Added moving floor, and solved bug of reversed Z in floor texture map…

…ping

ray.asm

@@ -188,18 +188,18 @@ e5:
  fldz
  fcomip ; Remove second operand.
  jbe e6
- fstp st0
  fld dword [bp+var_y]
  fadd dword [si]
- fdiv dword [bp+var_v]
+ fdivrp
  fst dword [bp+var_p] ; Perspective correction.
 
  fmul dword [bp+var_u] ; Adjust coordinates.
  fsubr dword [bp+var_x]
  frndint
  fld dword [bp+var_w]
  fmul dword [bp+var_p]
- fsubr dword [bp+var_z]
+ fadd dword [bp+var_z]
+ fadd dword [bp+var_a] ; Moving floor.
  frndint
  faddp
  fst dword [bp+var_s]
@@ -264,13 +264,13 @@ sphere:
  fmul dword [bp+var_u]
 
  fld dword [bp+var_y] ; Origin of ray.
- fsub dword [bp+var_i] ; Minus sphere position.
+ fsub dword [bp+var_i] ; Minus sphere position.
  fst dword [bp+var_f]
  fmul dword [bp+var_v]
 
  faddp
 
- fld dword [bp+var_z]
+ fld dword [bp+var_z] ; Origin of ray.
  fst dword [bp+var_g]
  fmul dword [bp+var_w]