Clearing

Before a camera renders the scene, it clears its render target — the screen, unless a render target is assigned. You can control what gets cleared and to what color:

camera.camera.clearColor = new pc.Color(0, 0, 0);

camera.camera.clearColorBuffer = true;   // clear the color buffer (default: true)
camera.camera.clearDepthBuffer = true;   // clear the depth buffer (default: true)
camera.camera.clearStencilBuffer = true; // clear the stencil buffer (default: true)

The clear color is effectively the background color of your scene — though if your scene has a skybox, it covers the clear color entirely.

Transparent Backgrounds

The clear color has an alpha channel, and the application's canvas supports transparency by default. This means a single camera can render the scene over the surrounding web page — useful for 3D product views, headers, and other embedded content:

// The web page shows through wherever nothing is drawn
camera.camera.clearColor = new pc.Color(0, 0, 0, 0);

Disabling Clearing

Disabling the clear flags keeps the existing contents of the render target, which is the building block for compositing several cameras into one image — see Camera Stacking.