import { ShadowMethodBase, _Shader_ShadowMethodBase } from './ShadowMethodBase';

/**
 * ShadowFilteredMethod provides a softened shadowing technique by bilinearly interpolating shadow comparison
 * results of neighbouring pixels.
 */
export class ShadowFilteredMethod extends ShadowMethodBase {
	public static assetType: string = '[asset ShadowFilteredMethod]';

	/**
	 * @inheritDoc
	 */
	public get assetType(): string {
		return ShadowFilteredMethod.assetType;
	}
}

import { ShaderRegisterCache, ShaderRegisterData, ShaderRegisterElement } from '@awayjs/stage';

import { ShaderBase } from '@awayjs/renderer';

import { LightingShader } from '../shaders/LightingShader';
import { _Shader_ShadowMapperBase } from '../mappers/ShadowMapperBase';

/**
 * _Shader_ShadowFilteredMethod provides a softened shadowing technique by bilinearly interpolating shadow comparison
 * results of neighbouring pixels.
 */
export class _Shader_ShadowFilteredMethod extends _Shader_ShadowMethodBase {
	private _fragmentConstantsIndex: number;

	/**
     * Creates a new _Shader_ShadowFilteredMethod.
     */
	public init(method: ShadowFilteredMethod, shader: LightingShader): void {
		super.init(method, shader);
	}

	/**
     * @inheritDoc
     */
	public _initConstants(): void {
		super._initConstants();

		const fragmentData: Float32Array = this._shader.fragmentConstantData;
		const index: number = this._fragmentConstantsIndex;
		fragmentData[index] = .5;
		const size: number = this._method.castingLight.shadowMapper.size;
		fragmentData[index + 1] = size;
		fragmentData[index + 2] = 1 / size;
	}

	/**
     * @inheritDoc
     */
	public _getFragmentCode(targetReg: ShaderRegisterElement, registerCache: ShaderRegisterCache, sharedRegisters: ShaderRegisterData): string {
		const dataReg: ShaderRegisterElement = registerCache.getFreeFragmentConstant();

		this._fragmentConstantsIndex = dataReg.index * 4;

		let code: string = '';
		const uvReg: ShaderRegisterElement = registerCache.getFreeFragmentVectorTemp();
		registerCache.addFragmentTempUsages(uvReg, 1);
		const temp: ShaderRegisterElement = registerCache.getFreeFragmentVectorTemp();
		registerCache.addFragmentTempUsages(temp, 1);

		code += 'mov ' + uvReg + ', ' + (<_Shader_ShadowMapperBase> this._baseChunk).depthMapCoordReg + '\n' +

            this._baseTexture._getFragmentCode(temp, registerCache, sharedRegisters, uvReg) +
            'mov ' + uvReg + '.w, ' + temp + '.w\n' +

            'add ' + uvReg + '.x, ' + (<_Shader_ShadowMapperBase> this._baseChunk).depthMapCoordReg + '.x, ' + dataReg + '.z\n' + 	// (1, 0)
            this._baseTexture._getFragmentCode(temp, registerCache, sharedRegisters, uvReg) +

            'mul ' + temp + '.x, ' + (<_Shader_ShadowMapperBase> this._baseChunk).depthMapCoordReg + '.x, ' + dataReg + '.y\n' +
            'frc ' + temp + '.x, ' + temp + '.x\n' +
            'sub ' + temp + '.w, ' + temp + '.w, ' + uvReg + '.w\n' +
            'mul ' + temp + '.w, ' + temp + '.w, ' + temp + '.x\n' +
            'add ' + targetReg + '.w, ' + uvReg + '.w, ' + temp + '.w\n' +

            'mov ' + uvReg + '.x, ' + (<_Shader_ShadowMapperBase> this._baseChunk).depthMapCoordReg + '.x\n' +
            'add ' + uvReg + '.y, ' + (<_Shader_ShadowMapperBase> this._baseChunk).depthMapCoordReg + '.y, ' + dataReg + '.z\n' +	// (0, 1)
            this._baseTexture._getFragmentCode(temp, registerCache, sharedRegisters, uvReg) +
            'mov ' + uvReg + '.w, ' + temp + '.w\n' +

            'add ' + uvReg + '.x, ' + (<_Shader_ShadowMapperBase> this._baseChunk).depthMapCoordReg + '.x, ' + dataReg + '.z\n' +	// (1, 1)
            this._baseTexture._getFragmentCode(temp, registerCache, sharedRegisters, uvReg) +

            // recalculate fraction, since we ran out of registers :(
            'mul ' + temp + '.x, ' + (<_Shader_ShadowMapperBase> this._baseChunk).depthMapCoordReg + '.x, ' + dataReg + '.y\n' +
            'frc ' + temp + '.x, ' + temp + '.x\n' +
            'sub ' + temp + '.w, ' + temp + '.w, ' + uvReg + '.w\n' +
            'mul ' + temp + '.w, ' + temp + '.w, ' + temp + '.x\n' +
            'add ' + uvReg + '.w, ' + uvReg + '.w, ' + temp + '.w\n' +

            'mul ' + temp + '.x, ' + (<_Shader_ShadowMapperBase> this._baseChunk).depthMapCoordReg + '.y, ' + dataReg + '.y\n' +
            'frc ' + temp + '.x, ' + temp + '.x\n' +
            'sub ' + uvReg + '.w, ' + uvReg + '.w, ' + targetReg + '.w\n' +
            'mul ' + uvReg + '.w, ' + uvReg + '.w, ' + temp + '.x\n' +
            'add ' + targetReg + '.w, ' + targetReg + '.w, ' + uvReg + '.w\n';

		registerCache.removeFragmentTempUsage(temp);
		registerCache.removeFragmentTempUsage(uvReg);

		super._getFragmentCode(targetReg, registerCache, sharedRegisters);

		return code;
	}
}

ShaderBase.registerAbstraction(_Shader_ShadowFilteredMethod, ShadowFilteredMethod);