void Atmosphere::computeColor
(double JD, Vec3d sunPos, Vec3d moonPos, float moonPhase, StelCore* core, float eclipseFac,
float latitude, float altitude, float temperature, float relativeHumidity)
{
// We lazily initialize vertex buffer at the first draw,
// so we can only call this after that.
// We also need a renderer reference (again lazily from draw()) to
// construct index buffers as they might change at every call to computeColor().
if(NULL == renderer) {return;}
const StelProjectorP prj = core->getProjection(StelCore::FrameAltAz, StelCore::RefractionOff);
if (viewport != prj->getViewport())
{
// The viewport changed: update the number of points in the grid
updateGrid(prj);
}
eclipseFactor = eclipseFac;
if(eclipseFac < 0.0001f)
eclipseFactor = 0.0001f;
// No need to calculate if not visible
if (!fader.getInterstate())
{
averageLuminance = 0.001f + lightPollutionLuminance;
return;
}
// Calculate the atmosphere RGB for each point of the grid
if (myisnan(sunPos.length()))
sunPos.set(0.,0.,-1.*AU);
if (myisnan(moonPos.length()))
moonPos.set(0.,0.,-1.*AU);
sunPos.normalize();
moonPos.normalize();
float sun_pos[3];
sun_pos[0] = sunPos[0];
sun_pos[1] = sunPos[1];
sun_pos[2] = sunPos[2];
float moon_pos[3];
moon_pos[0] = moonPos[0];
moon_pos[1] = moonPos[1];
moon_pos[2] = moonPos[2];
sky.setParamsv(sun_pos, 5.f);
skyb.setLocation(latitude * M_PI/180., altitude, temperature, relativeHumidity);
skyb.setSunMoon(moon_pos[2], sun_pos[2]);
// Calculate the date from the julian day.
int year, month, day;
StelUtils::getDateFromJulianDay(JD, &year, &month, &day);
skyb.setDate(year, month, moonPhase);
// Variables used to compute the average sky luminance
double sum_lum = 0.;
Vec3d point(1., 0., 0.);
skylightStruct2 b2;
float lumi;
vertexGrid->unlock();
// Compute the sky color for every point above the ground
for (int i=0; i<(1+skyResolutionX)*(1+skyResolutionY); ++i)
{
const Vec2f position = vertexGrid->getVertex(i).position;
prj->unProject(position[0], position[1], point);
Q_ASSERT(fabs(point.lengthSquared()-1.0) < 1e-10);
if (point[2]<=0)
{
point[2] = -point[2];
// The sky below the ground is the symmetric of the one above :
// it looks nice and gives proper values for brightness estimation
}
// Use the Skybright.cpp 's models for brightness which gives better results.
lumi = skyb.getLuminance(moon_pos[0]*point[0]+moon_pos[1]*point[1]+moon_pos[2]*point[2],
sun_pos[0]*point[0]+sun_pos[1]*point[1]+sun_pos[2]*point[2],
point[2]);
lumi *= eclipseFactor;
// Add star background luminance
lumi += 0.0001;
// Multiply by the input scale of the ToneConverter (is not done automatically by the xyYtoRGB method called later)
//lumi*=eye->getInputScale();
// Add the light pollution luminance AFTER the scaling to avoid scaling it because it is the cause
// of the scaling itself
lumi += lightPollutionLuminance;
// Store for later statistics
sum_lum+=lumi;
Q_ASSERT_X(NULL != vertexGrid, Q_FUNC_INFO,
"Vertex buffer not initialized when setting colors");
// Now need to compute the xy part of the color component
// This is done in a GLSL shader if possible
if(NULL != shader)
{
// Store the back projected position + luminance in the input color to the shader
const Vec4f color = Vec4f(point[0], point[1], point[2], lumi);
vertexGrid->setVertex(i, Vertex(position, color));
continue;
}
// Shaderless fallback
if (lumi > 0.01)
{
// Use the Skylight model for the color
b2.pos[0] = point[0];
b2.pos[1] = point[1];
b2.pos[2] = point[2];
sky.getxyYValuev(b2);
}
else
{
// Too dark to see atmosphere color, don't bother computing it
b2.color[0] = 0.25;
b2.color[1] = 0.25;
}
const Vec4f color = Vec4f(b2.color[0], b2.color[1], lumi, 1.0f);
vertexGrid->setVertex(i, Vertex(position, color));
}
vertexGrid->lock();
// Update average luminance
averageLuminance = sum_lum/((1+skyResolutionX)*(1+skyResolutionY));
}
void Atmosphere::updateGrid(const StelProjectorP projector)
{
viewport = projector->getViewport();
const float viewportWidth = projector->getViewportWidth();
const float viewportHeight = projector->getViewportHeight();
const float aspectRatio = viewportWidth / viewportHeight;
skyResolutionY = StelApp::getInstance()
.getSettings()
->value("landscape/atmosphereybin", 44)
.toInt();
const float resolutionX = skyResolutionY * 0.5 * sqrt(3.0) * aspectRatio;
skyResolutionX = static_cast<int>(floor(0.5 + resolutionX));
const float stepX = viewportWidth / (skyResolutionX - 0.5);
const float stepY = viewportHeight / skyResolutionY;
const float viewportLeft = projector->getViewportPosX();
const float viewportBottom = projector->getViewportPosY();
vertexGrid->unlock();
vertexGrid->clear();
// Construct the vertex grid.
for(int y = 0; y <= skyResolutionY; ++y)
{
const float yPos = viewportBottom + y * stepY;
for (int x = 0; x <= skyResolutionX; ++x)
{
const float offset = (x == 0) ? 0.0f :
(x == skyResolutionX) ? viewportWidth
: (x - 0.5 * (y & 1)) * stepX;
const float xPos = viewportLeft + offset;
vertexGrid->addVertex(Vertex(Vec2f(xPos, yPos), Vec4f()));
}
}
vertexGrid->lock();
// The grid is (resolutionX + 1) * (resolutionY + 1),
// so the rows are for 0 to resolutionY-1
// The last row includes vertices in row resolutionY
// Construct an index buffer for each row in the grid.
for(int row = 0; row < skyResolutionY; ++row)
{
StelIndexBuffer* buffer;
// Reuse previously used row index buffer.
if(rowIndices.size() > row)
{
buffer = rowIndices[row];
buffer->unlock();
buffer->clear();
}
// Add new row index buffer.
else
{
buffer = renderer->createIndexBuffer(IndexType_U16);
rowIndices.append(buffer);
}
uint g0 = row * (1 + skyResolutionX);
uint g1 = (row + 1) * (1 + skyResolutionX);
for (int col = 0; col <= skyResolutionX; ++col)
{
buffer->addIndex(g0++);
buffer->addIndex(g1++);
}
buffer->lock();
Q_ASSERT_X(buffer->length() == (skyResolutionX + 1) * 2, Q_FUNC_INFO,
"Unexpected grid row index buffer size");
}
Q_ASSERT_X(rowIndices.size() >= skyResolutionY, Q_FUNC_INFO,
"Not enough row index buffers");
}
