+++ /dev/null
-;-----------------------------------------------------------\r
-;\r
-; MXCC.ASM - Fast clip line function\r
-; Copyright (c) 1994 by Alessandro Scotti\r
-;\r
-;-----------------------------------------------------------\r
-WARN PRO\r
-NOWARN RES\r
-INCLUDE MODEX.DEF\r
-\r
-PUBLIC xsubClipLine\r
-\r
-MX_TEXT SEGMENT USE16 PARA PUBLIC 'CODE'\r
- ASSUME cs:MX_TEXT, ds:NOTHING, es:NOTHING\r
-\r
-EXTRN mx_BytesPerLine : WORD\r
-EXTRN mx_VideoSegment : WORD\r
-\r
-EXTRN mx_ClipX1 : WORD\r
-EXTRN mx_ClipY1 : WORD\r
-EXTRN mx_ClipX2 : WORD\r
-EXTRN mx_ClipY2 : WORD\r
-\r
-tblGroups LABEL WORD\r
- DW 10, tbl00\r
- DW 10, tbl10\r
- DW 9, tbl20\r
- DW -1, 0\r
- DW 10, tbl40\r
- DW 10, tbl50\r
- DW 9, tbl60\r
- DW -1, 0\r
- DW 6, tbl80\r
- DW 6, tbl90\r
- DW 5, tblA0\r
- DW -1, 0\r
- DW -1, 0\r
- DW -1, 0\r
- DW -1, 0\r
- DW -1, 0\r
-tbl00 DW cc00, cc01, cc02, ccFF, cc04, cc05, cc06, ccFF, cc08, cc09, cc0A\r
-tbl10 DW cc10, ccFF, cc12, ccFF, cc14, ccFF, cc16, ccFF, cc18, ccFF, cc1A\r
-tbl20 DW cc20, cc21, ccFF, ccFF, cc24, cc25, ccFF, ccFF, cc28, cc29\r
-tbl40 DW cc40, cc41, cc42, ccFF, ccFF, ccFF, ccFF, ccFF, cc48, cc49, cc4A\r
-tbl50 DW cc50, ccFF, cc52, ccFF, ccFF, ccFF, ccFF, ccFF, cc58, ccFF, cc5A\r
-tbl60 DW cc60, cc61, ccFF, ccFF, ccFF, ccFF, ccFF, ccFF, cc68, cc69\r
-tbl80 DW cc80, cc81, cc82, ccFF, cc84, cc85, cc86\r
-tbl90 DW cc90, ccFF, cc92, ccFF, cc94, ccFF, cc96\r
-tblA0 DW ccA0, ccA1, ccFF, ccFF, ccA4, ccA5\r
-\r
-ccTT: clc\r
- ret\r
-ccFF: stc\r
- ret\r
-\r
-; Group 00 -------------------------------------------------\r
-;\r
-cc00:\r
- clc\r
- ret\r
-cc01:\r
- jmp ClipQLeft\r
-cc02:\r
- jmp ClipQRight\r
-cc04:\r
- jmp ClipQTop\r
-cc05:\r
- call ClipQLeft\r
- cmp si, [mx_ClipY1]\r
- jge ccTT\r
- jmp ClipQTop\r
-cc06:\r
- call ClipQRight\r
- cmp si, [mx_ClipY1]\r
- jge ccTT\r
- jmp ClipQTop\r
-cc08:\r
- jmp ClipQBottom\r
-cc09:\r
- call ClipQLeft\r
- cmp si, [mx_ClipY2]\r
- jle ccTT\r
- jmp ClipQBottom\r
-cc0A:\r
- call ClipQRight\r
- cmp si, [mx_ClipY2]\r
- jle ccTT\r
- jmp ClipQBottom\r
-\r
-; Group 10 -------------------------------------------------\r
-;\r
-cc10FF:\r
- stc\r
- ret\r
-cc10TT:\r
- clc\r
- ret\r
-cc10:\r
- jmp ClipPLeft\r
-cc12:\r
- call ClipPLeft\r
- jmp ClipQRight\r
-cc14:\r
- call ClipPLeft\r
- cmp bx, [mx_ClipY1]\r
- jl cc10FF\r
- jmp ClipQTop\r
-cc16:\r
- call ClipPLeft\r
- cmp bx, [mx_ClipY1]\r
- jl cc10FF\r
- call ClipQTop\r
- cmp cx, [mx_ClipX2]\r
- jle cc10TT\r
- jmp ClipQRight\r
-cc18:\r
- call ClipPLeft\r
- cmp bx, [mx_ClipY2]\r
- jg cc10FF\r
- jmp ClipQBottom\r
-cc1A:\r
- call ClipPLeft\r
- cmp bx, [mx_ClipY2]\r
- jg cc10FF\r
- call ClipQBottom\r
- cmp cx, [mx_ClipX2]\r
- jle cc10TT\r
- jmp ClipQRight\r
-\r
-; Group 20 -------------------------------------------------\r
-;\r
-cc20TT:\r
- clc\r
- ret\r
-cc20FF:\r
- stc\r
- ret\r
-cc20:\r
- jmp ClipPRight\r
-cc21:\r
- call ClipPRight\r
- jmp ClipQLeft\r
-cc24:\r
- call ClipPRight\r
- cmp bx, [mx_ClipY1]\r
- jl cc20FF\r
- jmp ClipQTop\r
-cc25:\r
- call ClipPRight\r
- cmp bx, [mx_ClipY1]\r
- jl cc20FF\r
- call ClipQTop\r
- cmp cx, [mx_ClipX1]\r
- jge cc20TT\r
- jmp ClipQLeft\r
-cc28:\r
- call ClipPRight\r
- cmp bx, [mx_ClipY2]\r
- jg cc20FF\r
- jmp ClipQBottom\r
-cc29:\r
- call ClipPRight\r
- cmp bx, [mx_ClipY2]\r
- jg cc20FF\r
- call ClipQBottom\r
- cmp cx, [mx_ClipX1]\r
- jge cc20TT\r
- jmp ClipQLeft\r
-\r
-; Group 40 -------------------------------------------------\r
-;\r
-cc40TT:\r
- clc\r
- ret\r
-cc40FF:\r
- stc\r
- ret\r
-cc40:\r
- jmp ClipPTop\r
-cc41:\r
- call ClipPTop\r
- cmp di, [mx_ClipX1]\r
- jl cc40FF\r
- call ClipQLeft\r
- cmp si, [mx_ClipY1]\r
- jge cc40TT\r
- jmp ClipQTop\r
-cc42:\r
- call ClipPTop\r
- cmp di, [mx_ClipX2]\r
- jg cc40FF\r
- jmp ClipQRight\r
-cc48:\r
- call ClipPTop\r
- jmp ClipQBottom\r
-cc49:\r
- call ClipPTop\r
- cmp di, [mx_ClipX1]\r
- jl cc40FF\r
- call ClipQLeft\r
- cmp si, [mx_ClipY2]\r
- jle cc40TT\r
- jmp ClipQBottom\r
-cc4A:\r
- call ClipPTop\r
- cmp di, [mx_ClipX2]\r
- jg cc40FF\r
- call ClipQRight\r
- cmp si, [mx_ClipY2]\r
- jle cc40TT\r
- jmp ClipQBottom\r
-\r
-\r
-; Group 50 -------------------------------------------------\r
-;\r
-cc50TT:\r
- clc\r
- ret\r
-cc50FF:\r
- stc\r
- ret\r
-cc50:\r
- call ClipPLeft\r
- cmp bx, [mx_ClipY1]\r
- jge cc50TT\r
- jmp ClipPTop\r
-cc52:\r
- call ClipQRight\r
- cmp si, [mx_ClipY1]\r
- jl cc50FF\r
- call ClipPTop\r
- cmp di, [mx_ClipX1]\r
- jge cc50TT\r
- jmp ClipPLeft\r
-cc58:\r
- call ClipQBottom\r
- cmp cx, [mx_ClipX1]\r
- jl cc50FF\r
- call ClipPTop\r
- cmp di, [mx_ClipX1]\r
- jge cc50TT\r
- jmp ClipPLeft\r
-cc5A:\r
- call ClipPLeft\r
- cmp bx, [mx_ClipY2]\r
- jg cc50FF\r
- call ClipQRight\r
- cmp bx, [mx_ClipY1]\r
- jl cc50FF\r
- cmp si, [mx_ClipY2]\r
- jle cc50TT\r
- jmp ClipQBottom\r
-\r
-; Group 60 -------------------------------------------------\r
-;\r
-cc60TT:\r
- clc\r
- ret\r
-cc60FF:\r
- stc\r
- ret\r
-cc60:\r
- call ClipPRight\r
- cmp bx, [mx_ClipY1]\r
- jge cc60TT\r
- jmp ClipPTop\r
-cc61:\r
- call ClipQLeft\r
- cmp si, [mx_ClipY2]\r
- jl cc60FF\r
- call ClipPTop\r
- cmp di, [mx_ClipX2]\r
- jle cc60TT\r
- jmp ClipPRight\r
-cc68:\r
- call ClipQBottom\r
- cmp cx, [mx_ClipX2]\r
- jg cc60FF\r
- call ClipPRight\r
- cmp bx, [mx_ClipY1]\r
- jge cc60TT\r
- jmp ClipPTop\r
-cc69:\r
- call ClipQLeft\r
- cmp si, [mx_ClipY1]\r
- jl cc60FF\r
- call ClipPRight\r
- cmp bx, [mx_ClipY2]\r
- jg cc60FF\r
- cmp si, [mx_ClipY2]\r
- jle cc69_1\r
- call ClipQBottom\r
-cc69_1:\r
- cmp bx, [mx_ClipY1]\r
- jge cc60TT\r
- jmp ClipPTop\r
-\r
-; Group 80 -------------------------------------------------\r
-;\r
-cc80TT:\r
- clc\r
- ret\r
-cc80FF:\r
- stc\r
- ret\r
-cc80:\r
- jmp ClipPBottom\r
-cc81:\r
- call ClipPBottom\r
- cmp di, [mx_ClipX1]\r
- jl cc80FF\r
- jmp ClipQLeft\r
-cc82:\r
- call ClipPBottom\r
- cmp di, [mx_ClipX2]\r
- jg cc80FF\r
- jmp ClipQRight\r
-cc84:\r
- call ClipPBottom\r
- jmp ClipQTop\r
-cc85:\r
- call ClipPBottom\r
- cmp di, [mx_ClipX1]\r
- jl cc80FF\r
- call ClipQLeft\r
- cmp si, [mx_ClipY1]\r
- jge cc80FF\r
- jmp ClipQTop\r
-cc86:\r
- call ClipPBottom\r
- cmp di, [mx_ClipX2]\r
- jg cc80FF\r
- call ClipQRight\r
- cmp si, [mx_ClipY1]\r
- jge cc80TT\r
- jmp ClipQTop\r
-\r
-; Group 90 -------------------------------------------------\r
-;\r
-cc90TT:\r
- clc\r
- ret\r
-cc90FF:\r
- stc\r
- ret\r
-cc90:\r
- call ClipPLeft\r
- cmp bx, [mx_ClipY2]\r
- jle cc90TT\r
- jmp ClipPBottom\r
-cc92:\r
- call ClipQRight\r
- cmp si, [mx_ClipY2]\r
- jg cc90FF\r
- call ClipPBottom\r
- cmp di, [mx_ClipX1]\r
- jge cc90TT\r
- jmp ClipPLeft\r
-cc94:\r
- call ClipQTop\r
- cmp cx, [mx_ClipX1]\r
- jl cc90FF\r
- call ClipPLeft\r
- cmp bx, [mx_ClipY2]\r
- jle cc90TT\r
- jmp ClipPBottom\r
-cc96:\r
- call ClipPLeft\r
- cmp bx, [mx_ClipY1]\r
- jl cc90FF\r
- call ClipQRight\r
- cmp si, [mx_ClipY2]\r
- jg cc90FF\r
- cmp bx, [mx_ClipY2]\r
- jle cc96_1\r
- call ClipPBottom\r
-cc96_1:\r
- cmp si, [mx_ClipY1]\r
- jge cc90TT\r
- jmp ClipQTop\r
-\r
-; Group A0 -------------------------------------------------\r
-;\r
-ccA0TT:\r
- clc\r
- ret\r
-ccA0FF:\r
- stc\r
- ret\r
-ccA0:\r
- call ClipPRight\r
- cmp bx, [mx_ClipY2]\r
- jle ccA0TT\r
- jmp ClipPBottom\r
-ccA1:\r
- call ClipQLeft\r
- cmp si, [mx_ClipY2]\r
- jg ccA0FF\r
- call ClipPBottom\r
- cmp di, [mx_ClipX2]\r
- jle ccA0TT\r
- jmp ClipPRight\r
-ccA4:\r
- call ClipQTop\r
- cmp cx, [mx_ClipX2]\r
- jg ccA0FF\r
- call ClipPRight\r
- cmp bx, [mx_ClipY2]\r
- jle ccA0TT\r
- jmp ClipPBottom\r
-ccA5:\r
- call ClipQLeft\r
- cmp si, [mx_ClipY2]\r
- jg ccA0FF\r
- call ClipPRight\r
- cmp bx, [mx_ClipY1]\r
- jl ccA0FF\r
- cmp si, [mx_ClipY1]\r
- jge ccA5_1\r
- call ClipQTop\r
-ccA5_1:\r
- cmp bx, [mx_ClipY2]\r
- jle ccA0TT\r
- jmp ClipPBottom\r
-\r
-; Y1 = (Y2-Y1)*(mx_ClipX1-X1)/(X2-X1)+Y1 = (SI-BX)*(mx_ClipX1-DI)/(CX-DI)+BX\r
-; X1 = mx_ClipX1\r
-ClipPLeft:\r
- mov ax, si\r
- sub ax, bx\r
- mov dx, [mx_ClipX1]\r
- sub dx, di\r
- imul dx\r
- mov bp, cx\r
- sub bp, di\r
- idiv bp\r
- add bx, ax\r
- mov di, [mx_ClipX1]\r
- clc\r
- ret\r
-\r
-; Y1 = (Y2-Y1)*(mx_ClipX2-X1)/(X2-X1)+Y1 = (SI-BX)*(mx_ClipX2-DI)/(CX-DI)+BX\r
-; X1 = mx_ClipX2\r
-ClipPRight:\r
- mov ax, si\r
- sub ax, bx\r
- mov dx, [mx_ClipX2]\r
- sub dx, di\r
- imul dx\r
- mov bp, cx\r
- sub bp, di\r
- idiv bp\r
- add bx, ax\r
- mov di, [mx_ClipX2]\r
- clc\r
- ret\r
-\r
-; X1 = (X2-X1)*(mx_ClipY2-Y1)/(Y2-Y1)+X1 = (CX-DI)*(mx_ClipY2-BX)/(SI-BX)+DI\r
-; Y1 = mx_ClipY2\r
-ClipPBottom:\r
- mov ax, cx\r
- sub ax, di\r
- mov dx, [mx_ClipY2]\r
- sub dx, bx\r
- imul dx\r
- mov bp, si\r
- sub bp, bx\r
- idiv bp\r
- add di, ax\r
- mov bx, [mx_ClipY2]\r
- clc\r
- ret\r
-\r
-; X1 = (X2-X1)*(mx_ClipY1-Y1)/(Y2-Y1)+X1 = (CX-DI)*(mx_ClipY1-BX)/(SI-BX)+DI\r
-; Y1 = mx_ClipY1\r
-ClipPTop:\r
- mov ax, cx\r
- sub ax, di\r
- mov dx, [mx_ClipY1]\r
- sub dx, bx\r
- imul dx\r
- mov bp, si\r
- sub bp, bx\r
- idiv bp\r
- add di, ax\r
- mov bx, [mx_ClipY1]\r
- clc\r
- ret\r
-\r
-; Y2 = (Y1-Y2)*(mx_ClipX1-X2)/(X1-X2)+Y2 = (BX-SI)*(mx_ClipX1-CX)/(DI-CX)+SI\r
-; X2 = mx_ClipX1\r
-ClipQLeft:\r
- mov ax, bx\r
- sub ax, si\r
- mov dx, [mx_ClipX1]\r
- sub dx, cx\r
- imul dx\r
- mov bp, di\r
- sub bp, cx\r
- idiv bp\r
- add si, ax\r
- mov cx, [mx_ClipX1]\r
- clc\r
- ret\r
-\r
-; Y2 = (Y1-Y2)*(mx_ClipX2-X2)/(X1-X2)+Y2 = (BX-SI)*(mx_ClipX2-CX)/(DI-CX)+SI\r
-; X2 = mx_ClipX1\r
-ClipQRight:\r
- mov ax, bx\r
- sub ax, si\r
- mov dx, [mx_ClipX2]\r
- sub dx, cx\r
- imul dx\r
- mov bp, di\r
- sub bp, cx\r
- idiv bp\r
- add si, ax\r
- mov cx, [mx_ClipX2]\r
- clc\r
- ret\r
-\r
-; X2 = (X1-X2)*(mx_ClipY2-Y2)/(Y1-Y2)+X2 = (DI-CX)*(mx_ClipY2-SI)/(BX-SI)+CX\r
-; Y2 = mx_ClipY1\r
-ClipQBottom:\r
- mov ax, di\r
- sub ax, cx\r
- mov dx, [mx_ClipY2]\r
- sub dx, si\r
- imul dx\r
- mov bp, bx\r
- sub bp, si\r
- idiv bp\r
- add cx, ax\r
- mov si, [mx_ClipY2]\r
- clc\r
- ret\r
-\r
-; X2 = (X1-X2)*(mx_ClipY1-Y2)/(Y1-Y2)+X2 = (DI-CX)*(mx_ClipY1-SI)/(BX-SI)+CX\r
-; Y2 = mx_ClipY1\r
-ClipQTop:\r
- mov ax, di\r
- sub ax, cx\r
- mov dx, [mx_ClipY1]\r
- sub dx, si\r
- imul dx\r
- mov bp, bx\r
- sub bp, si\r
- idiv bp\r
- add cx, ax\r
- mov si, [mx_ClipY1]\r
- clc\r
- ret\r
-\r
-;-----------------------------------------------------------\r
-;\r
-; Checks the coordinates of a line against the active\r
-; clip region.\r
-; Uses the Sobkow-Pospisil-Yang (SPY) algorithm: this was\r
-; supposed to be twice as fast as Cohen-Sutherland, but my\r
-; tests show only a very small increase in speed and a noticeable\r
-; increase of the program size! Maybe this is caused by the\r
-; slow speed of VGA cards, so probably a better test should\r
-; be performed with lines drawn in RAM.\r
-;\r
-; Input:\r
-; AX, BX = X1, Y1\r
-; CX, DX = X2, Y2\r
-; Output:\r
-; CF = set if line is full clipped\r
-; AX, BX = clipped X1, Y1\r
-; CX, DX = clipped X2, Y2\r
-; Note:\r
-; destroys SI, DI\r
-;\r
-xsubClipLine PROC NEAR\r
- push bp\r
- xor si, si ; SPY code\r
-\r
- cmp dx, [mx_ClipY2]\r
- jle @@1\r
- or si, 08h\r
- jmp @@2\r
-@@1:\r
- cmp dx, [mx_ClipY1]\r
- jge @@2\r
- or si, 04h\r
-@@2:\r
-\r
- cmp cx, [mx_ClipX2]\r
- jle @@3\r
- or si, 02h\r
- jmp @@4\r
-@@3:\r
- cmp cx, [mx_ClipX1]\r
- jge @@4\r
- or si, 01h\r
-@@4:\r
-\r
- cmp bx, [mx_ClipY2]\r
- jle @@5\r
- or si, 80h\r
- jmp @@6\r
-@@5:\r
- cmp bx, [mx_ClipY1]\r
- jge @@6\r
- or si, 40h\r
-@@6:\r
-\r
- cmp ax, [mx_ClipX2]\r
- jle @@7\r
- or si, 20h\r
- jmp @@8\r
-@@7:\r
- cmp ax, [mx_ClipX1]\r
- jge @@8\r
- or si, 10h\r
-@@8:\r
-\r
- mov di, si\r
- and di, 000Fh ; Index of procedure\r
- and si, 00F0h\r
- .shr si, 2 ; Index of group (times 4)\r
- cmp di, cs:tblGroups[si] ; Is index within range?\r
- jg @@Exit ; No, line is full clipped\r
- mov si, cs:tblGroups[si+2] ; Get offset of group table\r
- shl di, 1 ; We must index word elements\r
- add si, di ; Make full offset\r
- mov di, ax ; Move X1 to DI and free AX\r
- mov si, cs:[si] ; Get subroutine address\r
- xchg dx, si ; Move Y2 to SI and free DX\r
- call dx ; Call the proper subroutine\r
- mov ax, di ; Restore AX to X1\r
- mov dx, si ; Restore DX to Y2\r
- pop bp\r
- ret\r
-\r
-@@Exit:\r
- pop bp\r
- stc\r
- ret\r
-xsubClipLine ENDP\r
-\r
-MX_TEXT ENDS\r
-END\r
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