A VRAM accessor for drawing graphics in the BG2 mode. More...

#include <sifteo/video/bg2.h>

Public Member Functions
CubeID	cube () const
	Return the CubeID associated with this drawable.

void	erase (uint16_t index=0)
	Erase mode-specific VRAM, filling the BG2 buffer with the specified absolute tile index value. More...

void	erase (const PinnedAssetImage &image)
	Erase mode-specific VRAM, filling the BG2 buffer with the first tile from the specified PinnedAssetImage.

void	fill (UInt2 topLeft, UInt2 size, unsigned tileIndex)
	Fill a rectangle of identical tiles, specified as a top-left corner location and a size. More...

RGB565	getBorder () const
	Get the last border color set by setBorder().

void	image (UInt2 pos, const AssetImage &image, unsigned frame=0)
	Draw a full AssetImage frame, with its top-left corner at the specified location. More...

void	image (UInt2 destXY, UInt2 size, const AssetImage &image, UInt2 srcXY, unsigned frame=0)
	Draw part of an AssetImage frame, with its top-left corner at the specified location. More...

void	plot (UInt2 pos, uint16_t tileIndex)
	Plot a single tile, by absolute tile index, at location 'pos' in tile units. More...

void	setBorder (RGB565 color)
	Set the border color, given an arbitrary 16-bit RGB565 color. More...

void	setMatrix (const AffineMatrix &m)
	Set the current affine transform matrix.

void	span (UInt2 pos, unsigned width, unsigned tileIndex)
	Plot a horizontal span of tiles, by absolue tile index, given the position of the leftmost tile and the number of tiles to plot. More...

void	text (Int2 topLeft, const AssetImage &font, const char *str, char firstChar= ' ')
	Draw text, using an AssetImage as a fixed width font. More...

uint16_t	tileAddr (UInt2 pos)
	Calculate the video buffer address of a particular tile. More...

_SYSVideoBuffer &	videoBuffer ()
	Return the VideoBuffer associated with this drawable.

Static Public Member Functions
static unsigned	pixelHeight ()
	Return the height, in pixel, of this mode.

static UInt2	pixelSize ()
	Return the size of this mode as a vector, in pixels.

static unsigned	pixelWidth ()
	Return the width, in pixels, of this mode.

static unsigned	sizeInBytes ()
	Returns the size of this drawable's tile data, in bytes.

static unsigned	sizeInWords ()
	Returns the size of this drawable's tile data, in 16-bit words.

static unsigned	tileHeight ()
	Return the height, in tiles, of this mode.

static UInt2	tileSize ()
	Return the size of this mode as a vector, in tiles.

static unsigned	tileWidth ()
	Return the width, in tiles, of this mode.

Detailed Description

A VRAM accessor for drawing graphics in the BG2 mode.

This is a special-purpose mode for doing scaling, rotation, and other effects using an affine transform matrix.

Conceptually, this mode is a 256x256-pixel canvas, repeating forever in both axes, in which the top-left quadrant is a 16x16-tile drawable, and the other three quadrants are painted with a solid "border" color.

This arrangement allows you to treat the 16x16 area as "centered" on the screen, with the border color poking through when that image is scaled down or rotated.

Note that the border color is not part of the Colormap, it is a separate piece of state that can be set through the BG2Drawable.

Member Function Documentation

void Sifteo::BG2Drawable::erase ( uint16_t index = 0 )

inline

Erase mode-specific VRAM, filling the BG2 buffer with the specified absolute tile index value.

Does not modify the affine transform or the border color.

void Sifteo::BG2Drawable::fill	(	UInt2	topLeft,
		UInt2	size,
		unsigned	tileIndex
	)

inline

Fill a rectangle of identical tiles, specified as a top-left corner location and a size.

All coordinates must be in range. This function performs no clipping.

void Sifteo::BG2Drawable::image	(	UInt2	pos,
		const AssetImage &	image,
		unsigned	frame = `0`
	)

inline

Draw a full AssetImage frame, with its top-left corner at the specified location.

Locations are specified in tile units, relative to the top-left of the 18x18 grid.

All coordinates must be in range. This function performs no clipping.

void Sifteo::BG2Drawable::image	(	UInt2	destXY,
		UInt2	size,
		const AssetImage &	image,
		UInt2	srcXY,
		unsigned	frame = `0`
	)

inline

Draw part of an AssetImage frame, with its top-left corner at the specified location.

Locations are specified in tile units, relative to the top-left of the 18x18 grid.

All coordinates must be in range. This function performs no clipping.

void Sifteo::BG2Drawable::plot	(	UInt2	pos,
		uint16_t	tileIndex
	)

inline

Plot a single tile, by absolute tile index, at location 'pos' in tile units.

All coordinates must be in range. This function performs no clipping.

void Sifteo::BG2Drawable::setBorder ( RGB565 color )

inline

Set the border color, given an arbitrary 16-bit RGB565 color.

This color is displayed 'outside' the 16x16-tile drawable region, in the other three quadrants of the virtual 256x256-pixel plane.

void Sifteo::BG2Drawable::span	(	UInt2	pos,
		unsigned	width,
		unsigned	tileIndex
	)

inline

Plot a horizontal span of tiles, by absolue tile index, given the position of the leftmost tile and the number of tiles to plot.

All coordinates must be in range. This function performs no clipping.

void Sifteo::BG2Drawable::text	(	Int2	topLeft,
		const AssetImage &	font,
		const char *	str,
		char	firstChar = `' '`
	)

inline

Draw text, using an AssetImage as a fixed width font.

Each character is represented by a consecutive 'frame' in the image. Characters not present in the font will be skipped.

uint16_t Sifteo::BG2Drawable::tileAddr ( UInt2 pos )

inline

Calculate the video buffer address of a particular tile.

All coordinates must be in range. This function performs no clipping.

The documentation for this struct was generated from the following file:

bg2.h

Public Member Functions

Static Public Member Functions

Detailed Description

Member Function Documentation