I've done it!
The main function:
private void DrawObjectSelection(SpriteBatch spriteBatch, Rectangle r)
{
r = Telecamera.Transform(r);
Vector2 v1 = new Vector2(r.X, r.Y);
Vector2 v2 = new Vector2(r.X + r.Width, r.Y);
Vector2 v3 = new Vector2(r.X, r.Y + r.Height);
Vector2 v4 = new Vector2(r.X + r.Width, r.Y + r.Height);
//The side rectangle
DrawEmptyRectangle(spriteBatch, v1, v2, v3, v4);
//4 squares at vertices
DrawFilledSquare(spriteBatch, v1);
DrawFilledSquare(spriteBatch, v2);
DrawFilledSquare(spriteBatch, v3);
DrawFilledSquare(spriteBatch, v4);
//the other 4 in the middle of every side
float height = v4.Y - v1.Y;
float width = v2.X - v1.X;
DrawFilledSquare(spriteBatch, new Vector2(v1.X, v1.Y + height / 2));
DrawFilledSquare(spriteBatch, new Vector2(v2.X, v2.Y + height / 2));
DrawFilledSquare(spriteBatch, new Vector2(v1.X + width / 2, v1.Y));
DrawFilledSquare(spriteBatch, new Vector2(v1.X + width / 2, v4.Y));
}
With these functions:
private void DrawLine(
SpriteBatch spriteBatch,
float width,
Vector2 point1, Vector2 point2)
{
float angle = (float)Math.Atan2(point2.Y - point1.Y, point2.X - point1.X);
float length = Vector2.Distance(point1, point2);
spriteBatch.Draw(
grid_texture,
point1,
null,
selection_color,
angle,
Vector2.Zero,
new Vector2(length, width),
SpriteEffects.None,
0);
}
private void DrawEmptyRectangle(
SpriteBatch spriteBatch,
Vector2 v1,
Vector2 v2,
Vector2 v3,
Vector2 v4)
{
/*
* V1****V2
* * *
* * *
* V3****V4
*/
DrawLine(spriteBatch, 1.0f, v1, v2);
DrawLine(spriteBatch, 1.0f, v1, v3);
DrawLine(spriteBatch, 1.0f, v2, v4);
DrawLine(spriteBatch, 1.0f, v3, v4);
}
private void DrawFilledSquare(
SpriteBatch spriteBatch,
Vector2 c_pos) //With center position
{
int lato = 8;
spriteBatch.Draw(
grid_texture,
new Rectangle(
(int)c_pos.X - lato/2,
(int)c_pos.Y - lato/2,
lato,
lato),
selection_color);
}
When I want to draw it, I just need a rectangle, for example:
//...
DrawObjectSelection(spriteBatch, Camera.Transform(gameObject1.PositionRectangle));
//...
The only thing missing is Handling of clicks on every square. This is done by a simple "Contains" test with mouse position coor.
A screen of the result: