[drape] line shader optimization

1 files changed, 10 insertions, 16 deletions

diff --git a/drape/shaders/line_fragment_shader.fsh b/drape/shaders/line_fragment_shader.fsh
index 49be8f77af..f92749062f 100644
--- a/drape/shaders/line_fragment_shader.fsh
+++ b/drape/shaders/line_fragment_shader.fsh
@@ -17,29 +17,23 @@ varying vec3 v_mask;
 
 void main(void)
 {
-  float r = v_radius.y;
-  float dist = abs(v_radius.x);
+  float squareDist = v_radius.x * v_radius.x;
+  float squareRadius = v_radius.y * v_radius.y;
+
+  float capY = (v_dx + 1.0 * sign(v_dx)) * v_radius.z / 2.0;
+  float joinY = (v_dx + 1.0) * v_radius.y / 2.0;
 
   if (v_type.x < -0.5)
   {
-    float y = (v_dx + 1.0) * v_radius.y / 2.0;
+    float y = joinY;
     if (v_type.y < 0.5)
-      y = v_radius.y - (v_dx + 1.0) * v_radius.y / 2.0;
+      y = v_radius.y - joinY;
 
-    float sq = dist * dist + y * y;
-    if (sq >= v_radius.y * v_radius.y)
+    if (squareDist + y * y > squareRadius)
       discard;
   }
-  else
-  {
-    if (v_type.y > 0.1 && abs(v_dx) >= 1.0)
-    {
-      float y = (v_dx + 1.0 * sign(v_dx)) * v_radius.z / 2.0;
-      float gip2 = dist * dist + y * y;
-      if(gip2 > v_radius.y * v_radius.y)
-        discard;
-    }
-  }
+  else if (v_type.y > 0.1 && abs(v_dx) >= 1.0 && (squareDist + capY > squareRadius))
+      discard;
 
   vec4 color = getTexel(int(v_color.z), v_color.xy);
   color.a = getTexel(int(v_mask.z), v_mask.xy).a;