StelPainter Class Reference

Provides functions for performing openGL drawing operations. More...

#include <StelPainter.hpp>

Public Types
enum	SphericalPolygonDrawMode { SphericalPolygonDrawModeFill =0, SphericalPolygonDrawModeBoundary =1, SphericalPolygonDrawModeTextureFill =2, SphericalPolygonDrawModeTextureFillColormodulated =3 }
	Define the drawing mode when drawing polygons. More...
enum	DrawingMode {   Points = 0x0000, Lines = 0x0001, LineLoop = 0x0002, LineStrip = 0x0003,   Triangles = 0x0004, TriangleStrip = 0x0005, TriangleFan = 0x0006 }
	Define the drawing mode when drawing vertex. More...
enum	DitheringMode {   DitheringMode::Disabled, DitheringMode::Color565, DitheringMode::Color666, DitheringMode::Color888,   DitheringMode::Color101010 }

Public Member Functions
	StelPainter (const StelProjectorP &prj)
QOpenGLFunctions *	glFuncs ()
	Returns a QOpenGLFunctions object suitable for drawing directly with OpenGL while this StelPainter is active. More...
const StelProjectorP &	getProjector () const
	Return the instance of projector associated to this painter.
void	setProjector (const StelProjectorP &p)
void	drawViewportShape (void)
	Fill with black around the viewport.
void	drawText (float x, float y, const QString &str, float angleDeg=0.f, float xshift=0.f, float yshift=0.f, bool noGravity=true)
	Draw the string at the given position and angle with the given font. More...
void	drawText (const Vec3d &v, const QString &str, float angleDeg=0.f, float xshift=0.f, float yshift=0.f, bool noGravity=true)
void	drawSphericalRegion (const SphericalRegion *region, SphericalPolygonDrawMode drawMode=SphericalPolygonDrawModeFill, const SphericalCap *clippingCap=Q_NULLPTR, bool doSubDivise=true, double maxSqDistortion=5.)
	Draw the given SphericalRegion. More...
void	drawGreatCircleArcs (const StelVertexArray &va, const SphericalCap *clippingCap=Q_NULLPTR)
void	drawSphericalTriangles (const StelVertexArray &va, bool textured, bool colored, const SphericalCap *clippingCap=Q_NULLPTR, bool doSubDivide=true, double maxSqDistortion=5.)
void	drawSmallCircleArc (const Vec3d &start, const Vec3d &stop, const Vec3d &rotCenter, void(*viewportEdgeIntersectCallback)(const Vec3d &screenPos, const Vec3d &direction, void *userData)=Q_NULLPTR, void *userData=Q_NULLPTR)
	Draw a small circle arc between points start and stop with rotation point in rotCenter. More...
void	drawGreatCircleArc (const Vec3d &start, const Vec3d &stop, const SphericalCap *clippingCap=Q_NULLPTR, void(*viewportEdgeIntersectCallback)(const Vec3d &screenPos, const Vec3d &direction, void *userData)=Q_NULLPTR, void *userData=Q_NULLPTR)
	Draw a great circle arc between points start and stop. More...
void	drawPath (const QVector< Vec3d > &points, const QVector< Vec4f > &colors)
	Draw a curve defined by a list of points. More...
void	drawCircle (float x, float y, float r)
	Draw a simple circle, 2d viewport coordinates in pixel.
void	drawSprite2dMode (float x, float y, float radius)
	Draw a square using the current texture at the given projected 2d position. More...
void	drawSprite2dMode (const Vec3d &v, float radius)
void	drawSprite2dModeNoDeviceScale (float x, float y, float radius)
	Same as drawSprite2dMode but don't scale according to display device scaling.
void	drawSprite2dMode (float x, float y, float radius, float rotation)
	Draw a rotated square using the current texture at the given projected 2d position. More...
void	drawPoint2d (float x, float y)
	Draw a GL_POINT at the given position. More...
void	drawLine2d (float x1, float y1, float x2, float y2)
	Draw a line between the 2 points. More...
void	drawRect2d (float x, float y, float width, float height, bool textured=true)
	Draw a rectangle using the current texture at the given projected 2d position. More...
void	sSphere (const double radius, const double oneMinusOblateness, const unsigned int slices, const unsigned int stacks, const bool orientInside=false, const bool flipTexture=false, const float topAngle=0.0f, const float bottomAngle=static_cast< float >(M_PI))
void	sCylinder (double radius, double height, int slices, int orientInside=0)
	Re-implementation of gluCylinder : glu is overridden for non-standard projection.
void	sSphereMap (double radius, unsigned int slices, unsigned int stacks, float textureFov=2.f *static_cast< float >(M_PI), int orientInside=0)
	Draw a fisheye texture in a sphere.
void	setFont (const QFont &font)
	Set the font to use for subsequent text drawing.
void	setColor (float r, float g, float b, float a=1.f)
	Set the color to use for subsequent drawing.
void	setColor (Vec3f rgb, float a=1.f)
	Set the color to use for subsequent drawing.
void	setColor (Vec4f rgba)
	Set the color to use for subsequent drawing.
Vec4f	getColor () const
	Get the color currently used for drawing.
QFontMetrics	getFontMetrics () const
	Get the font metrics for the current font.
void	setBlending (bool enableBlending, GLenum blendSrc=GL_SRC_ALPHA, GLenum blendDst=GL_ONE_MINUS_SRC_ALPHA)
	Enable OpenGL blending. More...
void	setDepthTest (bool enable)
void	setDepthMask (bool enable)
void	setCullFace (bool enable)
	Set the OpenGL GL_CULL_FACE state, by default face culling is disabled.
void	setLineSmooth (bool enable)
	Enables/disables line smoothing. By default, smoothing is disabled.
void	setLineWidth (float width)
	Sets the line width. Default is 1.0f.
float	getLineWidth () const
	Gets the line width.
void	setSaturation (float v)
	Sets the color saturation effect value, from 0 (grayscale) to 1 (no effect).
void	setVertexPointer (int size, GLenum type, const void *pointer)
	use instead of glVertexPointer
void	setTexCoordPointer (int size, GLenum type, const void *pointer)
	use instead of glTexCoordPointer
void	setColorPointer (int size, GLenum type, const void *pointer)
	use instead of glColorPointer
void	setNormalPointer (GLenum type, const void *pointer)
	use instead of glNormalPointer
void	enableClientStates (bool vertex, bool texture=false, bool color=false, bool normal=false)
	Simulates glEnableClientState, basically you describe what data the ::drawFromArray call has available.
void	setArrays (const Vec3d *vertices, const Vec2f *texCoords=Q_NULLPTR, const Vec3f *colorArray=Q_NULLPTR, const Vec3f *normalArray=Q_NULLPTR)
	convenience method that enable and set all the given arrays. More...
void	setArrays (const Vec3f *vertices, const Vec2f *texCoords=Q_NULLPTR, const Vec3f *colorArray=Q_NULLPTR, const Vec3f *normalArray=Q_NULLPTR)
void	drawFromArray (DrawingMode mode, int count, int offset=0, bool doProj=true, const unsigned short *indices=Q_NULLPTR)
	Draws primitives using vertices from the arrays specified by setArrays() or enabled via enableClientStates(). More...
void	drawStelVertexArray (const StelVertexArray &arr, bool checkDiscontinuity=true)
	Draws the primitives defined in the StelVertexArray. More...
DitheringMode	getDitheringMode () const

Static Public Member Functions
static StelVertexArray	computeSphereNoLight (double radius, double oneMinusOblateness, unsigned int slices, unsigned int stacks, int orientInside=0, bool flipTexture=false, float topAngle=0.0f, float bottomAngle=static_cast< float >(M_PI))
	Generate a StelVertexArray for a sphere. More...
static void	computeFanDisk (float radius, uint innerFanSlices, uint level, QVector< Vec3d > &vertexArr, QVector< Vec2f > &texCoordArr)
	Draw a disk with a special texturing mode having texture center at center of disk. More...
static void	initGLShaders ()
	Create the OpenGL shaders programs used by the StelPainter. More...
static void	deinitGLShaders ()
	Delete the OpenGL shaders objects. More...
static bool	linkProg (class QOpenGLShaderProgram *prog, const QString &name)
	Link an opengl program and show a message in case of error or warnings. More...

Friends
class	VertexArrayProjector
class	StelTextureMgr
class	StelTexture

Detailed Description

All coordinates are converted using the StelProjector instance passed at construction. Because openGL is not thread safe, only one instance of StelPainter can exist at a time, enforcing thread safety. As a coding rule, no openGL calls should be performed when no instance of StelPainter exist. Typical usage is to create a local instance of StelPainter where drawing operations are needed.

Member Enumeration Documentation

DitheringMode

enum StelPainter::DitheringMode

strong

Enumerator
Disabled	Dithering disabled, will leave the infamous color bands.
Color565	16-bit color (AKA High color) with R5_G6_B5 layout
Color666	TN+film typical color depth in TrueColor mode.
Color888	24-bit color (AKA True color)
Color101010	30-bit color (AKA Deep color)

DrawingMode

enum StelPainter::DrawingMode

Enumerator
Points	GL_POINTS.
Lines	GL_LINES.
LineLoop	GL_LINE_LOOP.
LineStrip	GL_LINE_STRIP.
Triangles	GL_TRIANGLES.
TriangleStrip	GL_TRIANGLE_STRIP.
TriangleFan	GL_TRIANGLE_FAN.

SphericalPolygonDrawMode

enum StelPainter::SphericalPolygonDrawMode

Enumerator
SphericalPolygonDrawModeFill	Draw the interior of the polygon.
SphericalPolygonDrawModeBoundary	Draw the boundary of the polygon.
SphericalPolygonDrawModeTextureFill	Draw the interior of the polygon filled with the current texture.
SphericalPolygonDrawModeTextureFillColormodulated	Draw the interior of the polygon filled with the current texture multiplied by vertex colors.

Member Function Documentation

computeFanDisk()

static void StelPainter::computeFanDisk ( float  radius, uint  innerFanSlices, uint  level, QVector< Vec3d > &  vertexArr, QVector< Vec2f > &  texCoordArr  )

static

The disk is made up of concentric circles with increasing refinement. The number of slices of the outmost circle is (innerFanSlices<<level).

Parameters

radius	the radius of the disk.
innerFanSlices	the number of slices.
level	the number of concentric circles.
vertexArr	the vertex array in which the resulting vertices are returned.
texCoordArr	the vertex array in which the resulting texture coordinates are returned.

computeSphereNoLight()

static StelVertexArray StelPainter::computeSphereNoLight ( double  radius, double  oneMinusOblateness, unsigned int  slices, unsigned int  stacks, int  orientInside = 0, bool  flipTexture = false, float  topAngle = 0.0f, float  bottomAngle = static_cast< float >(M_PI)  )

static

Parameters

radius
oneMinusOblateness
slices	number of vertical segments ("meridian zones")
stacks	number of horizontal segments ("latitude zones")
orientInside	1 to have normals point inside, e.g. for Milky Way, Zodiacal Light, etc.
flipTexture	if texture should be mapped to inside of sphere, e.g. Milky Way.
topAngle	An opening angle [radians] at top of the sphere. Useful if there is an empty region around the top pole, like North Galactic Pole.
bottomAngle	An opening angle [radians] at bottom of the sphere. Useful if there is an empty region around the bottom pole, like South Galactic Pole.

deinitGLShaders()

static void StelPainter::deinitGLShaders ( )

static

This method needs to be called once before exit.

drawFromArray()

void StelPainter::drawFromArray	(	DrawingMode	mode,
		int	count,
		int	offset = 0,
		bool	doProj = true,
		const unsigned short *	indices = Q_NULLPTR
	)

Parameters

mode	The type of primitive to draw. If
indices	is Q_NULLPTR, this operation will consume
count	values from the enabled arrays, starting at
offset.	Else it will consume
count	elements of
indices,starting	at
offset,which	are used to index into the enabled arrays. NOTE: Prefer to use drawStelVertexArray, else there are wrap-around rendering artifacts in a few projections.

drawGreatCircleArc()

void StelPainter::drawGreatCircleArc	(	const Vec3d &	start,
		const Vec3d &	stop,
		const SphericalCap *	clippingCap = Q_NULLPTR,
		void(*)(const Vec3d &screenPos, const Vec3d &direction, void *userData)	viewportEdgeIntersectCallback = Q_NULLPTR,
		void *	userData = Q_NULLPTR
	)

The angle between start and stop must be < 180 deg. The algorithm ensures that the line will look smooth, even for non linear distortion. Each time the great circle crosses the edge of the viewport, the viewportEdgeIntersectCallback is called with the screen 2d position, direction of the currently drawn arc toward the inside of the viewport.

Parameters

clippingCap

if not set to Q_NULLPTR, tells the painter to try to clip part of the region outside the cap.

drawLine2d()

void StelPainter::drawLine2d	(	float	x1,
		float	y1,
		float	x2,
		float	y2
	)

Parameters

x1	x position of point 1 in the viewport in pixels. 0 is at left.
y1	y position of point 1 in the viewport in pixels. 0 is at bottom.
x2	x position of point 2 in the viewport in pixels. 0 is at left.
y2	y position of point 2 in the viewport in pixels. 0 is at bottom.

drawPath()

void StelPainter::drawPath	(	const QVector< Vec3d > &	points,
		const QVector< Vec4f > &	colors
	)

The points should be already tesselated to ensure that the path will look smooth. The algorithm take care of cutting the path if it crosses a viewport discontinuity.

drawPoint2d()

void StelPainter::drawPoint2d	(	float	x,
		float	y
	)

Parameters

x	x position in the viewport in pixels.
y	y position in the viewport in pixels.

drawRect2d()

void StelPainter::drawRect2d	(	float	x,
		float	y,
		float	width,
		float	height,
		bool	textured = true
	)

This method is not thread safe.

Parameters

x	x position of the top left corner in the viewport in pixel.
y	y position of the tope left corner in the viewport in pixel.
width	width in pixel.
height	height in pixel.
textured	whether the current texture should be used for painting.

drawSmallCircleArc()

void StelPainter::drawSmallCircleArc	(	const Vec3d &	start,
		const Vec3d &	stop,
		const Vec3d &	rotCenter,
		void(*)(const Vec3d &screenPos, const Vec3d &direction, void *userData)	viewportEdgeIntersectCallback = Q_NULLPTR,
		void *	userData = Q_NULLPTR
	)

The angle between start and stop must be < 180 deg. The algorithm ensures that the line will look smooth, even for non linear distortion. Each time the small circle crosses the edge of the viewport, the viewportEdgeIntersectCallback is called with the screen 2d position, direction of the currently drawn arc toward the inside of the viewport. Example: A latitude circle has 0/0/sin(latitude) as rotCenter. If rotCenter is equal to 0,0,0, the method draws a great circle.

drawSphericalRegion()

void StelPainter::drawSphericalRegion	(	const SphericalRegion *	region,
		SphericalPolygonDrawMode	drawMode = SphericalPolygonDrawModeFill,
		const SphericalCap *	clippingCap = Q_NULLPTR,
		bool	doSubDivise = true,
		double	maxSqDistortion = 5.
	)

Parameters

region	The SphericalRegion to draw.
drawMode	define whether to draw the outline or the fill or both.
clippingCap	if not set to Q_NULLPTR, tells the painter to try to clip part of the region outside the cap.
doSubDivise	if true tesselates the object to follow projection distortions. Typically set that to false if you think that the region is fully contained in the viewport.

drawSprite2dMode() [1/2]

void StelPainter::drawSprite2dMode	(	float	x,
		float	y,
		float	radius
	)

This method is not thread safe.

Parameters

x	x position in the viewport in pixel.
y	y position in the viewport in pixel.
radius	the half size of a square side in pixel.
v	direction vector of object to draw. Will draw only if this is in the visible hemisphere.

drawSprite2dMode() [2/2]

void StelPainter::drawSprite2dMode	(	float	x,
		float	y,
		float	radius,
		float	rotation
	)

This method is not thread safe.

Parameters

x	x position in the viewport in pixel.
y	y position in the viewport in pixel.
radius	the half size of a square side in pixel.
rotation	rotation angle in degree.

drawStelVertexArray()

void StelPainter::drawStelVertexArray	(	const StelVertexArray &	arr,
		bool	checkDiscontinuity = true
	)

Parameters

checkDiscontinuity

will check and suppress discontinuities if necessary.

drawText()

void StelPainter::drawText	(	float	x,
		float	y,
		const QString &	str,
		float	angleDeg = 0.f,
		float	xshift = 0.f,
		float	yshift = 0.f,
		bool	noGravity = true
	)

If the gravity label flag is set, uses drawTextGravity180.

Parameters

x	horizontal position of the lower left corner of the first character of the text in pixel.
y	vertical position of the lower left corner of the first character of the text in pixel.
str	the text to print.
angleDeg	rotation angle in degree. Rotation is around x,y.
xshift	shift in pixel in the rotated x direction.
yshift	shift in pixel in the rotated y direction.
noGravity	don't take into account the fact that the text should be written with gravity.
v	direction vector of object to draw. GZ20120826: Will draw only if this is in the visible hemisphere.

glFuncs()

QOpenGLFunctions* StelPainter::glFuncs ( )

inline

This is recommended to be used instead of QOpenGLContext::currentContext()->functions() when a StelPainter is available, and you only need to call a few GL functions directly.

initGLShaders()

static void StelPainter::initGLShaders ( )

static

This method needs to be called once at init.

linkProg()

static bool StelPainter::linkProg ( class QOpenGLShaderProgram *  prog, const QString &  name  )

static

Returns

true if the link was successful.

setArrays()

void StelPainter::setArrays	(	const Vec3d *	vertices,
		const Vec2f *	texCoords = Q_NULLPTR,
		const Vec3f *	colorArray = Q_NULLPTR,
		const Vec3f *	normalArray = Q_NULLPTR
	)

It is equivalent to calling enableClientStates() and set the array pointer for each array.

setBlending()

void StelPainter::setBlending	(	bool	enableBlending,
		GLenum	blendSrc = GL_SRC_ALPHA,
		GLenum	blendDst = GL_ONE_MINUS_SRC_ALPHA
	)

By default, blending is disabled. The additional parameters specify the blending mode, the default parameters are suitable for "normal" blending operations that you want in most cases. Blending will be automatically disabled when the StelPainter is destroyed.