ShapePoint
XShape::geo_to_shape(const GeoPoint &origin, const GeoPoint &point) const
{
const GeoPoint d = point-origin;
ShapePoint pt;
pt.x = (ShapeScalar)fast_mult(point.latitude.fastcosine(),
fast_mult(d.longitude.Radians(),
fixed_earth_r, 12), 16);
pt.y = (ShapeScalar)-fast_mult(d.latitude.Radians(), fixed_earth_r, 12);
return pt;
}
ShapePoint
XShape::geo_to_shape(const GeoPoint &origin, const GeoPoint &point) const
{
const GeoPoint d = point-origin;
ShapePoint pt;
pt.x = (ShapeScalar)fast_mult(point.latitude.fastcosine(),
AngleToEarthDistance(d.longitude), 16);
pt.y = (ShapeScalar)-AngleToEarthDistance(d.latitude);
return pt;
}
RasterPoint
Projection::GeoToScreen(const GeoPoint &g) const
{
const GeoPoint d = GeoLocation-g;
const FastIntegerRotation::Pair p =
ScreenRotation.Rotate((int)fast_mult(g.Latitude.fastcosine(),
AngleToPixels(d.Longitude), 16),
(int)AngleToPixels(d.Latitude));
RasterPoint sc;
sc.x = ScreenOrigin.x - p.first;
sc.y = ScreenOrigin.y + p.second;
return sc;
}
/**
* Convert a an angle on Earth's surface to a pixel distance.
*/
gcc_pure
fixed AngleToPixels(Angle angle) const {
return fast_mult(angle.Radians(), draw_scale, 12);
}
gcc_const
static inline int
NATIVE_TO_INT_COS(fixed x)
{
return (iround(fast_mult(INT_ANGLE_MULT, 8, x, 2)) + 1024) & 0xfff;
}
/**
* Multiply two very small values (less than 4). This is an optimised
* fast path for fixed-point.
*/
constexpr
static inline fixed
SmallMult(fixed a, fixed b)
{
return fast_mult(a, b, 0);
}