Update to Depth Layer page

docs/user-manual/graphics/cameras/depth-layer.md

@@ -18,15 +18,64 @@ To access one of these buffers in the shader as a texture, these are the uniform
 - for the color map: `uSceneColorMap`
 - for the depth map: `uSceneDepthMap`
 
+## Color Space Handling
+
+When using `uSceneColorMap`, it's important to handle color space correctly. The scene color texture contains either gamma-corrected values (when rendering LDR to a non-sRGB target) or linear values (when using HDR rendering with CameraFrame).
+
+### SCENE_COLORMAP_GAMMA Define
+
+The engine automatically provides a `SCENE_COLORMAP_GAMMA` shader define when the scene color map contains gamma-corrected values that need to be converted to linear space. This typically occurs during LDR rendering when the camera outputs gamma-corrected colors to a standard (non-sRGB) render target.
+
+**GLSL Example:**
+
+```glsl
+vec3 sceneColor = texture2DLod(uSceneColorMap, uv, 0.0).rgb;
+
+#ifdef SCENE_COLORMAP_GAMMA
+// Convert from gamma to linear space
+sceneColor = decodeGamma(sceneColor);
+#endif
+
+// Now sceneColor is in linear space for lighting calculations
+```
+
+**WGSL Example:**
+
+```wgsl
+var sceneColor: vec3f = textureSampleLevel(uSceneColorMap, uSceneColorMapSampler, uv, 0.0).rgb;
+
+#ifdef SCENE_COLORMAP_GAMMA
+// Convert from gamma to linear space
+sceneColor = decodeGamma3(sceneColor);
+#endif
+
+// Now sceneColor is in linear space for lighting calculations
+```
+
+The `decodeGamma()` and `decodeGamma3()` functions are built-in utility functions that perform the gamma-to-linear conversion using the standard gamma 2.2 curve.
+
+For more information on linear workflow and color space handling, see the [Linear Workflow](/user-manual/graphics/linear-workflow/) documentation.
+
+## CameraFrame Integration
+
+When using [`CameraFrame`](/user-manual/graphics/posteffects/cameraframe/) for HDR post-processing, you can request depth and color maps through the [`rendering`](https://api.playcanvas.com/engine/classes/CameraFrame.html#rendering) settings:
+
+- **Color Map**: Set `cameraFrame.rendering.sceneColorMap = true` to enable access to `uSceneColorMap` (e.g., for refraction or custom post-processing effects)
+- **Depth Map**: Set `cameraFrame.rendering.sceneDepthMap = true` to enable access to `uSceneDepthMap` (e.g., for depth-dependent effects like custom fog or edge detection)
+
+The color map in CameraFrame contains linear HDR values (no gamma correction needed), so the `SCENE_COLORMAP_GAMMA` define will not be set. This ensures consistent color space handling across different rendering configurations.
+
 ## Examples
 
 These engine examples demonstrate the rendering of both the depth and the color map, and also custom shaders allowing their use:
 
 - GrabPass demonstrates the use of the color buffer: [`GrabPass`][2]
 - GroundFog demonstrates the use of the depth buffer: [`GroundFog`][3]
+- Dispersion demonstrates refraction and chromatic dispersion using the scene color texture: [`Dispersion`][5]
 
 [0]: https://api.playcanvas.com/engine/classes/CameraComponent.html#requestscenecolormap
 [1]: https://api.playcanvas.com/engine/classes/CameraComponent.html#requestscenedepthmap
 [2]: https://playcanvas.github.io/#/shaders/grab-pass
 [3]: https://playcanvas.github.io/#/shaders/ground-fog
 [4]: /user-manual/graphics/layers/#choosing-the-layer-order
+[5]: https://playcanvas.github.io/#/materials/dispersion