Fix in-air grime application causing pink instead of white in level i…

…mages.
PJB3005 · Jan 31, 2022 · 5b922e8 · 5b922e8
1 parent 472da5d
commit 5b922e8
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Showing 2 changed files with 20 additions and 2 deletions.
diff --git a/Drizzle.Logic/MathHelper.cs b/Drizzle.Logic/MathHelper.cs
@@ -0,0 +1,18 @@
+namespace Drizzle.Logic;
+
+public static class MathHelper
+{
+    public static void SatAdd(ref byte val, byte add)
+    {
+        val = SatAdd(val, add);
+    }
+
+    public static byte SatAdd(byte val, byte add)
+    {
+        var added = val + add;
+        if (added > byte.MaxValue)
+            return byte.MaxValue;
+
+        return (byte)added;
+    }
+}
diff --git a/Drizzle.Logic/Rendering/LevelRenderer.RenderColors.cs b/Drizzle.Logic/Rendering/LevelRenderer.RenderColors.cs
@@ -211,14 +211,14 @@ void RainbowifyPixel(Vector2i pxl)
             if (!IsPixelInFinalImageRainbowed(pxl + (-1, 0)))
             {
                 var currCol = finalImage.getpixel(pxl.X - 1, pxl.Y);
-                currCol.GreenByte += 4;
+                MathHelper.SatAdd(ref currCol.GreenByte, 4);
                 finalImage.setpixel(pxl.X - 1, pxl.Y, currCol);
             }
 
             if (!IsPixelInFinalImageRainbowed(pxl + (0, -1)))
             {
                 var currCol = finalImage.getpixel(pxl.X, pxl.Y - 1);
-                currCol.GreenByte += 4;
+                MathHelper.SatAdd(ref currCol.GreenByte, 4);
                 finalImage.setpixel(pxl.X, pxl.Y - 1, currCol);
             }