import { Matrix } from '@pixi/math';
import type { ISystem } from '../ISystem';
import type { Rectangle } from '@pixi/math';
import type { Renderer } from '../Renderer';
/**
* System plugin to the renderer to manage the projection matrix.
*
* The `projectionMatrix` is a global uniform provided to all shaders. It is used to transform points in world space to
* normalized device coordinates.
* @memberof PIXI
*/
export class ProjectionSystem implements ISystem
{
/**
* The destination frame used to calculate the current projection matrix.
*
* The destination frame is the rectangle in the render-target into which contents are rendered. If rendering
* to the screen, the origin is on the top-left. If rendering to a framebuffer, the origin is on the
* bottom-left. This "flipping" phenomenon is because of WebGL convention for (shader) texture coordinates, where
* the bottom-left corner is (0,0). It allows display-objects to map their (0,0) position in local-space (top-left)
* to (0,0) in texture space (bottom-left). In other words, a sprite's top-left corner actually renders the
* texture's bottom-left corner. You will also notice this when using a tool like SpectorJS to view your textures
* at runtime.
*
* The destination frame's dimensions (width,height) should be equal to the source frame. This is because,
* otherwise, the contents will be scaled to fill the destination frame. Similarly, the destination frame's (x,y)
* coordinates are (0,0) unless you know what you're doing.
* @readonly
*/
public destinationFrame: Rectangle;
/**
* The source frame used to calculate the current projection matrix.
*
* The source frame is the rectangle in world space containing the contents to be rendered.
* @readonly
*/
public sourceFrame: Rectangle;
/**
* Default destination frame
*
* This is not used internally. It is not advised to use this feature specifically unless you know what
* you're doing. The `update` method will default to this frame if you do not pass the destination frame.
* @readonly
*/
public defaultFrame: Rectangle;
/**
* Projection matrix
*
* This matrix can be used to transform points from world space to normalized device coordinates, and is calculated
* from the sourceFrame → destinationFrame mapping provided.
*
* The renderer's `globalUniforms` keeps a reference to this, and so it is available for all shaders to use as a
* uniform.
* @readonly
*/
public projectionMatrix: Matrix;
/**
* A transform to be appended to the projection matrix.
*
* This can be used to transform points in world-space one last time before they are outputted by the shader. You can
* use to rotate the whole scene, for example. Remember to clear it once you've rendered everything.
* @member {PIXI.Matrix}
*/
public transform: Matrix;
private renderer: Renderer;
/** @param renderer - The renderer this System works for. */
constructor(renderer: Renderer)
{
this.renderer = renderer;
this.destinationFrame = null;
this.sourceFrame = null;
this.defaultFrame = null;
this.projectionMatrix = new Matrix();
this.transform = null;
}
/**
* Updates the projection-matrix based on the sourceFrame → destinationFrame mapping provided.
*
* NOTE: It is expected you call `renderer.framebuffer.setViewport(destinationFrame)` after this. This is because
* the framebuffer viewport converts shader vertex output in normalized device coordinates to window coordinates.
*
* NOTE-2: RenderTextureSystem#bind updates the projection-matrix when you bind a render-texture. It is expected
* that you dirty the current bindings when calling this manually.
* @param destinationFrame - The rectangle in the render-target to render the contents into. If rendering to the canvas,
* the origin is on the top-left; if rendering to a render-texture, the origin is on the bottom-left.
* @param sourceFrame - The rectangle in world space that contains the contents being rendered.
* @param resolution - The resolution of the render-target, which is the ratio of
* world-space (or CSS) pixels to physical pixels.
* @param root - Whether the render-target is the screen. This is required because rendering to textures
* is y-flipped (i.e. upside down relative to the screen).
*/
update(destinationFrame: Rectangle, sourceFrame: Rectangle, resolution: number, root: boolean): void
{
this.destinationFrame = destinationFrame || this.destinationFrame || this.defaultFrame;
this.sourceFrame = sourceFrame || this.sourceFrame || destinationFrame;
// Calculate object-space to clip-space projection
this.calculateProjection(this.destinationFrame, this.sourceFrame, resolution, root);
if (this.transform)
{
this.projectionMatrix.append(this.transform);
}
const renderer = this.renderer;
renderer.globalUniforms.uniforms.projectionMatrix = this.projectionMatrix;
renderer.globalUniforms.update();
// this will work for now
// but would be sweet to stick and even on the global uniforms..
if (renderer.shader.shader)
{
renderer.shader.syncUniformGroup(renderer.shader.shader.uniforms.globals);
}
}
/**
* Calculates the `projectionMatrix` to map points inside `sourceFrame` to inside `destinationFrame`.
* @param _destinationFrame - The destination frame in the render-target.
* @param sourceFrame - The source frame in world space.
* @param _resolution - The render-target's resolution, i.e. ratio of CSS to physical pixels.
* @param root - Whether rendering into the screen. Otherwise, if rendering to a framebuffer, the projection
* is y-flipped.
*/
calculateProjection(_destinationFrame: Rectangle, sourceFrame: Rectangle, _resolution: number, root: boolean): void
{
const pm = this.projectionMatrix;
const sign = !root ? 1 : -1;
pm.identity();
pm.a = (1 / sourceFrame.width * 2);
pm.d = sign * (1 / sourceFrame.height * 2);
pm.tx = -1 - (sourceFrame.x * pm.a);
pm.ty = -sign - (sourceFrame.y * pm.d);
}
/**
* Sets the transform of the active render target to the given matrix.
* @param _matrix - The transformation matrix
*/
setTransform(_matrix: Matrix): void
{
// this._activeRenderTarget.transform = matrix;
}
destroy(): void
{
this.renderer = null;
}
}