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Club Amiga de Montreal - CAM
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262.lha
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BlitLab_v1.4
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math.c
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C/C++ Source or Header
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1989-06-29
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4KB
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174 lines
/*
* This is the math routines of BlitLab. It checks a possible blit to
* insure that it is safe. It also handles the line calculations.
*/
#include "structures.h"
/*
* The externals we use.
*/
extern long gvals[] ;
extern struct Gadget *gadgets[] ;
extern short *realbits ;
extern struct Window *mywindow ;
extern char errorbuf[] ;
/*
* This routine insures that a blit is safe. It returns 1 if it is
* okay, and 0 if it is not.
*/
int blitsafe() {
long x1, x2, x3, x4 ;
long lower, upper ;
if (gvals[GDGUSED]==0)
return(1) ;
lower = (long)realbits ;
upper = 382 + (long)realbits ;
if (gvals[GDGH] < 1 || gvals[GDGV] < 1
|| gvals[GDGH] > 64 || gvals[GDGV] > 1024)
return(0) ;
if (gvals[GDGLINE]) {
} else {
x1 = gvals[GDGDPT] ;
if (gvals[GDGDESC]) {
x2 = x1 - gvals[GDGH] * 2 + 2 ;
x3 = x1 - (gvals[GDGV] - 1) * ((gvals[GDGH] * 2) +
(gvals[GDGDMOD] & ~1)) ;
x4 = x3 - gvals[GDGH] * 2 + 2 ;
if (x1 < lower || x2 < lower || x3 < lower || x4 < lower ||
x1 > upper || x2 > upper || x3 > upper || x4 > upper)
return(0) ;
else
return(1) ;
} else {
x2 = x1 + gvals[GDGH] * 2 - 2 ;
x3 = x1 + (gvals[GDGV] - 1) * ((gvals[GDGH] * 2) +
(gvals[GDGDMOD] & ~1)) ;
x4 = x3 + gvals[GDGH] * 2 - 2 ;
if (x1 < lower || x2 < lower || x3 < lower || x4 < lower ||
x1 > upper || x2 > upper || x3 > upper || x4 > upper)
return(0) ;
else
return(1) ;
}
}
}
/*
* This routine stuffs a value in a gadget. Could be dangerous, but
* that's life.
*/
stuff(id, s)
int id ;
char *s ;
{
gvals[id] = parse(s) ;
RemoveGadget(mywindow, gadgets[id]) ;
strcpy(((struct StringInfo *)(gadgets[id]->SpecialInfo))->Buffer, s) ;
AddGadget(mywindow, gadgets[id], -1) ;
RefreshGadgets(gadgets[id], mywindow, NULL) ;
}
/*
* This routine flips the state of a toggle gadget.
*/
flipgadg(id)
int id ;
{
struct IntuiText *temp ;
struct Gadget *gp = gadgets[id] ;
RemoveGadget(mywindow, gp) ;
temp = gp->GadgetText ;
gp->GadgetText = (struct IntuiText *)gp->UserData ;
gp->UserData = (APTR)temp ;
gp->NextGadget = NULL ;
AddGadget(mywindow, gp, -1) ;
RefreshGadgets(gp, mywindow, NULL) ;
gvals[id] = 1 - gvals[id] ;
}
/*
* This routine sets up a line.
*/
setupline() {
int x, y ;
int i ;
int X, Y ;
int q = 0 ;
parseall() ;
stuff(GDGADAT, "$8000") ;
stuff(GDGBDAT, "$ffff") ;
x = gvals[GDGSX] ;
y = gvals[GDGSY] ;
sprintf(errorbuf, "%d", x & 15) ;
stuff(GDGASH, errorbuf) ;
i = ((x >> 3) & ~1) + y * 12 ;
sprintf(errorbuf, "M+%d", i) ;
stuff(GDGCPT, errorbuf) ;
stuff(GDGDPT, errorbuf) ;
stuff(GDGCMOD, "12") ;
stuff(GDGDMOD, "12") ;
stuff(GDGH, "2") ;
x = (gvals[GDGEX] - gvals[GDGSX]) ;
y = (gvals[GDGEY] - gvals[GDGSY]) ;
if (x < 0)
X = - x ;
else
X = x ;
if (y < 0)
Y = - y ;
else
Y = y ;
if (x > 0) {
if (y > 0) {
q = (X > Y ? 1 : 0) ;
} else {
q = (X > Y ? 3 : 4) ;
}
} else {
if (y > 0) {
q = (X > Y ? 5 : 2) ;
} else {
q = (X > Y ? 7 : 6) ;
}
}
if (Y > X) {
i = X ;
X = Y ;
Y = i ;
}
sprintf(errorbuf, "%d", X+1) ;
stuff(GDGV, errorbuf) ;
sprintf(errorbuf, "%d", 4 * Y - 2 * X) ;
stuff(GDGAPT, errorbuf) ;
if (2 * Y - X < 0) {
if (!gvals[GDGSIGN])
flipgadg(GDGSIGN) ;
} else {
if (gvals[GDGSIGN])
flipgadg(GDGSIGN) ;
}
sprintf(errorbuf, "%d", 4 * (Y - X)) ;
stuff(GDGAMOD, errorbuf) ;
sprintf(errorbuf, "%d", 4 * Y) ;
stuff(GDGBMOD, errorbuf) ;
stuff(GDGAFWM, "%1111111111111111") ;
stuff(GDGALWM, "%1111111111111111") ;
if (! gvals[GDGLINE])
flipgadg(GDGLINE) ;
if ((q & 1) != gvals[GDGEFE])
flipgadg(GDGEFE) ;
if (((q >> 1) & 1) != gvals[GDGIFE])
flipgadg(GDGIFE) ;
if (((q >> 2) & 1) != gvals[GDGFCI])
flipgadg(GDGFCI) ;
if (! gvals[GDGUSEA])
flipgadg(GDGUSEA) ;
if (gvals[GDGUSEB])
flipgadg(GDGUSEB) ;
if (! gvals[GDGUSEC])
flipgadg(GDGUSEC) ;
if (! gvals[GDGUSED])
flipgadg(GDGUSED) ;
if (gvals[GDGOVF])
flipgadg(GDGOVF) ;
}