586 lines
10 KiB
NASM
586 lines
10 KiB
NASM
;TEX_X = 512
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;TEX_Y = 512
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;ROUND equ 8
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;SIZE_X = 512
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;SIZE_Y = 512
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;TEX_SHIFT = 9
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CATMULL_SHIFT equ 8
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;------------------------------------------------------------------------
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;- Procedure drawing textured triangle using Catmull Z-buffer algorithm -
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;------------------------------------------------------------------------
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tex_triangle_z:
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;----------in - eax - x1 shl 16 + y1
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;-------------- ebx - x2 shl 16 + y2
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;---------------ecx - x3 shl 16 + y3
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;---------------edx - pointer to Z-buffer
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;---------------esi - pointer to texture buffer
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;---------------edi - pointer to screen buffer
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;-------------stack - texture coordinates
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;------------------ - z coordinates
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.tex_x1 equ ebp+4
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.tex_y1 equ ebp+6
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.tex_x2 equ ebp+8
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.tex_y2 equ ebp+10
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.tex_x3 equ ebp+12
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.tex_y3 equ ebp+14
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.z1 equ word[ebp+16]
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.z2 equ word[ebp+18]
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.z3 equ word[ebp+20]
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.tex_ptr equ dword[ebp-4] ; pointer to texture
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.z_ptr equ dword[ebp-8] ; pointer to z-buffer
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.x1 equ word[ebp-10]
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.y1 equ word[ebp-12]
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.x2 equ word[ebp-14]
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.y2 equ word[ebp-16]
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.x3 equ word[ebp-18]
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.y3 equ word[ebp-20]
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.dx12 equ dword[ebp-24]
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.tex_dx12 equ dword[ebp-28]
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.tex_dy12 equ dword[ebp-32]
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.dz12 equ dword[ebp-36]
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.dx13 equ dword[ebp-40]
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.tex_dx13 equ dword[ebp-44]
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.tex_dy13 equ dword[ebp-48]
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.dz13 equ dword[ebp-52]
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.dx23 equ dword[ebp-56]
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.tex_dx23 equ dword[ebp-60]
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.tex_dy23 equ dword[ebp-64]
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.dz23 equ dword[ebp-68]
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.scan_x1 equ dword[ebp-72]
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.scan_x2 equ dword[ebp-76]
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.scan_y1 equ dword[ebp-80]
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.scan_y2 equ dword[ebp-84]
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.cz1 equ dword[ebp-88]
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.cz2 equ dword[ebp-92]
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mov ebp,esp
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push esi ; store memory pointers
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push edx
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.tt_sort3:
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cmp ax,bx ;sort all parameters
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jle .tt_sort1
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xchg eax,ebx
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mov edx,dword [.tex_x1]
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xchg edx,dword [.tex_x2]
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mov dword[.tex_x1],edx
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mov dx,.z1
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xchg dx,.z2
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mov .z1,dx
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.tt_sort1:
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cmp bx,cx
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jle .tt_sort2
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xchg ebx,ecx
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mov edx,dword [.tex_x2]
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xchg edx,dword [.tex_x3]
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mov dword [.tex_x2],edx
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mov dx,.z2
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xchg dx,.z3
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mov .z2,dx
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jmp .tt_sort3
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.tt_sort2:
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push eax ; and store to user friendly variables
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push ebx
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push ecx
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mov edx,80008000h ; eax,ebx,ecx are ANDd together into edx which means that
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and edx,ebx ; if *all* of them are negative a sign flag is raised
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and edx,ecx
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and edx,eax
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test edx,80008000h ; Check both X&Y at once
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jne .tt_loop2_end
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cmp ax,SIZE_Y
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jl @f
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cmp bx,SIZE_Y
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jl @f
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cmp cx,SIZE_Y
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jl @f
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ror eax,16
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ror ebx,16
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ror ecx,16
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cmp ax,SIZE_X
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jl @f
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cmp bx,SIZE_X
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jl @f
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cmp cx,SIZE_X
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jl @f
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jmp .tt_loop2_end
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@@:
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mov eax,dword[.tex_x1] ; texture coords must be in [0..TEX_X(Y)]
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mov ebx,dword[.tex_x2]
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mov ecx,dword[.tex_x3]
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mov edx,eax
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or edx,ebx
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or edx,ecx
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test edx,80008000h
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jne .tt_loop2_end
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cmp ax,TEX_X
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jge .tt_loop2_end
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cmp bx,TEX_X
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jge .tt_loop2_end
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cmp cx,TEX_X
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jge .tt_loop2_end
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ror eax,16
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ror ebx,16
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ror ecx,16
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cmp ax,TEX_Y
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jge .tt_loop2_end
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cmp bx,TEX_Y
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jge .tt_loop2_end
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cmp cx,TEX_Y
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jge .tt_loop2_end
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movsx ebx,.y2 ; calc delta
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sub bx,.y1
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jnz .tt_dx12_make
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xor edx,edx
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mov ecx,4
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@@:
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push edx
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loop @b
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jmp .tt_dx12_done
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.tt_dx12_make:
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mov ax,.x2
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sub ax,.x1
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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; mov .dx12,eax ; dx12 = (x2-x1)/(y2-y1)
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push eax
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mov ax,word[.tex_x2]
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sub ax,word[.tex_x1]
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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; mov [.tex_dx12],eax ; tex_dx12 = (tex_x2-tex_x1)/(y2-y1)
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push eax
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mov ax,word[.tex_y2]
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sub ax,word[.tex_y1]
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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; mov [.tex_dy12],eax ; tex_dy12 = (tex_y2-tex_y1)/(y2-y1)
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push eax
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mov ax,.z2
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sub ax,.z1
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cwde
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shl eax,CATMULL_SHIFT
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cdq
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idiv ebx
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push eax
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.tt_dx12_done:
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movsx ebx,.y3 ; calc delta
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sub bx,.y1
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jnz .tt_dx13_make
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xor edx,edx
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mov ecx,4
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@@:
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push edx
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loop @b
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jmp .tt_dx13_done
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.tt_dx13_make:
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mov ax,.x3
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sub ax,.x1
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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; mov .dx12,eax ; dx13 = (x3-x1)/(y3-y1)
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push eax
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mov ax,word[.tex_x3]
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sub ax,word[.tex_x1]
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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; mov [.tex_dx12],eax ; tex_dx13 = (tex_x3-tex_x1)/(y3-y1)
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push eax
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mov ax,word[.tex_y3]
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sub ax,word[.tex_y1]
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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; mov [.tex_dy12],eax ; tex_dy13 = (tex_y3-tex_y1)/(y3-y1)
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push eax
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mov ax,.z3
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sub ax,.z1
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cwde
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shl eax,CATMULL_SHIFT
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cdq
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idiv ebx
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push eax
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.tt_dx13_done:
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mov bx,.y3 ; calc delta
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sub bx,.y2
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jnz .tt_dx23_make
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xor edx,edx
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mov ecx,4
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@@:
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push edx
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loop @b
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jmp .tt_dx23_done
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.tt_dx23_make:
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mov ax,.x3
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sub ax,.x2
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cwde
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shl eax,ROUND
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cdq
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movzx ebx,bx
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idiv ebx
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; mov .dx23,eax ; dx23 = (x3-x2)/(y3-y2)
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push eax
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mov ax,word[.tex_x3]
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sub ax,word[.tex_x2]
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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; mov [.tex_dx23],eax ; tex_dx23 = (tex_x3-tex_x2)/(y3-y2)
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push eax
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mov ax,word[.tex_y3]
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sub ax,word[.tex_y2]
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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; mov [.tex_dy23],eax ; tex_dy23 = (tex_y3-tex_y2)/(y3-y2)
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push eax
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mov ax,.z3
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sub ax,.z2
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cwde
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shl eax,CATMULL_SHIFT
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cdq
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idiv ebx
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push eax
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.tt_dx23_done:
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movsx eax,.x1 ;eax - cur x1
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shl eax,ROUND ;ebx - cur x2
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mov ebx,eax
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movsx edx, word[.tex_x1]
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shl edx,ROUND
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; mov [.scan_x1],edx
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; mov [.scan_x2],edx
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push edx
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push edx
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movsx edx, word[.tex_y1]
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shl edx,ROUND
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; mov [.scan_y1],edx
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; mov [.scan_y2],edx
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push edx
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push edx
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movsx edx,.z1
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shl edx,CATMULL_SHIFT
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push edx
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push edx
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mov cx,.y1
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cmp cx,.y2
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jge .tt_loop1_end
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.tt_loop1:
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pushad
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push .z_ptr
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push .cz1 ; z coords shifted shl catmull_shift
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push .cz2
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mov edx, .scan_y2
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sar edx, ROUND
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push dx
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mov edx, .scan_x2
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sar edx, ROUND
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push dx
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mov edx, .scan_y1
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sar edx, ROUND
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push dx
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mov edx, .scan_x1
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sar edx, ROUND
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push dx
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push esi ;[.tex_ptr]
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push cx
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sar ebx,ROUND
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push bx
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sar eax,ROUND
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push ax
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call textured_line_z
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popad
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mov edx,.dz13
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add .cz1,edx
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mov edx,.dz12
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add .cz2,edx
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mov edx, .tex_dx13
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add .scan_x1, edx
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mov edx, .tex_dx12
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add .scan_x2, edx
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mov edx, .tex_dy13
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add .scan_y1, edx
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mov edx, .tex_dy12
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add .scan_y2, edx
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add eax, .dx13
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add ebx, .dx12
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inc cx
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cmp cx,.y2
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jl .tt_loop1
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.tt_loop1_end:
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mov cx,.y2
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cmp cx,.y3
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jge .tt_loop2_end
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movsx ebx,.x2
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shl ebx,ROUND
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movsx edx,.z2
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shl edx,CATMULL_SHIFT
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mov .cz2,edx
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movzx edx, word [.tex_x2]
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shl edx,ROUND
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mov .scan_x2,edx
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movzx edx, word[.tex_y2]
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shl edx,ROUND
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mov .scan_y2,edx
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.tt_loop2:
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pushad
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push .z_ptr
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push .cz1 ; z coords shifted shl catmull_shift
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push .cz2
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mov edx, .scan_y2
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sar edx, ROUND
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push dx
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mov edx, .scan_x2
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sar edx, ROUND
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push dx
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mov edx, .scan_y1
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sar edx, ROUND
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push dx
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mov edx, .scan_x1
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sar edx, ROUND
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push dx
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push esi ;[.tex_ptr]
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push cx
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sar ebx,ROUND
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push bx
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sar eax,ROUND
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push ax
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call textured_line_z
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popad
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mov edx,.dz13
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add .cz1,edx
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mov edx,.dz23
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add .cz2,edx
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mov edx, .tex_dx13
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add .scan_x1, edx
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mov edx, .tex_dx23
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add .scan_x2, edx
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mov edx, .tex_dy13
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add .scan_y1, edx
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mov edx, .tex_dy23
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add .scan_y2, edx
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add eax, .dx13
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add ebx, .dx23
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inc cx
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cmp cx,.y3
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jl .tt_loop2
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.tt_loop2_end:
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.tt_end:
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mov esp,ebp
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ret 18
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textured_line_z:
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;-----in -edi screen buffer pointer
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;------------ stack:
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.x1 equ word [ebp+4]
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.x2 equ word [ebp+6]
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.y equ word [ebp+8]
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.tex_ptr equ dword [ebp+10]
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.tex_x1 equ ebp+14
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.tex_y1 equ ebp+16
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.tex_x2 equ ebp+18
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.tex_y2 equ ebp+20
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.z2 equ dword [ebp+22] ;z1, z2 coords shifted shl CATMULL_SHIFT
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.z1 equ dword [ebp+26]
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.z_ptr equ dword [ebp+30]
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.tex_dx equ dword [ebp-4]
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.tex_dy equ dword [ebp-8]
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.dz equ dword [ebp-12]
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.cz equ dword [ebp-16]
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.c_tex_x equ dword [ebp-20] ; current tex x
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mov ebp,esp
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mov ax,.y
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or ax,ax
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jl .tl_quit
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cmp ax,SIZE_Y
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jge .tl_quit
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mov ax,.x1
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cmp ax,.x2
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je .tl_quit
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jl .tl_ok
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xchg ax,.x2 ; sort params
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mov .x1,ax
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mov eax,dword[.tex_x1]
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xchg eax,dword[.tex_x2]
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mov dword[.tex_x1],eax
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mov eax,.z1
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xchg eax,.z2
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mov .z1,eax
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.tl_ok:
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cmp .x1,SIZE_X
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jge .tl_quit
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cmp .x2,0
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jle .tl_quit
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mov bx,.x2
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sub bx,.x1
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movsx ebx,bx
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mov ax,word[.tex_x2] ; calc .dtx
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sub ax,word[.tex_x1]
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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push eax
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mov ax,word[.tex_y2] ; calc .dty
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sub ax,word[.tex_y1]
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cwde
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shl eax,ROUND
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cdq
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idiv ebx
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push eax
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mov eax,.z2 ; calc .dz
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sub eax,.z1
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cdq
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idiv ebx
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push eax
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cmp .x1,0 ; clipping
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jge @f
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movsx ebx,.x1
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neg ebx
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imul ebx ; eax = .dz * abs(.x1)
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add .z1,eax
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mov .x1,0
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mov eax,.tex_dy
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sar eax,ROUND
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imul ebx
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add word[.tex_y1],ax
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mov eax,.tex_dx
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sar eax,ROUND
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imul ebx
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add word[.tex_x1],ax
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@@:
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cmp .x2,SIZE_X
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jl @f
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mov .x2,SIZE_X
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@@:
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movsx ebx,.y ; calc mem begin in buffers
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mov eax,SIZE_X
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mul ebx
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movsx ebx,.x1
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add eax,ebx
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mov ebx,eax
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lea eax,[eax*3]
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add edi,eax ; edi - scr buff
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shl ebx,2
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add .z_ptr,ebx ; z buffer pointer
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mov cx,.x2
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sub cx,.x1
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movzx ecx,cx
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movzx eax,word[.tex_x1]
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shl eax,ROUND
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movzx ebx,word[.tex_y1]
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shl ebx,ROUND
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push .z1 ; .cz
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push eax ;.c_tex_x
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.tl_loop:
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mov edx,.z_ptr ; eax - temp
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mov eax,.cz ; ebx - cur tex y shl ROUND
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cmp eax,[edx] ; ecx - l.lenght
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jge .skip ; ebx - cur tex_y ; edx - temp
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mov esi,ebx ; edi - scr buff
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sar esi,ROUND ; esi - tex_ptr temp
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shl esi,TEX_SHIFT ; .z_ptr - cur pointer to z buff
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mov eax,.c_tex_x ; .cz - cur z coord shl CATMULL_SHIFT
|
|
sar eax,ROUND
|
|
add esi,eax
|
|
and esi,TEXTURE_SIZE
|
|
lea esi,[esi*3]
|
|
add esi,.tex_ptr
|
|
movsd
|
|
dec edi
|
|
mov eax,.cz
|
|
mov esi,.z_ptr
|
|
mov dword[esi],eax ; renew z buffer
|
|
jmp .no_skip
|
|
.skip:
|
|
add edi,3
|
|
.no_skip:
|
|
add .z_ptr,4
|
|
mov eax,.dz
|
|
add .cz,eax
|
|
mov eax,.tex_dx
|
|
add .c_tex_x,eax
|
|
add ebx,.tex_dy
|
|
loop .tl_loop
|
|
.tl_quit:
|
|
mov esp,ebp
|
|
ret 30
|
|
|