javascript
/
three.js
espejo de https://github.com/tazdij/three.js.git


			
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							<!DOCTYPE html>
<html lang="zh">
	<head>
		<meta charset="utf-8" />
		<base href="../../../" />
		<script src="page.js"></script>
		<link type="text/css" rel="stylesheet" href="page.css" />
	</head>
	<body>
		[page:Object3D] &rarr; [page:Light] &rarr;

		<h1>聚光灯（[name]）</h1>

		<p class="desc">
			光线从一个点沿一个方向射出，随着光线照射的变远，光线圆锥体的尺寸也逐渐增大。<br /><br />

			该光源可以投射阴影 - 跳转至 [page:SpotLightShadow] 查看更多细节。
		</p>

		<h2>代码示例</h2>
		<code>
		// white spotlight shining from the side, modulated by a texture, casting a shadow

		const spotLight = new THREE.SpotLight( 0xffffff );
		spotLight.position.set( 100, 1000, 100 );
		spotLight.map = new THREE.TextureLoader().load( url );

		spotLight.castShadow = true;

		spotLight.shadow.mapSize.width = 1024;
		spotLight.shadow.mapSize.height = 1024;

		spotLight.shadow.camera.near = 500;
		spotLight.shadow.camera.far = 4000;
		spotLight.shadow.camera.fov = 30;

		scene.add( spotLight );
		</code>

		<h2>例子</h2>

		<p>
			[example:webgl_lights_spotlight lights / spotlight ]<br />
			[example:webgl_lights_spotlights lights / spotlights ]
		</p>

		<h2>构造器（Constructor）</h2>


		<h3>[name]( [param:Integer color], [param:Float intensity], [param:Float distance], [param:Radians angle], [param:Float penumbra], [param:Float decay] )</h3>
		<p>
			[page:Integer color] - (可选参数) 十六进制光照颜色。 缺省值 0xffffff (白色)。<br />
			[page:Float intensity] - (可选参数) 光照强度。 缺省值 1。<br />
			[page:Float distance] - 从光源发出光的最大距离，其强度根据光源的距离线性衰减。 <br />
			[page:Radians angle] - 光线散射角度，最大为Math.PI/2。<br />
			[page:Float penumbra] - 聚光锥的半影衰减百分比。在0和1之间的值。默认为0。<br />
			[page:Float decay] - 沿着光照距离的衰减量。<br /><br />

			创建一个新的聚光灯。
		</p>

		<h2>属性（Properties）</h2>

		<p>公共属性请查看基类[page:Light Light]。</p>

		<h3>[property:Float angle]</h3>
		<p>
			从聚光灯的位置以弧度表示聚光灯的最大范围。应该不超过 *Math.PI/2*。默认值为 *Math.PI/3*。
		</p>


		<h3>[property:Boolean castShadow]</h3>
		<p>
			此属性设置为 *true* 聚光灯将投射阴影。警告: 这样做的代价比较高而且需要一直调整到阴影看起来正确。
			查看 [page:SpotLightShadow] 了解详细信息。
			默认值为 *false*
		</p>

		<h3>[property:Float decay]</h3>
		<p>
			The amount the light dims along the distance of the light. Default is `2`.<br />
			In context of physically-correct rendering the default value should not be changed.
		</p>

		<h3>[property:Float distance]</h3>
		<p>
			`Default mode` — When distance is zero, light does not attenuate. When
			distance is non-zero, light will attenuate linearly from maximum intensity
			at the light's position down to zero at this distance from the light.
		</p>
		<p>
			When [page:WebGLRenderer.useLegacyLights legacy lighting mode] is disabled —
			When distance is zero, light will attenuate according to inverse-square
			law to infinite distance. When distance is non-zero, light will attenuate
			according to inverse-square law until near the distance cutoff, where it
			will then attenuate quickly and smoothly to `0`. Inherently, cutoffs are
			not physically correct.
		</p>
		<p>Default is `0.0`.</p>

		<h3>[property:Float intensity]</h3>
		<p>
			The light's intensity. Default is `1`.<br />
			When [page:WebGLRenderer.useLegacyLights legacy lighting mode] is disabled,
			intensity is the luminous intensity of the light measured in candela
			(cd).<br /><br />
			Changing the intensity will also change the light's power.
		</p>

		<h3>[property:Boolean isSpotLight]</h3>
		<p>
			Read-only flag to check if a given object is of type [name].
		</p>

		<h3>[property:Float penumbra]</h3>
		<p>
				聚光锥的半影衰减百分比。在0和1之间的值。
				默认值 — 0.0。
		</p>

		<h3>[property:Vector3 position]</h3>
		<p>
			假如这个值设置等于 [page:Object3D.DEFAULT_UP] (0, 1, 0)，那么光线将会从上往下照射。
		</p>

		<h3>[property:Float power]</h3>
		<p>
			The light's power.<br />
			When [page:WebGLRenderer.useLegacyLights legacy lighting mode] is disabled,
			power is the luminous power of the light measured in lumens (lm).
			<br /><br />
			Changing the power will also change the light's intensity.
		</p>

		<h3>[property:SpotLightShadow shadow]</h3>
		<p>
			[page:SpotLightShadow]用与计算此光照的阴影。
		</p>


		<h3>[property:Object3D target]</h3>
		<p>
				聚光灯的方向是从它的位置到目标位置.默认的目标位置为原点 *(0,0,0)*。<br />
				注意: 对于目标的位置，要将其更改为除缺省值之外的任何位置，它必须被添加到 [page:Scene scene]
				场景中去。
			<code>
				scene.add( light.target );
			</code>

			这使得属性target中的 [page:Object3D.matrixWorld matrixWorld] 会每帧自动更新。<br /><br />

			它也可以设置target为场景中的其他对象(任意拥有 [page:Object3D.position position] 属性的对象), 示例如下:
			<code>
const targetObject = new THREE.Object3D();
scene.add(targetObject);

light.target = targetObject;
			</code>
			完成上述操作后，聚光灯现在就可以追踪到目标对像了。
		</p>

		<h3>[property:Texture map]</h3>
		<p>
			A [page:Texture] used to modulate the color of the light. The spot light color is mixed
			with the RGB value of this texture, with a ratio corresponding to its
			alpha value. The cookie-like masking effect is reproduced using pixel values (0, 0, 0, 1-cookie_value).
			*Warning*: [param:SpotLight map] is disabled if [param:SpotLight castShadow] is *false*.
		</p>


		<h2>方法（Methods）</h2>

		<p>公共方法请查看基类 [page:Light Light]。</p>

		<h3>[method:this copy]( [param:SpotLight source] )</h3>
		<p>
			将所有属性的值从源 [page:SpotLight source] 复制到此聚光灯光源对象。
		</p>

		<p>
			[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]
		</p>
	</body>
</html>