Render to Texture

You can use the Render to Texture component to render the scene from a specific camera to a texture. You can use this feature to create rear-view mirrors, security camera screens, and draw 3D models in the viewport.

To enable this component, you must enable the Render to Texture gem. To enable gems, see Enabling Gems.

Topics

• Adding the Render to Texture Component in a Scene
• Adding a Render Target to a UI Element
• Render to Texture Properties
• EBus Request Bus Interface
• EBus Notification Bus Interface
• Known Limitations

Adding the Render to Texture Component in a Scene

Example
Entity (1) has a Camera component and a Render to Texture component. This entity faces a game object, entity (2). In entity (1), the Render to Texture component specifies a render target. A material file references that render target as its diffuse texture. The material is then added to entity (3), so that the render target appears in the viewport.

To use the Render to Texture component

1. In Lumberyard Editor, create an entity in the viewport. For more information, see Creating an Entity.

2. In the Entity Inspector, click Add Component.

3. Select the Camera component, choose Be this camera, and then move the camera entity using the viewport camera controls to look at an object in your level.

4. In the Entity Inspector, click Add Component.

5. Select the Render to Texture component.

6. For Texture name, enter a name that starts with the $ character, such as $rendertarget. Note
   The $ character tells Lumberyard that the texture will not be loaded from disk. If you don’t specify the $ character, Lumberyard will try to locate the texture file from disk, which can impact performance.

7. To open the Material Editor, choose Tools, Material Editor or press M.

8. Click the Add New Item icon to create a material, enter a name such as RenderToTexture, and then click Save.

9. In the Texture Maps section, for Diffuse, enter the Texture name that you specified, such as $rendertarget.

10. In the Asset Browser, navigate to primitive_plane.cgf, and then select and drag the file into the viewport.

11. Assign the material to the primitive plane entity. In the Mesh component, for the Material override property, specify the material file that you created, such as RenderToTexture.mtl.

    The primitive plane entity now shows the texture from the Render to Texture component.

Adding a Render Target to a UI Element

You can also specify the render target in an Image component for a UI element. For example, you can add the render target to appear in a button or object that a user can select in a UI menu.

For more information, see Visual Components.

Example
A camera entity (1) faces the Render to Texture entity (2), which has a Render to Texture component attached. The Texture name is $rendertarget.

To add a render target to a UI Image component

1. Complete steps 1 to 6 in the previous procedure. See Adding the Render to Texture Component in a Scene.

2. In Lumberyard Editor, choose Tools, UI Editor.

3. In the UI Editor, create or open a UI canvas.

4. Right-click the canvas and choose New, Element from Slice Library, Image.

5. In the Image component, for SpriteType, click the drop-down menu, and then select Render target.

6. For Render target name, enter the same texture name in the Render to Texture component, such as $rendertarget.

   The UI Image component displays the render target in the UI Editor.
   

Render to Texture Properties

The Render to Texture component has the following properties.

EBus Request Bus Interface

You can use the event bus (EBus) interface to communicate with other components in your game.

For more information, see Working with the Event Bus (EBus) system.

EBus Notification Bus Interface

You can use the event bus (EBus) interface to communicate with other components in your game.

For more information, see Working with the Event Bus (EBus) system.

Known Limitations

The Render to Texture component supports DirectX 11 for Windows.

Prevent Graphical Artifacts When Render to Texture is Active with the Following CVARs

Forces the object LOD to update at the beginning of the frame instead of the end of the previous frame. If you don’t set this console variable, you may see LOD flickering.

For more information about setting console variables, see Using the Console Window.

e_LodForceUpdate=1

Disables precaching of the streaming system due to common large jumps in the camera position when the render to texture feature is active.

e_AutoPrecacheCameraJumpDist=0

Enables subpixel morphological antialiasing (SMAA) instead of temporal antialiasing (TAA).

r_AntialiasingMode=2

Disables volumetric fog.

e_volumetricFog=0

Disables multi-GPU mode.

r_MultiGPU=0

Disables sparse voxel octree global illumination (SVOGI gem).

e_GI=0

You might see flickering, black or blurry textures if the streaming system thrashes while the Render to Texture component is active. This can occur in a scene that uses a large amount of texture memory.

To fix this, increase the value for r_TexturesStreamPoolSize, or set the Max FPS property to 0 so that the component updates each frame. This might help the streaming system balance texture priorities.

Tip
To verify if the graphics artifacts are a result of streaming thrashing, set r_TexturesStreamingDebug to 2. This console variable shows the textures that are streamed in and the memory usage.

Unsupported Features in the Render Target

The following features are not supported for the Render to Texture component because they don’t work with multiple cameras.

• TAA and SMAA
• Lens flares
• Sun shafts
• Volumetric fog
• CBuffer (constant buffer) occlusion (vis areas are supported)
• Motion blur
• Merged mesh vegetation
• Shadows cache