114 lines
3.3 KiB
JavaScript
114 lines
3.3 KiB
JavaScript
/*
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* @Description: 流动线
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*/
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function FlowLine() {
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class FlowLineMaterialProperty {
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constructor(options) {
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this._definitionChanged = new Cesium.Event();
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this._color = undefined;
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this._duration = undefined;
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this.color = new Cesium.Color.fromCssColorString(options.color || "rgba(255,255,255,1)");
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this.duration = options.duration || 10.0;
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this.lineBackAlpha = options.lineBackAlpha || 0.05;
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}
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get isConstant() {
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return false;
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}
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get definitionChanged() {
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return this._definitionChanged;
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}
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getType(time) {
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return Cesium.Material.FlowLineMaterialType;
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}
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getValue(time, result) {
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if (!Cesium.defined(result)) {
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result = {};
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}
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result.color = Cesium.Property.getValueOrDefault(
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this._color,
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time,
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Cesium.Color.RED,
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result.color
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);
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result.duration = Cesium.Property.getValueOrDefault(
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this._duration,
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time,
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10,
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result.duration
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);
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result.lineBackAlpha = this.lineBackAlpha;
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result.frameNumber = Cesium.getTimestamp();
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return result;
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}
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equals(other) {
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return (
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this === other ||
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(other instanceof FlowLineMaterialProperty &&
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Cesium.Property.equals(this._color, other._color) &&
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Cesium.Property.equals(this._duration, other.duration) &&
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Cesium.Property.equals(this.lineBackAlpha, other.lineBackAlpha))
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);
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}
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}
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Object.defineProperties(FlowLineMaterialProperty.prototype, {
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color: Cesium.createPropertyDescriptor("color"),
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duration: Cesium.createPropertyDescriptor("duration"),
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transparency: Cesium.createPropertyDescriptor("lineBackAlpha"),
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});
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Cesium.FlowLineMaterialProperty = FlowLineMaterialProperty;
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Cesium.Material.FlowLineMaterialProperty = "FlowLineMaterialProperty";
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Cesium.Material.FlowLineMaterialType = "FlowLineMaterialType";
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Cesium.Material.FlowLineMaterialSource = `
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uniform vec4 color;
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uniform float duration;
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uniform float lineBackAlpha;
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czm_material czm_getMaterial(czm_materialInput materialInput)
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{
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//生成默认的基础材质
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czm_material material = czm_getDefaultMaterial(materialInput);
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//获取st（uv）
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vec2 st = materialInput.st;
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//获取当前帧数，10秒内变化0-1
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float time = fract(czm_frameNumber / (60.0*duration));
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//长度1/10
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time = time * (1.0 + 0.1);
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//平滑过渡函数
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float alpha = smoothstep(time-0.1,time,st.s) * step(-time,-st.s);
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//光带轨迹（不会完全透明）
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alpha += lineBackAlpha;
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material.alpha = alpha;
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material.diffuse = color.rgb;
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return material;
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}
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`;
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Cesium.Material._materialCache.addMaterial(
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Cesium.Material.FlowLineMaterialType,
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{
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fabric: {
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type: Cesium.Material.FlowLineMaterialType,
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uniforms: {
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color: new Cesium.Color(1.0, 1.0, 1.0, 1.0),
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duration: 10.0,
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lineBackAlpha: 0.05,
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},
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source: Cesium.Material.FlowLineMaterialSource,
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},
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translucent: function (material) {
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return true;
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},
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}
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);
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}
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export { FlowLine }
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