Open topic with navigation

Frame Scrubber

Understanding the Scrubber

For the sake of discussion when it comes to graphics debugging, it helps to note some common terminology.

• An event is a single call to the API. It could be a draw call, or clear, or a less obvious call, like configuring API state.
• An action is a subset of the event types. It can be a draw call, clear, blit, compute dispatch, or swap buffers. Actions are interesting since they explicitly change buffers, which may result in visual changes.

The default view will show the events in your application, in addition to any performance markers you have defined. Clicking the Add... button will open a dialog that allows you to select what type of range you want to add.

• Program Ranges — Actions that use the same shader program.
• Viewport — Actions that render to the same viewport rectangle.
• Alpha Blending Enabled — Actions that have alpha blending enabled.
• Alpha Test Enabled — Actions that have alpha test enabled.
• Back Face Cull Enabled — Actions that have back face cull enabled.
• User — A range defined by you on the fly. Use SHIFT + left-click and drag the scrubber on the created "User" row to create a new range.

Scrubbing on the Host

Zooming In and Out

There are several ways to zoom in and out of the scrubber in the Frame Debugger.

1. Select an event range: hold down the SHIFT key and click-and-drag the mouse along the event timeline.
   The selected range appears as a dark gray area.
2. Click inside the range.
   The event timeline zooms in, expanding the range to the borders of the timeline.

Alternatively, you can click-and-drag the either of the handles of the horizontal scroll bar.

You can also zoom in and out by holding the CTRL key while moving the scroll wheel on the mouse.

Scaling and Hierarchy

There are several ways to view the Scrubber. From the Scaling drop-down menu, you can choose one of the following:

• Unit Scale is the default view, which simply shows the actions and events on the timeline.
• Sequence ID shows how the calls may have executed on the GPU in parallel.
  Note that Sequence ID is only used in APIs that allow for simultaneous execution, so it will look the same as Event ID ordering for APIs like OpenGL and OpenGL ES.
• GPU Time Scale displays the GPU activity and how much each event or action cost the GPU.
• CPU Time Scale displays the CPU activity and how much each event or action cost the CPU.
• X by CPU, Y by GPU displays the CPU time scale on a horizontal X-axis, and the GPU time scale on a vertical Y-axis.

From the Hierarchy drop-down, you can choose either of the following:

• Queue Centric sorts the events by queue.
• Thread Centric sorts the events by the thread.

Using Hotkeys to Scrub Through a Frame

When the scrubber has focus, you can use the following hotkeys to move the scrubber cursor from one event to another.

HOTKEY	ACTION
Zooming and Panning
CTRL + Scroll mouse wheel up, or CTRL + NumPadPlus	Zoom in X-axis
CTRL + Scroll mouse wheel down, or CTRL + NumPadMinus	Zoom out X-axis
CTRL + 0	Reset zoom to encompass the entire frame
CTRL + SHIFT + Scroll mouse wheel up	Increase row height (all rows)
CTRL + SHIFT + Scroll mouse wheel down	Decrease row height (all rows)
CTRL + Left mouse click and drag	Pan
Cursor and Selection
Left mouse click on desired cursor location	Set current event/action
Left mouse click on desired row	Select row (The selected row is highlighted in orange.)
CTRL + Right Arrow	Move cursor to the next action
CTRL + Left Arrow	Move cursor to the previous action
SHIFT + Left mouse click and drag	Make range selection
Left mouse click on selection	Zoom to range
Left double-click on event action, or Right-click menu, Open API Inspector	Open API Inspector
Right-click menu, Run Range Profiler	Run Range Profiler
CTRL + A	Select all events

When moving the scrubber cursor, you will only stop on action events, as mentioned above.

For example, if you are looking for the next draw method that was called, you can press the CTRL + RIGHT ARROW on the keyboard to skip over events that are not typically of interest, and only stop on events that are considered action events.

NVIDIA® GameWorks™ Documentation Rev. 1.0.180426 ©2014-2018. NVIDIA Corporation. All Rights Reserved.