LDRAW

Syntax LDRAW x1,y1 TO x2,y2, col
Location HCO

This command is similar to DRAW, ie. it draws quite a thick line on the screen, but LDRAW is part of the same Toolkit as SET and uses a different col parameter to DRAW, see SET for that.

Example

Well, the sample listing which follows on below, is a bit too long for a simple demonstration of LDRAW.

The variable rstep% in line 110 determines via pics% how much memory is required to run the animation.

Unless you have SMS or Minerva, you will have to replace i% and j% by i and j.

100 WINDOW 512,64,0,0: PAPER 0: INK 3: CLS
110 rstep% = 20
120 pics% = 360 / rstep%: DIM adr(pics%): i% = 0
130 FOR r = 0 TO 360-rstep% STEP rstep%
140   i%=i%+1: CLS: AT 0,0: PRINT "(";i%;")";TO 6;r;"ø"
150   PYRAMID 20, 256, 32, r, r, r, 3
160   adr(i%) = ALCHP(HEX("2000"))
170   IF NOT adr(i%) THEN CLCHP: STOP: REMark memory overflow
180   MM_MOVE HEX("20000"), adr(i%), HEX("2000")
190 END FOR r
200 REPeat Animation
210   FOR i% = 1 TO pics%
220     MM_MOVE adr(i%), HEX("20000"), HEX("2000")
230     IF KEYROW(1)&&8 THEN EXIT Animation
240   END FOR i%
250 END REPeat Animation
260 CLCHP: STOP
270 :
290 DEFine PROCedure PYRAMID (size, px%,py%, rotx,roty,rotz, c%)
300   LOCal i%, j%, p1(2), p2(2)
310   RESTORE 410
320   FOR i% = 1 TO 8
330     READ p1(0),p1(1),p1(2), p2(0),p2(1),p2(2)
340     ROTATION p1(0),p1(1),p1(2), rotx, roty, rotz
350     ROTATION p2(0),p2(1),p2(2), rotx, roty, rotz
360     FOR j%=0 TO 2: p1(j%)=size*p1(j%): p2(j%)=size*p2(j%)
370     LDRAW px%+p1(0),py%+p1(1) TO px%+p2(0),py%+p2(1), c%
380   END FOR i%
390   RETurn
400 :
410   REMark base square
420   DATA -1, -1, 0, 1,-1, 0
430   DATA 1, -1, 0, 1, 1, 0
440   DATA 1, 1, 0, -1, 1, 0
450   DATA -1, 1, 0, -1,-1, 0
460   REMark top
470   DATA -1, -1, 0, 0, 0, 2
480   DATA 1, -1, 0, 0, 0, 2
490   DATA 1, 1, 0, 0, 0, 2
500   DATA -1, 1, 0, 0, 0, 2
510 END DEFine PYRAMID
520 :
530 :
540 DEFine PROCedure ROTATION (x, y, z, wx, wy, wz)
550   REMark rotate point (x,y,z) by angles wx, wy and wz
560   REMark in degrees around point (0,0,0)
570   LOCal x1, y1, x2, z2
580   LOCal cx, cy, cz, sx, sy, sz
590   cx = COS(RAD(wx)): cy = COS(RAD(wy)): cz = COS(RAD(wz))
600   sx = SIN(RAD(wx)): sy = SIN(RAD(wy)): sz = SIN(RAD(wz))
610   x1 = x * cz -y * sz
620   y1 = x * sz + y * cz
630   x = x1 * cy - z * sy
640   z2 = x1 * sy + z * cy
650   y = y1 * cx + z2 * sx
660   z = -y1 * sx + z2 * cx
670 END DEFine ROTATION
680 :
700 DEFine PROCedure MM_MOVE (addr1, addr2, bytes)
710   REMark move memory
720   LOCal routine
730   IF VER$ = "JSL1" THEN
740     routine = PEEK_W(344) + 16384
750     CALL routine, bytes, 2, 3, 4, 5, 6, 7, addr2, addr1
760   ELSE
770     REMark with HCO:
780     BMOVE addr1, addr1+bytes TO addr2
790   END IF
800 END DEFine MM_MOVE

NOTE 1

LDRAW assumes that the screen is in a resolution of 512x256 pixels and is located at $20000.

NOTE 2

LDRAW only works correctly in MODE 4.

WARNINGS

See SET.

CROSS-REFERENCE

DRAW. Please use LDRAW only if you know what you are doing, do not intend to write user-friendly programs, and especially if you do not intend to show your program listing to someone else! You can always use LINE and LINE_R, commands, DOTLIN and XDRAW, which can draw dotted lines (DOTLIN) or work in XOR mode (XDRAW).