+#define BoxInsideBox(a,b,c,d) ((a)[0] >= (c)[0] && (b)[0] <= (d)[0] && (a)[1] >= (c)[1] && (b)[1] <= (d)[1] && (a)[2] >= (c)[2] && (b)[2] <= (d)[2])
+#define TriangleBBoxOverlapsBox(a,b,c,d,e) (min((a)[0], min((b)[0], (c)[0])) < (e)[0] && max((a)[0], max((b)[0], (c)[0])) > (d)[0] && min((a)[1], min((b)[1], (c)[1])) < (e)[1] && max((a)[1], max((b)[1], (c)[1])) > (d)[1] && min((a)[2], min((b)[2], (c)[2])) < (e)[2] && max((a)[2], max((b)[2], (c)[2])) > (d)[2])
+
+#define TriangleNormal(a,b,c,n) ( \
+ (n)[0] = ((a)[1] - (b)[1]) * ((c)[2] - (b)[2]) - ((a)[2] - (b)[2]) * ((c)[1] - (b)[1]), \
+ (n)[1] = ((a)[2] - (b)[2]) * ((c)[0] - (b)[0]) - ((a)[0] - (b)[0]) * ((c)[2] - (b)[2]), \
+ (n)[2] = ((a)[0] - (b)[0]) * ((c)[1] - (b)[1]) - ((a)[1] - (b)[1]) * ((c)[0] - (b)[0]) \
+ )
+
+/*! Fast PointInfrontOfTriangle.
+ * subtracts v1 from v0 and v2, combined into a crossproduct, combined with a
+ * dotproduct of the light location relative to the first point of the
+ * triangle (any point works, since any triangle is obviously flat), and
+ * finally a comparison to determine if the light is infront of the triangle
+ * (the goal of this statement) we do not need to normalize the surface
+ * normal because both sides of the comparison use it, therefore they are
+ * both multiplied the same amount... furthermore a subtract can be done on
+ * the point to eliminate one dotproduct
+ * this is ((p - a) * cross(a-b,c-b))
+ */
+#define PointInfrontOfTriangle(p,a,b,c) \
+( ((p)[0] - (a)[0]) * (((a)[1] - (b)[1]) * ((c)[2] - (b)[2]) - ((a)[2] - (b)[2]) * ((c)[1] - (b)[1])) \
++ ((p)[1] - (a)[1]) * (((a)[2] - (b)[2]) * ((c)[0] - (b)[0]) - ((a)[0] - (b)[0]) * ((c)[2] - (b)[2])) \
++ ((p)[2] - (a)[2]) * (((a)[0] - (b)[0]) * ((c)[1] - (b)[1]) - ((a)[1] - (b)[1]) * ((c)[0] - (b)[0])) > 0)
+
+#if 0
+// readable version, kept only for explanatory reasons
+int PointInfrontOfTriangle(const float *p, const float *a, const float *b, const float *c)
+{
+ float dir0[3], dir1[3], normal[3];
+
+ // calculate two mostly perpendicular edge directions
+ VectorSubtract(a, b, dir0);
+ VectorSubtract(c, b, dir1);
+
+ // we have two edge directions, we can calculate a third vector from
+ // them, which is the direction of the surface normal (its magnitude
+ // is not 1 however)
+ CrossProduct(dir0, dir1, normal);
+
+ // compare distance of light along normal, with distance of any point
+ // of the triangle along the same normal (the triangle is planar,
+ // I.E. flat, so all points give the same answer)
+ return DotProduct(p, normal) > DotProduct(a, normal);
+}
+#endif
+
+#define lhcheeserand(seed) ((seed) = ((seed) * 987211u) ^ ((seed) >> 13u) ^ 914867)
+#define lhcheeserandom(seed,MIN,MAX) ((double)(lhcheeserand(seed) + 0.5) / ((double)4096.0*1024.0*1024.0) * ((MAX)-(MIN)) + (MIN))
+#define VectorCheeseRandom(seed,v) do{(v)[0] = lhcheeserandom(seed,-1, 1);(v)[1] = lhcheeserandom(seed,-1, 1);(v)[2] = lhcheeserandom(seed,-1, 1);}while(DotProduct(v, v) > 1)
+#define VectorLehmerRandom(seed,v) do{(v)[0] = Math_crandomf(seed);(v)[1] = Math_crandomf(seed);(v)[2] = Math_crandomf(seed);}while(DotProduct(v, v) > 1)