Mouse Over in SDL/C++ not working - c++

Question

I have a simple script where by i want the script to load a second button when the mouse is hovering over the first initial button. But it won't return true so i can't seem to get it to work.
This is my class which checks the situation:
class Button
{
private:
int m_x, m_y;
int m_width, m_height;
public:
Button(int x, int y, int width, int height)
{
m_x = x;
m_y = y;
m_width = width;
m_height = height;
}
bool IsIn( int mouseX, int mouseY )
{
if (((mouseX > m_x) && (mouseX < m_x + m_width))
&& ((mouseY > m_y) && (mouseY < m_y + m_height ) ) ) {
return true;
} else {
return false;
}
}
void Render(SDL_Surface *source,SDL_Surface *destination)
{
SDL_Rect offset;
offset.x = m_x;
offset.y = m_y;
offset.w = m_width;
offset.h = m_height;
source = IMG_Load("button.png");
SDL_BlitSurface( source, NULL, destination, &offset );
}
};
Its the IsIn function I am trying to get to work... in my main loop i have:
while(!quit){
while( SDL_PollEvent( &event ) )
switch( event.type ){
case SDL_QUIT: quit = true; break;
case SDL_MOUSEMOTION: mouseX = event.motion.x; mouseY = event.motion.y; break;
}
Button btn_quit(screen->w/2,screen->h/2,0,0);
btn_quit.Render(menu,screen);
if(btn_quit.IsIn(mouseX,mouseY)){
Button btn_settings(screen->w/2,screen->h/2+70,0,0);
btn_settings.Render(menu,screen);
}
SDL_Quit works fine but i can't seem to get the if statement after the case statement to return true when i hover the mouse over the btn_quit button. Any ideas why this might be ?

Answer 1

Because btn_quit has no width or height, and therefore you can never be inside it's bounds.
Button btn_quit(screen->w/2,screen->h/2,0,0);
You checks will fail because your mouse position can never be >x && <x+0 or >y && <y+0.
Perhaps a better way would be to define the location of your button, and let get the dimensions from the loaded image?
class Button
{
public:
// Construct the button with an image name, and position on screen.
// This is important, your existing code loaded the image each render.
// That is not necessary, load it once when you construct the class.
Button(std::string name, int x, int y) : img(IMG_Load(name))
{
if(img) // If the image didn't load, NULL is returned.
{
// Set the dimensions using the image width and height.
offset.x = x; offset.y = y;
offset.w = img.w; offset.h = img.h;
}
else { throw; } // Handle the fact that the image didn't load somehow.
}
~Button() { SDL_FreeSurface(img); } // Make sure you free your resources!
void Render(SDL_Surface *destination)
{
// Simplified render call.
SDL_BlitSurface(img, NULL, destination, &offset );
}
bool Contains(int x, int y)
{
if((x>offset.x) && (x<offset.x+offset.w)
&& (y>offset.y) && (y<offset.y+offset.h))
return true; // If your button contains this point.
return false; // Otherwise false.
}
private:
SDL_Rect offset; // Dimensions of the button.
SDL_Surface* img; // The button image.
}