diff --git a/DebugUtils/Include/DebugDraw.h b/DebugUtils/Include/DebugDraw.h
index 712c3f9..81c8c2a 100644
--- a/DebugUtils/Include/DebugDraw.h
+++ b/DebugUtils/Include/DebugDraw.h
@@ -19,6 +19,9 @@
 #ifndef DEBUGDRAW_H
 #define DEBUGDRAW_H
 
+// Some math headers don't have PI defined.
+static const float DU_PI = 3.14159265f;
+
 enum duDebugDrawPrimitives
 {
 	DU_DRAW_POINTS,
diff --git a/DebugUtils/Source/DebugDraw.cpp b/DebugUtils/Source/DebugDraw.cpp
index 5bd6043..d794c66 100644
--- a/DebugUtils/Source/DebugDraw.cpp
+++ b/DebugUtils/Source/DebugDraw.cpp
@@ -169,7 +169,7 @@ void duAppendCylinderWire(struct duDebugDraw* dd, float minx, float miny, float
 		init = true;
 		for (int i = 0; i < NUM_SEG; ++i)
 		{
-			const float a = (float)i/(float)NUM_SEG*(float)M_PI*2;
+			const float a = (float)i/(float)NUM_SEG*DU_PI*2;
 			dir[i*2] = cosf(a);
 			dir[i*2+1] = sinf(a);
 		}
@@ -425,7 +425,7 @@ void duAppendCircle(struct duDebugDraw* dd, const float x, const float y, const
 		init = true;
 		for (int i = 0; i < NUM_SEG; ++i)
 		{
-			const float a = (float)i/(float)NUM_SEG*(float)M_PI*2;
+			const float a = (float)i/(float)NUM_SEG*DU_PI*2;
 			dir[i*2] = cosf(a);
 			dir[i*2+1] = sinf(a);
 		}
diff --git a/DebugUtils/Source/RecastDebugDraw.cpp b/DebugUtils/Source/RecastDebugDraw.cpp
index e986584..52861e1 100644
--- a/DebugUtils/Source/RecastDebugDraw.cpp
+++ b/DebugUtils/Source/RecastDebugDraw.cpp
@@ -57,7 +57,7 @@ void duDebugDrawTriMeshSlope(duDebugDraw* dd, const float* verts, int /*nverts*/
 	if (!tris) return;
 	if (!normals) return;
 	
-	const float walkableThr = cosf(walkableSlopeAngle/180.0f*(float)M_PI);
+	const float walkableThr = cosf(walkableSlopeAngle/180.0f*DU_PI);
 
 	dd->begin(DU_DRAW_TRIS);
 	for (int i = 0; i < ntris*3; i += 3)
diff --git a/Recast/Include/Recast.h b/Recast/Include/Recast.h
index 5fc8d89..1fd5dc2 100644
--- a/Recast/Include/Recast.h
+++ b/Recast/Include/Recast.h
@@ -19,6 +19,9 @@
 #ifndef RECAST_H
 #define RECAST_H
 
+// Some math headers don't have PI defined.
+static const float RC_PI = 3.14159265f;
+
 enum rcLogCategory
 {
 	RC_LOG_PROGRESS = 1,
diff --git a/Recast/Source/Recast.cpp b/Recast/Source/Recast.cpp
index 369e1ee..d051418 100644
--- a/Recast/Source/Recast.cpp
+++ b/Recast/Source/Recast.cpp
@@ -200,7 +200,7 @@ void rcMarkWalkableTriangles(rcContext* /*ctx*/, const float walkableSlopeAngle,
 	// TODO: VC complains about unref formal variable, figure out a way to handle this better.
 //	rcAssert(ctx);
 	
-	const float walkableThr = cosf(walkableSlopeAngle/180.0f*(float)M_PI);
+	const float walkableThr = cosf(walkableSlopeAngle/180.0f*RC_PI);
 
 	float norm[3];
 	
@@ -222,7 +222,7 @@ void rcClearUnwalkableTriangles(rcContext* /*ctx*/, const float walkableSlopeAng
 	// TODO: VC complains about unref formal variable, figure out a way to handle this better.
 //	rcAssert(ctx);
 	
-	const float walkableThr = cosf(walkableSlopeAngle/180.0f*(float)M_PI);
+	const float walkableThr = cosf(walkableSlopeAngle/180.0f*RC_PI);
 	
 	float norm[3];