判断一个点是否在三角形区域内

float TriangleArea (float v0x, float v0y, float v1x, float v1y, float v2x, float v2y)
{
return Mathf.Abs ((v0x * v1y + v1x * v2y + v2x * v0y
- v1x * v0y - v2x * v1y - v0x * v2y) / 2f);
}
public bool IsINTriangle (Vector3 point, Vector3 v0, Vector3 v1, Vector3 v2)
{
float x = point.x;
float y = point.z;

float v0x = v0.x;
float v0y = v0.z;

float v1x = v1.x;
float v1y = v1.z;

float v2x = v2.x;
float v2y = v2.z;

float t = TriangleArea (v0x, v0y, v1x, v1y, v2x, v2y);
float a = TriangleArea (v0x, v0y, v1x, v1y, x, y) + TriangleArea (v0x, v0y, x, y, v2x, v2y) + TriangleArea (x, y, v1x, v1y, v2x, v2y);

if (Mathf.Abs (t - a) <= 0.01f) {
return true;
} else {
return false;
}
}