javascript
/
three.js
镜像来自 https://github.com/tazdij/three.js.git


			
				
					
						
						
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		[page:Object3D] &rarr; [page:Light] &rarr;

		<h1>[name]</h1>

		<p class="desc">
			A light that gets emitted from a single point in all directions. A common use case for this
			is to replicate the light emitted from a bare lightbulb.<br /><br />

			 This light can cast shadows - see [page:PointLightShadow] page for details.
		</p>

		<h2>Code Example</h2>

		<code>
const light = new THREE.PointLight( 0xff0000, 1, 100 );
light.position.set( 50, 50, 50 );
scene.add( light );
		</code>

		<h2>Examples</h2>

		<p>
			[example:webgl_lights_pointlights lights / pointlights ]<br />
			[example:webgl_effects_anaglyph effects / anaglyph ]<br />
			[example:webgl_geometry_text geometry / text ]<br />
			[example:webgl_lensflares lensflares ]
		</p>

		<h2>Constructor</h2>

		<h3>[name]( [param:Integer color], [param:Float intensity], [param:Number distance], [param:Float decay] )</h3>
		<p>
			[page:Integer color] - (optional) hexadecimal color of the light. Default is 0xffffff (white).<br />
			[page:Float intensity] - (optional) numeric value of the light's strength/intensity. Default is 1.<br />
			[page:Number distance] - Maximum range of the light. Default is 0 (no limit).<br />
			[page:Float decay] - The amount the light dims along the distance of the light. Default is 2.<br /><br />

			Creates a new [name].
		</p>

		<h2>Properties</h2>
		<p>
			See the base [page:Light Light] class for common properties.
		</p>
		
		<h3>[property:Boolean castShadow]</h3>
		<p>
			If set to `true` light will cast dynamic shadows. *Warning*: This is expensive and
			requires tweaking to get shadows looking right. See the [page:PointLightShadow] for details.
			The default is `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>
			`[page:WebGLRenderer.physicallyCorrectLights Physically correct] mode` — 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 />
			In [page:WebGLRenderer.physicallyCorrectLights physically correct] mode, 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:Float power]</h3>
		<p>
			The light's power.<br />
			In [page:WebGLRenderer.physicallyCorrectLights physically correct] mode, 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:PointLightShadow shadow]</h3>
		<p>
			A [page:PointLightShadow] used to calculate shadows for this light.<br /><br />

			 The lightShadow's [page:LightShadow.camera camera]
			is set to a [page:PerspectiveCamera] with [page:PerspectiveCamera.fov fov] of 90,
			[page:PerspectiveCamera.aspect aspect] of 1, [page:PerspectiveCamera.near near]
			clipping plane at 0.5 and	[page:PerspectiveCamera.far far] clipping plane at 500.
		</p>

		<h2>Methods</h2>
		<p>
			See the base [page:Light Light] class for common methods.
		</p>

		<h3>[method:undefined dispose]()</h3>
		<p>
			Frees the GPU-related resources allocated by this instance. Call this method whenever this instance is no longer used in your app.
		</p>

		<h3>[method:this copy]( [param:PointLight source] )</h3>
		<p>
		Copies value of all the properties from the [page:PointLight source] to this
		PointLight.
		</p>

		<h2>Source</h2>

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