diff --git a/src/shader.wgsl b/src/shader.wgsl
index 41c0e59..c44f459 100644
--- a/src/shader.wgsl
+++ b/src/shader.wgsl
@@ -47,8 +47,8 @@ struct GroundOutput {
 @vertex
 fn vs_ground(@builtin(vertex_index) vertex_index: u32) -> GroundOutput {
     // hacky way to draw two triangles that make a square
-    let tmp1 = (i32(vertex_index)-i32(vertex_index)/3*2) / 2;
-    let tmp2 = (i32(vertex_index)-i32(vertex_index)/3*2) & 1;
+    let tmp1 = i32(vertex_index)/2-i32(vertex_index)/3;
+    let tmp2 = i32(vertex_index)&1;
     let pos = vec3<f32>(
         f32(tmp1) * 2.0 - 1.0,
         0.0,