So do you have the coordinates of the objects?

So do you have the coordinates of the objects?

Yes, the coordinates of the objects are in a tilemap

I hate when someone says "make a hash" lmao jk.

I really do need to get to work on this now that the static is out of the way.

I was considering looping the angle you are standing at and scanning the distance for objects, but that might be harder than some of the proposed solutions, that I don't entirely get. I may also be able to use trig functions to figure out the area that is viewable, and then check nearby objects to see if points fall in range. If this is indeed ray-casting, I have zero experience. What is the quickest way to do it?

You simply loop through angle values between the left edge of the field of view and the right edge. If you're raycasting for rendering purposes, the step size should usually be set such that one ray is cast for each column of pixels in the output. If you're raycasting for other purposes, it should usually be the largest value that is still small enough not to "miss" seeing objects between two rays.

5 binary degrees seems like it could work to me. If not, you can just decrease it easily enough.

Update: Got a routine. Let me know if I goofed up anywhere:

The routine should create an 11-entry stack for the rendering-routine to process. Each "entry" corresponds to a section of the "screen". Entry 1 is far left, 2 is next to that, and so on. If the renderer hits a $ff, it skips that section of screen. Otherwise, it renders the masked greyscale sprite (which is based through a scale-down routine, based on distance) for that section and moves on.

Feel free to correct/optimize, but let me know what I did wrong so I learn from it :p

#define distance tempSwapArea ; 1 byte
#define rayCurrent distance+1 ; 2 bytes
#define angleCurrent rayEnd+2 ; 1 byte
#define angleStart angleCurrent+1 ; 1 byte
#define angleStop angleStart+1 ; 1 byte
#define iterVector angleStop+1  ; 2 bytes
#define rcStack iterVector+2 ; 2 bytes, a pointer to the start of the raycaster object stack
#define renderDistance 10 ; adjust this to change the render distance
#define priorAngle rcStack+2 ; 1 byte


engine_raycaster_Init:
ld hl,smallEditCol
ld (rcStack),hl ; reset pointer to start of raycaster stack
ld a,(playerDirection)
ld hl,priorAngle
cp (hl)
jr z,{1@}
ld a,b
ld b,5
add a,b
ld (angleStop),a
ld b,-10
add a,b
ld (angleStart),a
@: ld a,(angleStart) ; sorry about this bit, but needs to be here for the jump to work
ld (angleCurrent),a ; shouldnt be too time-consuming to do that
rc_loop_angle:
call _getTempVector
ld a,(playerPosX)
ld h,a
ld a,(playerPosY)
ld l,a
ld bc,(iterVector)
rc_loop_ray:
add hl,bc
call rc_getDistance
ld (distance),a
ld a,l
multAbyWidth
ld c,h
ld b,0
add hl,bc
call rc_getMap
ld a,(hl)
or a
jr z,rc_tilepush_skip
; rc_tilepush: if tile is something, push this object onto rcStack, renderer will handle it
ld de,(rcStack)
ld (de),a ; object type Id
inc de
ld a,(distance)
ld (de),a
inc de
ld (rcStack),de
jr rc_skip_writeempty
rc_tiletest_skip:
ld a,(distance)
cp renderDistance
jr z,rc_loop_angle_next
jr c,rc_loop_angle_next
jr rc_loop_ray
rc_loop_angle_next:
ld de,(rcStack)
ld a,$ff
ld (de),a
inc de
ld (rcStack),de
rc_skip_writeempty:
ld a,(angleCurrent)
inc a
ld (angleCurrent),a
jr rc_loop_angle








rc_getTempVector:
; using current angle, gets vectors. each vector is in 8.8 FP format, so we only save the .8 part
; input: a = angle
; output: new vectors loaded into (iterVector) word
push af
call calcSin ; a = angle
ld (iterVector),l ; hl = 8.8 FP
pop af
call calcCos
ld (iterVector+1),l
ret

rc_getMap:
; input: hl = offset in map
; output: hl points to tile
ld bc,(SlendMapPtr)
add hl,bc
ret

rc_getDistance:
; input: hl = current testing location
; output: a = distance from origin
ret


That does what your code does (and will actually assemble). But i'm not sure if you really wanted to be using playerDirection to add those values to or priorAngle. Probably priorAngle. Shouldn't you at least try to assemble your code first?

I can't comment on the code as a whole because i don't really understand raycasting or what you're trying to do, sorry...

I know there are certain technicalities within it like the ld b,** stuff. However, I want to get the routine conceptually working, then i fix that.
To answer your question about priorAngle, that is actually just a check if whether the current angle and the last angle we calculated are the same. If they are, then we skip the part where we figure out angleStop and the starting angle (which I just found a mistake... angle current needs to be manually set if we do that, or angleStart and angleCurrent need to be separate).

***Edit*** fixed all instances of that, and amended my code to above to reflect

***Edit 2 *** found another mistake. As of now, the raycaster, when calculating the vectors for the present angle, only saves the .8 part of the 8.8FP number. However, in the routine, i add hl (where h= x origin integer and l= y origin integer) to bc (where b is the .8 part of the x vector and c is the .8 part of the y vector). Clearly, that's a mistake, but short of adding more RAM and using the full 8.8 location, i don't see a workaround.