public static float GetAngleBetweenVectors(
ShiftStorageCache.PointInfo a,
ShiftStorageCache.PointInfo b)
{
Debug.Assert(
a.vector_from_correction_to_cursor.Length ==
b.vector_from_correction_to_cursor.Length);
float dot_product = 0;
for (int i = 0; i < a.vector_from_correction_to_cursor.Length; i++)
{
dot_product += a.vector_from_correction_to_cursor[i] * b.vector_from_correction_to_cursor[i];
}
float cos = dot_product / a.distance / b.distance;
if (cos > 1.0)
{
cos = 1.0f;
}
else if (cos < -1.0)
{
cos = -1.0f;
}
return((float)Math.Acos(cos));
}
private float GetShadeOpacity(
ShiftStorageCache.PointInfo source_of_shade,
ShiftStorageCache.PointInfo shaded_correction)
{
Debug.Assert(source_of_shade.distance <= shaded_correction.distance);
float opacity = 1;
float angle_in_percents = (float)(Helpers.GetAngleBetweenVectors(source_of_shade, shaded_correction) * 100 / Math.PI);
Debug.Assert(angle_in_percents <= 100);
// Opacity descendes gradualy in the sector between opaque and transparent sectors.
if (angle_in_percents < calibration_mode.size_of_opaque_sector_in_percents)
{
opacity = 1;
}
else if (angle_in_percents > 100 - calibration_mode.size_of_transparent_sector_in_percents)
{
opacity = 0;
}
else
{
opacity = (angle_in_percents + calibration_mode.size_of_transparent_sector_in_percents - 100) /
(calibration_mode.size_of_opaque_sector_in_percents + calibration_mode.size_of_transparent_sector_in_percents - 100);
}
float distance_from_shade_shell_to_shaded_correction = shaded_correction.distance - source_of_shade.distance;
if (distance_from_shade_shell_to_shaded_correction < calibration_mode.shade_thickness_in_pixels)
{
opacity *= distance_from_shade_shell_to_shaded_correction / calibration_mode.shade_thickness_in_pixels;
}
return(opacity * source_of_shade.weight);
}