Fix off-by-factor-of-2 in the vertex shader

client/webgl_shaders.js

@@ -162,7 +162,7 @@ const sdf_vs_src = `#version 300 es
         }
       
         vec2 pos = origin + normalize(outwards) * radius;
-        screen02 = (pos.xy * u_scale + u_translation) / u_res + outwards * pixel;
+        screen02 = (pos.xy * u_scale + u_translation) / u_res * 2.0 + outwards * pixel;
         v_texcoord = pos.xy + outwards * rscale;
 
         screen02.y = 2.0 - screen02.y;