
Pretty much every 3D programmer runs into depth buffer issues sooner or later. 
This is especially true when creating outer-space scenes where object distances can be in light years.

In such cases, the linear depth buffer (the default) can generate glitches when distances start reaching large numbers.
In short, the depth values are proportional to the reciprocal of Z. This gives good precision near the camera, but less precision in the distance.

You can read an interesting analysis by Brano Kemen on this blog: http://www.gamasutra.com/blogs/BranoKemen/20090812/85207/Logarithmic_Depth_Buffer.php

To help with this issue, you may want to use a better Z-value distribution: the logarithmic depth buffer, where Z = log(C*z + 1) / log(C*Far + 1) * w

StandardMaterials can enable the logarithmic depth buffer if the browser supports the *GL_EXT_frag_depth* extension.

To enable it, just use this code:
```
material.useLogarithmicDepth = true;
```

If the extension is not supported, Babylon.js will revert to linear depth buffering.



## Meshes

In the 3D virtual world, shapes are built from meshes: lots of triangular facets joined together, each made from three vertices.

![A mesh](/img/features/scene/custom1.webp)

Babylon.js provides predefined meshes, supports your own custom meshes, and can import meshes created by 3D design software. For all meshes, the underlying data structure is exposed and can be updated.


BABYLON.DepthRenderer is a tool used to generate a depth texture (a texture that contains the depth buffer and can be used to read scene depth values).

Using it is pretty straightforward:

```javascript
const renderer = scene.enableDepthRenderer();
```

Starting from there, the scene will fill the renderer with depth values for you. All active meshes (meshes that are visible from the current camera's point of view) are drawn by the DepthRenderer.

**Warning: Transparent meshes are not drawn because they are not written to the depth buffer**

You can then use the texture associated with the renderer like any other texture by using the `getDepthMap()` function:

```javascript
const mat = new BABYLON.StandardMaterial("mat01", scene);
mat.emissiveTexture = renderer.getDepthMap();
```

If you want to disable the renderer, just call the following code:

```javascript
scene.disableDepthRender();
```

As you can see, you can use the depth map associated with the DepthRenderer with any materials or post-processes.

**Note: By default, the generated texture uses float components thanks to the _WebGL OES_texture_float_ extension. If this extension is not supported, Babylon.js reverts to byte components, which means less precision for depth values.**


Logarithmic Depth Buffer