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#591: Fix sky flickering at certain sun/view angles

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Commit 5f0066c resulted in an incorrect angle calculation. At certain view/sun
angles "hor_rotation" and "rf1" would skip from the minimum to the maximum
value).
Also, an offset angle of 90 degrees (PI/2) is added, which seems to align
the sky effect with the sun position. Calculation is probably still wrong,
but seems less wrong than before - and the flickering is gone...
This commit is contained in:
ThorstenB 2012-03-07 20:43:52 +01:00
parent 644bb8c4f4
commit db098593be
1 changed files with 8 additions and 10 deletions
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18
src/Time/light.cxx
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@ -349,8 +349,6 @@ void FGLight::update_adj_fog_color () {
// direction to the sun
//double vert_rotation = pitch + pitch_offset;
double hor_rotation = -_sun_rotation + SGD_PI - heading + heading_offset;
// revert to unmodified values before using them.
//
SGSky* thesky = globals->get_renderer()->getSky();
@ -379,15 +377,15 @@ void FGLight::update_adj_fog_color () {
if (sif < 1e-4)
sif = 1e-4;
float rf1 = fabs(fmod(hor_rotation, SGD_2PI) - SGD_PI) / SGD_PI;
// determine horizontal angle between current view direction and sun
double hor_rotation = -_sun_rotation - SGD_PI_2 - heading + heading_offset;
if (hor_rotation < 0 )
hor_rotation = fmod(hor_rotation, SGD_2PI) + SGD_2PI;
else
hor_rotation = fmod(hor_rotation, SGD_2PI);
float rf1 = fabs((hor_rotation - SGD_PI) / SGD_PI); // 0.0 .. 1.0
float rf2 = avf * pow(rf1*rf1, 1/sif) * 1.0639 * _saturation * _scattering;
// HACK: clamp rf2 to 1.0.
// Somehow, rf2 is huge at certain sun angles (around midnight), which results in
// rf3 being negative and hence negative fog colors and weird display issues...
// Something more fundamental may be wrong with the formulas here...
if (rf2>1.0) rf2 = 1.0;
float rf3 = 1.0 - rf2;
gamma = system_gamma * (0.9 - sif*avf);