diff --git a/include/blah/math/rectI.h b/include/blah/math/rectI.h
index fb4e10e..d05acda 100644
--- a/include/blah/math/rectI.h
+++ b/include/blah/math/rectI.h
@@ -31,6 +31,8 @@ namespace Blah
 		Point bottom_right() const;
 
 		bool overlaps(const RectI& other) const;
+		RectI overlap_rect(const Rect& against) const;
+
 		bool contains(const Point& pt) const;
 		bool contains(const Vec2& pt) const;
 
diff --git a/src/math/rectI.cpp b/src/math/rectI.cpp
index fd4b28a..2262f38 100644
--- a/src/math/rectI.cpp
+++ b/src/math/rectI.cpp
@@ -2,6 +2,7 @@
 #include <blah/math/rect.h>
 #include <blah/math/point.h>
 #include <blah/math/vec2.h>
+#include <blah/math/calc.h>
 
 using namespace Blah;
 
@@ -89,6 +90,25 @@ bool RectI::overlaps(const RectI& other) const
 		&& other.y < y + h;
 }
 
+RectI RectI::overlap_rect(const Rect& against) const
+{
+	RectI result(0, 0, 0, 0);
+
+	if (x + w >= against.x && x < against.x + against.w)
+	{
+		result.x = Calc::max(x, against.x);
+		result.w = Calc::min(x + w, against.x + against.w) - result.x;
+	}
+
+	if (y + h >= against.y && y < against.y + against.h)
+	{
+		result.y = Calc::max(y, against.y);
+		result.h = Calc::min(y + h, against.y + against.h) - result.y;
+	}
+
+	return result;
+}
+
 bool RectI::contains(const Point& point) const
 {
 	return point.x >= x && point.x < x + w && point.y >= y && point.y < y + h;