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added better random function

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zzzzrrr 2010-02-07 18:58:36 -05:00
parent 759bc5fe89
commit 73b1fa917a
1 changed files with 47 additions and 12 deletions
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59
testbed/main.cc
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@ -49,7 +49,8 @@ void Draw(const double zoom);
void DrawMap(const double zoom); void DrawMap(const double zoom);
void ConstrainedColor(bool constrain); void ConstrainedColor(bool constrain);
double StringToDouble(const std::string& s); double StringToDouble(const std::string& s);
float RandomFloat(float min, float max); double Random(double (*fun)(double), double xmin, double xmax);
double Fun(double x);
/// Dude hole examples /// Dude hole examples
vector<Point*> CreateHeadHole(); vector<Point*> CreateHeadHole();
@ -79,7 +80,8 @@ bool random_distribution = false;
int main(int argc, char* argv[]) int main(int argc, char* argv[])
{ {
int num_points = 0, max, min; int num_points = 0;
double max, min;
double zoom; double zoom;
if (argc != 5) { if (argc != 5) {
@ -92,7 +94,8 @@ int main(int argc, char* argv[])
if(string(argv[1]) == "random") { if(string(argv[1]) == "random") {
num_points = atoi(argv[2]); num_points = atoi(argv[2]);
random_distribution = true; random_distribution = true;
max = atoi(argv[3]); char* pEnd;
max = strtod(argv[3], &pEnd);
min = -max; min = -max;
cx = cy = 0; cx = cy = 0;
zoom = atof(argv[4]); zoom = atof(argv[4]);
@ -103,7 +106,7 @@ int main(int argc, char* argv[])
} }
vector<p2t::Point*> polyline; vector<p2t::Point*> polyline;
if(random_distribution) { if(random_distribution) {
// Create a simple bounding box // Create a simple bounding box
polyline.push_back(new Point(min,min)); polyline.push_back(new Point(min,min));
@ -171,12 +174,11 @@ int main(int argc, char* argv[])
polylines.push_back(head_hole); polylines.push_back(head_hole);
polylines.push_back(chest_hole); polylines.push_back(chest_hole);
} else if (random_distribution) { } else if (random_distribution) {
max-=1; max-=(1e-4);
min+=1; min+=(1e-4);
srand (time(NULL));
for(int i = 0; i < num_points; i++) { for(int i = 0; i < num_points; i++) {
double x = RandomFloat(min, max); double x = Random(Fun, min, max);
double y = RandomFloat(min, max); double y = Random(Fun, min, max);
cdt->AddPoint(new Point(x, y)); cdt->AddPoint(new Point(x, y));
} }
} }
@ -401,7 +403,40 @@ double StringToDouble(const std::string& s)
return x; return x;
} }
float RandomFloat(float min, float max) { double Fun(double x)
float r = (float)rand() / (float)RAND_MAX; {
return min + r * (max - min); return 2.5 + sin(10 * x) / x;
}
double Random(double (*fun)(double), double xmin = 0, double xmax = 1)
{
static double (*Fun)(double) = NULL, YMin, YMax;
static bool First = true;
// Initialises random generator for first call
if (First)
{
First = false;
srand((unsigned) time(NULL));
}
// Evaluates maximum of function
if (fun != Fun)
{
Fun = fun;
YMin = 0, YMax = Fun(xmin);
for (int iX = 1; iX < RAND_MAX; iX++)
{
double X = xmin + (xmax - xmin) * iX / RAND_MAX;
double Y = Fun(X);
YMax = Y > YMax ? Y : YMax;
}
}
// Gets random values for X & Y
double X = xmin + (xmax - xmin) * rand() / RAND_MAX;
double Y = YMin + (YMax - YMin) * rand() / RAND_MAX;
// Returns if valid and try again if not valid
return Y < fun(X) ? X : Random(Fun, xmin, xmax);
} }