Help please! My game gets slower and slower... and I can't figure out why!

agent4125

Hello - I'm attempting to write a simple Xonix/Qix type game. It's my first try at Godot (Version 3.0.2). I am developing on Ubuntu 64-bit.

Here is my project source:- - https://drive.google.com/file/d/1znAoO3NSjDY97NXqkCEqqGuATaOahJxR/view?usp=sharing

The code takes the design-time filled in rectangles (Polygon2D's) and generates a grid from them of filled in cells (160 x 100). There is then a routine that regenerates the rectangles to render from the cells in the grid.

The player can move around and fill sections by moving into the unfilled area and back into the filled area.

When he reaches the filled area again, his yellow "trail" finishes and the code executes to work out what area to "fill". This then generates more filled "cells" that are added to the grid... then the rects are regenerated from the grid again.

That's it...

It seems to slow down each time I fill an area and finish_trail() is called - and I can't figure out why! finish_trail() is not called excessively (where all the work happens) and the number of rects it is rendering is going up as I expect it to.

After only a few areas are filled, FPS goes down from 200+ to an unbearable 15. The more areas you fill, the slower it gets. :(

Any help much appreciated - Thanks!

PS. Incidentally - this does the same in Godot 2.1.4, but it is MUCH quicker in that, it seems much slower in 3.0.2 (so that's another issue I will need to solve). It still slows down over time, in both versions though.

TwistedTwigleg

I download the project and ran it. I consistently get around 200 FPS minimum, though I start with something close to 1600 FPS.

Here's my computer specs, not sure if it'll help, but it gives something to compare with: OS: Windows 10 (64-bit) CPU: Intel i7 3.40GHz GPU: Nvidia 660 ti 2gb Ram: 8gb

I did notice the FPS drops as you fill areas. Not sure why the FPS drops though, but I only briefly glanced through the code. My hunch is something is being left over when making new rectangles, because there's FPS drops even when the entire screen is filled with only one rectangle.

I might try debugging it later. Without looking really closely at the code I think the performance issue is due to something remaining from previous rectangles.

agent4125

Aaaah... I've got it :)

This code in finish_trail() was (for some reason, probably during testing) accidentally commented: -

# remove all active trail rects (they'll be converted to filled grid cells in the room)
var trail_rects = get_tree().get_nodes_in_group("TrailRects")
for rect in trail_rects:
	rect.queue_free()

This explains it as the trail cells (converted to rects) were never removed but added to each time the trail finished and an area was filled.

However... the other issue I have is that this is WAY slower in general in Godot 3.0.2. In 2.1.4 I get massively higher frame rates (like, twice as high). I thought 3.0.2 was supposed to be faster?

Cheers

TwistedTwigleg

However... the other issue I have is that this is WAY slower in general in Godot 3.0.2. In 2.1.4 I get massively higher frame rates (like, twice as high). I thought 3.0.2 was supposed to be faster?

Godot 3 is faster, depending on your use case.

By using OpenGL 3.3 (and OpenGL 3.0 ES on mobile), Godot can use more modern shaders/graphics code that allows for cooler looking visuals, and smoother performance across the board. However, OpenGL 3 is more intensive than OpenGL 2.

For 3D, there is a decent performance boost from Godot 2 to Godot 3 since there was a lot of workarounds to get OpenGL 2 working nicely with 3D. For 2D, the performance boost is minor, and in some cases (like in your case) performance is lower due to the increased overhead OpenGL 3 creates over OpenGL 2.

Since Godot 3.1 will have OpenGL 2 support, I imagine performance will get much better on the 2D side of things.

(All of what I wrote above is just an educated guess. I know some about graphics programming and how it works in Godot, but not enough to say what is happening for sure)

agent4125

Thanks - makes sense. Hopefully 3.1 not too far away! :)