A-Taco-Lypse Driving

Wed, 16 Aug 2017 18:56:19 UTC

A-Taco-Lypse Driving

by LikeTheRogue

[Click to Play]

For LOWREZJAM

Trouble with vertical scrolling loop

Thu, 03 Aug 2017 15:25:08 UTC

Working on a game for LOWREZJAM 2017 and I'm running into some issues with getting the background to scroll up to simulate movement while still maintaining the player's position.

Here is the current issue I'm encountering:

My issue is arising from the camera moving up along the drawn map and snapping back to the bottom when it reaches a certain y value. That works fine for the background but I'm not sure how to get the player to maintain their y position when the map snaps back to the bottom.

The code I've written is as follows:

function _init()
  --renders game at 64x64
  poke(0x5f2c,3)
    cls()

  --creates variable t to store timer info later in code
    t=0

  --establishes boundaries of the level
  level={
    w=64,
    h=250,
    cy=0
  }
  cam_x=0
  cam_y=0
  player = {
    sp=1,
    x=28,
    y=50,
    h=100,
    t=0,
    imm=false
  }
end

function _update()

  --autoscrolling code
  --moves both the level/background and the player at the same speed, to simulate movement
  if level.cy<level.h-64 then
    level.cy-=2
    player.y-=2
  end

  --statement that will trigger invincibility frames
  --inactive atm
 if player.imm then
   player.t += 1
   if player.t >30 then
     player.imm = false
     player.t = 0
   end
 end

  --timer and statement that flickers back and forth between sprites to simulate movement
  t=t+1
    if(t%8<3) then
        player.sp=1
    else
        player.sp=2
    end

  --basic movement code
    if btn(0) then player.x-=1 end
    if btn(1) then player.x+=1 end
    if btn(2) then player.y-=1 end
    if btn(3) then player.y+=1 end
end

function _draw()
  cls()
  --camera that follows level's movement
  --also keeps player on screen
  camera(0,level.cy)
  if level.cy<-80 then
    level.cy=0
    player.y=50
  end
  --draws map, extended to -100 to allow for longer stretch of road
  map(0,0,0,-100,12,63)
  --draws player car
  spr(player.sp,player.x,player.y,.75,2)
end

I'm still fairly new to programming so good coding practices and math functions aren't things I'm entirely familiar with yet. If anyone could help me figure out what tools I should look into to solve my problem or different approaches I should be taking with vertical scrolling loops, I'd greatly appreciate it!

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A-Taco-Lypse Driving

Trouble with vertical scrolling loop