Render Textures

RenderTexture is a fixed-size GPU texture that can receive a camera's world output. Use it for minimaps, security cameras, portals, and low-resolution composition. It can be sampled anywhere a normal Texture2D is accepted.

Render a camera off screen

Create render textures after the game window loads. A scene's Load method runs at the correct time:

public sealed class MinimapScene(
    Rendering rendering,
    CameraManager cameras,
    SpriteBatch sprites) : BaseScene
{
    private RenderTexture minimap = null!;
    private Camera2D minimapCamera = null!;

    public override void Load()
    {
        minimap = rendering.CreateRenderTexture(256, 256);
        minimapCamera = cameras.Create("Minimap");
        minimapCamera.RenderTarget = minimap;
        minimapCamera.Zoom = 0.25f;
        minimapCamera.Priority = -1;
    }

    public override void Draw(double frameDelta, double frameRate) =>
        sprites.Draw(minimap.Texture, new Vector2(920, 140), new Vector2(240, 240),
            space: CoordinateSpace.Screen);

    public override void Unload()
    {
        minimapCamera.RenderTarget = null;
        cameras.Remove(minimapCamera);
        minimap.Dispose();
    }
}

A camera with RenderTarget set writes to that texture instead of the window. Other cameras continue rendering normally. Camera priorities determine production order, so assign an earlier priority when its texture is sampled later in the same frame.

Use CullingMask and sprite lighting layers to choose which world objects the target camera sees.

Fixed-resolution output

Nearest filtering keeps low-resolution pixels sharp when the texture is enlarged:

var pixelView = rendering.CreateRenderTexture(
    320, 180, RenderTextureFilter.Nearest);

Change Filter at runtime or call Resize(width, height). Resizing preserves the public Texture reference, so existing sprites remain valid.

The camera retains its normal window-based logical viewport while the target controls raster resolution. Adjust camera zoom to change the visible world area.

Post-processing and lifetime

Camera post-processing works with render textures. Intermediate targets use the render texture dimensions, so uResolution and uTexelSize describe the final off-screen image.

RenderTexture owns its framebuffer and GPU texture. Dispose it when its scene or owning system unloads. Drawing its Texture after disposal throws. The renderer also releases remaining render textures during game shutdown.

See the TARGETS screen in Axolotl2D.Example for a moving camera rendered at 320x180 and enlarged with nearest filtering.