import { LinearFilter, UnsignedByteType, WebGLRenderTarget } from "three";

import { LuminanceMaterial } from "../materials";

import { Resolution } from "../core/Resolution";

import { Pass } from "./Pass";

/**

* A pass that renders luminance.

*/

export class LuminancePass extends Pass {

/**

* Constructs a new luminance pass.

*

* @param {Object} [options] - The options. See {@link LuminanceMaterial} for additional options.

* @param {Number} [options.width=Resolution.AUTO_SIZE] - The render width.

* @param {Number} [options.height=Resolution.AUTO_SIZE] - The render height.

* @param {WebGLRenderTarget} [options.renderTarget] - A custom render target.

*/

constructor({

width = Resolution.AUTO_SIZE,

height = Resolution.AUTO_SIZE,

renderTarget,

luminanceRange,

colorOutput

} = {}) {

super("LuminancePass");

this.fullscreenMaterial = new LuminanceMaterial(colorOutput, luminanceRange);

this.needsSwap = false;

/**

* The luminance render target.

*

* @type {WebGLRenderTarget}

* @private

*/

this.renderTarget = renderTarget;

if(this.renderTarget === undefined) {

this.renderTarget = new WebGLRenderTarget(1, 1, {

minFilter: LinearFilter,

magFilter: LinearFilter,

stencilBuffer: false,

depthBuffer: false

});

this.renderTarget.texture.name = "LuminancePass.Target";

this.renderTarget.texture.generateMipmaps = false;

}

/**

* The resolution.

*

* @type {Resolution}

*/

const resolution = this.resolution = new Resolution(this, width, height);

resolution.addEventListener("change", (e) => this.setSize(resolution.baseWidth, resolution.baseHeight));

}

/**

* The luminance texture.

*

* @type {Texture}

*/

get texture() {

return this.renderTarget.texture;

}

/**

* Returns the luminance texture.

*

* @deprecated Use texture instead.

* @return {Texture} The texture.

*/

getTexture() {

return this.renderTarget.texture;

}

/**

* Returns the resolution settings.

*

* @deprecated Use resolution instead.

* @return {Resolution} The resolution.

*/

getResolution() {

return this.resolution;

}

/**

* Renders the luminance.

*

* @param {WebGLRenderer} renderer - The renderer.

* @param {WebGLRenderTarget} inputBuffer - A frame buffer that contains the result of the previous pass.

* @param {WebGLRenderTarget} outputBuffer - A frame buffer that serves as the output render target unless this pass renders to screen.

* @param {Number} [deltaTime] - The time between the last frame and the current one in seconds.

* @param {Boolean} [stencilTest] - Indicates whether a stencil mask is active.

*/

render(renderer, inputBuffer, outputBuffer, deltaTime, stencilTest) {

const material = this.fullscreenMaterial;

material.inputBuffer = inputBuffer.texture;

renderer.setRenderTarget(this.renderToScreen ? null : this.renderTarget);

renderer.render(this.scene, this.camera);

}

/**

* Updates the size of this pass.

*

* @param {Number} width - The width.

* @param {Number} height - The height.

*/

setSize(width, height) {

const resolution = this.resolution;

resolution.setBaseSize(width, height);

this.renderTarget.setSize(resolution.width, resolution.height);

}

/**

* Performs initialization tasks.

*

* @param {WebGLRenderer} renderer - A renderer.

* @param {Boolean} alpha - Whether the renderer uses the alpha channel.

* @param {Number} frameBufferType - The type of the main frame buffers.

*/

initialize(renderer, alpha, frameBufferType) {

if(frameBufferType !== undefined && frameBufferType !== UnsignedByteType) {

this.fullscreenMaterial.defines.FRAMEBUFFER_PRECISION_HIGH = "1";

}

}

}