_widths);
+
+  gsk_rounded_rect_transform(outside, u_modelview);
+  gsk_rounded_rect_transform(inside, u_modelview);
+
+  gsk_rounded_rect_encode(outside, transformed_outside_outline);
+  gsk_rounded_rect_encode(inside, transformed_inside_outline);
+}
+
+// FRAGMENT_SHADER:
+// filled_border.glsl
+
+uniform vec4[3] u_outline_rect;
+
+_IN_ vec4 outer_color;
+_IN_ vec4 inner_color;
+_IN_ _GSK_ROUNDED_RECT_UNIFORM_ transformed_outside_outline;
+_IN_ _GSK_ROUNDED_RECT_UNIFORM_ transformed_inside_outline;
+
+void main() {
+  vec2 frag = gsk_get_frag_coord();
+  float outer_coverage = gsk_rounded_rect_coverage(gsk_decode_rect(transformed_outside_outline), frag);
+  float inner_coverage = gsk_rounded_rect_coverage(gsk_decode_rect(transformed_inside_outline), frag);
+
+  float alpha = clamp(outer_coverage - inner_coverage, 0.0, 1.0);
+  float alpha2 = clamp(inner_coverage, 0.0, 1.0);
+
+  gskSetOutputColor((outer_color * alpha) + (inner_color * alpha2));
+}