Xrb::Render Namespace Reference

Houses all of the basic rendering primitives used by XuqRijBuh. More...

Functions
void	DrawLine (RenderContext const &render_context, FloatVector2 const &from, FloatVector2 const &to, Color const &color)
	Draws a line between from and to in the given color.
void	DrawArrow (RenderContext const &render_context, FloatVector2 const &from, FloatVector2 const &to, Color const &color)
	Draws an arrow with tail at from and head at to, in the given color.
void	DrawPolygon (RenderContext const &render_context, FloatVector2 const &center, Float radius, Float angle, Color const &color, Uint32 vertex_count)
	Draws a regular polygon.
void	DrawCircle (RenderContext const &render_context, FloatMatrix2 const &transformation, FloatVector2 const &center, Float radius, Color const &color)
	Draws a circle with the given center and radius, in the given color.
void	DrawCircularArc (RenderContext const &render_context, FloatMatrix2 const &transformation, FloatVector2 const &center, Float radius, Float start_angle, Float end_angle, Color const &color)
	Draws a circular arc with the given center and radius, start angle and end angle, in the given color.
void	DrawScreenRect (RenderContext const &render_context, Color const &color, ScreenCoordRect const &screen_rect)
	Fills the given rectangle with the given color.
void	DrawScreenRectTexture (RenderContext const &render_context, GLTexture const *gl_texture, ScreenCoordRect const &screen_rect, FloatSimpleTransform2 const &transformation=FloatSimpleTransform2::ms_identity)
	Maps the given texture to the given rectangle.
void	SetupTextureUnits (GLuint gltexture_handle, Color const &color_mask, Color const &color_bias)
	Sets up texture units 0 and 1 for texturing, color masking and color biasing.

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Detailed Description

Houses all of the basic rendering primitives used by XuqRijBuh.

The rendering primitives are

• Drawing a line.
• Drawing an arrow, with arrow's head size proportional to the arrow's length.
• Drawing a circle.
• Drawing a circular arc.
• Filling a rectangle with a solid color.
• Mapping a texture to a rectangle.

All functions requires a RenderContext (with a few exceptions).

Some functions operate using the existing OpenGL modelview matrix, while others reset it to the identity.

None of the functions change the OpenGL projection matrix. However, it should be noted that each function depends on the projection matrix being set up in a particular mode. Specifically, there are two types of modes currently: in-Widget rendering, and in-WorldView rendering. In-Widget rendering takes place when the projection matrix is set up to make the modelview coordinates exactly coincide with the screen's pixel coordinates (though in a right-handed coordinate system). The in-WorldView rendering mode assumes the projection matrix is set up so that the zooming, scaling, and positioning of the view is taken into account, and so the modelview coordinates represent actual world coordinates.

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Function Documentation

void Xrb::Render::DrawLine	(	RenderContext const &	render_context,
		FloatVector2 const &	from,
		FloatVector2 const &	to,
		Color const &	color
	)

Draws a line between from and to in the given color.

Obliterates the modelview matrix.

Parameters:

	render_context	The required RenderContext.
	from	One of the line's endpoints, in modelspace.
	to	The other of the line's endpoints, in modelspace.
	color	The color to use to render the line.

Definition at line 19 of file xrb_render.cpp.

References Xrb::Dim::A, Xrb::RenderContext::ColorBias(), Xrb::RenderContext::MaskAndBiasWouldResultInNoOp(), Xrb::RenderContext::MaskedColor(), and SetupTextureUnits().

void Xrb::Render::DrawArrow	(	RenderContext const &	render_context,
		FloatVector2 const &	from,
		FloatVector2 const &	to,
		Color const &	color
	)

Draws an arrow with tail at from and head at to, in the given color.

The size of the arrow's head is proportional to its length.

Obliterates the modelview matrix.

Parameters:

	render_context	The required RenderContext.
	from	The tail endpoint of the arrow, in modelspace.
	to	The head endpoint of the arrow, in modelspace.
	color	The color to use to render the arrow.

Definition at line 48 of file xrb_render.cpp.

References Xrb::Dim::A, Xrb::RenderContext::ColorBias(), Xrb::RenderContext::MaskAndBiasWouldResultInNoOp(), Xrb::RenderContext::MaskedColor(), Xrb::PerpendicularVector2(), and SetupTextureUnits().

void Xrb::Render::DrawPolygon	(	RenderContext const &	render_context,
		FloatVector2 const &	center,
		Float	radius,
		Float	angle,
		Color const &	color,
		Uint32	vertex_count
	)

Draws a regular polygon.

The vertices of the polygon will be placed on the bounding circle specified by center and radius.

Obliterates the modelview matrix.

Parameters:

	render_context	The required RenderContext.
	center	The center of the bounding circle that the polygon's vertices will lay upon, in modelspace.
	radius	The radius of the bounding circle that the polygon's vertices will lay upon, in modelspace.
	angle	The angle at which the first vertex will be placed upon the bounding circle.
	color	The color to use to render the polygon.
	vertex_count	The number of vertices the polygon should have.

Definition at line 91 of file xrb_render.cpp.

References Xrb::RenderContext::ColorBias(), Xrb::RenderContext::MaskAndBiasWouldResultInNoOp(), Xrb::RenderContext::MaskedColor(), Xrb::Math::Radians(), and SetupTextureUnits().

Referenced by DrawCircle().

void Xrb::Render::DrawCircle	(	RenderContext const &	render_context,
		FloatMatrix2 const &	transformation,
		FloatVector2 const &	center,
		Float	radius,
		Color const &	color
	)

Draws a circle with the given center and radius, in the given color.

The number of lines used to draw the circle is dependent on transformation. The larger the circle appears, the more lines will be used to draw it. No more than 30 lines and no less than 6 lines will be used to draw the circle.

Obliterates the modelview matrix.

Parameters:

	render_context	The required RenderContext.
	transformation	The world-to-screen transformation matrix which is used to calculate the necessary number of lines to use to draw the circle.
	center	The center of the circle, in modelspace.
	radius	The radius of the circle, in modelspace.
	color	The color to use to render the circle.

Definition at line 137 of file xrb_render.cpp.

References DrawPolygon(), Xrb::RenderContext::MaskAndBiasWouldResultInNoOp(), Xrb::Max(), and Xrb::Vector< Float, 2 >::ms_zero.

void Xrb::Render::DrawCircularArc	(	RenderContext const &	render_context,
		FloatMatrix2 const &	transformation,
		FloatVector2 const &	center,
		Float	radius,
		Float	start_angle,
		Float	end_angle,
		Color const &	color
	)

Draws a circular arc with the given center and radius, start angle and end angle, in the given color.

The number of lines used to draw the arc is dependent on transformation. The larger the arc appears, the more lines will be used to draw it. No more than 30 lines per full 360 degree arc, and no less than 6 lines per full 360 degree arc will be used to draw the circular arc.

Obliterates the modelview matrix.

Parameters:

	render_context	The required RenderContext.
	transformation	The world-to-screen transformation matrix which is used to calculate the necessary number of lines to use to draw the circular arc.
	center	The center of the circle that the arc lies on, in modelspace.
	radius	The radius of the circle that the arc lies on, in modelspace.
	start_angle	The angle at which to start the arc, in modelspace, where 0 degrees is along the positive X axis, and degrees increase to move counterclockwise.
	end_angle	The angle at which to end the arc, in modelspace, where 0 degrees is along the positive X axis, and degrees increase to move counterclockwise. The total angle spanned by end_angle - start_angle can be greater than 360 if desired.
	color	The color to use to render the arc.

Definition at line 181 of file xrb_render.cpp.

References Xrb::Math::Ceiling(), Xrb::RenderContext::ColorBias(), Xrb::RenderContext::MaskAndBiasWouldResultInNoOp(), Xrb::RenderContext::MaskedColor(), Xrb::Vector< Float, 2 >::ms_zero, Xrb::Math::Radians(), and SetupTextureUnits().

void Xrb::Render::DrawScreenRect	(	RenderContext const &	render_context,
		Color const &	color,
		ScreenCoordRect const &	screen_rect
	)

Fills the given rectangle with the given color.

Obliterates the modelview matrix.

Parameters:

	render_context	The required RenderContext.
	color	The color to use to render the rectangle.
	screen_rect	The screen-coordinate rectangle to fill.

Definition at line 274 of file xrb_render.cpp.

References Xrb::Rect< T >::BottomLeft(), Xrb::Rect< T >::BottomRight(), Xrb::RenderContext::ColorBias(), Xrb::RenderContext::MaskAndBiasWouldResultInNoOp(), Xrb::RenderContext::MaskedColor(), SetupTextureUnits(), Xrb::Rect< T >::TopLeft(), Xrb::Rect< T >::TopRight(), Xrb::Dim::X, and Xrb::Dim::Y.

Referenced by Xrb::WidgetBackgroundColored::Draw().

void Xrb::Render::DrawScreenRectTexture	(	RenderContext const &	render_context,
		GLTexture const *	gl_texture,
		ScreenCoordRect const &	screen_rect,
		FloatSimpleTransform2 const &	transformation = FloatSimpleTransform2::ms_identity
	)

Maps the given texture to the given rectangle.

Obliterates the modelview matrix.

Parameters:

	render_context	The required RenderContext.
	gl_texture	A pointer to the GLTexture which should be used.
	screen_rect	The screen rectangle to be filled with the texture.
	transformation	An optional transformation to the texture coordinates (e.g. for flipping horizontally, vertically, or scaling the texture).

Definition at line 316 of file xrb_render.cpp.

References Xrb::Rect< T >::BottomLeft(), Xrb::Rect< T >::BottomRight(), Xrb::RenderContext::ColorBias(), Xrb::RenderContext::ColorMask(), Xrb::GLTexture::Handle(), Xrb::RenderContext::MaskAndBiasWouldResultInNoOp(), SetupTextureUnits(), Xrb::Rect< T >::TopLeft(), Xrb::Rect< T >::TopRight(), Xrb::Dim::X, and Xrb::Dim::Y.

Referenced by Xrb::WidgetBackgroundStylized::Draw(), and Xrb::WidgetBackgroundTextured::Draw().

void Xrb::Render::SetupTextureUnits	(	GLuint	gltexture_handle,
		Color const &	color_mask,
		Color const &	color_bias
	)

Sets up texture units 0 and 1 for texturing, color masking and color biasing.

This setup is done in so many places that it was deemed function-worthy, eliminating possible copy/paste errors.

Parameters:

	gltexture_handle	The OpenGL texture handle to bind to texture unit 0.
	color_mask	The masking color modulate the bound texture with.
	color_bias	The color bias to interpolate the results of texture unit 0 with.

Note:

When this function returns, texture unit 1 will be active.

Definition at line 372 of file xrb_render.cpp.

References Xrb::Dim::B, Xrb::Dim::G, and Xrb::Dim::R.

Referenced by DrawArrow(), DrawCircularArc(), DrawLine(), DrawPolygon(), DrawScreenRect(), and DrawScreenRectTexture().