GPU Graphics: Make Changes to a Shader
Make changes to a shader program during a debug session.
Run the app on an iOS device, and capture a frame.
In the GPU graphics call trace, select the call you’re interested in.
In the assistant editor jump bar, choose one of the Function call types that you’re interested in.
From the first segment after the Function segment in the assistant jump bar, choose the shader you want to modify.
Modify the shader program code, and click Update Shaders.
Making shader program modifications in a debug session lets you try several changes to find out which ones provide the best results. When you click Update Shaders, Xcode rebuilds the code. The objects then reflect the effect of the change.
Resume app execution to see the effect of the change in the running app.