+#define VectorScale(in, scale, out) ((out)[0] = (in)[0] * (scale),(out)[1] = (in)[1] * (scale),(out)[2] = (in)[2] * (scale))
+#define VectorCompare(a,b) (((a)[0]==(b)[0])&&((a)[1]==(b)[1])&&((a)[2]==(b)[2]))
+#define VectorMA(a, scale, b, c) ((c)[0] = (a)[0] + (scale) * (b)[0],(c)[1] = (a)[1] + (scale) * (b)[1],(c)[2] = (a)[2] + (scale) * (b)[2])
+#define VectorM(scale1, b1, c) ((c)[0] = (scale1) * (b1)[0],(c)[1] = (scale1) * (b1)[1],(c)[2] = (scale1) * (b1)[2])
+#define VectorMAM(scale1, b1, scale2, b2, c) ((c)[0] = (scale1) * (b1)[0] + (scale2) * (b2)[0],(c)[1] = (scale1) * (b1)[1] + (scale2) * (b2)[1],(c)[2] = (scale1) * (b1)[2] + (scale2) * (b2)[2])
+#define VectorMAMAM(scale1, b1, scale2, b2, scale3, b3, c) ((c)[0] = (scale1) * (b1)[0] + (scale2) * (b2)[0] + (scale3) * (b3)[0],(c)[1] = (scale1) * (b1)[1] + (scale2) * (b2)[1] + (scale3) * (b3)[1],(c)[2] = (scale1) * (b1)[2] + (scale2) * (b2)[2] + (scale3) * (b3)[2])
+#define VectorMAMAMAM(scale1, b1, scale2, b2, scale3, b3, scale4, b4, c) ((c)[0] = (scale1) * (b1)[0] + (scale2) * (b2)[0] + (scale3) * (b3)[0] + (scale4) * (b4)[0],(c)[1] = (scale1) * (b1)[1] + (scale2) * (b2)[1] + (scale3) * (b3)[1] + (scale4) * (b4)[1],(c)[2] = (scale1) * (b1)[2] + (scale2) * (b2)[2] + (scale3) * (b3)[2] + (scale4) * (b4)[2])
+#define VectorNormalizeFast(_v)\
+{\
+ float _y, _number;\
+ _number = DotProduct(_v, _v);\
+ if (_number != 0.0)\
+ {\
+ *((long *)&_y) = 0x5f3759df - ((* (long *) &_number) >> 1);\
+ _y = _y * (1.5f - (_number * 0.5f * _y * _y));\
+ VectorScale(_v, _y, _v);\
+ }\
+}
+#define VectorRandom(v) do{(v)[0] = lhrandom(-1, 1);(v)[1] = lhrandom(-1, 1);(v)[2] = lhrandom(-1, 1);}while(DotProduct(v, v) > 1)
+#define VectorBlend(b1, b2, blend, c) do{float iblend = 1 - (blend);VectorMAM(iblend, b1, blend, b2, c);}while(0)
+#define BoxesOverlap(a,b,c,d) ((a)[0] <= (d)[0] && (b)[0] >= (c)[0] && (a)[1] <= (d)[1] && (b)[1] >= (c)[1] && (a)[2] <= (d)[2] && (b)[2] >= (c)[2])
+
+// 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 the subtract can be done
+// on the vectors, saving a little bit of math in the dotproducts
+#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 (it's 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