diff --git a/src/camera.cpp b/src/camera.cpp
index c68ef01..a1b4575 100644
--- a/src/camera.cpp
+++ b/src/camera.cpp
@@ -355,6 +355,21 @@ Camera::setFarPlane(float32 far)
 	calczShiftScale(this);
 }
 
+int32
+Camera::frustumTestSphere(Sphere *s)
+{
+	int32 res = SPHEREINSIDE;
+	FrustumPlane *p = this->frustumPlanes;
+	for(int32 i = 0; i < 6; i++){
+		float32 dist = dot(p->plane.normal, s->center) - p->plane.distance;
+		if(s->radius < dist)
+			return SPHEREOUTSIDE;
+		if(s->radius > -dist)
+			res = SPHEREBOUNDARY;
+	}
+	return res;
+}
+
 struct CameraChunkData
 {
 	V2d viewWindow;
diff --git a/src/geometry.cpp b/src/geometry.cpp
index 6e87f7b..3989222 100644
--- a/src/geometry.cpp
+++ b/src/geometry.cpp
@@ -105,6 +105,7 @@ Geometry::streamRead(Stream *stream)
 	GeoStreamData buf;
 	SurfaceProperties surfProps;
 	MaterialList *ret;
+	static SurfaceProperties reset = { 1.0f, 1.0f, 1.0f };
 
 	if(!findChunk(stream, ID_STRUCT, nil, &version)){
 		RWERROR((ERR_CHUNK, "STRUCT"));
@@ -154,7 +155,7 @@ Geometry::streamRead(Stream *stream)
 		defaultSurfaceProps = surfProps;
 	ret = MaterialList::streamRead(stream, &geo->matList);
 	if(version < 0x34000)
-		defaultSurfaceProps = (SurfaceProperties){ 1.0f, 1.0f, 1.0f };
+		defaultSurfaceProps = reset;
 	if(ret == nil)
 		goto fail;
 	if(s_plglist.streamRead(stream, geo))
diff --git a/src/rwbase.h b/src/rwbase.h
index 0f8b4f3..85b64a0 100644
--- a/src/rwbase.h
+++ b/src/rwbase.h
@@ -2,6 +2,9 @@
 #include <stdint.h>
 #endif
 #include <cmath>
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
 
 #ifdef RW_GL3
 #define RW_OPENGL
diff --git a/src/rwobjects.h b/src/rwobjects.h
index 3ee0cee..508ae31 100644
--- a/src/rwobjects.h
+++ b/src/rwobjects.h
@@ -572,6 +572,8 @@ struct Camera : PluginBase<Camera>
 	enum { ID = 4 };
 	enum { PERSPECTIVE = 1, PARALLEL };
 	enum { CLEARIMAGE = 0x1, CLEARZ = 0x2};
+	// return value of frustumTestSphere
+	enum { SPHEREOUTSIDE, SPHEREBOUNDARY, SPHEREINSIDE };
 
 	ObjectWithFrame object;
 	void (*beginUpdateCB)(Camera*);
@@ -612,6 +614,7 @@ struct Camera : PluginBase<Camera>
 	void clear(RGBA *col, uint32 mode);
 	void setNearPlane(float32);
 	void setFarPlane(float32);
+	int32 frustumTestSphere(Sphere *s);
 	static Camera *streamRead(Stream *stream);
 	bool streamWrite(Stream *stream);
 	uint32 streamGetSize(void);