Messages

1

Graphics / Deleting points in a shape

« on: March 25, 2010, 04:48:32 pm »

Thanks for the prompt replies!

My application only needs to display the shape so I know where my logical shape is. So I just added this to the SFML Shape source code:

Code: [Select]


void Shape::ClearShape()
{
myPoints.clear();
    // Put a placeholder for the center of the shape
    myPoints.push_back(Point())
}


Pretty easy. Although, I am not too sure how much it "breaks" the shape, but it doesn't matter for me since I just use the logical shape anyway.

2

Graphics / Deleting points in a shape

« on: March 25, 2010, 01:56:49 pm »

Hello again,

I searched high and low for a function or a way to delete the points within a shape, and I haven't been able to find anything!

How do I delete points from a shape?

Thanks

3

Graphics / Point inside polygon shape?

« on: March 24, 2010, 05:37:58 am »

I've done a bit of research and created some code (with help from http://local.wasp.uwa.edu.au/~pbourke/geometry/insidepoly/).

Below is my code, sloppy as it is, it does the trick. I hope it is helpful to those who need it. For this code, I found that I had to add the point twice into the vector. Can anyone refine the process, or am I on the right track?

Code: [Select]


#include <SFML/Graphics.hpp>
#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

const double pi = 3.14;
const double twopi = 6.28;

struct Point
{
int x, y;
};

bool InsidePolygon(vector<Point> Poly, int sides, Point mouseCoods);
double Angle2D(double x1, double y1, double x2, double y2);

int main()
{
sf::RenderWindow App(sf::VideoMode(800,600,32), "Inside Polygon Test");

App.SetFramerateLimit(60);

sf::Event appEvent;
vector<Point> vPolygon;

sf::Shape Polygon;

while(App.IsOpened())
{
while(App.GetEvent(appEvent))
{
if(appEvent.Type == sf::Event::Closed)
{
App.Close();
}

if(appEvent.Type == sf::Event::MouseButtonPressed)
{
if(appEvent.MouseButton.Button == sf::Mouse::Left)
{
Point temp;

temp.x = appEvent.MouseButton.X;
temp.y = appEvent.MouseButton.Y;

if(InsidePolygon(vPolygon, vPolygon.size(), temp))
{
cout << "Inside." << endl;
}
}
if(appEvent.MouseButton.Button == sf::Mouse::Right)
{
Point temp;
temp.x = appEvent.MouseButton.X;
temp.y = appEvent.MouseButton.Y;

Polygon.AddPoint(temp.x, temp.y);

vPolygon.push_back(temp);
vPolygon.push_back(temp);
}
}
}

App.Clear();

App.Draw(Polygon);

App.Display();
}

return 0;
}

bool InsidePolygon(vector<Point> Poly, int sides, Point mouseCoods)
{
int i;
double angle=0;
Point p1,p2;

for (i=0;i<sides;i++) {
p1.x = Poly[i].x - mouseCoods.x;
p1.y = Poly[i].y - mouseCoods.y;
p2.x = Poly[(i+1)%sides].x - mouseCoods.x;
p2.y = Poly[(i+1)%sides].y - mouseCoods.y;
angle += Angle2D(p1.x,p1.y,p2.x,p2.y);
}

if (abs(angle) < pi)
return(FALSE);
else
return(TRUE);
}

double Angle2D(double x1, double y1, double x2, double y2)
{
   double dtheta,theta1,theta2;

   theta1 = atan2(y1,x1);
   theta2 = atan2(y2,x2);
   dtheta = theta2 - theta1;
   while (dtheta > pi)
      dtheta -= twopi;
   while (dtheta < -pi)
      dtheta += twopi;

   return(dtheta);
}


Thanks.  

4

Graphics / Point inside polygon shape?

« on: March 22, 2010, 03:01:32 pm »

Thanks, that piece of code helped out a lot!

5

Graphics / Point inside polygon shape?

« on: March 22, 2010, 02:07:27 pm »

Hello,

Is there any way to test if a point is within a polygon shape?

Also,

When a sprite is rotated, does it rotate the bounding box aswell?

Thanks!