forked from KolibriOS/kolibrios
343 lines
6.6 KiB
NASM
343 lines
6.6 KiB
NASM
CATMULL_SHIFT equ 16
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fill_Z_buffer:
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mov eax,0x70000000
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mov edi,Z_buffer
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mov ecx,SIZE_X*SIZE_Y
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rep stosd
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ret
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flat_triangle_z:
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; procedure drawing triangle with Z cordinate interpolation ------
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; (Catmull alghoritm)--------------------------------------------
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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 - color 0x00RRGGBB --------------------
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; -------------------- esi - pointer to Z-buffer -----------------
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; -------------------- edi - pointer to screen buffer-------------
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; -------------------- stack : z coordinates
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; -------------------- Z-buffer : each z variable as dword
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; -------------------- (Z coor. as word) shl CATMULL_SHIFT
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.z1 equ word[ebp+4]
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.z2 equ word[ebp+6] ; each z coordinate as word integer
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.z3 equ word[ebp+8]
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.col equ dword[ebp-4]
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.x1 equ word[ebp-6]
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.y1 equ word[ebp-8]
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.x2 equ word[ebp-10]
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.y2 equ word[ebp-12]
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.x3 equ word[ebp-14]
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.y3 equ word[ebp-16]
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.dx12 equ dword[ebp-20]
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.dz12 equ dword[ebp-24]
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.dx13 equ dword[ebp-28]
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.dz13 equ dword[ebp-32]
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.dx23 equ dword[ebp-36]
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.dz23 equ dword[ebp-40]
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.zz1 equ dword[ebp-44]
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.zz2 equ dword[ebp-48]
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mov ebp,esp
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push edx ; store edx in variable .col
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.sort2:
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cmp ax,bx
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jle .sort1
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xchg eax,ebx
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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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.sort1:
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cmp bx,cx
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jle .sort3
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xchg ebx,ecx
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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 .sort2
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.sort3:
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push eax ; store triangle coordinates in 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 .ft_loop2_end
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; cmp ax,SIZE_Y
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; jle @f
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; cmp bx,SIZE_Y
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; jle @f
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; cmp cx,SIZE_Y
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; jge @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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; jle @f
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; cmp bx,SIZE_X
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; jle @f
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; cmp cx,SIZE_X
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; jle @f
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; jmp .ft_loop2_end
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;@@:
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sub esp,32
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mov bx,.y2 ; calc delta 12
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sub bx,.y1
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jnz .ft_dx12_make
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mov .dx12,0
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mov .dz12,0
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jmp .ft_dx12_done
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.ft_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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movsx ebx,bx
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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
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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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mov .dz12,eax
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.ft_dx12_done:
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mov bx,.y3 ; calc delta 13
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sub bx,.y1
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jnz .ft_dx13_make
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mov .dx13,0
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mov .dz13,0
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jmp .ft_dx13_done
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.ft_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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movsx ebx,bx
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shl eax,ROUND
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cdq
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idiv ebx
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mov .dx13,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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mov .dz13,eax
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.ft_dx13_done:
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mov bx,.y3 ; calc delta 23
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sub bx,.y2
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jnz .gt_dx23_make
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mov .dx23,0
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mov .dz23,0
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jmp .gt_dx23_done
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.gt_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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movsx ebx,bx
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shl eax,ROUND
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cdq
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idiv ebx
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mov .dx23,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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mov .dz23,eax
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.gt_dx23_done:
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movsx edx,.z1
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shl edx,CATMULL_SHIFT
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mov .zz1,edx
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mov .zz2,edx
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movsx eax,.x1
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shl eax,ROUND ; eax - x1
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mov ebx,eax ; ebx - x2
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mov cx,.y1
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cmp cx,.y2
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jge .ft_loop1_end
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.ft_loop1:
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pushad
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push .col
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push cx ; y
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sar ebx,ROUND
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push bx ; x2
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sar eax,ROUND
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push ax ; x1
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push .zz2 ; z2 shl CATMULL_SHIFT
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push .zz1 ; z1 shl CATMULL_SHIFT
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call flat_line_z
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popad
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add eax,.dx13
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add ebx,.dx12
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mov edx,.dz13
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add .zz1,edx
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mov edx,.dz12
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add .zz2,edx
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inc cx
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cmp cx,.y2
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jl .ft_loop1
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.ft_loop1_end:
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movsx edx,.z2
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shl edx,CATMULL_SHIFT
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mov .zz2,edx
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movsx ebx,.x2
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shl ebx,ROUND
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mov cx,.y2
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cmp cx,.y3
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jge .ft_loop2_end
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.ft_loop2:
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pushad
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push .col
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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 ; x1
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push .zz2 ; z2 shl CATMULL_SHIFT
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push .zz1 ; z1 shl CATMULL_SHIFT
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call flat_line_z
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popad
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add eax,.dx13
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add ebx,.dx23
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mov edx,.dz13
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add .zz1,edx
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mov edx,.dz23
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add .zz2,edx
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inc cx
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cmp cx,.y3
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jl .ft_loop2
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.ft_loop2_end:
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mov esp,ebp
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ret 6
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flat_line_z:
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;----------------
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;-------------in edi - pointer to screen buffer ----------------------------------
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;--------------- esi - pointer to z-buffer (each Z varible dword)-----------------
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;----------stack - (each z coordinate shifted shl CATMULL_SHIFT)------------------
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.z1 equ dword [ebp+4]
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.z2 equ dword [ebp+8]
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.x1 equ word [ebp+12]
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.x2 equ word [ebp+14]
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.y equ word [ebp+16]
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.col equ dword [ebp+18]
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.dz equ dword [ebp-4]
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mov ebp,esp
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;; sub esp,4
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mov ax,.y
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or ax,ax
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jl .fl_quit
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cmp ax,SIZE_Y-1
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jg .fl_quit
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; cmp .x1,0
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; jge .fl_ok1
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; cmp .x2,0
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; jl .fl_quit
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; .fl_ok1:
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; cmp .x1,SIZE_X
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; jle .fl_ok2
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; cmp .x2,SIZE_X
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; jg .fl_quit
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; .fl_ok2:
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mov ax,.x1
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cmp ax,.x2
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je .fl_quit
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jl .fl_ok
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xchg ax,.x2
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mov .x1,ax
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mov edx,.z1
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xchg edx,.z2
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mov .z1,edx
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.fl_ok:
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cmp .x1,SIZE_X-1
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jg .fl_quit
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cmp .x2,0
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jle .fl_quit
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mov eax,.z2
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sub eax,.z1
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cdq
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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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idiv ebx
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;; mov .dz,eax ; calculated delta - shifted .dz
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push eax
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cmp .x1,0
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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
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add .z1,eax
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mov .x1,0
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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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mov edx,SIZE_X
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movsx eax,.y
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mul edx ; edi = edi + (SIZE_X * y + x1)*3
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movsx edx,.x1
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add eax,edx
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push eax
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lea eax,[eax*3]
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add edi,eax ; esi = esi + (SIZE_X * y + x1)*4
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pop eax
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shl eax,2
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add esi,eax
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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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mov eax,.col
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mov ebx,.z1 ; ebx : curr. z
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mov edx,.dz
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.ddraw:
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;pushad
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;show
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;popad
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cmp ebx,dword[esi]
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jge .skip
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stosd
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dec edi
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mov dword[esi],ebx
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jmp .no_skip
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.skip:
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add edi,3
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.no_skip:
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add esi,4
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add ebx,edx
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loop .ddraw
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.fl_quit:
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mov esp,ebp
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ret 18
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