CocosCreator如何实现划过的位置显示纹理

const {
	class,
	property
} = ._decorator;


@class

export default class Follow_spot extends .Component {

	@property(.Node)

	bg: .Node = null;

	material: .Material = null;

	center: number[] = [0.5, 0.5];

	testArr: number[] = [];


	onLoad() {

		this.material = this.bg.getComponent(.Sprite).getMaterial(0);

		this.material.setProperty('wh_ratio', this.bg.width / this.bg.height);

		this.material.setProperty('center', this.center);


		//js 中最重要是这一句,这里参数是数组长度数组里向量的维度

		this.material.setProperty('colorArr', new Float32Array(400));

		//这里设置的时候需要把数组里向量的分量展开到一个一维数组

		this.material.setProperty('colorArr', []);


		this.bg.on(.Node.EventType.TOUCH_MOVE, this.touchMoveEvent, this);

	}


	touchMoveEvent(evt: .Event.EventTouch) {

		this.center[0] = evt.getLocation().x / this.bg.width;

		this.center[1] = 1 - evt.getLocation().y / this.bg.height;

		console.log(this.center);

		this.material.setProperty('center', this.center);

		if (this.testArr.length >= 400) {

			this.testArr.shift();

			this.testArr.shift();

		}

		this.testArr.push(this.center[0]);

		this.testArr.push(this.center[1]);



		//js 中最重要是这一句,这里参数是数组长度数组里向量的维度

		this.material.setProperty('colorArr', new Float32Array(this.testArr));

		//这里设置的时候需要把数组里向量的分量展开到一个一维数组

		this.material.setProperty('colorArr', this.testArr);

	}

}



SliderPointLight.effect


CCEffect % {

		techniques:

			-passes:

			-vert: vs

		frag: fs

		blendState:

			targets:

			-blend: true

		rasterizerState:

			cullMode: none

		properties:

			texture: {
				value: white
			}

		wh_ratio: {

			value: 1.78,

			editor: {

				tooltip: "宽高比"

			}

		}

		blur: {

			value: 0.35,

			editor: {

				tooltip: "光圈模糊程度"

			}

		}

		radius: {

			value: 0.5,

			editor: {

				tooltip: "光圈半径"

			}

		}

		center: {

			value: [0.5, 0.5],

			editor: {

				tooltip: "光圈起点"

			}

		}

		colorArr: {
			value: [0.5, 0.5, 0.5, 0.5]
		}

	} %



	CCProgram vs % {

		precision highp float;


		#include <-global>

		#include <-local>


		in vec3 a_position;

		in vec4 a_color;

		out vec4 v_color;


		#if USE_TEXTURE

		in vec2 a_uv0;

		out vec2 v_uv0;

		#endif


		void main() {

			vec4 pos = vec4(a_position, 1);


			#if CC_USE_MODEL

			pos = _matViewProj  _matWorld  pos;

			#else

			pos = _matViewProj  pos;

			#endif


			#if USE_TEXTURE

			v_uv0 = a_uv0;

			#endif


			v_color = a_color;


			gl_Position = pos;

		}

	} %


	CCProgram fs % {


		precision highp float;


		#include <alpha-test>


		in vec4 v_color;


		#if USE_TEXTURE

		in vec2 v_uv0;

		uniform sampler2D texture;

		#endif


		uniform ARGS {

			float radius;

			float blur;

			vec2 center;

			float wh_ratio;

		};


		//effect定义

		uniform Metaball {

			vec4 colorArr[100];

		};


		void main() {

			vec4 o = vec4(1, 1, 1, 0);

			o = texture(texture, v_uv0);

			o = v_color;

			float circle = radius  radius;

			for (int i = 0; i < 100; i++) {

				float colorX = colorArr[i].x;

				float colorY = colorArr[i].y;

				float rx = colorX  wh_ratio;

				float ry = colorY;

				float dis = (v_uv0.x  wh_ratio - rx)  (v_uv0.x  wh_ratio - rx) + (v_uv0.y - ry)  (v_uv0.y - ry);


				o.a = smoothstep(circle, circle - blur, dis) + o.a;

			}


			gl_FragColor = o;

		}

	}%