Messages

1

General / Re: Separated Axis Theorm Problem

« on: April 06, 2015, 12:11:52 am »

Sorry

PS: The problem was the projection...

2

General / Separated Axis Theorm Problem

« on: April 05, 2015, 07:17:32 pm »

Hello,

I'm trying to implement the SAT, and when I move poly2 around it detects the collision even if it don't intersect poly1.

Here's my code:

#include <iostream>
#include <SFML/Graphics.hpp>
#include <vector>
#include "Vector2D.h"

using namespace std;

float getVectorMax(const vector<float>& v)
{
        float max = v[0];

        for (int i = 0; i < v.size(); i++)
        {
                if (v[i] > max)
                        max = v[i];
        }

        return max;
}

float getVectorMin(const vector<float>& v)
{
        float min = v[0];

        for (int i = 0; i < v.size(); i++)
        {
                if (v[i] < min)
                        min = v[i];
        }

        return min;
}


bool SAT(const sf::ConvexShape& one, const sf::ConvexShape& two)
{
        vector<Vector2D> normals;

        //Normals of shape One
        for (int i = 0; i < one.getPointCount(); i++)
        {
                Vector2D side(0,0);
                if (i < one.getPointCount() - 1)
                {
                        side.x = (one.getPoint(i + 1).x + one.getPosition().x) - (one.getPoint(i).x + one.getPosition().x);
                        side.y = (one.getPoint(i + 1).y + one.getPosition().y) - (one.getPoint(i).y + one.getPosition().y);
                }
                else
                {
                        side.x = (one.getPoint(0).x + one.getPosition().x) - (one.getPoint(i).x + one.getPosition().x);
                        side.y = (one.getPoint(0).y + one.getPosition().y) - (one.getPoint(i).y + one.getPosition().y);
                }

                normals.push_back(side.normalVectorOuter());
        }

        //Normals of shape two
        for (int i = 0; i < two.getPointCount(); i++)
        {
                Vector2D side(0, 0);
                if (i < two.getPointCount() - 1)
                {
                        side.x = (two.getPoint(i + 1).x + two.getPosition().x) - (two.getPoint(i).x + two.getPosition().x);
                        side.y = (two.getPoint(i + 1).y + two.getPosition().y) - (two.getPoint(i).y + two.getPosition().y);
                }
                else
                {
                        side.x = (two.getPoint(0).x + two.getPosition().x) - (two.getPoint(i).x + two.getPosition().x);
                        side.y = (two.getPoint(0).y + two.getPosition().y) - (two.getPoint(i).y + two.getPosition().y);
                }

                normals.push_back(side.normalVectorOuter());
        }


        //Project points on normals
        for (int n = 0; n < normals.size(); n++)
        {
                vector<float> projectedPointsOne;
                vector<float> projectedPointsTwo;

                //Get the projected points from shape one
                for (int i = 0; i < one.getPointCount(); i++)
                {
                        projectedPointsOne.push_back(Vector2D((one.getPoint(i).x + one.getPosition().x),
                                                                                (one.getPoint(i).y + one.getPosition().y)).projectedVector(normals[n]).lenght());
                }

                //Get the projected points from shape two
                for (int i = 0; i < two.getPointCount(); i++)
                {
                        projectedPointsTwo.push_back(Vector2D((two.getPoint(i).x + two.getPosition().x),
                                                                                (two.getPoint(i).y + two.getPosition().y)).projectedVector(normals[n]).lenght());
                }

                //Get the min and max of shape one
                float maxOne = getVectorMax(projectedPointsOne);
                float minOne = getVectorMin(projectedPointsOne);

                //Get the min and max of shape two
                float maxTwo = getVectorMax(projectedPointsTwo);
                float minTwo = getVectorMin(projectedPointsTwo);

                //Check if there is at least one gap, if true then -> collision !

                if (maxOne < minTwo || maxTwo < minOne)
                {
                        return false;
                }
        }

        return true;
}


int main(int argc, char** argv)
{
       
        Vector2D v1(1, 1), v2(-1, 1);

        cout << v1.projectedVector(v2) << endl;

        sf::RenderWindow window(sf::VideoMode(500,500,32), "Test");

        sf::ConvexShape poly1;
        poly1.setPointCount(3);
        poly1.setPoint(0, sf::Vector2f(50, -50));
        poly1.setPoint(1, sf::Vector2f(50, 50));
        poly1.setPoint(2, sf::Vector2f(-50, 50));
        poly1.setOutlineThickness(2);
        poly1.setOutlineColor(sf::Color::Red);
        poly1.setPosition(200,200);

        sf::ConvexShape poly2;
        poly2.setPointCount(4);
        poly2.setPoint(0, sf::Vector2f(50, -50));
        poly2.setPoint(1, sf::Vector2f(50, 50));
        poly2.setPoint(2, sf::Vector2f(-50, 50));
        poly2.setPoint(3, sf::Vector2f(-50, -50));
        poly2.setOutlineThickness(2);
        poly2.setOutlineColor(sf::Color::Red);
        poly2.setFillColor(sf::Color::Blue);
        poly2.setPosition(220, 100);

        bool quit = false;
        sf::Event event;

        while (!quit)
        {
                while (window.pollEvent(event))
                {
                        if (event.type == sf::Event::EventType::Closed)
                        {
                                quit = true;
                        }

                        if (event.type == sf::Event::EventType::KeyPressed && event.key.code == sf::Keyboard::Escape)
                        {
                                quit = true;
                        }
                }

                sf::Vector2i mouse = sf::Mouse::getPosition(window);
                poly2.setPosition(sf::Vector2f(mouse.x, mouse.y));

                if (SAT(poly1, poly2))
                {
                        poly1.setFillColor(sf::Color::Green);
                }
                else{
                        poly1.setFillColor(sf::Color::White);
                }
               
                window.clear(sf::Color::Black);

                window.draw(poly1);
                window.draw(poly2);
                window.display();
        }


        return 0;
}

And My vector class:

#pragma once
#include <iostream>
#include <cmath>

struct Vector2D
{
        float x;
        float y;

        Vector2D(float x, float y)
        {
                this->x = x;
                this->y = y;
        }

        Vector2D operator+(float s)
        {
                return Vector2D(x + s, y + s);
        }

        Vector2D operator+(const Vector2D& v2)
        {
                return Vector2D(x + v2.x, y + v2.y);
        }

        Vector2D operator-(float s)
        {
                return Vector2D(x - s, y - s);
        }

        Vector2D operator-(const Vector2D& v2)
        {
                return Vector2D(x - v2.x, y - v2.y);
        }

        Vector2D operator/(float s)
        {
                return Vector2D(x / s, y / s);
        }

        Vector2D operator*(float s)
        {
                return Vector2D(x * s, y * s);
        }

        float dot(const Vector2D& v2)
        {
                return x * v2.x + y * v2.y;
        }

        float lenght()
        {
                return sqrt((x*x) + (y*y));
        }

        Vector2D normalized()
        {
                return (*this) / this->lenght();
        }

        Vector2D projectedVector(Vector2D& v2)
        {
                return v2 * ((this->dot(v2) / this->lenght()));
        }

        Vector2D normalVectorOuter()
        {
                return Vector2D(-y, x).normalized();
        }

        Vector2D normalVectorInner()
        {
                return Vector2D(y, -x).normalized();
        }
};

std::ostream& operator<<(std::ostream& out, const Vector2D& v)
{
        out << v.x << "," << v.y << std::endl;
        return out;
}

Note that i'm going to refactor that later.

Any idea where I missed something.

Thanks in advance.

Have a nice day

3

Graphics / Re: getPoint() Absolute coordinates

« on: August 04, 2014, 09:15:28 pm »

Okay thank you, what I've done (for pepole who want to know):

rect.getTransform().transformPoint(rect.getPoint(0));

See ya

4

Graphics / Re: getPoint() Absolute coordinates

« on: August 04, 2014, 09:04:46 pm »

Hum, can I get more informations please, becasue I dont know how I could get points from getGlobalBounds....

5

Graphics / getPoint() Absolute coordinates

« on: August 04, 2014, 08:48:43 pm »

Hello,

I'm trying to get the points of a RectangleShape, while he is moving. But it seams that the getPoint() method gives me only the local coordinates of the points.

Do you know how I can get that ?

Thank in advance.

6

General / Re: Probleme with a SpriteManager

« on: May 23, 2014, 11:31:15 pm »

Yes I know that I do not delete my texture but later I can do it beacause of the deleteSprite methode that will through the spriteCollection, get the texture from the sprite at a certain index and delete it.

But i'm working arround that bug for a few time now and I dont find it :/
 

7

General / Probleme with a SpriteManager

« on: May 23, 2014, 10:13:12 pm »

Hello,

I'm doing a simple GameEngine and currently i'm working on the SpriteManager.
So i've a function addSprite(const std::string file) wich will load a texture and create a sprite that will be added to a spriteCollection (and then the game objects will have an index wich referes to that sprite). But i've a Bad Acess Memory. My vector is empty. What did I missed ?

int SpriteManager::addSprite(const std::string file)
{
    sf::Texture* tmpTexture = new sf::Texture;
    if(tmpTexture->loadFromFile(file)){
       
        spriteCollection.push_back(new sf::Sprite);
        spriteCollection[spriteCollection.size() - 1]->setTexture(*tmpTexture);
       
    }else{
        return -1;
    }
   
    return spriteCollection.size() - 1;
}

sf::Sprite* SpriteManager::getSprite(int index)
{
    return spriteCollection[index]; //There is a BAD ACCESS (of course beacause spriteCollection is empty)
}

 

Thank in advance