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...

Function Documentation

◆ checkOpenGLError()

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

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

Definition at line 143 of file gl_utils.cpp.

References GL_NO_ERROR, and glGetError().

◆ 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 216 of file gl_utils.cpp.

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

◆ glDrawText()

mrpt::img::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 (BSD, http://www.edwardrosten.com/cvd/ )

Definition at line 532 of file gl_utils.cpp.

References GL_MODELVIEW, glMatrixMode(), glPopMatrix(), glPushMatrix(), glScaled(), MRPT_UNUSED_PARAM, and THROW_EXCEPTION.

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().

◆ glGetExtends()

mrpt::img::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 (BSD, http://www.edwardrosten.com/cvd/ )

Definition at line 553 of file gl_utils.cpp.

References MRPT_UNUSED_PARAM, THROW_EXCEPTION, mrpt::img::TPixelCoordf::x, and mrpt::img::TPixelCoordf::y.

Referenced by renderMessageBox().

◆ glGetFont()

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

returns the name of the currently active font

Definition at line 523 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 514 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().

◆ 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::img::TColor &	back_col = `mrpt::img::TColor(0, 0, 50, 150)`,
		const mrpt::img::TColor &	border_col = `mrpt::img::TColor(0, 0, 0, 140)`,
		const mrpt::img::TColor &	text_col = `mrpt::img::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 387 of file gl_utils.cpp.

References mrpt::img::TColor::A, mrpt::img::TColor::B, mrpt::img::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::img::TColor::R, mrpt::img::TPixelCoordf::x, and mrpt::img::TPixelCoordf::y.

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

◆ 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 205 of file gl_utils.cpp.

References renderTriangleWithNormal().

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

◆ 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 35 of file gl_utils.cpp.

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

◆ 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 258 of file gl_utils.cpp.

References MRPT_UNUSED_PARAM.

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

◆ 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 157 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().

◆ 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 181 of file gl_utils.cpp.

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

◆ textBitmapWidth()

int mrpt::opengl::gl_utils::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().

See also: renderTextBitmap

Definition at line 301 of file gl_utils.cpp.

References aux_mrptfont2glutfont(), and MRPT_UNUSED_PARAM.

Referenced by mrpt::opengl::CRenderizable::textBitmapWidth().

Detailed Description

Classes

Function Documentation

◆ checkOpenGLError()

◆ getCurrentRenderingInfo()

◆ glDrawText()

◆ glGetExtends()

◆ glGetFont()

◆ glSetFont()

◆ renderMessageBox()

◆ renderQuadWithNormal()

◆ renderSetOfObjects()

◆ renderTextBitmap()

◆ renderTriangleWithNormal() [1/2]

◆ renderTriangleWithNormal() [2/2]

◆ textBitmapWidth()