void Trace_Cercle( SDL_Surface* ecran, SDL_Rect C, int R, Couleur couleur )
{
float Theta;
SDL_Rect M;
for(Theta=0 ; Theta <= 2*M_PI; Theta = Theta + M_PI/180)
{
M.x = C.x + R*cos(Theta);
M.y = C.y + R*sin(Theta);
Trace_Point( ecran, M, couleur );
}
}
void Trace_Segment( SDL_Surface* ecran, SDL_Rect A, SDL_Rect B, Couleur couleur )
{
SDL_Rect M;
float a, b;
if( A.x == B.x)
{
M.x = A.x;
for(M.y=A.y; M.y<=B.y; M.y++)
Trace_Point(ecran, M, couleur);
for(M.y=A.y; M.y>=B.y; M.y--)
Trace_Point(ecran, M, couleur);
}
else
{
if( A.y == B.y)
{
M.y = A.y;
for(M.x=A.x; M.x<=B.x; M.x++)
Trace_Point(ecran, M, couleur);
for(M.x=A.x; M.x>=B.x; M.x--)
Trace_Point(ecran, M, couleur);
}
else
{
a = (float)(B.y-A.y)/(B.x-A.x);
b = A.y - a*A.x;
for(M.x=A.x; M.x<=B.x; M.x++)
{
M.y = a*M.x + b;
Trace_Point(ecran, M, couleur);
}
for(M.x=A.x; M.x>=B.x; M.x--)
{
M.y = a*M.x + b;
Trace_Point(ecran, M, couleur);
}
for(M.y=A.y; M.y<=B.y; M.y++)
{
M.x = (M.y-b)/a;
Trace_Point(ecran, M, couleur);
}
for(M.y=A.y; M.y>=B.y; M.y--)
{
M.x = (M.y-b)/a;
Trace_Point(ecran, M, couleur);
}
}
}
}
//---------------------------------------------------------
void CVisibility_BASE::Set_Visibility(CSG_Grid *pDTM, CSG_Grid *pVisibility, int x_Pos, int y_Pos, double z_Pos, double dHeight, int iMethod)
{
double Exaggeration = 1.0;
double aziDTM, decDTM,
aziSrc, decSrc,
d, dx, dy, dz;
for(int y=0; y<pDTM->Get_NY() && SG_UI_Process_Set_Progress(y, pDTM->Get_NY()); y++)
{
for(int x=0; x<pDTM->Get_NX(); x++)
{
if( pDTM->is_NoData(x, y) )
{
pVisibility->Set_NoData(x, y);
}
else
{
dx = x_Pos - x;
dy = y_Pos - y;
dz = z_Pos - pDTM->asDouble(x, y);
//-----------------------------------------
if( Trace_Point(pDTM, x, y, dx, dy, dz) )
{
switch( iMethod )
{
case 0: // Visibility
pVisibility->Set_Value(x, y, 1);
break;
case 1: // Shade
pDTM->Get_Gradient(x, y, decDTM, aziDTM);
decDTM = M_PI_090 - atan(Exaggeration * tan(decDTM));
decSrc = atan2(dz, sqrt(dx*dx + dy*dy));
aziSrc = atan2(dx, dy);
d = acos(sin(decDTM) * sin(decSrc) + cos(decDTM) * cos(decSrc) * cos(aziDTM - aziSrc));
if( d > M_PI_090 )
d = M_PI_090;
if( pVisibility->asDouble(x, y) > d )
pVisibility->Set_Value(x, y, d);
break;
case 2: // Distance
d = pDTM->Get_Cellsize() * sqrt(dx*dx + dy*dy);
if( pVisibility->is_NoData(x, y) || pVisibility->asDouble(x, y) > d )
pVisibility->Set_Value(x, y, d);
break;
case 3: // Size
if( (d = pDTM->Get_Cellsize() * sqrt(dx*dx + dy*dy)) > 0.0 )
{
d = atan2(dHeight, d);
if( pVisibility->is_NoData(x, y) || pVisibility->asDouble(x, y) < d )
pVisibility->Set_Value(x, y, d);
}
break;
}
}
}
}
}
return;
}
