1 files changed, 6 insertions, 1 deletions
diff --git a/src/mbgl/shaders/debug.cpp b/src/mbgl/shaders/debug.cpp
index d39dcf25be..d18f3be5d1 100644
--- a/src/mbgl/shaders/debug.cpp
+++ b/src/mbgl/shaders/debug.cpp
@@ -12,7 +12,12 @@ attribute vec2 a_pos;
 uniform mat4 u_matrix;
 
 void main() {
-    gl_Position = u_matrix * vec4(a_pos, step(32767.0, a_pos.x), 1);
+    // We are using Int16 for texture position coordinates to give us enough precision for
+    // fractional coordinates. We use 8192 to scale the texture coordinates in the buffer
+    // as an arbitrarily high number to preserve adequate precision when rendering.
+    // This is also the same value as the EXTENT we are using for our tile buffer pos coordinates,
+    // so math for modifying either is consistent.
+    gl_Position = u_matrix * vec4(a_pos, step(8192.0, a_pos.x), 1);
 }
 
 )MBGL_SHADER";