Frame Debugger - Unity Official Tutorials

In Unity rendering a frame to the screen

occurs in a linear sequence of events.

The Frame Debugger is a tool which lets

you see all the steps involved

in rendering a frame step by step.

It allows you to the see intermediate render targets,

shadow maps and each draw call

that contributes to the frame, in order.

The frame debugger is accessed from

Window - Frame Debugger.

The editor will pause and in the frame debug window

a sequential list of each step involved

in current frame will displayed.

Many of these are draw called.

But they also involve other render related events

like frame buffer clears,

which set the initial colours of the screen,

or compute shader invocation.

A draw call is a command in which the CPU

sends content to be rendered, like meshes,

to the GPU to be rendered as pixels for display.

At the top of the window are two

forward and back buttons

along with a slider, which will allow you to step through this list in order.

Selecting a single step in the process from the main list

will cause that draw call or event,

along with the steps prior to it,

to be drawn in the game view.

If that step is drawing a mesh renderer

the game object with that mesh renderer attached

will be highlighted in the hierarchy.

Viewing a step in the main list allows

you to see where in the overall

process of drawing the frame it occurs.

Related steps are grouped together

and their views can be expanded or collapsed.

Analysing frames in this way is useful

to learn precisely how and in what order

Unity is rendering your frame.

When setting up a new project we

can choose between 4 different render paths.

Each render path renders content differently.

Choosing which to use is highly

dependent on the nature of your project.

To choose a render path for your project

navigate to Edit - Project Settings - Player

and select a rendering path from the drop-down

under Other Settings.

For more information about the available

render paths please see the information linked below.

Each render path can use a different

number of render targets.

A render target is a feature of

GPUs that allow a scene

to be rendered to an intermediate memory buffer.

Using the for Forward rendering path

1 render target is used by default.

Here shown as RT0,

along with a depth buffer.

Using customer shaders it's possible

to use more render targets in forward rendering

but using the standard shader this is

the default behaviour.

This project is in differed rendering mode.

In differed rendering mode multiple render targets are used.

When rendering to multiple targets at once

you can select which display using the drop down menu.

In this example we can see the diffuse,

specular,

normals,

and emission and indirect lighting buffers

in in Unity 5 differed shading mode

using the standard shader.

You can also see the depth buffer by

selecting it from the same drop down.

When an event is highlighted

information will be displayed about that event

in the information panel.

In the case of draw calls the information

panel also includes buttons which will

allow you to isolate and visualise information,

including the red,

green,

blue and alpha channels

of the selected render target.

You can also adjust the brightness of the

display using the levels bracketed slider here.

This can be useful in HDR rendering

to isolate certain luminance ranges

of a frame for analysis.