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agm_ultimatex

SFML TransformToGlobal - bad idea?

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Just working on a bit for a game, getting a simple square bouncing off the edges of the window. Presently, I have the window set at 800 x 600. I draw this box at 50, 50. It is 30 x 30 in size. I'm currently animating it, so it moves over to the right hand side of the screen. The problem is, even though I've done a check for this, it goes past the edge of the screen. However, if I start it at 0, 50 position, it does not. If I output the x value of the box (I use a class to store position and size info), it stays the same regardless. I'm fairly certain this is because of where ever it's drawn, that is its origin or 0,0. I am wondering if using TransformToGlobal might help, by specifying the 50, 50 in that, and starting the box at 0, 0. My concern is that I don't want to get into a bad habit of using this function, where game objects or sprites should refer to origin as the local starting position.

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here ya go sorry.


// Pong.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <SFML/Graphics.hpp>
#include "Piece.hpp"
#include <iostream>

void updateBallPosition(Piece& ball, float ballSpeed, float timePassed);

void updateBallPosition(Piece& ball, float ballSpeed, float timePassed)
{
float x = ball.GetX();
float y = ball.GetY();

float max_x = 800 - ball.GetSizeX();
float max_y = 600 - ball.GetSizeY();

if((x + (ballSpeed * timePassed)) <= max_x)
{
std::cout << "x: " << x << "\n";
ball.IncrementX(ballSpeed * timePassed);
}
}


int _tmain(int argc, _TCHAR* argv[])
{
sf::RenderWindow app(sf::VideoMode(800, 600, 32), "Pong Clone");
Piece theBall(50, 50, 30, 30);
sf::Shape squarePiece;

squarePiece.AddPoint(theBall.GetX(), theBall.GetY(), sf::Color(255, 255, 255), sf::Color(255, 255, 255));
squarePiece.AddPoint(theBall.GetRightX(), theBall.GetY(), sf::Color(255, 255, 255), sf::Color(255, 255, 255));
squarePiece.AddPoint(theBall.GetRightX(), theBall.GetBottomY(), sf::Color(255, 255, 255), sf::Color(255, 255, 255));
squarePiece.AddPoint(theBall.GetX(), theBall.GetBottomY(), sf::Color(255, 255, 255), sf::Color(255, 255, 255));
squarePiece.AddPoint(theBall.GetX(), theBall.GetY(), sf::Color(255, 255, 255), sf::Color(255, 255, 255));
squarePiece.EnableFill(true);
app.SetFramerateLimit(100);

app.UseVerticalSync(false);
while(app.IsOpened())
{
sf::Event e;
while(app.GetEvent(e))
{
if(e.Type == sf::Event::Closed)
{
app.Close();
}
// if escape was pressed
if((e.Type == sf::Event::KeyPressed) && (e.Key.Code == sf::Key::Escape))
{
app.Close();
}
}
float timePassed = app.GetFrameTime();
app.Clear();
app.Draw(squarePiece);
app.Display();
squarePiece.SetX(theBall.GetX());
squarePiece.SetY(theBall.GetY());

updateBallPosition(theBall, 150.0f, timePassed);
}
return EXIT_SUCCESS;
}



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The squarePeice in your code states:
Create a rectangle sized 30 by 30, whose origin is at (-50, -50). Therefore when I translate the shape to (0,0), the top-left corner of the rectangle is at (50,50)

Try this:

const int width = 30;
const int height = 30;
Piece theBall(50, 50, width, height);
sf::Shape squarePiece;

const sf::Color& ballColor = sf::Color::White;
squarePiece.AddPoint(0, 0, ballColor, ballColor);
squarePiece.AddPoint(width, 0, ballColor, ballColor);
squarePiece.AddPoint(width, height, ballColor, ballColor);
squarePiece.AddPoint(0, height, ballColor, ballColor);
squarePiece.AddPoint(0, 0, ballColor, ballColor);




This states:
Create a rectangle sized 30 by 30, whose origin is at (0, 0). Therefore when I translate the shape to (0,0), the top-left corner of the rectangle is at (0,0)

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That did the trick thanks :).

Though I had to change the code for the color to:
const sf::Color& ballColor = sf::Color(255, 255, 255);
as well as the height and width to float.

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