Hello,
I don't know if this should be in the "window help" section or here, but the problem i am presensting here, started when i wanted to get the Bounding boxes of my entities.
I made a class using vertices and wanted to get the bounding boxes through the function "getBounds" by inhereting the class from the "VertexArray" class, like this :
class VertexClass : public sf::VertexArray, public sf::Transformable , public sf::Drawable
{
private: /// ///////////////////////////////////////////
sf::VertexArray V;
sf::Texture Tex;
virtual void draw(sf::RenderTarget& target, sf::RenderStates states) const {
states.transform *= getTransform();
states.texture = &Tex;
//states.texture = nullptr;
target.draw(V, states);
}
public:/// ////////////////////////////////////////////////////////////////////////////////////////////////
bool VertexFunction(sf::Vector2f v0,sf::Vector2f v1,sf::Vector2f v2 ) //(...,PrimitiveType type)
{
V.setPrimitiveType(sf::Triangles);
V.resize(3);
V[0].position = v0;
V[1].position = v1;
V[2].position = v2;
V[0].texCoords = v0;
V[1].texCoords = v1;
V[2].texCoords = v2;
return true;
}
};
One problem when calling the "draw" function :
//main
VertexClass VClass;
VClass.VertexFunction(sf::Vector2f(200,200),sf::Vector2f(400,200),sf::Vector2f(400,400));
....
window.draw(VClass);
Error message is :
'sf::Drawable' is an ambiguous base of 'VertexClass'
I searched on the internet and found these solutions : https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.1.0/com.ibm.zos.v2r1.cbclx01/cplr138.htm
Maybe i did not get it but i tried the following options :
window.sf::Drawable::draw(VClass);
//or
window.sf::VertexClass::draw(VClass);
I tried then to modify the class declaration, and added "sf::Drawable" before the draw function declaration. Still have the problem..
1) So how do we solve this situation if anyone knows?
2) Is there a better method to get the bound box of my verticesClass? (This is way i choose to put the post in the graphics section of the forum).
Public inheritance is not a solution here -- as you noticed, it brings more problems than solutions.
What's the problem with this?
class VertexClass
{
sf::FloatRect getBounds() const {return m_geometry.getBounds();}
sf::VertexArray m_geometry;
}
Public inheritance is not a solution here -- as you noticed, it brings more problems than solutions.
What's the problem with this?
class VertexClass
{
sf::FloatRect getBounds() const {return m_geometry.getBounds();}
sf::VertexArray m_geometry;
}
Perfect! Worked perfecetly fine. SFML is fun, but i don't know when to use "const" yet, i shall use sf variable more often.
Thank you
Hello, i met with a problem : "GetBounds Gives always the same results"
My first SFML tutorial was the making of Pong game. It used the "getGlobalBounds" from the Shape class, and "intersects" from the Rect class. The ball AND the pad from the PONG game Were moving .. So the result of the intrescetion was sometimes "1" sometimes "0".
Fast forward to the example of this forum post, i have a VertexArray and i am using the "getBounds()" function. The problem simplly IS : "When The vertex shape MOVES, its bounds "getbounds values" are not changing. "
I thought maybe it was because the Getbound function was a "const", i redeclared it inside the vertexClass as a function without "const", and it did not change the result : getbounds gives the same results whichever is the position of the vertex shape.
Let's take an example, here is the class and its 2 functions (the : "Contruction4noTex()" and "getBounds()" :
class VertexFun : public sf::Transformable , public sf::Drawable
{
private: /// ///////////////////////////////////////////
sf::VertexArray V;
sf::Texture Tex;
virtual void draw(sf::RenderTarget& target, sf::RenderStates states) const {
states.transform *= getTransform();
states.texture = &Tex;
//states.texture = nullptr;
target.draw(V, states);
}///
public:
bool Contruction4noTex(sf::Vector2f v0,sf::Vector2f v1,sf::Vector2f v2,sf::Vector2f v3,sf::Color c0, sf::Color c1,sf::Color c2,sf::Color c3)
{
V.setPrimitiveType(sf::Quads);
V.resize(4);
sf::Vertex* quad = &V[0];
quad[0].position = v0;
quad[1].position = v1;
quad[2].position = v2;
quad[3].position = v3;
quad[0].color = c0;
quad[1].color = c1;
quad[2].color = c2;
quad[3].color = c3;
return true;
}
sf::FloatRect getBounds() {return V.getBounds();}
};
Declaration of a vertex shape called "v1" inside the main :
VertexFun v1;
v1.Contruction4noTex(sf::Vector2f(2,2),sf::Vector2f(3,2),sf::Vector2f(3,7),sf::Vector2f(2,7),red,blue,red,magenta);
v1.move(sf::Vector2f(0,64)); // giving the shape its initial position
Testing the intersection of the shape called v1 and a FloatRect :
/// Testing bounds
sf::FloatRect Rect3(64,64,32,32);
float a1= v1.getBounds().left;
float a2= v1.getBounds().top;
float a3= v1.getBounds().width;
float a4= v1.getBounds().height;
float b1= Rect3.left;
float b2= Rect3.top;
float b3= Rect3.width;
float b4= Rect3.height;
cout << " v1 bounds : " << a1 << " " << a2 << " " <<a3 << " " <<a4 << " - And v1 position is : " << v1.getPosition().x << " " << v1.getPosition().y << endl;
cout << " icon 0 bounds : " << b1 << " " << b2 << " " <<b3 << " " <<b4 << endl;
bool c1 = v1.getBounds().intersects(Rect3);
cout << " intesection : " << c1 << endl;
As you can see i i tried to follow the values on the console using "std::cout" while watching the position of the shape while it is moving.
Here is what the console shows :
(https://i.postimg.cc/T11LKRXt/screenshot-148.png)
The intersection result is "0" but if i defined Rect3 as (0,0,32,32) the result would be "1" but that's not the problem, the problem is getbounds() gives always the same values despite v1 moving, what i am missing?
I forgot to say: don't hesitate to have a look at how other SFML entities implement similar stuff.
Look at sf::Sprite:
FloatRect Sprite::getGlobalBounds() const
{
return getTransform().transformRect(getLocalBounds());
}
Where getLocalBounds() is equivalent to vertexArray.getBounds() in your case.
sf::Transform is a transformation, its final goal is to transform things. So that's how you're supposed to use it, and I think the API documentation is more than enough to find out what you can transform with it -- in your case, a sf::FloatRect. The 'S' in SFML is for 'Simple', so don't go in crazy directions, like wondering how to use the transform's matrix elements directly... ;)
To test if the entity reached the house, you have to use the "intersects" function
That's just a convenience function to quickly check if two aligned rectangles intersect. As you can guess, it won't give accurate results for testing a triangle (or any other polygonal shape). But then, it depends what your requirements are.
..
I had a very very hard time trying to try to use the sf::sprite getglobal bounds idea. Also i moved to another method, and removed "sf::sprite" from the function you suggested and tried what follows (it was supposed to be posted in a different post but i got an error while posting)
Hello, I am getting an error message trying to post a new post on the forum and it says : report it to the admin if it happens again, which did.
Here the content of the post so i dont lose it :
Hello, so here is the shape i made, and my goal ultimately is to be able to test the intersections between some entity and the elements of this image specifically (it means : not the rectangle surrounding the shape).
(https://i.postimg.cc/7h8YSrrY/screenshot-158.png)
Its construction follow the tilemap example, its has a vertexArray as an attributes which is resized to match the size of the total numbers of vertices needed to make the shape in the image above. So total numbers of vertices is :
1) +4 (for the rectangle in the middle)
2) +(6*4) for the diamond shapes on every side.
3) multiply line 2 by 4.
Totat vertices = 4+(6*4)*4= 100.
I proceed to construct the vertices with a function member of the class
class VertexFun : public sf::Transformable , public sf::Drawable
{private:
sf::VertexArray V;
...}
And the function would be :
public :
bool VertexShapeQuad(const std::string& address, sf::Vector2f centerOfVertex, sf::Vector2f Dimensions, sf::Vector2f halfRadius, int NumberOfWings, int NumberOfElements )
{...} /// i dont need the first parameter, it's just in case i want to use a texture
Final result is shown at the beginning of this post.
VertexFun shape1;
shape1.VertexShapeQuad("data/tilemap.png",sf::Vector2f(400,400),sf::Vector2f(30,30),sf::Vector2f(10,10),4,6);
....
window.clear(sf::Color::White);
window.draw(shape1);
window.display();
Okay now i am taking the advice i was given lastly here : https://en.sfml-dev.org/forums/index.php?topic=27161.0
And i am trying to get the global bounds of the vertexArray:
i implemented this function member :
sf::FloatRect getGlobalBounds()
{
return getTransform().transformRect(V.getBounds());
}
And when using it in the main :
sf::FloatRect ff;
ff=shape1.getGlobalBounds();
int aa,bb,cc,dd;
aa=ff.left;bb=ff.top;cc=ff.width;dd=ff.height;
cout << " left top width height : " << aa << " " << bb << " " << cc << " " << dd << " " << endl;
I find that it has what i presume the bound of the rectangle made by the whole shape :
(https://i.postimg.cc/v8gnJ5Y5/screenshot-159.png)
AND, when i use a moving function:
up = (sf::Keyboard::isKeyPressed(sf::Keyboard::Up) ? 1 : 0);
if(up==1)
{
shape1.move(0,-10);
cout << " left top width height : " << aa << " " << bb << " " << cc << " " << dd << " " << endl;
}
The bounds are the same.
___
To the questions :
1) I think i should have a member function (sf::FloatRect getGlobalBounds()) that applies to each little structures (the rectangle + diamonds) i made, and then proceed to test them ALL, to be able to check the "intersection" of an entity with my vertexclass?
But IS THAT POSSIBLE? Since i have only one "VertexArray" in my Class? The GetBounds applies to the wholes points of the vertexArray and not individually for each 4 vertices.... (reminder : all the elements in the image are 4-vertices shapes inside ONE vertexAray)
2) Any other idea how to do it?
Thanks