| 0,0 → 1,205 |
|---|
| 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 |
| |
| .col equ ebp-4 ;dd ? |
| .x1 equ ebp-6 ;dw ? |
| .y1 equ ebp-8 ;dw ?;+8 |
| .x2 equ ebp-10 ;dw ? |
| .y2 equ ebp-12 ;dw ? |
| .x3 equ ebp-14 ;dw ? |
| .y3 equ ebp-16 ;dw ?;+16 |
| .dx12 equ ebp-20 ; dd ? |
| .dx13 equ ebp-24 ; dd ?;+24 |
| .dx23 equ ebp-28 ; dd ? |
| |
| mov ebp,esp |
| ; sub esp,28 |
| push edx |
| .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 |
| push eax |
| push ebx |
| push ecx |
| sub esp,12 |
| 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 word[.x1],SIZE_X ; { |
| jg .end_triangle |
| cmp word[.x2],SIZE_X ; This can be optimized with effort |
| jg .end_triangle |
| cmp word[.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 dword[.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 dword[.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 dword[.dx23],0 |
| jmp .yesZero3 |
| .noZero3: |
| idiv ebx |
| mov [.dx23],eax |
| .yesZero3: |
| |
| movsx eax,word[.x1] ; eax - xk1 ;;; |
| shl eax,ROUND |
| mov ebx,eax ; ebx - xk2 ;;; |
| movsx 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: |
| |
| mov esp,ebp |
| 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 |
| dec ecx |
| jecxz .last_pix |
| .ddraw: ; Drawing horizontally: |
| ;push eax |
| stosd ; 4 bytes at a time |
| dec edi ; point to the 4th |
| loop .ddraw |
| .last_pix: |
| stosw |
| shr eax,16 |
| stosb |
| ; mov byte[edi],0 ; The last 4th will be reset |
| .end_hor_l: |
| ret |