Package com.prineside.tdi2.scene2d.utils

Class ScissorStack

java.lang.Object

com.prineside.tdi2.scene2d.utils.ScissorStack

public class ScissorStack
extends Object

A stack of Rectangle objects to be used for clipping via GL20.glScissor(int, int, int, int). When a new Rectangle is pushed onto the stack, it will be merged with the current top of stack. The minimum area of overlap is then set as the real top of the stack.

Author:

mzechner

Constructor Summary

Constructors

Constructor	Description
ScissorStack()

Method Summary

Modifier and Type	Method	Description
static void	calculateScissors(Camera camera, float viewportX, float viewportY, float viewportWidth, float viewportHeight, Matrix4 batchTransform, Rectangle area, Rectangle scissor)	Calculates a scissor rectangle in OpenGL ES window coordinates from a Camera, a transformation Matrix4 and an axis aligned Rectangle.
static void	calculateScissors(Camera camera, Matrix4 batchTransform, Rectangle area, Rectangle scissor)	Calculates a scissor rectangle using 0,0,Gdx.graphics.getWidth(),Gdx.graphics.getHeight() as the viewport.
static Rectangle	getViewport()
static Rectangle	peekScissors()
static Rectangle	popScissors()	Pops the current scissor rectangle from the stack and sets the new scissor area to the new top of stack rectangle.
static boolean	pushScissors(Rectangle scissor)	Pushes a new scissor Rectangle onto the stack, merging it with the current top of the stack.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ScissorStack

public ScissorStack()

Method Details

pushScissors

public static boolean pushScissors(Rectangle scissor)

Pushes a new scissor Rectangle onto the stack, merging it with the current top of the stack. The minimal area of overlap between the top of stack rectangle and the provided rectangle is pushed onto the stack. This will invoke GL20.glScissor(int, int, int, int) with the final top of stack rectangle. In case no scissor is yet on the stack this will also enable GL20.GL_SCISSOR_TEST automatically.

Any drawing should be flushed before pushing scissors.

Returns:

true if the scissors were pushed. false if the scissor area was zero, in this case the scissors were not pushed and no drawing should occur.

popScissors

public static Rectangle popScissors()

Pops the current scissor rectangle from the stack and sets the new scissor area to the new top of stack rectangle. In case no more rectangles are on the stack, GL20.GL_SCISSOR_TEST is disabled.

Any drawing should be flushed before popping scissors.

peekScissors

@Null
public static Rectangle peekScissors()

Returns:

null if there are no scissors.

calculateScissors

public static void calculateScissors(Camera camera,
 Matrix4 batchTransform,
 Rectangle area,
 Rectangle scissor)

Calculates a scissor rectangle using 0,0,Gdx.graphics.getWidth(),Gdx.graphics.getHeight() as the viewport.

See Also:

• calculateScissors(Camera, float, float, float, float, Matrix4, Rectangle, Rectangle)

calculateScissors

public static void calculateScissors(Camera camera,
 float viewportX,
 float viewportY,
 float viewportWidth,
 float viewportHeight,
 Matrix4 batchTransform,
 Rectangle area,
 Rectangle scissor)

Calculates a scissor rectangle in OpenGL ES window coordinates from a Camera, a transformation Matrix4 and an axis aligned Rectangle. The rectangle will get transformed by the camera and transform matrices and is then projected to screen coordinates. Note that only axis aligned rectangles will work with this method. If either the Camera or the Matrix4 have rotational components, the output of this method will not be suitable for GL20.glScissor(int, int, int, int).

Parameters:

camera - the Camera

batchTransform - the transformation Matrix4

area - the Rectangle to transform to window coordinates

scissor - the Rectangle to store the result in

getViewport

public static Rectangle getViewport()

Returns:

the current viewport in OpenGL ES window coordinates based on the currently applied scissor