A common technique used in the games industry to analyse the state of a game in development and look for where improvements can be made is to capture a frame(all the GPU work being done between each frame being shown to the user) from the game and analyse the results to see the impact of the different elements on the screen and how they might be able to be rearranged.

In doing this we can look at the relative costs of the different aspects of the processes in the scene. An example of this would be that the programmer suspects that the newly implemented bloom post-effect has had too big an impact on performance. So the programmer grabs a few frames from the game and looks at the time that is being taken to perform that effect at different places in the game, and what the cost of that is relative to the rest of the scene.

Another use for this approach is for new programmers coming onto a complex project to get a quick look at the rendering 'pipeline' that has been implemented. As in, what is rendered when, by what shader and in what order. This is quite useful for someone who only needs to make a minor change on a project.

An interesting side-effect of this is that we are able to frame-capture fully finished games and look at what the code is asking our computer to do and from that derive how the rendering system of that game works to some extent.

In this post we will be looking at Europa Universalis 4(EU4) frame captures and constructing a flow chart of how that game is rendered. EU4 is the forth game in the Europa series from Paradox Interactive released in 2013.

To capture frames from the game we will be using Intel's GPA. GPA is one of the simpler and less detailed frame capturing tools available but is good enough for this example and will allow someone with GPU to be able to follow along if they wish.

(For those interested in more complex capture tools the most popular amongst those I know in industry is RenderDoc, but AMD and NVidia each have there own tools which provide specific functionality for features of their cards in Radeon GPU Profiler and NVIDIA NSight respectively. Microsoft also have a tool called PIX but I haven't personally used that in some time but have heard it works with AMDs tools now.)