1 files changed, 83 insertions, 0 deletions
diff --git a/src/mbgl/shaders/collision_circle.cpp b/src/mbgl/shaders/collision_circle.cpp
new file mode 100644
index 0000000000..1e85d99a33
--- /dev/null
+++ b/src/mbgl/shaders/collision_circle.cpp
@@ -0,0 +1,83 @@
+// NOTE: DO NOT CHANGE THIS FILE. IT IS AUTOMATICALLY GENERATED.
+
+#include <mbgl/shaders/collision_circle.hpp>
+
+namespace mbgl {
+namespace shaders {
+
+const char* collision_circle::name = "collision_circle";
+const char* collision_circle::vertexSource = R"MBGL_SHADER(
+attribute vec2 a_pos;
+attribute vec2 a_anchor_pos;
+attribute vec2 a_extrude;
+attribute vec2 a_placed;
+
+uniform mat4 u_matrix;
+uniform vec2 u_extrude_scale;
+uniform float u_camera_to_center_distance;
+
+varying float v_placed;
+varying float v_notUsed;
+varying float v_radius;
+
+varying vec2 v_extrude;
+varying vec2 v_extrude_scale;
+
+void main() {
+    vec4 projectedPoint = u_matrix * vec4(a_anchor_pos, 0, 1);
+    highp float camera_to_anchor_distance = projectedPoint.w;
+    highp float collision_perspective_ratio = 0.5 + 0.5 * (camera_to_anchor_distance / u_camera_to_center_distance);
+
+    gl_Position = u_matrix * vec4(a_pos, 0.0, 1.0);
+
+    highp float padding_factor = 1.2; // Pad the vertices slightly to make room for anti-alias blur
+    gl_Position.xy += a_extrude * u_extrude_scale * padding_factor * gl_Position.w / collision_perspective_ratio;
+
+    v_placed = a_placed.x;
+    v_notUsed = a_placed.y;
+    v_radius = abs(a_extrude.y); // We don't pitch the circles, so both units of the extrusion vector are equal in magnitude to the radius
+
+    v_extrude = a_extrude * padding_factor;
+    v_extrude_scale = u_extrude_scale * u_camera_to_center_distance / collision_perspective_ratio;
+}
+
+)MBGL_SHADER";
+const char* collision_circle::fragmentSource = R"MBGL_SHADER(
+
+varying float v_placed;
+varying float v_notUsed;
+varying float v_radius;
+varying vec2 v_extrude;
+varying vec2 v_extrude_scale;
+
+void main() {
+    float alpha = 0.5;
+
+    // Red = collision, hide label
+    vec4 color = vec4(1.0, 0.0, 0.0, 1.0) * alpha;
+
+    // Blue = no collision, label is showing
+    if (v_placed > 0.5) {
+        color = vec4(0.0, 0.0, 1.0, 0.5) * alpha;
+    }
+
+    if (v_notUsed > 0.5) {
+        // This box not used, fade it out
+        color *= .2;
+    }
+
+    float extrude_scale_length = length(v_extrude_scale);
+    float extrude_length = length(v_extrude) * extrude_scale_length;
+    float stroke_width = 3.0;
+    float radius = v_radius * extrude_scale_length;
+
+    float distance_to_edge = abs(extrude_length - radius);
+    float opacity_t = smoothstep(-stroke_width, 0.0, -distance_to_edge);
+
+    gl_FragColor = opacity_t * color;
+}
+
+)MBGL_SHADER";
+
+} // namespace shaders
+} // namespace mbgl