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314 lines
15 KiB
314 lines
15 KiB
'''''''''''''''' |
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' Let's see if we can make us some 3D graphics! In Basic, Hehe. |
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DECLARE FUNCTION maxval% (v1%, v2%, limit%) |
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DECLARE FUNCTION minval% (v1%, v2%, v3%) |
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DECLARE SUB hline (x1%, x2%, y%, c%) |
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DECLARE FUNCTION min% (v1%, v2%, v3%) |
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DECLARE FUNCTION max% (v1%, v2%, v3%) |
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DECLARE SUB pal () |
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DECLARE SUB pixel (x%, y%, c%) |
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DEFINT A-Z 'set default var type to int 'cos it's my fav. |
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'$STATIC 'use static arrays |
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CLS 'clear the screen. duh |
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SCREEN 13 'initialize screen mode 13 (0x013 (19) 4 real) |
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CONST SCRX = 320 'sort of like #define so I can use SCRX/Y instead |
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CONST SCRY = 200 'of the actual #'s in case the width changes, etc. |
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CONST CLRS = 255 'ditto w/ color depth |
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CONST HLFX = 160 'half the screen width |
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CONST HLFY = 100 'half screen height (both use lots, should save calc.) |
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CONST PI = 3.141592654# 'close enuf |
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CONST VIEWRANGE = 16 'how far before fade to blackness |
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CONST MSZE = 16 'size of the map (x & y are = ) |
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CONST MHGT = 4 'height of random mountains (TEMP) |
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CONST MININT = -32768 'lowest possible integer |
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CONST CONTRAST = 20 'multiplied by light values |
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CONST AMBIENT = 50 'added to light values |
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LOCATE 1, 1: COLOR 200: PRINT "Loading" |
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' make lookup-tables |
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DIM sine(0 TO 255) AS SINGLE |
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DIM cosine(0 TO 255) AS SINGLE |
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FOR i = 0 TO 255 |
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sine(i) = SIN(i) * PI / 200 'Convert rad to "hex" |
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cosine(i) = COS(i) * PI / 200 'Convert rad to "hex" |
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NEXT i |
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'Note to self: REMEMBER I'm using "hexians" (256) NOT degrees (360) |
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'Layout of the landscape. . . just some random sample data for now! |
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DIM land(1 TO MSZE, 1 TO MSZE) AS INTEGER 'array containing landscape |
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RANDOMIZE TIMER 'use timer to seed random |
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'# generator |
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FOR x = 1 TO MSZE |
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FOR y = 1 TO MSZE |
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land(x, y) = INT(RND * MHGT) 'fill w/ random data |
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NEXT y |
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NEXT x |
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'make a variable to hold edge buffers |
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TYPE edge |
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ls AS INTEGER |
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rs AS INTEGER |
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END TYPE |
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DIM edge(0 TO SCRY) AS edge |
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'. . . and make an gradiant green palette |
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OUT &H3C8, 0 ' tell port whole palette is coming (otherwise # of color) |
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FOR i = 0 TO 255 |
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OUT &H3C9, 0 'red |
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OUT &H3C9, INT(i / 4) 'green |
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OUT &H3C9, 0 'blue |
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'Hahaha! I'll never use THIS command again, |
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'PALETTE i, INT(i / 4) * 256 |
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NEXT i |
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' Initialize the player variale to hold info on player position |
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TYPE spot |
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x AS INTEGER 'x runs horizontally to player (pitch) |
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y AS INTEGER 'y runs out from player (roll) |
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z AS INTEGER 'z runs up and down (yaw) aka altitude |
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'I know these are not std. but they fit better w/ the flat map |
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END TYPE |
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DIM pov AS spot |
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DIM currentpoint AS spot ' used w/i the program loop |
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pov.x = 8 |
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pov.y = -8 |
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pov.z = 7 |
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'temp |
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DIM points(1 TO MSZE, 1 TO MSZE) AS spot'uses x and y as screen co-ords & z as |
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'distance |
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DIM ver(1 TO 3) AS spot 'vertex: used for drawing polygons, x |
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'and y are co-ords & z is color |
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DIM tmp(1 TO 3) AS spot 'used w/ ver for sorting |
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BEEP |
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CLS |
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DO |
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a$ = INKEY$ |
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SELECT CASE a$ |
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CASE "a": pov.x = pov.x + 1: CLS |
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CASE "d": pov.x = pov.x - 1: CLS |
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CASE "w": pov.y = pov.y + 1: CLS |
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CASE "s": pov.y = pov.y - 1: CLS |
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CASE "e": pov.z = pov.z + 1: CLS |
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CASE "c": pov.z = pov.z - 1: CLS |
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CASE CHR$(27): SYSTEM |
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END SELECT |
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FOR x = 1 TO MSZE |
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FOR y = 1 TO MSZE |
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'in front of us |
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rely = y - pov.y |
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relx = x - pov.x |
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relz = land(x, y) - pov.z |
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IF rely > 0 AND ABS(relx) <= rely AND ABS(relz) <= rely THEN |
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points(x, y).y = HLFY - relz * HLFY / rely |
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points(x, y).x = HLFX - relx * HLFX / rely |
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'a^3 = b^3 + c^3 + d^3 to find z (pixel dist.) |
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points(x, y).z = (ABS(relz) ^ 3 + ABS(rely) ^ 3 + ABS(relx) ^ 3) ^ (1 / 3) |
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ELSE points(x, y).z = -1 |
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IF points(x, y).y < 0 OR points(x, y).y > SCRY OR points(x, y).x < 0 OR points(x, y).x > SCRX OR points(x, y).z > VIEWRANGE THEN points(x, y).z = -1 |
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END IF |
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NEXT y |
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NEXT x |
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FOR y = MSZE - 1 TO 1 STEP -1 |
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FOR x = MSZE - 1 TO 1 STEP -1 |
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'if the current point has not been flagged as offscreen, out of FOV, or not w/i range of VIEWRANGE (z=-1) |
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IF points(x, y).z >= 0 THEN |
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'seperate into two triangles |
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FOR p = 0 TO 1 |
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'get points of tri. |
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IF p = 0 THEN |
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ver(1).x = points(x, y).x: ver(1).y = points(x, y).y: ver(1).z = points(x, y).z |
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ver(2).x = points(x, y + 1).x: ver(2).y = points(x, y + 1).y: ver(2).z = points(x, y + 1).z |
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ver(3).x = points(x + 1, y + 1).x: ver(3).y = points(x + 1, y + 1).y: ver(3).z = points(x + 1, y + 1).z |
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ELSE |
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'sides 1 & 3 are reversed so will be |
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'in same rotational order (this could |
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'be more efficient - swap lables) |
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ver(3).x = points(x, y).x: ver(3).y = points(x, y).y: ver(3).z = points(x, y).z |
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ver(1).x = points(x + 1, y + 1).x: ver(1).y = points(x + 1, y + 1).y: ver(1).z = points(x + 1, y + 1).z |
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'side 2 is other corner of square |
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ver(2).x = points(x + 1, y).x: ver(2).y = points(x + 1, y).y: ver(2).z = points(x + 1, y).z |
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END IF |
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'translate tri. so ver[1] is origin |
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'of tmp, w/ V2 & V3 as vectors |
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tmp(2).x = ver(2).x - ver(1).x |
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tmp(2).y = ver(2).y - ver(1).y |
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tmp(3).x = ver(3).x - ver(1).x |
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tmp(3).y = ver(3).y - ver(1).y |
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'if we are facing the polygon (uses |
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'vectors to find if c.clockwise) |
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IF tmp(2).x * tmp(3).y < tmp(3).x * tmp(2).y THEN |
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'sort ver[] tp-bt |
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GOSUB sort |
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'find tri. height |
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dy = ver(1).y - ver(3).y |
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'delta-y for short side 1 |
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dy1 = ver(1).y - ver(2).y |
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'slope of long side |
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m! = (ver(3).x - ver(1).x) / dy |
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'find width at middle |
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midwidth = ver(2).x - (ver(1).x + (m! * dy1)) |
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'if long side is on the left |
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'IF midwidth > 1 THEN |
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'if width is big enough to see |
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IF ABS(midwidth) > 1 THEN |
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'if height is big enough to see |
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IF dy > 1 THEN |
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'delta-y of short side 2 |
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dy2 = ver(2).y - ver(3).y |
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'slope of short side 1 (clause prevents div by 0) |
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IF ABS(dy1) > 0 THEN m1! = (ver(2).x - ver(1).x) / dy1 |
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'slope of short side 2 (clause prevents division by 0) |
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IF ABS(dy2) > 0 THEN m2! = (ver(3).x - ver(2).x) / dy2 |
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'calculate the color |
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'colr = points(x, y).y - points(x + 1, y + 1).y + 30'VIEWRANGE - ver(1).z + 20 |
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IF p = 0 THEN |
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colr = (land(x, y + 1) - (land(x, y) + land(x + 1, y + 1)) / 2) * CONTRAST + AMBIENT |
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ELSE |
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colr = ((land(x, y) + land(x + 1, y + 1)) / 2 - land(x + 1, y)) * CONTRAST + AMBIENT |
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END IF |
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FOR h = 0 TO dy |
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ypos = ver(1).y - h |
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IF h <= dy1 THEN |
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LINE (ver(1).x + (m! * h), ypos)-(ver(1).x + (m1! * h), ypos), colr |
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'xa = ver(1).x + (m! * h) |
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'xb = ver(1).x + (m1! * h) |
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'x1 = minval(xa, xb, 0) |
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'x2 = maxval(xa, xb, SCRX) |
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'hline x1, x2, ypos, colr |
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ELSE |
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LINE (ver(1).x + (m! * h), ypos)-(ver(2).x + (m2! * (h - dy1)), ypos), colr |
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'xa = ver(1).x + (m! * h) |
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'xb = ver(2).x + (m2! * h) |
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'x1 = minval(xa, xb, 0) |
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'x2 = maxval(xa, xb, SCRX) |
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'hline x1, x2, ypos, colr |
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END IF |
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NEXT h |
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END IF |
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END IF |
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'END IF |
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'if long side is on the right |
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'IF midwidth < -1 THEN |
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'END IF |
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'else is too thin to see |
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'LINE (ver(1).x, ver(1).y)-(ver(2).x, ver(2).y), 255'VIEWRANGE - ver(1).z |
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'LINE (ver(2).x, ver(2).y)-(ver(3).x, ver(3).y), 255'VIEWRANGE - ver(1).z |
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'LINE (ver(3).x, ver(3).y)-(ver(1).x, ver(1).y), 255'VIEWRANGE - ver(1).z |
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END IF |
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NEXT p |
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END IF |
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NEXT x |
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NEXT y |
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LOOP |
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sort: |
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'assign tmp the values of ver |
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FOR i = 1 TO 3 |
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tmp(i).x = ver(i).x |
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tmp(i).y = ver(i).y |
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tmp(i).z = ver(i).z |
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NEXT i |
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'order them top to bottom [1st pnt] |
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flag = max(tmp(1).y, tmp(2).y, tmp(3).y) |
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'used to skip 3rd calculation |
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topflag = flag |
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'assign values to the first vertex |
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ver(1).x = tmp(flag).x: ver(1).y = tmp(flag).y: ver(1).z = tmp(flag).z |
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'make y lowest possible # 4 further compares |
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tmp(flag).y = MININT |
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'order top-bottom 2 (prev. top is now -32768) |
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flag = max(tmp(1).y, tmp(2).y, tmp(3).y) |
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'add to flag to find which of 3 is not used |
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topflag = topflag + flag |
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'assign values to the 2nd vertex |
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ver(2).x = tmp(flag).x: ver(2).y = tmp(flag).y: ver(2).z = tmp(flag).z |
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'use topflag to find last point in order |
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SELECT CASE topflag |
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CASE 3 'used 1 & 2 |
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flag = 3 |
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CASE 4 'used 1 & 3 |
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flag = 2 |
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CASE 5 'used 2 & 3 |
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flag = 1 |
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CASE ELSE 'just in case |
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BEEP |
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flag = 1 |
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END SELECT |
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'assign values to the 3rd vertex |
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ver(3).x = tmp(flag).x: ver(3).y = tmp(flag).y: ver(3).z = tmp(flag).z |
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RETURN |
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SUB hline (x1, x2, y, c) |
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FOR i = x1 TO x2 |
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pixel i, y, c |
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NEXT i |
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END SUB |
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'''''''''''''''' |
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' Returns 1, 2, or 3, depending on which value: 1st, 2nd, or 3d is largest |
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FUNCTION max (v1, v2, v3) |
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r = 0 |
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IF v1 >= v2 AND v1 >= v3 THEN r = 1 |
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IF v2 >= v1 AND v2 >= v3 THEN r = 2 |
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IF v3 >= v2 AND v3 >= v1 THEN r = 3 |
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max = r |
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END FUNCTION |
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'''''''''''''''' |
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' Returns the largest of the three values passed to it w/i limit |
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FUNCTION maxval (v1, v2, limit) |
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r = 0 |
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IF v1 >= v2 THEN r = v1 |
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IF v2 >= v1 THEN r = v2 |
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IF r > limit THEN r = limit |
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maxval = r |
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END FUNCTION |
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'''''''''''''''' |
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' Returns the smallest of the three values passed to it w/i limit |
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FUNCTION minval (v1, v2, limit) |
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r = 0 |
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IF v1 <= v2 THEN r = v1 |
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IF v2 <= v1 THEN r = v2 |
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IF r < limit THEN r = limit |
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minval = r |
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END FUNCTION |
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'This SUB does the same thing as PSET only by writing directly to the video |
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'memory which *should* be much faster (Muahahaha!) |
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' |
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SUB pixel (x, y, c) |
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DEF SEG = &HA000 'A000h is where the video mem. starts in mode |
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'13h, which we're using |
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IF x < 0 OR x > SCRX THEN EXIT SUB 'make sure x is on the screen |
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IF y < 0 OR y > SCRY THEN EXIT SUB 'make sure y is on the screen |
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'(We do NOT want to be writing directly into |
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'memory somewhere we're not supposed to!) |
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IF c < 0 OR c > CLRS THEN EXIT SUB 'make sure c is w/i the color palette |
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y& = y 'needed to prevent overflow (where's an |
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'unsigned int when you need it?) |
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POKE y& * SCRX + x, c 'put c into the right spot offset from A000h |
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'(pixels go lt-rt, tp-bt in a linear fashion) |
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END SUB |
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