Fill in TODOs (#9964)

Fill in all the TODOs in the material, and add more info about a few
factors.

docs/api/materials/MeshStandardMaterial.html

@@ -12,7 +12,7 @@
 
 		<h1>[name]</h1>
 
-		<div class="desc">TODO</div>
+		<div class="desc">A standard physically-based material</div>
 
 		<iframe id="scene" src="scenes/material-browser.html#MeshStandardMaterial"></iframe>
 
@@ -91,28 +91,28 @@
 
 		<h3>[property:Float roughness]</h3>
 		<div>
-		TODO.<br />
+		How rough the material appears. 0.0 means a smooth mirror reflection, 1.0 means fully diffuse.<br />
 		</div>
 
 		<h3>[property:Float metalness]</h3>
 		<div>
-		TODO<br />
+		How much the material is like a metal. Non-metallic materials such as wood or stone use 0.0, metallic use 1.0, nothing in between. A value between 0.0 and 1.0 could be used for a rusty metal look.<br />
 		</div>
 
 		<h3>[property:Texture map]</h3>
 		<div>Set color texture map. Default is null. The texture map color is modulated by the diffuse color.</div>
 
 		<h3>[property:Texture lightMap]</h3>
-		<div>Set light map. Default is null. The lightMap requires a second set of UVs.</div>
+		<div>Set light map, a texture that contains pre-baked diffuse lighting added to the surface. Default is null. The lightMap requires a second set of UVs.</div>
 
 		<h3>[property:Float lightMapIntensity]</h3>
-		<div>TODO</div>
+		<div>A scale factor for the light map's effect, higher being brighter.</div>
 
 		<h3>[property:Texture aoMap]</h3>
-		<div>Set ambient occlusion map. Default is null. The aoMap requires a second set of UVs.</div>
+		<div>Set ambient occlusion map, a texture that contains pre-baked darkening due to crevices on the surface. Default is null. The aoMap requires a second set of UVs.</div>
 
 		<h3>[property:Float aoMapIntensity]</h3>
-		<div>TODO</div>
+		<div>A scale factor for the ambient occlusion map's effect, higher being darker and more pronounced.</div>
 
 		<h3>[property:Color emissive]</h3>
 		<div>
@@ -165,13 +165,11 @@
 		</div>
 
 		<h3>[property:Texture roughnessMap]</h3>
-		<div>
-			TODO.
+		<div>The red channel of this texture is used to alter the roughness of the material.
 		</div>
 
 		<h3>[property:Texture metalnessMap]</h3>
-		<div>
-			TODO.
+		<div>The red channel of this texture is used to alter the metalness of the material.
 		</div>
 
 		<h3>[property:Texture alphaMap]</h3>
@@ -182,7 +180,7 @@
 		<div>Set env map. Default is null.</div>
 
 		<h3>[property:Float envMapIntensity]</h3>
-		<div>TODO</div>
+		<div>Scales the effect of the environment map by multiplying its color.</div>
 
 		<h3>[property:Float refractionRatio]</h3>
 		<div>The index of refraction for an environment map using [page:Textures THREE.CubeRefractionMapping]. Default is *0.98*.</div>