Exploring the limits of Lua sprites

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This repository includes 9 lua files. Each can be renamed to main.lua and put into your project's Source folder. Play around with the number of sprites and what each sprite does to make new discoveries!

Summary

In each file, the refresh rate is set to 50 FPS and an effective frame rate of 48-50 FPS is achieved. In each file except overlapping-call-main.lua and overlapping-collisions-main.lua, the sprite update function is assigned directly to playdate.update. In overlapping-call-main.lua and overlapping-collisions-main.lua, a function that calls the playdate sprite update and allOverlappingSprites functions is assigned to playdate.update.

  • empty-sprite-main.lua
    • 500 empty sprites.
  • image-sprite-main.lua
    • 476 sprites with the same image (a 40px black square).
  • movement-main.lua
    • 200 instances of a class that extends the Playdate sprite class. The update method uses moveTo with the sprite's dx and dy values added to its x and y values.
  • collision-movement-main.lua
    • 40 instances of a class that extends the Playdate sprite class. The update method uses moveWithCollisions with the sprite's dx and dy values added to its x and y values. Each has a collide rect of 1x1, groups = {1}, and collidesWithGroups = {2}.
  • collision-movement-collisions-main.lua
    • 40 instances of a class that extends the Playdate sprite class. The update method uses moveWithCollisions with the sprite's dx and dy values added to its x and y values. Each has a collide rect of 1x1, groups = {1}, and collidesWithGroups = {1}.
  • mixed-main.lua
    • 20 instances of a class that extends the Playdate sprite class. The update method uses moveWithCollisions with the sprite's dx and dy values added to its x and y values. Each has a collide rect of 1x1, groups = {1}, and collidesWithGroups = {2}.
    • 100 instances of a class that extends the Playdate sprite class. The update method uses moveTo with the sprite's dx and dy values added to its x and y values.
    • 125 empty sprites.
  • overlapping-call-main.lua
    • 95 instances of a class that extends the Playdate sprite class. The update method uses moveTo with the sprite's dx and dy values added to its x and y values.
    • allOverlappingSprites is called in the playdate.update function.
  • overlapping-collisions-main.lua
    • 8 instances of a class that extends the Playdate sprite class. The update method uses moveTo with the sprite's dx and dy values added to its x and y values. Each has a collide rect of 1x1, groups = {1}, and collidesWithGroups = {1}.
    • allOverlappingSprites is called in the playdate.update function.
  • overlapping-sprites-main.lua
    • 21 instances of a class that extends the Playdate sprite class. The update method uses moveTo with the sprite's dx and dy values added to its x and y values, then it calls sprite:overlappingSprites. Each has a collide rect of 1x1, groups = {1}, and collidesWithGroups = {1}.

Conclusions

Collision detection is an expensive operation. Although moveTo is faster than moveWithCollisions, using moveTo with either of the overlapping sprite functions scales worse than using only moveWithCollisions.

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