/**
** Init the move.
**
** @param missile missile to initialise for movement.
**
** @return 1 if goal is reached, 0 else.
*/
static int MissileInitMove(Missile *missile)
{
int dx;
int dy;
dx = missile->DX - missile->X;
dy = missile->DY - missile->Y;
MissileNewHeadingFromXY(missile, dx, dy);
if (!(missile->State & 1)) {
missile->CurrentStep = 0;
missile->TotalStep = 0;
if (dx == 0 && dy == 0) {
return 1;
}
// initialize
missile->TotalStep = MapDistance(missile->SourceX, missile->SourceY, missile->DX, missile->DY);
missile->State++;
return 0;
}
Assert(missile->TotalStep != 0);
missile->CurrentStep += missile->Type->Speed;
if (missile->CurrentStep >= missile->TotalStep) {
missile->X = missile->DX;
missile->Y = missile->DY;
return 1;
}
return 0;
}
/**
** Calculate parabolic trajectories.
**
** @param missile Missile pointer.
**
** @return 1 if target is reached, 0 otherwise
**
** @todo Find good values for ZprojToX and Y
*/
static int ParabolicMissile(Missile *missile)
{
int orig_x; // position before moving.
int orig_y; // position before moving.
int xstep;
int ystep;
int k; // Coefficient of the parabol.
int zprojToX; // Projection of Z axis on axis X.
int zprojToY; // Projection of Z axis on axis Y.
int z; // should be missile->Z later.
int x;
int y;
k = -2048; //-1024; // Should be initialised by an other method (computed with distance...)
zprojToX = 4;
zprojToY = 1024;
if (MissileInitMove(missile) == 1) {
return 1;
}
Assert(missile->Type != NULL);
orig_x = missile->X;
orig_y = missile->Y;
xstep = missile->DX - missile->SourceX;
ystep = missile->DY - missile->SourceY;
Assert(missile->TotalStep != 0);
xstep = xstep * 1000 / missile->TotalStep;
ystep = ystep * 1000 / missile->TotalStep;
missile->X = missile->SourceX + xstep * missile->CurrentStep / 1000;
missile->Y = missile->SourceY + ystep * missile->CurrentStep / 1000;
Assert(k != 0);
z = missile->CurrentStep * (missile->TotalStep - missile->CurrentStep) / k;
// Until Z is used for drawing, modify X and Y.
missile->X += z * zprojToX / 64;
missile->Y += z * zprojToY / 64;
MissileNewHeadingFromXY(missile, missile->X - orig_x, missile->Y - orig_y);
if (missile->Type->SmokeMissile && missile->CurrentStep) {
x = missile->X + missile->Type->Width / 2;
y = missile->Y + missile->Type->Height / 2;
MakeMissile(missile->Type->SmokeMissile, x, y, x, y);
}
return 0;
}
/**
** Handle point to point missile.
*/
local int PointToPointMissile(int missile)
{
int dx;
int dy;
int xstep;
int ystep;
int i;
if( !(Missiles[missile].State&1) ) {
// initialize
dy=Missiles[missile].DY-Missiles[missile].Y;
ystep=1;
if( dy<0 ) {
dy=-dy;
ystep=-1;
}
dx=Missiles[missile].DX-Missiles[missile].X;
xstep=1;
if( dx<0 ) {
dx=-dx;
xstep=-1;
}
// FIXME: could be better written
MissileNewHeadingFromXY(missile,dx*xstep,dy*ystep);
if( dy==0 ) { // horizontal line
if( dx==0 ) {
return 1;
}
} else if( dx==0 ) { // vertical line
} else if( dx<dy ) { // step in vertical direction
Missiles[missile].D=dy-1;
dx+=dx;
dy+=dy;
} else if( dx>dy ) { // step in horizontal direction
Missiles[missile].D=dx-1;
dx+=dx;
dy+=dy;
}
Missiles[missile].Dx=dx;
Missiles[missile].Dy=dy;
Missiles[missile].Xstep=xstep;
Missiles[missile].Ystep=ystep;
++Missiles[missile].State;
DebugLevel3("Init: %d,%d, %d,%d, =%d\n"
,dx,dy,xstep,ystep,Missiles[missile].D);
return 0;
} else {
dx=Missiles[missile].Dx;
dy=Missiles[missile].Dy;
xstep=Missiles[missile].Xstep;
ystep=Missiles[missile].Ystep;
}
//
// Move missile
//
if( dy==0 ) { // horizontal line
for( i=0; i<MISSILE_STEPS; ++i ) {
if( Missiles[missile].X==Missiles[missile].DX ) {
return 1;
}
Missiles[missile].X+=xstep;
}
return 0;
}
if( dx==0 ) { // vertical line
for( i=0; i<MISSILE_STEPS; ++i ) {
if( Missiles[missile].Y==Missiles[missile].DY ) {
return 1;
}
Missiles[missile].Y+=ystep;
}
return 0;
}
if( dx<dy ) { // step in vertical direction
for( i=0; i<MISSILE_STEPS; ++i ) {
if( Missiles[missile].Y==Missiles[missile].DY ) {
return 1;
}
Missiles[missile].Y+=ystep;
Missiles[missile].D-=dx;
if( Missiles[missile].D<0 ) {
Missiles[missile].D+=dy;
Missiles[missile].X+=xstep;
}
}
return 0;
}
if( dx>dy ) { // step in horizontal direction
for( i=0; i<MISSILE_STEPS; ++i ) {
if( Missiles[missile].X==Missiles[missile].DX ) {
return 1;
}
Missiles[missile].X+=xstep;
Missiles[missile].D-=dy;
if( Missiles[missile].D<0 ) {
Missiles[missile].D+=dx;
Missiles[missile].Y+=ystep;
}
}
return 0;
}
// diagonal line
for( i=0; i<MISSILE_STEPS; ++i ) {
if( Missiles[missile].Y==Missiles[missile].DY ) {
return 1;
}
Missiles[missile].X+=xstep;
Missiles[missile].Y+=ystep;
}
return 0;
}
