From 167e31655b63aa4d4548532cf0410cea9fd145ca Mon Sep 17 00:00:00 2001
From: Kai Stevenson <kai@kaistevenson.com>
Date: Sun, 9 Aug 2026 16:30:29 -0700
Subject: drawing

---
 src/sim/overlay.rs | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 src/sim/overlay.rs

(limited to 'src/sim/overlay.rs')

diff --git a/src/sim/overlay.rs b/src/sim/overlay.rs
new file mode 100644
index 0000000..36a810b
--- /dev/null
+++ b/src/sim/overlay.rs
@@ -0,0 +1,50 @@
+use crate::{Config, Input, sim::board::Board};
+
+pub fn create_compute_combined_overlay_offset(
+    board: &Board,
+    config: &Config,
+    input: &Input,
+) -> impl Fn(i32, i32) -> (u8, u8, u8, u8) {
+    |x: i32, y: i32| {
+        // could allow negative offsets too
+        let mut offset: (u8, u8, u8, u8) = (0x00, 0x00, 0x00, 0x00);
+
+        // bounds
+        // left
+        let xl = -((board.size_x / 2 + 1) as i32);
+        // right
+        let xu = (board.size_x / 2 + 1) as i32;
+        // bottom
+        let yl = -((board.size_y / 2 + 1) as i32);
+        // top
+        let yu = (board.size_y / 2 + 1) as i32;
+
+        if ((x == xl || x == xu) && (y <= yu && y >= yl))
+            || (y == yl || y == yu) && (x <= xu && x >= xl)
+        {
+            offset.0 = offset.0.saturating_add(0xFF);
+            offset.1 = offset.1.saturating_add(0xFF);
+            offset.2 = offset.2.saturating_add(0xFF);
+        }
+
+        // grid
+        if x % 30 == 0 || y % 30 == 0 {
+            offset.0 = offset.0.saturating_add(0x10);
+            offset.1 = offset.1.saturating_add(0x10);
+            offset.2 = offset.2.saturating_add(0x10);
+        }
+
+        // brush/selection
+        if (((x - input.last_mouse_pos_on_board.0).pow(2)
+            + (y - input.last_mouse_pos_on_board.1).pow(2)) as f32)
+            .sqrt()
+            < config.brush_size as f32
+        {
+            offset.0 = offset.0.saturating_add(0xAA);
+            offset.1 = offset.1.saturating_add(0x00);
+            offset.2 = offset.2.saturating_add(0xAA);
+        }
+
+        return offset;
+    }
+}
-- 
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