Working with sprites in a 3D world (like on Super Nes)

Questions
#1

Hello,
I’m trying to reproduce my game here in Defold, a “whack a mole” where each pest has a fixed x,y position and a varying z position.
https://pauloud.github.io/FrappHooper/
I wonder if it is possible to use sprites with x,y,z position and orientation and an accurate matrix to automaticaly transform world position into the convenient screen-position and scaling.

And I wonder if it’s possible to change a rectangular sprite into a trapezoid one (so each line hasn’t the same x-scaling)

Thanks folks

#2

Hi!

That would be very easy to do in Defold. I would suggest cutting your trapezoid sprite into four equally sized sections (cut perpendicular to the x axis) then setting the highest up/furthest back one to a Z layer of 0, the middle ones to a Z layer of 0.25, and 0.75 and the lowest down/closest one to 1.

Make the holes in your trapezoid transparent.

Set the z position of the faces to 0.1, 0.26, and 0.76 according to what row they are in.

Should be easy!

Screenshot 2023-01-10 at 13.51.01
Screenshot 2023-01-10 at 13.51.011378×1402 65.9 KB

#3

Thanks for your reply
I didn’t consider splitting it in four, it’s a good idea

I’m not sure to understand what you mean about holes, do you speak about the black holes for the maules, or the white space around ? Should a black hole of the nearest row be attached (in the scene graphe) to the Z=1.0 or the Z=0.75 trapezoid part ?

And if I had a rectangular sprite and I would like to make it non-rectangular at runtime in Defold (or the inverse : trapezoid non-rectangular to rectangular) would it be possible (with a camera or other stuff) ?

Thanks again

#4

I ping you, to be sure you see my above reply,
Sorry if it bothers you.

#5

@ramoneur the alternative to using sprites is to use model or mesh components to get correct perspective correction. There is some discussion about this here: Perpective behavior incoherence - #4 by Dragosha

1 Like
#6

Delete the black holes. Make them transparent.

You can do this very easily by using a 3D camera and perspective (and indeed with meshes and models, if you want to make things really complicated!), but I would suggest first you try the 2D method with Z-layer adjustment first!

#7

Ok thank you both, I’ll tell you what option I’ll have picked

#8

Let us know if you need any more help and show us the final project!

#9

I paused the project, to resume it I would like to do it like this :
Using 2d sprites give each object an x,y,z varying world-position and have the render like this : the y screen-position is a function of y and z game-position
the object is resized depending how it z world-position is
I didn’t find how doing it
Hoping someone could give me the solution
Thanks

#10

A feasible solution I considered : having a x,y,z “world-position” properties but the game engine ignore it’s related to position and I use a regular script to transform this x,y,z position into the screen position and scaling. But I don’t find it very elegant, easy to use and optimized, since computations are made by the CPU and not the GPU

EDIT : I reopened the code, the solution I’ve chosen was to manually create 9 game objects for the 9 holes, I was a bit sad about doing it this way but it works

#11

Ok here is the game, the same link as the old version (the sound is currently loud for the joke, it will probably change in the next days
FrappHooper 2.0

3 Likes
#12

Amazing game. Need part 2