A function that is used very often in combination with shapes is Cuts. There are quite a lot of different versions of this function, but its meaning is always the same: do two shapes overlap, or don’t they? The Cuts function allows you to check if a dot is inside a circle, if a circle (partially) overlaps a rectangle, if a line cuts a rectangle and so on.
To check if a dot is inside a circle, use the code below:
Vec2 pos(0.1, 0.1);
Circle area(0.3, Vec2(0));
if(Cuts(pos, area)) area.draw(RED);
5
Of course, in this example it is already certain the dot will always be inside the circle. But you could use the same principle to see if the mouse pointer is inside the circle, like this:
Circle area(0.1, Vec2(0));
if(Cuts(Ms.pos(), area)) area.draw(RED);
else area.draw(BLACK);
5
The code above is the starting point for many possible interactions. Often, this will be in combination with other rules. Try to find out what the code below does:
Rect button(Vec2(-0.2, -0.1), Vec2(0.2, 0.1));
bool hover = false;
// in the update function:
5if (Cuts(Ms.pos(), button)) {
hover = true;
if(Ms.bp(0)) exit();
} else hover = false;
10// in the draw function:
if(hover) {
button.draw(Color(0, 255, 0));
} else {
button.draw(Color(0, 155, 0));
15}