Detailed Description

A set of auxiliary functions that can be called to render OpenGL primitives from MRPT or user code.

Classes
struct	TRenderInfo
	Information about the rendering process being issued. More...

Functions
Miscellaneous rendering methods
void	renderSetOfObjects (const mrpt::opengl::CListOpenGLObjects &objs)
	For each object in the list: More...

void	checkOpenGLError ()
	Checks glGetError and throws an exception if an error situation is found. More...

void	renderTriangleWithNormal (const mrpt::math::TPoint3D &p1, const mrpt::math::TPoint3D &p2, const mrpt::math::TPoint3D &p3)
	Can be used by derived classes to draw a triangle with a normal vector computed automatically - to be called within a glBegin()-glEnd() block. More...

void	renderTriangleWithNormal (const mrpt::math::TPoint3Df &p1, const mrpt::math::TPoint3Df &p2, const mrpt::math::TPoint3Df &p3)

void	renderQuadWithNormal (const mrpt::math::TPoint3Df &p1, const mrpt::math::TPoint3Df &p2, const mrpt::math::TPoint3Df &p3, const mrpt::math::TPoint3Df &p4)
	Can be used by derived classes to draw a quad with a normal vector computed automatically - to be called within a glBegin()-glEnd() block. More...

void	getCurrentRenderingInfo (TRenderInfo &ri)
	Gather useful information on the render parameters. More...

void	renderMessageBox (const float msg_x, const float msg_y, const float msg_w, const float msg_h, const std::string &text, float text_scale, const mrpt::utils::TColor &back_col=mrpt::utils::TColor(0, 0, 50, 150), const mrpt::utils::TColor &border_col=mrpt::utils::TColor(0, 0, 0, 140), const mrpt::utils::TColor &text_col=mrpt::utils::TColor(255, 255, 255, 220), const float border_width=4.0f, const std::string &text_font=std::string("sans"), mrpt::opengl::TOpenGLFontStyle text_style=mrpt::opengl::FILL, const double text_spacing=1.5, const double text_kerning=0.1)
	Draws a message box with a centered (possibly multi-lined) text. More...

OpenGL bitmapped 2D fonts
void	renderTextBitmap (const char str, void fontStyle)
	This method is safe for calling from within ::render() methods. More...

int	textBitmapWidth (const std::string &str, mrpt::opengl::TOpenGLFont font=mrpt::opengl::MRPT_GLUT_BITMAP_TIMES_ROMAN_24)
	Return the exact width in pixels for a given string, as will be rendered by renderTextBitmap(). More...

OpenGL vector 3D fonts
void	glSetFont (const std::string &fontname)
	sets the font to use for future font rendering commands. More...

const std::string &	glGetFont ()
	returns the name of the currently active font More...

mrpt::utils::TPixelCoordf	glDrawText (const std::string &text, const double textScale, enum TOpenGLFontStyle style=NICE, double spacing=1.5, double kerning=0.1)
	renders a string in GL using the current settings. More...

mrpt::utils::TPixelCoordf	glGetExtends (const std::string &text, const double textScale, double spacing=1.5, double kerning=0.1)
	returns the size of the bounding box of a text to be rendered, similar to glDrawText but without any visual output More...

Function Documentation

◆ checkOpenGLError()

void mrpt::opengl::gl_utils::checkOpenGLError ( )

Checks glGetError and throws an exception if an error situation is found.

Definition at line 140 of file gl_utils.cpp.

References GL_NO_ERROR, and glGetError().

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◆ getCurrentRenderingInfo()

void mrpt::opengl::gl_utils::getCurrentRenderingInfo ( TRenderInfo & ri )

Gather useful information on the render parameters.

It can be called from within the render() method of CRenderizable-derived classes, and the returned matrices can be used to determine whether a given point (lx,ly,lz) in local coordinates wrt the object being rendered falls within the screen or not:

  TRenderInfo ri;
  getCurrentRenderingInfo(ri);
  Eigen::Matrix<float,4,4> M= ri.proj_matrix * ri.model_matrix *
HomogeneousMatrix(lx,ly,lz);
  const float rend_x = M(0,3)/M(3,3);
  const float rend_y = M(1,3)/M(3,3);

where (rend_x,rend_y) are both in the range [-1,1].

It can be called from within the render() method of derived classes.

Definition at line 213 of file gl_utils.cpp.

Referenced by mrpt::opengl::CPointCloudColoured::render(), and mrpt::opengl::CPointCloud::render().

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◆ glDrawText()

mrpt::utils::TPixelCoordf mrpt::opengl::gl_utils::glDrawText	(	const std::string &	text,
		const double	textScale,
		enum TOpenGLFontStyle	style = `NICE`,
		double	spacing = `1.5`,
		double	kerning = `0.1`
	)

renders a string in GL using the current settings.

Font coordinates are +X along the line and +Y along the up direction of glyphs. The origin is at the top baseline at the left of the first character. Characters have a maximum size of 1. linefeed is interpreted as a new line and the start is offset in -Y direction by spacing . Individual characters are separated by kerning + plus their individual with.

Parameters

text	string to be rendered, unknown characters are replaced with '?'
textScale	The size of the characters (default=1.0)
style	rendering style
spacing	distance between individual text lines
kerning	distance between characters

Note: This functions comes from libcvd (LGPL, http://www.edwardrosten.com/cvd/ )

Definition at line 640 of file gl_utils.cpp.

References mrpt::opengl::FILL, fill(), GL_BLEND, GL_COLOR_BUFFER_BIT, GL_LINE_BIT, GL_LINE_SMOOTH, GL_MODELVIEW, GL_ONE_MINUS_SRC_ALPHA, GL_SRC_ALPHA, GL_VERTEX_ARRAY, glBlendFunc(), glDisableClientState(), glEnable(), glEnableClientState(), glLineWidth(), glMatrixMode(), glPopAttrib(), glPopMatrix(), glPushAttrib(), glPushMatrix(), glScaled(), glTranslated(), MRPT_UNUSED_PARAM, mrpt::opengl::NICE, mrpt::opengl::OUTLINE, THROW_EXCEPTION, and void().

Referenced by mrpt::opengl::CColorBar::render_dl(), mrpt::opengl::CAxis::render_dl(), mrpt::opengl::CText3D::render_dl(), mrpt::opengl::CTextMessageCapable::render_text_messages(), and renderMessageBox().

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◆ glGetExtends()

mrpt::utils::TPixelCoordf mrpt::opengl::gl_utils::glGetExtends	(	const std::string &	text,
		const double	textScale,
		double	spacing = `1.5`,
		double	kerning = `0.1`
	)

returns the size of the bounding box of a text to be rendered, similar to glDrawText but without any visual output

Note: This functions comes from libcvd (LGPL, http://www.edwardrosten.com/cvd/ )

Definition at line 743 of file gl_utils.cpp.

References MRPT_UNUSED_PARAM, and THROW_EXCEPTION.

Referenced by renderMessageBox().

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◆ glGetFont()

const std::string & mrpt::opengl::gl_utils::glGetFont ( )

returns the name of the currently active font

Definition at line 631 of file gl_utils.cpp.

References THROW_EXCEPTION.

◆ glSetFont()

void mrpt::opengl::gl_utils::glSetFont ( const std::string & fontname )

sets the font to use for future font rendering commands.

currently "sans", "serif" and "mono" are available.

Parameters

fontname string containing font name

Definition at line 621 of file gl_utils.cpp.

References MRPT_UNUSED_PARAM.

Referenced by mrpt::opengl::CColorBar::render_dl(), mrpt::opengl::CText3D::render_dl(), mrpt::opengl::CTextMessageCapable::render_text_messages(), and renderMessageBox().

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◆ renderMessageBox()

void mrpt::opengl::gl_utils::renderMessageBox	(	const float	msg_x,
		const float	msg_y,
		const float	msg_w,
		const float	msg_h,
		const std::string &	text,
		float	text_scale,
		const mrpt::utils::TColor &	back_col = `mrpt::utils::TColor(0, 0, 50, 150)`,
		const mrpt::utils::TColor &	border_col = `mrpt::utils::TColor(0, 0, 0, 140)`,
		const mrpt::utils::TColor &	text_col = `mrpt::utils::TColor(255, 255, 255, 220)`,
		const float	border_width = `4.0f`,
		const std::string &	text_font = `std::string("sans")`,
		mrpt::opengl::TOpenGLFontStyle	text_style = `mrpt::opengl::FILL`,
		const double	text_spacing = `1.5`,
		const double	text_kerning = `0.1`
	)

Draws a message box with a centered (possibly multi-lined) text.

It consists of a filled rectangle with a frame around and the centered text in the middle.

The appearance of the box is highly configurable via parameters.

Parameters

[in]	msg_x,msg_y	The left-lower corner coordinates, in ratio [0,1] of the viewport size. (0,0) if the left-bottom corner of the viewport.
[in]	msg_w,msg_h	The width & height, in ratio [0,1] of the viewport size.
[in]	text	The text to display. Multiple lines can be drawn with the ' ' character.
[in]	text_scale	Size of characters, in ration [0,1] of the viewport size. Note that this size may be scaled automatically reduced to fit the text withtin the rectangle of the message box.
[in]	back_col	Color of the rectangle background. Alpha can be <255 to enable transparency.
[in]	border_col	Color of the rectangle frame. Alpha can be <255 to enable transparency.
[in]	text_col	Color of the text background. Alpha can be <255 to enable transparency.
[in]	border_width	Width of the border, in pixels
[in]	text_font,text_style,text_spacing,text_kerning	See mrpt::opengl::gl_utils::glDrawText()

Example (see directory: 'samples/display3D_custom_render'):

Definition at line 384 of file gl_utils.cpp.

References mrpt::utils::TColor::A, mrpt::utils::TColor::B, mrpt::utils::TColor::G, GL_BLEND, GL_DEPTH_TEST, GL_LIGHTING, GL_LINE_LOOP, GL_MODELVIEW, GL_ONE_MINUS_SRC_ALPHA, GL_PROJECTION, GL_SRC_ALPHA, GL_TRIANGLE_FAN, GL_VIEWPORT, glBegin(), glBlendFunc(), glColor4ub(), glDisable(), glDrawText(), glEnable(), glEnd(), glGetExtends(), glGetIntegerv(), glLineWidth(), glLoadIdentity(), glMatrixMode(), glOrtho(), glPopMatrix(), glPushMatrix(), glSetFont(), glTranslatef(), glVertex2f(), min, MRPT_UNUSED_PARAM, mrpt::utils::TColor::R, mrpt::utils::TPixelCoordf::x, and mrpt::utils::TPixelCoordf::y.

Referenced by mrpt::graphslam::CWindowObserver::OnEvent().

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◆ renderQuadWithNormal()

void mrpt::opengl::gl_utils::renderQuadWithNormal	(	const mrpt::math::TPoint3Df &	p1,
		const mrpt::math::TPoint3Df &	p2,
		const mrpt::math::TPoint3Df &	p3,
		const mrpt::math::TPoint3Df &	p4
	)

Can be used by derived classes to draw a quad with a normal vector computed automatically - to be called within a glBegin()-glEnd() block.

Definition at line 202 of file gl_utils.cpp.

References renderTriangleWithNormal().

Referenced by mrpt::opengl::CFrustum::render_dl().

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◆ renderSetOfObjects()

void mrpt::opengl::gl_utils::renderSetOfObjects ( const mrpt::opengl::CListOpenGLObjects & objs )

For each object in the list:

checks visibility of each object
prepare the GL_MODELVIEW matrix according to its coordinates
call its ::render()
shows its name (if enabled).

Note: Used by COpenGLViewport, CSetOfObjects

checks visibility of each object
prepare the GL_MODELVIEW matrix according to its coordinates
call its ::render()
shows its name (if enabled).

Definition at line 32 of file gl_utils.cpp.

Referenced by mrpt::opengl::CSetOfObjects::render(), and mrpt::opengl::COpenGLViewport::render().

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◆ renderTextBitmap()

void mrpt::opengl::gl_utils::renderTextBitmap	(	const char *	str,
		void *	fontStyle
	)

This method is safe for calling from within ::render() methods.

See also: renderTextBitmap

Definition at line 255 of file gl_utils.cpp.

References MRPT_UNUSED_PARAM.

Referenced by mrpt::opengl::CText::render(), renderSetOfObjects(), and mrpt::opengl::CRenderizable::renderTextBitmap().

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◆ renderTriangleWithNormal() [1/2]

void mrpt::opengl::gl_utils::renderTriangleWithNormal	(	const mrpt::math::TPoint3D &	p1,
		const mrpt::math::TPoint3D &	p2,
		const mrpt::math::TPoint3D &	p3
	)

Can be used by derived classes to draw a triangle with a normal vector computed automatically - to be called within a glBegin()-glEnd() block.

Definition at line 154 of file gl_utils.cpp.

References glNormal3f(), glVertex3f(), MRPT_UNUSED_PARAM, mrpt::math::TPoint3D::x, mrpt::math::TPoint3D::y, and mrpt::math::TPoint3D::z.

Referenced by mrpt::opengl::CBox::render_dl(), and renderQuadWithNormal().

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◆ renderTriangleWithNormal() [2/2]

void mrpt::opengl::gl_utils::renderTriangleWithNormal	(	const mrpt::math::TPoint3Df &	p1,
		const mrpt::math::TPoint3Df &	p2,
		const mrpt::math::TPoint3Df &	p3
	)

Definition at line 178 of file gl_utils.cpp.

References glNormal3f(), glVertex3f(), MRPT_UNUSED_PARAM, mrpt::math::TPoint3Df::x, mrpt::math::TPoint3Df::y, and mrpt::math::TPoint3Df::z.

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◆ textBitmapWidth()

int mrpt::opengl::gl_utils::textBitmapWidth	(	const std::string &	str,
		mrpt::opengl::TOpenGLFont	font = `mrpt::opengl::MRPT_GLUT_BITMAP_TIMES_ROMAN_24`
	)