[Request] rot/scale texture drawer frontend (tri drawer)

[Nash]

Hi, can someone please make a wrapper function that simply allows the user to draw a 2D texture on to the screen that can be scaled and rotated easily? Thanks.

[Nash]

Here is a rotating texture example wrote by Marisa that was buried in obscurity, so I'm re-uploading it here so that others can benefit and learn from it.

[Marisa the Magician]

Here's generalised functions for creating/preparing a square shape and then applying a scale, rotation and translation. I've only just written it without testing it, so do tell me if anything's wrong.

Code: Select all

// create a square shape (not usable until calling MoveSquare)
static clearscope Shape2D MakeSquare()
{
	// the shape that will be drawn
	Shape2D square = new("Shape2D");
	// texture coordinates of each corner
	square.PushCoord((0,0));
	square.PushCoord((1,0));
	square.PushCoord((0,1));
	square.PushCoord((1,1));
	// two triangles make up the square
	// the points have to be in counter-clockwise order
	square.PushTriangle(0,3,1);
	square.PushTriangle(0,2,3);
	return square;
}

// set the positions of an existing square shape's vertices
static clearscope void MoveSquare( Shape2D shape, Vector2 size, Vector2 pos, double angle )
{
	// clear any vertices already set
	shape.Clear(Shape2D.C_Verts);
	// corners of a square centered on 0,0
	Vector2 points[4];
	points[0] = (-0.5*size.x,-0.5*size.y);
	points[1] = ( 0.5*size.x,-0.5*size.y);
	points[2] = (-0.5*size.x, 0.5*size.y);
	points[3] = ( 0.5*size.x, 0.5*size.y);
	// apply a 2D rotation matrix:
	//
	// ┌               ┐   ┌   ┐
	// │ cos θ  -sin θ │   │ X │
	// │               │ * │   │
	// │ sin θ   cos θ │   │ Y │
	// └               ┘   └   ┘
	//
	// then move the points by the set offset
	for ( int i=0; i<4; i++ )
	{
		Vector2 oldpos = points[i];
		points[i].x = oldpos.x*cos(angle)-oldpos.y*sin(angle) + pos.x;
		points[i].y = oldpos.x*sin(angle)+oldpos.y*cos(angle) + pos.y;
		square.PushVertex(points[i]);
	}
}

[Talon1024]

Here's generalised functions for creating/preparing a square shape and then applying a scale, rotation and translation. I've only just written it without testing it, so do tell me if anything's wrong.

What's the license for that code?

We're using it in Blade of Agony, and I'm trying to sort out some code licensing issues right now.