Shaders

Question 1

3 Shader Categories

Answer 1

Graphics pipeline Shaders
Compute Shaders
Ray tracing Shaders

Question 2

What is the Graphics pipeline Shader?

Answer 2

Most common shader.
Performs calculations that determine the color of the pixels on the screen.
Uses shader objects

Question 3

What are Compute Shaders?

Answer 3

They perform calculations on the GPU outside of the regular graphics pipeline.

Question 4

What are Ray tracing Shaders?

Answer 4

Perform calculations related to ray tracing

Question 5

What are shader objects?

Answer 5

An instance of the shader class. A wrapper for shader programs and other information.

Question 6

What is a Shader Lab?

Answer 6

A unity-specific language for writing Shaders

Question 7

What is a Shader graph?

Answer 7

A tool for creating Shaders without writing code

Question 8

What is a Shader Asset?

Answer 8

A file in your project that defines a Shader object.

Question 9

What are Shaders?

Answer 9

Shaders are part of the Graphics pipeline.
An instance of the shader class is called a Shader object.

Question 10

What is a Shader Object?

Answer 10

Shader objects is a way of working with shader programs; it is a wrapper for shader programs and other information.
It let’s you define multiple shader programs in the same file and tell unity how to use them

Question 11

What do shader objects contain?

Answer 11

A Shader object contains shader programs, instructions for changing settings on the GPU (collectively called render states), and information that tells unity how to use them.

Question 12

What do you use shader objects for/with?

Answer 12

You can use shader objects with materials to determine the appearance of your scene

Question 13

How do you create shader objects? (2 ways)

Answer 13

1) You can write code to create a Shader asset, which is a text file with the (.Shader) extension.
2) You can use a Shader graph to create a Shader graph asset.

Question 14

An instance of the shader is called?

Answer 14

A Shader object

Question 15

Inside a Shader object…

Answer 15

A Shader object has a nested structure.
It organizes information into structures called Subshaders and Passes.
It organizes shader programs into shader varients.

Question 16

What does a Shader object contain?

Answer 16

1) Information about its self such as it’s name.
2) An optional fallback shader object, which unity uses if it can’t use the current one.
3) One or more Subshaders

Question 17

What else can you do with shader objects?

Answer 17

You can also define additional information such as shared shader code, or whether to use a custom editor.

Question 18

What is a SubShader?

Answer 18

Subshaders let you separate your shader object into parts that are compatible with different hardware, render pipelines, and runtime settings.

Question 19

What does a SubShader contain?

Answer 19

1) Information about which hardware, render pipelines, and runtime settings this shader is compatible with
2) Subshader tags, which are key-value pairs that provide information about the Subshader
3) One or more passes

Question 20

What else can you do with Subshaders?

Answer 20

You can also define information, such as render state that is common to all of its passes

Question 21

Passes in Subshaders… What do they contain?

Answer 21

A Pass contains…

1) Pass tags. Which are key-value pairs that provide information about the pass.
2) Instructions for updating the render state before running its shader programs.
3) Shader programs, organized into one or more shader varients.

Question 22

What are Shader Varients?

Answer 22

The Shader programs that a Pass contains are organized into shader varients.
Shader varients share common code, but have different functionality when a given keyword is enabled or disabled.
The number of shader variant in a Pass depends on how many keywords you define in your shader code, and the target platform
Each pass contains at least one variant.

Question 23

Before unity uses a Shader object..

Answer 23

Unity creates a list of Subshaders for the shader object.
It adds all of the Subshaders defined in the shader object, and then adds all of the Subshaders in any fallback shader objects, in order.

Question 24

When Unity first renders geometry using the Shader object, or when the shader LOD value or active render pipeline changes…

Answer 24

1) Unity iterates over the list of all the Subshaders and examines them to determine if they are: Compatible with the device hardware at all or below the current shader LOD value, and compatable with the active render pipeline.
2) If the list contains one or more Subshaders that meet these requirements, it selects the first one. This is the active Subshader.

3) If the list does not contain any Subshaders that meet all the requirements:
If the list contains one or more Subshaders that meet the hardware requirements (but do not meet the LOD or render pipeline requirements) Unity selects the first one to be the active Subshader.
If the list does not contain a u Subshaders that meet the hardware requirements, Unity displays the error Shader.

Question 25

Can Unity identify geometry?

Answer 25

Unity identifies geometry that uses the same shader variant and organize it into batches for more efficient rendering.
Once per frame, for every batch of geometry.

Question 26

Once every frame, for every batch of geometry…

Answer 26

1) Unity determines which of the Passes in the active Subshader it should render, and at which point in the frame. This behavior varies by the render pipeline.

2) For Every Pass that it renders :
- If the current render state does not match the render state defined in the Pass, Unity sets the render state as defined in the pass.
- The GPU renders the geometry using the relevant shader variant.

Question 27

Error shader and error loading Shaders…

Answer 27

Unity sometimes can’t render objects with regular Shaders, when this happens Unity renders the objects with special shaders

Question 28

Special error shaders

Answer 28

The default error shader
The loading shader
The streaming virtual texturing error material

The special Shader Unity uses depends on the reason that Unity can’t load the original Shader.

Question 29

The Default error shader..

Answer 29

The default error shader is Magenta(bright pink)
Unity uses the default error shader in the editor, and in builds.
Used when there’s a problem with that objects material or shader, I. E, if no material is assigned, if the shader doesn’t compile or if the shader isn’t supported.

Question 30

With the BatchRendererGroup API

Answer 30

Unity doesn’t display the default error shader

Unity doesn’t display the loading shader

Question 31

The Loader Shader…

Answer 31

Used to indicate that Unity is compiling the shader variant needed to display that object

Question 32

When does the Loading shader showed?

Answer 32

When the Asynchronous shader compilation is enabled, or in a development build when the Shader Live Link Support is enabled
The Loading Shader is Cyan (Bright blue)

Question 33

Virtual Texturing Error Material

Answer 33

If your project uses Streaming Virtual Texturing (STV), Unity uses a special material to indicate problems in your STV setup.