The Framebuffer pane shows the contents of the currently bound framebuffer. Depending on the item you select in the Commands pane, it can show onscreen or offscreen framebuffers.

When you select a command in the Commands pane, the Framebuffer pane displays the contents of the framebuffer after that call finishes. If you select a group, it displays the framebuffer after the last call in that group finishes.

In essence, you can start by selecting the first call within a frame, and then click each successive call to watch the framebuffer components draw one-by-one until the end of the frame. These framebuffer displays, for both onscreen and offscreen graphics, help you to locate the source of any rendering errors.

If the framebuffer contains undefined data, you’ll see diagonal bright green lines, as shown in figure 5.

The following table describes the operations you can perform with the toolbar buttons.

Button Description
Zoom to Fit Click the button to adjust the graphic to fit completely within the Framebuffer pane.
Right-clicking the image is another way to Zoom to Fit.
Zoom to Actual Size Click the button to show the image at no scale, where one device pixel is equivalent to one screen pixel.
Zoom In Click the button to zoom in. You can also use your mouse wheel, or two-finger swipes on a touchpad, to scroll in and out. You can drag the image with your cursor.
Zoom Out Click the button to zoom out. You can also use your mouse wheel, or two-finger swipes on a touchpad, to scroll in and out.
Color Channels Click the button and then select the color channels to render or deselect color channels so they aren't rendered. The options are Red, Green, Blue, and Alpha (transparency).
Background Select the button to display a checkerboard background or solid color.
Flip Vertically Flips the image vertically.