When a shaderA program that runs on the GPU. More info
See in Glossary program includes conditionals that are evaluated at compile time, it uses static branching. The compiler excludes the code from the unused branch, so it does not appear in the compiled shader program.
Internally, Unity uses static branching when it creates shader variants. Static branching on its own does not have any of the performance disadvantages of shader variants.
The main advantage of static branching is that it has no negative impact on runtime performance. The main disadvantage of static branching is that you can only use it at compile time.
Static branching means that the compiler excludes unneeded code from the shader program. It results in small, specialized shader programs that contain only the necessary code. There is no runtime performance cost to static branching; in fact, the smaller programs are likely to result in quicker load times and lower runtime memory usage.
To use static branching, the conditions must be constant at compile time. This means that you can’t use it to execute code for different conditions at runtime.
When a shader program includes conditionals that are evaluated at runtime, it uses dynamic branching.
There are two types of dynamic branching: dynamic branching based on uniform variables, and dynamic branching based on any other runtime value. Uniform-based branching is usually more efficient, because the uniform value is constant for the whole draw call.
You can use shader keywords for dynamic branching. This allows you to use C# scriptsA piece of code that allows you to create your own Components, trigger game events, modify Component properties over time and respond to user input in any way you like. More info
See in Glossary and the Material InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
See in Glossary to configure runtime branching behavior for your shaders. This results is uniform-based branching; when you do this, Unity compiles the shader keywords as uniforms.
The main advantage of dynamic branching is that it allows you to use conditionals at runtime without increasing the number of shader variants in your project. The main disadvantage of dynamic branching is that it impacts GPU performance.
The GPU performance impact varies by hardware, and by shader code. The reasons are:
In general, if your code branches on uniform values and both branches have roughly similar workloads, then the impact on GPU performance is likely to be small. However, you should always profile your application and consider the advantages and disadvantages case-by-case.
Note: Dynamic branching can also lead to large shader programs, because the code for all conditions is compiled into the same shader program. However, the effect of these larger files on load times and memory usage is usually less significant than the impact of shader variants.
For information about other ways of using conditionals in shaders, and how to decide which technique is right for your use case, see Conditionals in shaders.
Did you find this page useful? Please give it a rating:
Thanks for rating this page!
What kind of problem would you like to report?
Thanks for letting us know! This page has been marked for review based on your feedback.
If you have time, you can provide more information to help us fix the problem faster.
Provide more information
You've told us this page needs code samples. If you'd like to help us further, you could provide a code sample, or tell us about what kind of code sample you'd like to see:
You've told us there are code samples on this page which don't work. If you know how to fix it, or have something better we could use instead, please let us know:
You've told us there is information missing from this page. Please tell us more about what's missing:
You've told us there is incorrect information on this page. If you know what we should change to make it correct, please tell us:
You've told us this page has unclear or confusing information. Please tell us more about what you found unclear or confusing, or let us know how we could make it clearer:
You've told us there is a spelling or grammar error on this page. Please tell us what's wrong:
You've told us this page has a problem. Please tell us more about what's wrong:
Thank you for helping to make the Unity documentation better!
Your feedback has been submitted as a ticket for our documentation team to review.
We are not able to reply to every ticket submitted.
When you visit any website, it may store or retrieve information on your browser, mostly in the form of cookies. This information might be about you, your preferences or your device and is mostly used to make the site work as you expect it to. The information does not usually directly identify you, but it can give you a more personalized web experience. Because we respect your right to privacy, you can choose not to allow some types of cookies. Click on the different category headings to find out more and change our default settings. However, blocking some types of cookies may impact your experience of the site and the services we are able to offer.
More information
These cookies enable the website to provide enhanced functionality and personalisation. They may be set by us or by third party providers whose services we have added to our pages. If you do not allow these cookies then some or all of these services may not function properly.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
These cookies may be set through our site by our advertising partners. They may be used by those companies to build a profile of your interests and show you relevant adverts on other sites. They do not store directly personal information, but are based on uniquely identifying your browser and internet device. If you do not allow these cookies, you will experience less targeted advertising. Some 3rd party video providers do not allow video views without targeting cookies. If you are experiencing difficulty viewing a video, you will need to set your cookie preferences for targeting to yes if you wish to view videos from these providers. Unity does not control this.
These cookies are necessary for the website to function and cannot be switched off in our systems. They are usually only set in response to actions made by you which amount to a request for services, such as setting your privacy preferences, logging in or filling in forms. You can set your browser to block or alert you about these cookies, but some parts of the site will not then work. These cookies do not store any personally identifiable information.