forked from KolibriOS/kolibrios
189 lines
3.5 KiB
NASM
189 lines
3.5 KiB
NASM
draw_triangle:
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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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;---------------edi - pointer to screen buffer
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@ch3:
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cmp ax,bx
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jg @ch1
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@ch4: ; sort parameters
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cmp bx,cx
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jg @ch2
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jle @chEnd
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@ch1:
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xchg eax,ebx
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jmp @ch4
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@ch2:
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xchg ebx,ecx
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jmp @ch3
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@chEnd:
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mov dword[@y1],eax ; ....and store to user friendly variables
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mov dword[@y2],ebx
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mov dword[@y3],ecx
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mov [@col],edx
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mov edx,eax ; eax,ebx,ecx are ORd together into edx which means that
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or edx,ebx ; if any *one* of them is negative a sign flag is raised
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or edx,ecx
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test edx,80008000h ; Check both X&Y at once
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jne @end_triangle
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cmp [@x1],SIZE_X ; {
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jg @end_triangle
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cmp [@x2],SIZE_X ; This can be optimized with effort
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jg @end_triangle
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cmp [@x3],SIZE_X
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jg @end_triangle ; }
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shr eax,16
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shr ebx,16
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shr ecx,16
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neg ax ; calculate delta 12
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add ax,bx
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cwde
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shl eax,ROUND
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cdq
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mov bx,[@y2]
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mov cx,[@y1]
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sub bx,cx
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;cmp ebx,0
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jne @noZero1
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mov [@dx12],0
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jmp @yesZero1
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@noZero1:
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idiv ebx
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mov [@dx12],eax
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@yesZero1:
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mov ax,[@x3] ; calculate delta 13
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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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mov bx,[@y3]
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mov cx,[@y1]
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sub bx,cx
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;cmp ebx,0
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jne @noZero2
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mov [@dx13],0
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jmp @yesZero2
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@noZero2:
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idiv ebx
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mov [@dx13],eax
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@yesZero2:
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mov ax,[@x3] ; calculate delta 23 [dx23]
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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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mov bx,[@y3]
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mov cx,[@y2]
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sub bx,cx
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;cmp ebx,0
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jne @noZero3
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mov [@dx23],0
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jmp @yesZero3
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@noZero3:
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idiv ebx
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mov [@dx23],eax
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@yesZero3:
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movzx eax,word[@x1] ; eax - xk1
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shl eax,ROUND
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mov ebx,eax ; ebx - xk2
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movzx esi,word[@y1] ; esi - y
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@next_line1:
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mov ecx,eax ; ecx - x11
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sar ecx,ROUND
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mov edx,ebx ; edx - x12
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sar edx,ROUND
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cmp ecx,edx
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jle @nochg
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xchg ecx,edx
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@nochg:
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pusha
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mov ebx,ecx
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sub edx,ecx
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mov ecx,edx
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mov edx,esi
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mov eax,[@col]
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call @horizontal_line
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popa
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add eax,[@dx13]
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add ebx,[@dx12]
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inc esi
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cmp si,[@y2]
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jl @next_line1
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movzx esi,word[@y2]
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movzx ebx,word[@x2]
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shl ebx,ROUND
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@next_line2:
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mov ecx,eax
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sar ecx,ROUND
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mov edx,ebx
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sar edx,ROUND
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cmp ecx,edx
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jle @nochg1
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xchg ecx,edx
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@nochg1:
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pusha
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mov ebx,ecx
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sub edx,ecx
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mov ecx,edx
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mov edx,esi
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mov eax,[@col]
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call @horizontal_line
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popa
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add eax,[@dx13]
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add ebx,[@dx23]
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inc esi
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cmp si,[@y3]
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jl @next_line2
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@end_triangle:
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ret
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@horizontal_line:
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;---------in
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;---------eax - color of line, 0x00RRGGBB
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;---------ebx - x1 - x position of line begin
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;---------ecx - lenght of line
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;---------edx - y position of line
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;---------edi - pointer to buffer
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jcxz @end_hor_l
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; or edx,edx
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; jl @end_hor_l
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cmp edx,SIZE_Y
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jg @end_hor_l
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push eax
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mov eax,SIZE_X*3
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mul edx
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add edi,eax ; calculate line begin adress
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;add edi,ebx
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;shl ebx,1
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lea edi,[edi+ebx*2]
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add edi,ebx
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pop eax
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cld
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;mov dword[edi-3],0000FF00h
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@ddraw: ; Drawing horizontally:
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;push eax
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stosd ; 4 bytes at a time
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dec edi ; point to the 4th
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;shr eax,16
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;stosb
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;pop eax
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;pusha ; If you want to draw pixel-by-pixel
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; mov eax,7 ; put image
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; mov ebx,screen
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; mov ecx,SIZE_X shl 16 + SIZE_Y
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; mov edx,5 shl 16 + 20
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; int 0x40
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;popa
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loop @ddraw
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mov byte[edi],0 ; The last 4th will be reset
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@end_hor_l:
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ret
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