Week 15: Finished platform-graph save/load and started learning Unity

Precalculating platform graphs and saving them to JSON files!
(I know, very exciting stuff)

tl;dr: I finished implementing platform-graph save/load support, and I started learning Unity.

What happened last week?

Highlights:

• Finished implementing save/load support of platform graphs.
• This gives a huge improvement to load times, since the graph has already been calculated.

If the platform graph file isn't found, the graph is calculated on-demand.

Soooo many lines in one platform-graph save file.

• Started learning how to use Unity!
• I'll talk more about my impressions with Unity in a separate post.

Laundry list:

• Spent a couple hours debugging a strange issue with Godot’s collision engine giving inconsistent (and bogus) results in my precompute screen rather than in the normal game screen.
• The bug:
• Godot shows the collision position as being in the middle of the air, nowhere near any tile.
• However, Godot is detecting the collision as happening in the correct frame—it just reports the wrong position.
• Only repros in precompute mode.
• Level rendered within GUI Control node wrapper.
• Wrapper set to have width/height of zero, clip contents, and have opacity of 0.
• If I change the precompute screen node hierarchy to instead place the level within the same viewport arrangement as in the GameScreen, then Godot's collision calculations work correctly again.
• That led me to believe that the problem stems from me not having the outer viewport configured correctly for Godot’s 2D collision engine to work.
• I think this isn't the first time I've seen issues like this when I had the viewport misconfigured for 3D.
• Added new fonts.
• Added better app-lifecycle events for running things after the initial window size has been set.
• Added some folder-opening utils.
• Include a button in the platform-graph precompute screen for opening the folder where the platform-graph encoding was saved.
• Auto-open the screenshot folder when closing the app if a screenshot was taken.
• Renamed some lingering things from “Scaffold” to “Scaffolder”.
• Finished implementing the first working version of platform-graph precalculation.
• Added support for configuring platform graphs to omit trajectory frame-by-frame position/velocity state.
• This then requires the player to use the mode of instruction-based movement and Godot physics, rather than trajectory state-matching movement.
• I occasionally see a bizarre bug with Godot’s debugger:
• I set a breakpoint somewhere.
• Then Godot infinitely loops at some unrelated getter within that file.
• The loop causes the debugger stacktrace to grow for a few minutes until Godot presumably has a stackoverflow.
• The stacktrace only shows the one getter line repeated.
• The editor and debugger are sorta responsive during this time, but they quickly snap back to the problem line, so it’s not really usable.
• This makes it very difficult to debug things.
• I have a new theory about why this happens:
• Probably during object instantiation, Godot tries to call these getters internally for some reason (even though there is no explicit call from any GDScript lines)
• This has become a problem, since I’ve updated my Edge classes to now sometimes be instantiated with null state, when populating them from JSON state.
• The getters weren’t previously set up to allow this null state.
• So I spent some time replacing getters in my Edge.gd with proper function calls.
• Spent some time debugging how Godot’s JSON parsing creates floats instead of ints for all values.
• Added float-to-int parsing as needed throughout my graph-decoding logic.
• Added a new minimal-string encoding syntax for low-level objects, such as Vector2, Vector3, Rect2, and Color.
• For example, output for Vector2:
• Before: {x:2.2,y:3.3}
• After: "2.2,3.3"
• Some platform-graph encoding metrics:
• "Level 7":
• Old encoding syntax (using JSON objects): 8.46 MB
• New encoding syntax (using minimal strings): 7.99 MB
• New encoding syntax (with trajectory frame-by-frame position/velocity state omitted): 4.34 MB
• Added support for graph-calculation progress bars:
• Updated the precompute screen, the platform-graph parser, and the platform-graph class to all support forcing calculations to split each iteration into a separate frame.
• Then we can update the UI between frames, since the CPU isn’t locked on just the graph calculation.
• GDScript/Python newline cleanup:
• Removed redundant \ when inside parens.
• Removed redundant + for concatenating strings across newlines.
• Created a progress bar screen to show when calculating the level at play time.
• Adjusted some GUI spacing.
• Updated Scaffolder window positioning to always move game window to other monitor if there is a second monitor.
• Fixed a bug in my time calculations when any physics frame takes longer than the expected “fixed” physics framerate.
• https://github.com/godotengine/godot/issues/23974
• Added profiler timing metrics to the platform-graph precompute screen.
• Fixed platform-graph file-loading in HTML exports.
• Fixed issues with initial screen size.

What's next?

• Continue learning how to do 3D stuff in Unity.
• Ludum Dare 48!

🎉 Cheers!