Subversion Repositories Kolibri OS

draw_triangle:

    ;----------in - eax - x1 shl 16 + y1

    ;------------- -ebx - x2 shl 16 + y2

    ;---------------ecx - x3 shl 16 + y3

    ;---------------edx - color 0x00rrggbb

    ;---------------edi - pointer to screen buffer

    @ch3:

	cmp	ax,bx

	jg	@ch1

    @ch4:			; sort parameters

	cmp	bx,cx

	jg	@ch2

	jle	@chEnd

    @ch1:

	xchg	eax,ebx

	jmp	@ch4

    @ch2:

	xchg	ebx,ecx

	jmp	@ch3

    @chEnd:

	mov	dword[@y1],eax	; ....and store to user friendly  variables

	mov	dword[@y2],ebx

	mov	dword[@y3],ecx

	mov	[@col],edx

	mov	edx,eax 	; eax,ebx,ecx are ORd together into edx which means that

	or	edx,ebx 	; if any *one* of them is negative a sign flag is raised

	or	edx,ecx

	test	edx,80008000h	; Check both X&Y at once

	jne	@end_triangle

	cmp	[@x1],SIZE_X	; {

	jg	@end_triangle

	cmp	[@x2],SIZE_X	 ; This can be optimized with effort

	jg	@end_triangle

	cmp	[@x3],SIZE_X

	jg	@end_triangle	; }

	shr	eax,16

	shr	ebx,16

	shr	ecx,16

	neg	ax		; calculate delta 12

	add	ax,bx

	cwde

	shl	eax,ROUND

	cdq

	mov	bx,[@y2]

	mov	cx,[@y1]

	sub	bx,cx

	;cmp     ebx,0

	jne	@noZero1

	mov	[@dx12],0

	jmp	@yesZero1

    @noZero1:

	idiv	ebx

	mov	[@dx12],eax

    @yesZero1:

	mov	ax,[@x3]	; calculate delta 13

	sub	ax,[@x1]

	cwde

	shl	eax,ROUND

	cdq

	mov	bx,[@y3]

	mov	cx,[@y1]

	sub	bx,cx

	;cmp     ebx,0

	jne	@noZero2

	mov	[@dx13],0

	jmp	@yesZero2

    @noZero2:

	idiv	ebx

	mov	[@dx13],eax

    @yesZero2:

	mov	ax,[@x3]     ; calculate delta 23 [dx23]

	sub	ax,[@x2]

	cwde

	shl	eax,ROUND

	cdq

	mov	bx,[@y3]

	mov	cx,[@y2]

	sub	bx,cx

	;cmp     ebx,0

	jne	@noZero3

	mov	[@dx23],0

	jmp	@yesZero3

    @noZero3:

	idiv	ebx

	mov	[@dx23],eax

    @yesZero3:

	movzx	eax,word[@x1]	; eax - xk1

	shl	eax,ROUND

	mov	ebx,eax 	; ebx - xk2

	movzx	esi,word[@y1]	; esi - y

    @next_line1:

	mov	ecx,eax 	; ecx - x11

	sar	ecx,ROUND

	mov	edx,ebx 	; edx - x12

	sar	edx,ROUND

	cmp	ecx,edx

	jle	@nochg

	xchg	ecx,edx

    @nochg:

	pusha

	mov	ebx,ecx

	sub	edx,ecx

	mov	ecx,edx

	mov	edx,esi

	mov	eax,[@col]

	call	@horizontal_line

	popa

	add	eax,[@dx13]

	add	ebx,[@dx12]

	inc	esi

	cmp	si,[@y2]

	jl	@next_line1

	movzx	esi,word[@y2]

	movzx	ebx,word[@x2]

	shl	ebx,ROUND

    @next_line2:

	mov	ecx,eax

	sar	ecx,ROUND

	mov	edx,ebx

	sar	edx,ROUND

	cmp	ecx,edx

	jle	@nochg1

	xchg	ecx,edx

    @nochg1:

	pusha

	mov	ebx,ecx

	sub	edx,ecx

	mov	ecx,edx

	mov	edx,esi

	mov	eax,[@col]

	call	@horizontal_line

	popa

	add	eax,[@dx13]

	add	ebx,[@dx23]

	inc	esi

	cmp	si,[@y3]

	jl	@next_line2

    @end_triangle:

ret

@horizontal_line:

    ;---------in

    ;---------eax - color of line,  0x00RRGGBB

    ;---------ebx - x1 - x position of line begin

    ;---------ecx - lenght of line

    ;---------edx - y position of line

    ;---------edi - pointer to buffer

	jcxz	@end_hor_l

;        or      edx,edx

;        jl      @end_hor_l

	cmp	edx,SIZE_Y

	jg	@end_hor_l

	push	eax

	mov	eax,SIZE_X*3

	mul	edx

	add	edi,eax 	; calculate line begin adress

	;add     edi,ebx

	;shl     ebx,1

	lea	edi,[edi+ebx*2]

	add	edi,ebx

	pop	eax

	cld

	;mov dword[edi-3],0000FF00h

    @ddraw:			; Drawing horizontally:

	;push    eax

	stosd			; 4 bytes at a time

	dec edi 		; point to the 4th

	;shr     eax,16

	;stosb

	;pop     eax

	;pusha                    ; If you want to draw pixel-by-pixel

	;    mov  eax,7           ; put image

	;    mov  ebx,screen

	;    mov  ecx,SIZE_X shl 16 + SIZE_Y

	;    mov  edx,5 shl 16 + 20

	;    int  0x40

	;popa

	loop	@ddraw

	mov	byte[edi],0	; The last 4th will be reset

    @end_hor_l:

ret