[docs] Include uncompressed shader source in .cpp comments

This is meant to
(1) Make it easier for new developers to find the source
(2) Make it easier to look at shader diffs when the GL JS pin changes

1 files changed, 80 insertions, 0 deletions

diff --git a/src/mbgl/shaders/collision_circle.cpp b/src/mbgl/shaders/collision_circle.cpp
index bcbe569a09..be8b93ba44 100644
--- a/src/mbgl/shaders/collision_circle.cpp
+++ b/src/mbgl/shaders/collision_circle.cpp
@@ -10,5 +10,85 @@ const char* collision_circle::name = "collision_circle";
 const char* collision_circle::vertexSource = source() + 15671;
 const char* collision_circle::fragmentSource = source() + 16977;
 
+// Uncompressed source of collision_circle.vertex.glsl:
+/*
+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 = clamp(
+        0.5 + 0.5 * (u_camera_to_center_distance / camera_to_anchor_distance),
+        0.0, // Prevents oversized near-field circles in pitched/overzoomed tiles
+        4.0);
+
+    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;
+}
+
+*/
+
+// Uncompressed source of collision_circle.fragment.glsl:
+/*
+uniform float u_overscale_factor;
+
+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 = 15.0 * extrude_scale_length / u_overscale_factor;
+    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;
+}
+
+*/
+
 } // namespace shaders
 } // namespace mbgl