1 files changed, 30 insertions, 0 deletions
diff --git a/src/mbgl/shader/outlinepattern.fragment.glsl b/src/mbgl/shader/outlinepattern.fragment.glsl
new file mode 100644
index 0000000000..dd1efd63e6
--- /dev/null
+++ b/src/mbgl/shader/outlinepattern.fragment.glsl
@@ -0,0 +1,30 @@
+uniform float u_opacity;
+uniform vec2 u_pattern_tl_a;
+uniform vec2 u_pattern_br_a;
+uniform vec2 u_pattern_tl_b;
+uniform vec2 u_pattern_br_b;
+uniform float u_mix;
+
+uniform sampler2D u_image;
+
+varying vec2 v_pos_a;
+varying vec2 v_pos_b;
+varying vec2 v_pos;
+
+void main() {
+    vec2 imagecoord = mod(v_pos_a, 1.0);
+    vec2 pos = mix(u_pattern_tl_a, u_pattern_br_a, imagecoord);
+    vec4 color1 = texture2D(u_image, pos);
+
+    vec2 imagecoord_b = mod(v_pos_b, 1.0);
+    vec2 pos2 = mix(u_pattern_tl_b, u_pattern_br_b, imagecoord_b);
+    vec4 color2 = texture2D(u_image, pos2);
+
+    // find distance to outline for alpha interpolation
+
+    float dist = length(v_pos - gl_FragCoord.xy);
+    float alpha = smoothstep(1.0, 0.0, dist);
+    
+
+    gl_FragColor = mix(color1, color2, u_mix) * alpha * u_opacity;
+}
+\ No newline at end of file