[Python] Raycasting periodically crashes HP Prime calculator

I have recently been trying to write a more basic, Wolfstein style version of Doom for the HP Prime graphing calculator. I've been using Python for this and successfully got simple 3d working using raycasting. However, the graphing calculator quickly crashes a few seconds after the program is launched. After doing some troubleshooting, it seems like the calculator's RAM is being entirely exhausted. I have tried tinkering with the garbage collection, but when the threshold is adjusted, it often triggers errors seemingly by deleting actual objects used in the code, such as functions.

My calculator is hardware revision D. It is running the most recent firmware version as of writing this question, which was released February of 2025.

Adding wait statements in between the stepping of rays seems to have helped a little, but it is not a good solution due to the heavy amount of time casting large amounts of rays will take.

My code is as follows. I am terribly sorry for it being so messy - it was written on the actual calculator, so writing comments proves to be very difficult.

#PYTHON Doom

import math
import hpprime
import gc
import micropython
micropython.opt_level(3)
gc.enable()
#gc.threshold(1000000)

from builtins import *

"""
grid = [
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
]
"""
grid = [
[0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0],
[0,0,0,0,0,0,0,0,0],
]
class Enemy:
pass

class Player:
def __init__(self,hp,x,y,r,fov=(60),density=10):
self.hp = hp
self.x = x
self.y = y
self.r = r
self.density = density
self.fov = fov * math.pi/180
self.fov2 = self.fov/2
self.fov3 = (self.fov/self.density)


def cast(self):
res = []
for i in range(self.density):
tmp = Ray(self.x,self.y,(self.r-self.fov2)+(self.fov3*i),0.2)
tmp.seek()
res.append(math.sqrt(((tmp.x-self.x)**2)+( (tmp.y-self.y)**2))*math.cos(tmp.r-self.r))
return res

class Ray:
def __init__(self,x,y,r,i):
self.x = x
self.y = y
self.r = r
self.i = i
self.sr = math.sin(self.r) * self.i
self.cr = math.cos(self.r) * self.i


def step(self):
self.x -= self.sr
self.y -= self.cr
if (self.x > len(grid[0])-1) or (self.y > len(grid)-1) or (self.x < 0) or (self.y < 0):
return True #ray is out of bounds
if grid[int(self.y)][int(self.x)] == 1:
return True
return False

def seek(self):
tmp = self.step()
while not tmp:
tmp = self.step()
hpprime.eval("WAIT(0.0003);")
return tmp
hpprime.dimgrob(1,320,240,0)
e = Player(100,3,3,0)
e320 = 320/e.density
while True:
#micropython.mem_info()
hpprime.eval("WAIT(0.015);")
hits = e.cast()
c = 0
hpprime.fillrect(1,0,0,320,240,0,0)
#hpprime.fillrect(1,0,120,320,240,0,0)
p = []
p2 = []
for t in hits:
c+=1

p.append((8-(t))*12)
b = (t*30)*(t/10)
if b > 255:
b = 255
if b < 0:
b = 0
p2.append(b)

for i in range(e.density-1):
x0= (e320)*(i+0.5)
y0= 120+p
x1= (e320)*(i+1.5)
y1= 120+p[i+1]
x2= (e320)*(i+1.5)
y2= 120-p[i+1]
x3= (e320)*(i+0.5)
y3= 120-p
co1=[x0,y0,x1,y1,x2,y2,x3]
co2=""

for v in co1:
co2+=str(v)
co2+=","

co2+=str(y3)
del co1
#hpprime.line(1,(320/e.density)*i,120+p[i-1],(320/e.density)*(i+1),120+p,255)
#hpprime.line(1,(320/e.density)*i,120-p[i-1],(320/e.density)*(i+1),120-p,255)
#hpprime.line(1,(320/e.density)*i,120+p[i-1],(320/e.density)*(i+1),120-p,255)
hpprime.eval("FILLPOLY_P(G1,{"+co2+"},RGB("+str(int(255-p2))+","+str(int(255-p2))+","+str(int(255-p2))+"));")
#print(gc.mem_free())
del p
del p2
if hpprime.keyboard() == 2**7:
e.r -= 0.05
if hpprime.keyboard() == 2**8:
e.r += 0.05
if hpprime.keyboard() == 2**2:
e.x -= math.sin(e.r) * 0.05
e.y -= math.cos(e.r) * 0.05
if grid[int(e.y)][int(e.x)] == 1:
e.x += math.sin(e.r) * 0.06
e.y += math.cos(e.r) * 0.06
if e.x < 0: e.x = 0
if e.y < 0: e.y = 0
if hpprime.keyboard() == 2**12:
e.x += math.sin(e.r) * 0.05
e.y += math.cos(e.r) * 0.05
if grid[int(e.y)][int(e.x)] == 1:
e.x -= math.sin(e.r) * 0.06
e.y -= math.cos(e.r) * 0.06
if e.x < 0: e.x = 0
if e.y < 0: e.y = 0
#hpprime.line(1,160,120,160-10*math.sin(e.r*(math.pi/math.pi)),120-10*math.cos(e.r*(math.pi/math.pi)),255255)
hpprime.blit(0,0,0,1)
#end

EXPORT DOOM()
BEGIN
PYTHON(Doom);
END;

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