From bbdd84afef3694dadfa2bb08c4d0b4ebee8f81dd Mon Sep 17 00:00:00 2001
From: Uko Kokņevičs
Date: Tue, 27 Sep 2022 22:59:22 +0300
Subject: Performance improvements

---
 sneed.p8 | 47 +++++++++++++++++++++--------------------------
 1 file changed, 21 insertions(+), 26 deletions(-)

diff --git a/sneed.p8 b/sneed.p8
index fb29349..e66a476 100644
--- a/sneed.p8
+++ b/sneed.p8
@@ -9,6 +9,8 @@ pl = {
    ["a"] = 0.7,
 }
 
+sprite_size = 8
+
 -- low quality raycast
 -- returns x, y :: the coordinates of the tile that was hit
 function shit_cast(x, y, dx, dy)
@@ -74,45 +76,38 @@ function cast(x, y, a)
 end
 
 -- returns
--- + dist :: distance to the hit
--- + tile :: tile index
--- + col  :: tile column index
+-- + dist   :: distance to the hit
+-- + sprite :: index in spritemap
 function ray(x, y, a)
    local tx, ty, lx, ly, dist = cast(x, y, a)
-   local tile = mget(tx, ty)
+   local sprite = mget(tx, ty)
 
    if lx == 0 then
-      return dist, tile, 1-ly
+      return dist, sprite_size * (sprite + 1 - ly)
    elseif lx == 1 then
-      return dist, tile, ly
+      return dist, sprite_size * (sprite + ly)
    elseif ly == 0 then
-      return dist, tile, lx
+      return dist, sprite_size * (sprite + lx)
    else
-      return dist, tile, 1-lx
+      return dist, sprite_size * (sprite + 1 - lx)
    end
 end
 
+function _init()
+   -- I use index 0 (black) in my sprites
+   palt(0, false)
+end
 
 function _draw()
    cls(12)
-   local col
-   for col=0,1-1/128,1/128 do
-      local c,d,da,h,x,y,t
-      da = col*fov-fov/2
-      d,t,c = ray(pl.x,pl.y,pl.a+da)
-      c *= 8
-      d = d*cos(da)
-      h = flr(128/d)
-      x = 128*col
-      y = (128-h)/2
-      for row=0,1-1/8,1/8 do
-         local tc, sy, ey
-         tc = sget(8*t+c,row*8)
-         sy = y+row*h
-         ey = y+(row+1/8)*h
-         line(x,sy,x,ey,tc)
-      end
-      line(x, h+y, x, 128, 3)
+   rectfill(0, 64, 128, 128, 3)
+   local x
+   for x = 0, 127 do
+      local da = x * fov / 128 - fov / 2
+      local dist, sprite = ray(pl.x, pl.y, pl.a + da)
+      local height = 128 / (dist * cos(da) + 0.1)
+      local y = (128 - height) / 2
+      sspr(sprite, 0, 1, sprite_size, x, y, 1, height)
    end
 
    ?"cpu "..(stat(1)*100).."%",0,0,7
-- 
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