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Fixed bugs and enhancements in new sky grid code: 

- Parallel spacing was off by a factor of two
- Fixed rotation bug that caused problems with grid orientations other than equatorial and ecliptic
- Allow labeling of longitude in degrees instead of hours
ver1_6_1
Chris Laurel 2008-05-29 19:24:39 +00:00
parent 42fd60366c
commit c1f1054b2f
2 changed files with 212 additions and 105 deletions
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291
src/celengine/skygrid.cpp
View File

@ -1,6 +1,6 @@
// skygrid.cpp
//
// Longitude/latitude grids for ellipsoidal bodies.
// Celestial longitude/latitude grids.
//
// Copyright (C) 2008, the Celestia Development Team
// Initial version by Chris Laurel, <claurel@gmail.com>
@ -139,7 +139,8 @@ static const int DEG_MIN_SEC_STEPS[] =
SkyGrid::SkyGrid() :
m_orientation(1.0),
m_lineColor(Color::White),
m_labelColor(Color::White)
m_labelColor(Color::White),
m_latitudeUnits(LatitudeHours)
{
}
@ -184,6 +185,33 @@ static void updateAngleRange(double a, double b, double* maxDiff, double* minAng
}
// Get the horizontal alignment for the coordinate label along the specified frustum plane
static Renderer::LabelAlignment
getCoordLabelHAlign(int planeIndex)
{
switch (planeIndex)
{
case 2:
return Renderer::AlignLeft;
case 3:
return Renderer::AlignRight;
default:
return Renderer::AlignCenter;
}
}
// Get the vertical alignment for the coordinate label along the specified frustum plane
static Renderer::LabelVerticalAlignment
getCoordLabelVAlign(int planeIndex)
{
if (planeIndex == 1)
return Renderer::VerticalAlignTop;
else
return Renderer::VerticalAlignBottom;
}
// Find the intersection of a circle and the plane with the specified normal and
// containing the origin. The circle is defined parametrically by:
// center + cos(t)*u + sin(t)*u
@ -247,12 +275,135 @@ template<class T> static bool planeCircleIntersection(const Vector3<T>& planeNor
}
// Get the a string with a label for the specified latitude. Both
// the latitude and latitudeStep are given in milliarcseconds.
string
SkyGrid::latitudeLabel(int latitude, int latitudeStep) const
{
// Produce a sexigesimal string
ostringstream out;
if (latitude < 0)
out << '-';
out << std::abs(latitude / DEG) << UTF8_DEGREE_SIGN;
if (latitudeStep % DEG != 0)
{
out << ' ' << setw(2) << setfill('0') << std::abs((latitude / MIN) % 60) << '\'';
if (latitudeStep % MIN != 0)
{
out << ' ' << setw(2) << setfill('0') << std::abs((latitude / SEC) % 60);
if (latitudeStep % SEC != 0)
out << '.' << setw(3) << setfill('0') << latitude % SEC;
out << '"';
}
}
return out.str();
}
// Get the a string with a label for the specified longitude. Both
// the longitude and longitude are given in milliarcseconds.
string
SkyGrid::longitudeLabel(int longitude, int longitudeStep) const
{
int totalUnits = HOUR_MIN_SEC_TOTAL;
int baseUnit = HR;
char* baseUnitSymbol = "h";
char minuteSymbol = 'm';
char secondSymbol = 's';
if (m_latitudeUnits == LatitudeDegrees)
{
totalUnits = DEG_MIN_SEC_TOTAL * 2;
baseUnit = DEG;
baseUnitSymbol = UTF8_DEGREE_SIGN;
minuteSymbol = '\'';
secondSymbol = '"';
}
// Produce a sexigesimal string
ostringstream out;
if (longitude < 0)
longitude += totalUnits;
out << longitude / baseUnit << baseUnitSymbol;
if (longitudeStep % baseUnit != 0)
{
out << ' ' << setw(2) << setfill('0') << (longitude / MIN) % 60 << minuteSymbol;
if (longitudeStep % MIN != 0)
{
out << ' ' << setw(2) << setfill('0') << (longitude / SEC) % 60;
if (longitudeStep % SEC != 0)
out << '.' << setw(3) << setfill('0') << longitude % SEC;
out << secondSymbol;
}
}
return out.str();
}
// Compute the angular step between parallels
int
SkyGrid::parallelSpacing(double idealSpacing) const
{
// We want to use parallels and meridian spacings that are nice multiples of hours, degrees,
// minutes, or seconds. Choose spacings from a table. We take the table entry that gives
// the spacing closest to but not less than the ideal spacing.
int spacing = DEG_MIN_SEC_TOTAL;
// Scan the tables to find the best spacings
unsigned int tableSize = sizeof(DEG_MIN_SEC_SPACING) / sizeof(DEG_MIN_SEC_SPACING[0]);
for (unsigned int i = 0; i < tableSize; i++)
{
if (PI * (double) DEG_MIN_SEC_SPACING[i] / (double) DEG_MIN_SEC_TOTAL < idealSpacing)
break;
spacing = DEG_MIN_SEC_SPACING[i];
}
return spacing;
}
// Compute the angular step between meridians
int
SkyGrid::meridianSpacing(double idealSpacing) const
{
const int* spacingTable = HOUR_MIN_SEC_SPACING;
unsigned int tableSize = sizeof(HOUR_MIN_SEC_SPACING) / sizeof(HOUR_MIN_SEC_SPACING[0]);
int totalUnits = HOUR_MIN_SEC_TOTAL;
// Use degree spacings if the latitude units are degrees instead of hours
if (m_latitudeUnits == LatitudeDegrees)
{
spacingTable = DEG_MIN_SEC_SPACING;
tableSize = sizeof(DEG_MIN_SEC_SPACING) / sizeof(DEG_MIN_SEC_SPACING[0]);
totalUnits = DEG_MIN_SEC_TOTAL * 2;
}
int spacing = totalUnits;
for (unsigned int i = 0; i < tableSize; i++)
{
if (2 * PI * (double) spacingTable[i] / (double) totalUnits < idealSpacing)
break;
spacing = spacingTable[i];
}
return spacing;
}
void
SkyGrid::render(Renderer& renderer,
const Observer& observer,
int windowWidth,
int windowHeight)
{
// 90 degree rotation about the x-axis used to transform coordinates
// to Celestia's system.
Quatd xrot90 = Quatd::xrotation(-PI / 2.0);
double vfov = observer.getFOV();
double viewAspectRatio = (double) windowWidth / (double) windowHeight;
@ -283,7 +434,7 @@ SkyGrid::render(Renderer& renderer,
Vec3d c3( w, h, -1.0);
Quatd cameraOrientation = observer.getOrientation();
Mat3d r = (cameraOrientation * ~m_orientation).toMatrix3();
Mat3d r = (cameraOrientation * xrot90 * ~m_orientation * ~xrot90).toMatrix3();
// Transform the frustum corners by the camera and grid
// rotations.
@ -378,49 +529,27 @@ SkyGrid::render(Renderer& renderer,
idealMeridianSpacing /= max(cos(PI / 2.0 - 5.0 * idealParallelSpacing), cos(maxAbsDec));
#endif
// We want to use parallels and meridian spacings that are nice multiples of hours, degrees,
// minutes, or seconds. Choose spacings from a table. We take the table entry that gives
// the spacing closest to but not less than the ideal spacing.
int raIncrement = HOUR_MIN_SEC_TOTAL;
int decIncrement = DEG_MIN_SEC_TOTAL;
int totalLatitudeUnits = HOUR_MIN_SEC_TOTAL;
if (m_latitudeUnits == LatitudeDegrees)
totalLatitudeUnits = DEG_MIN_SEC_TOTAL * 2;
// Scan the tables to find the best spacings
{
unsigned int i = 0;
for (i = 0; i < sizeof(DEG_MIN_SEC_SPACING) / sizeof(DEG_MIN_SEC_SPACING[0]); i++)
{
if (2 * PI * (double) DEG_MIN_SEC_SPACING[i] / (double) DEG_MIN_SEC_TOTAL < idealParallelSpacing)
break;
decIncrement = DEG_MIN_SEC_SPACING[i];
}
for (i = 0; i < sizeof(HOUR_MIN_SEC_SPACING) / sizeof(HOUR_MIN_SEC_SPACING[0]); i++)
{
if (2 * PI * (double) HOUR_MIN_SEC_SPACING[i] / (double) HOUR_MIN_SEC_TOTAL < idealMeridianSpacing)
break;
raIncrement = HOUR_MIN_SEC_SPACING[i];
}
int raIncrement = meridianSpacing(idealMeridianSpacing);
int decIncrement = parallelSpacing(idealParallelSpacing);
#ifdef CONSTRAIN_GRID_BLOCK_ASPECT_RATIO
double MAX_BLOCK_ASPECT_RATIO = 3.0;
double raSpacingAngle = (double) raIncrement / (double) HOUR_MIN_SEC_TOTAL * 2 * PI;
double decSpacingAngle = (double) decIncrement / (double) DEG_MIN_SEC_TOTAL * 2 * PI;
if (raSpacingAngle / decSpacingAngle > MAX_BLOCK_ASPECT_RATIO)
{
if (i < sizeof(HOUR_MIN_SEC_SPACING) / sizeof(HOUR_MIN_SEC_SPACING[0]) - 1)
raIncrement = HOUR_MIN_SEC_SPACING[i + 1];
}
#endif
}
int startRa = (int) std::ceil (HOUR_MIN_SEC_TOTAL * (minTheta / (PI * 2.0f)) / (float) raIncrement) * raIncrement;
int endRa = (int) std::floor(HOUR_MIN_SEC_TOTAL * (maxTheta / (PI * 2.0f)) / (float) raIncrement) * raIncrement;
int startRa = (int) std::ceil (totalLatitudeUnits * (minTheta / (PI * 2.0f)) / (float) raIncrement) * raIncrement;
int endRa = (int) std::floor(totalLatitudeUnits * (maxTheta / (PI * 2.0f)) / (float) raIncrement) * raIncrement;
int startDec = (int) std::ceil (DEG_MIN_SEC_TOTAL * (minDec / PI) / (float) decIncrement) * decIncrement;
int endDec = (int) std::floor(DEG_MIN_SEC_TOTAL * (maxDec / PI) / (float) decIncrement) * decIncrement;
// Get the orientation at single precision
Quatd q = xrot90 * m_orientation * ~xrot90;
Quatf orientationf((float) q.w, (float) q.x, (float) q.y, (float) q.z);
glColor(m_lineColor);
// Render the parallels
glPushMatrix();
glRotate(~m_orientation);
glRotate(xrot90 * ~m_orientation * ~xrot90);
// Radius of sphere is arbitrary, with the constraint that it shouldn't
// intersect the near or far plane of the view frustum.
@ -454,26 +583,13 @@ SkyGrid::render(Renderer& renderer,
{
Vec3d isect0(0.0, 0.0, 0.0);
Vec3d isect1(0.0, 0.0, 0.0);
Renderer::LabelAlignment hAlign = getCoordLabelHAlign(k);
Renderer::LabelVerticalAlignment vAlign = getCoordLabelVAlign(k);
if (planeCircleIntersection(frustumNormal[k], center, axis0, axis1,
&isect0, &isect1))
{
// Generate the coordinate label string
ostringstream out;
if (dec < 0)
out << '-';
out << std::abs(dec / DEG) << UTF8_DEGREE_SIGN;
if (decIncrement % DEG != 0)
{
out << ' ' << setw(2) << setfill('0') << std::abs((dec / MIN) % 60) << '\'';
if (decIncrement % MIN != 0)
{
out << ' ' << setw(2) << setfill('0') << std::abs((dec / SEC) % 60);
if (decIncrement % SEC != 0)
out << '.' << setw(3) << setfill('0') << dec % SEC;
clog << '"';
}
}
string labelText = out.str();
string labelText = latitudeLabel(dec, decIncrement);
Point3f p0((float) isect0.x, (float) isect0.z, (float) -isect0.y);
Point3f p1((float) isect1.x, (float) isect1.z, (float) -isect1.y);
@ -489,27 +605,18 @@ SkyGrid::render(Renderer& renderer,
#endif
Mat3f m = conjugate(observer.getOrientationf()).toMatrix3();
Quatf gridf((float) m_orientation.w, (float) m_orientation.x,
(float) m_orientation.y, (float) m_orientation.z);
p0 = p0 * (gridf).toMatrix3();
p1 = p1 * (gridf).toMatrix3();
p0 = p0 * orientationf.toMatrix3();
p1 = p1 * orientationf.toMatrix3();
Renderer::LabelAlignment halign = Renderer::AlignCenter;
if (k == 2)
halign = Renderer::AlignLeft;
else if (k == 3)
halign = Renderer::AlignRight;
Renderer::LabelVerticalAlignment valign = (k == 1) ? Renderer::VerticalAlignTop : Renderer::VerticalAlignBottom;
if ((p0 * m).z < 0.0)
{
renderer.addBackgroundAnnotation(labelText, m_labelColor, p0, halign, valign);
renderer.addBackgroundAnnotation(labelText, m_labelColor, p0, hAlign, vAlign);
}
if ((p1 * m).z < 0.0)
{
renderer.addBackgroundAnnotation(labelText, m_labelColor, p1, halign, valign);
}
renderer.addBackgroundAnnotation(labelText, m_labelColor, p1, hAlign, vAlign);
}
}
}
}
@ -529,7 +636,7 @@ SkyGrid::render(Renderer& renderer,
for (int ra = startRa; ra <= endRa; ra += raIncrement)
{
double theta = 2.0 * PI * (double) ra / (double) HOUR_MIN_SEC_TOTAL;
double theta = 2.0 * PI * (double) ra / (double) totalLatitudeUnits;
double cosTheta = cos(theta);
double sinTheta = sin(theta);
@ -553,54 +660,30 @@ SkyGrid::render(Renderer& renderer,
{
Vec3d isect0(0.0, 0.0, 0.0);
Vec3d isect1(0.0, 0.0, 0.0);
Renderer::LabelAlignment hAlign = getCoordLabelHAlign(k);
Renderer::LabelVerticalAlignment vAlign = getCoordLabelVAlign(k);
if (planeCircleIntersection(frustumNormal[k], center, axis0, axis1,
&isect0, &isect1))
{
// Generate the coordinate label string
ostringstream out;
int labelRa = ra;
if (labelRa < 0)
labelRa += 24 * HR;
out << std::abs(labelRa / HR) << 'h';
if (raIncrement % HR != 0)
{
out << ' ' << setw(2) << setfill('0') << (labelRa / MIN) % 60 << 'm';
if (raIncrement % MIN != 0)
{
out << ' ' << setw(2) << setfill('0') << (labelRa / SEC) % 60;
if (raIncrement % SEC != 0)
out << '.' << setw(3) << setfill('0') << labelRa % SEC;
out << 's';
}
}
string labelText = out.str();
string labelText = longitudeLabel(ra, raIncrement);
Point3f p0((float) isect0.x, (float) isect0.z, (float) -isect0.y);
Point3f p1((float) isect1.x, (float) isect1.z, (float) -isect1.y);
Mat3f m = conjugate(observer.getOrientationf()).toMatrix3();
Quatf gridf((float) m_orientation.w, (float) m_orientation.x,
(float) m_orientation.y, (float) m_orientation.z);
p0 = p0 * (gridf).toMatrix3();
p1 = p1 * (gridf).toMatrix3();
p0 = p0 * orientationf.toMatrix3();
p1 = p1 * orientationf.toMatrix3();
Renderer::LabelAlignment halign = Renderer::AlignCenter;
if (k == 2)
halign = Renderer::AlignLeft;
else if (k == 3)
halign = Renderer::AlignRight;
Renderer::LabelVerticalAlignment valign = (k == 1) ? Renderer::VerticalAlignTop : Renderer::VerticalAlignBottom;
if ((p0 * m).z < 0.0 && axis0 * isect0 >= cosMaxMeridianAngle)
{
renderer.addBackgroundAnnotation(labelText, m_labelColor, p0, halign, valign);
renderer.addBackgroundAnnotation(labelText, m_labelColor, p0, hAlign, vAlign);
}
if ((p1 * m).z < 0.0 && axis0 * isect1 >= cosMaxMeridianAngle)
{
renderer.addBackgroundAnnotation(labelText, m_labelColor, p1, halign, valign);
}
renderer.addBackgroundAnnotation(labelText, m_labelColor, p1, hAlign, vAlign);
}
}
}
}

26
src/celengine/skygrid.h
View File

@ -1,6 +1,6 @@
// skygrid.h
//
// Longitude/latitude grids for ellipsoidal bodies.
// Celestial longitude/latitude grids.
//
// Copyright (C) 2008, the Celestia Development Team
// Initial version by Chris Laurel, <claurel@gmail.com>
@ -13,6 +13,7 @@
#ifndef _CELENGINE_SKYGRID_H_
#define _CELENGINE_SKYGRID_H_
#include <string>
#include <celutil/color.h>
#include <celmath/quaternion.h>
@ -23,6 +24,12 @@ class Observer;
class SkyGrid
{
public:
enum LatitudeUnits
{
LatitudeDegrees,
LatitudeHours,
};
SkyGrid();
~SkyGrid();
@ -61,10 +68,27 @@ public:
m_labelColor = labelColor;
}
LatitudeUnits latitudeUnits() const
{
return m_latitudeUnits;
}
void setLatitudeUnits(LatitudeUnits latitudeUnits)
{
m_latitudeUnits = latitudeUnits;
}
private:
std::string latitudeLabel(int latitude, int latitudeStep) const;
std::string longitudeLabel(int longitude, int longitudeStep) const;
int parallelSpacing(double idealSpacing) const;
int meridianSpacing(double idealSpacing) const;
private:
Quatd m_orientation;
Color m_lineColor;
Color m_labelColor;
LatitudeUnits m_latitudeUnits;
};
#endif // _CELENGINE_PLANETGRID_H_