"Background API Access"

Enumerations
enum	BgSize {   BgSize_R_128x128 = (0 << 14),   BgSize_R_256x256 = (1 << 14),   BgSize_R_512x512 = (2 << 14),   BgSize_R_1024x1024 = (3 << 14),   BgSize_T_256x256 = (0 << 14) | (1 << 16),   BgSize_T_512x256 = (1 << 14) | (1 << 16),   BgSize_T_256x512 = (2 << 14) | (1 << 16),   BgSize_T_512x512 = (3 << 14) | (1 << 16),   BgSize_ER_128x128 = (0 << 14) | (2 << 16),   BgSize_ER_256x256 = (1 << 14) | (2 << 16),   BgSize_ER_512x512 = (2 << 14) | (2 << 16),   BgSize_ER_1024x1024 = (3 << 14) | (2 << 16),   BgSize_B8_128x128 = ((0 << 14) | BIT(7) | (3 << 16)),   BgSize_B8_256x256 = ((1 << 14) | BIT(7) | (3 << 16)),   BgSize_B8_512x256 = ((2 << 14) | BIT(7) | (3 << 16)),   BgSize_B8_512x512 = ((3 << 14) | BIT(7) | (3 << 16)),   BgSize_B8_1024x512 = (1 << 14) | (3 << 16),   BgSize_B8_512x1024 = (0) | (3 << 16),   BgSize_B16_128x128 = ((0 << 14) | BIT(7) | BIT(2) | (4 << 16)),   BgSize_B16_256x256 = ((1 << 14) | BIT(7) | BIT(2) | (4 << 16)),   BgSize_B16_512x256 = ((2 << 14) | BIT(7) | BIT(2) | (4 << 16)),   BgSize_B16_512x512 = ((3 << 14) | BIT(7) | BIT(2) | (4 << 16)) }
	Allowed background Sizes The lower 16 bits of these defines can be used directly to set the background control register bits. More...
enum	BgType {   BgType_Text8bpp,   BgType_Text4bpp,   BgType_Rotation,   BgType_ExRotation,   BgType_Bmp8,   BgType_Bmp16 }
	Allowed background types, used in bgInitMain and bgInitSub. More...
Functions
static void	bgClearControlBits (int id, u16 bits)
	Clears the specified bits from the backgrounds control register.
static u16 *	bgGetGfxPtr (int id)
	Gets a pointer to the background graphics.
static int	bgGetMapBase (int id)
	Gets the current map base for the supplied background.
static u16 *	bgGetMapPtr (int id)
	Gets a pointer to the background map.
static int	bgGetPriority (int id)
	Gets the background priority.
static int	bgGetTileBase (int id)
	Gets the background tile base.
static void	bgHide (int id)
	Hides the current background via the display control register.
static int	bgInit (int layer, BgType type, BgSize size, int mapBase, int tileBase)
	Initializes a background on the main display Sets up background control register with specified settings and defaults to 256 color mode for tiled backgrounds. Sets the rotation/scale attributes for rot/ex rot backgrounds to 1:1 scale and 0 angle of rotation.
static int	bgInitSub (int layer, BgType type, BgSize size, int mapBase, int tileBase)
	Initializes a background on the sub display Sets up background control register with specified settings and defaults to 256 color mode for tiled backgrounds. Sets the rotation/scale attributes for rot/ex rot backgrounds to 1:1 scale and 0 angle of rotation.
static void	bgMosaicDisable (int id)
	Disables mosaic on the specified background.
static void	bgMosaicEnable (int id)
	Enables mosaic on the specified background.
static void	bgRotate (int id, int angle)
	Rotates the background counter clockwise by the specified angle. (this rotation is cumulative).
static void	bgScroll (int id, int dx, int dy)
	Scrolls the background by the specified relative values.
static void	bgScrollf (int id, s32 dx, s32 dy)
	Scrolls the background by the specified relative values (fixed point).
static void	bgSet (int id, int angle, s32 sx, s32 sy, s32 scrollX, s32 scrollY, s32 rotCenterX, s32 rotCenterY)
	Sets the rotation and scale of the background and update background control registers.
static void	bgSetAffineMatrixScroll (int id, int hdx, int vdx, int hdy, int vdy, int scrollx, int scrolly)
	directly sets the affine matrix and scroll registers of a background.
static void	bgSetCenter (int id, int x, int y)
	Sets the center of rotation for the supplied background.
static void	bgSetCenterf (int id, s32 x, s32 y)
	Sets the center of rotation for the supplied background (fixed point).
static vuint16 *	bgSetControlBits (int id, u16 bits)
	allows direct access to background control for the chosen layer, returns a pointer to the current control bits
static void	bgSetMapBase (int id, unsigned int base)
	Sets the background map base.
static void	bgSetMosaic (unsigned int dx, unsigned int dy)
	Sets the horizontal and vertical mosaic values for all backgrounds.
static void	bgSetMosaicSub (unsigned int dx, unsigned int dy)
	Sets the horizontal and vertical mosaic values for all backgrounds (Sub Display).
static void	bgSetPriority (int id, unsigned int priority)
	Sets the background priority.
static void	bgSetRotate (int id, int angle)
	Sets the rotation angle of the specified background and updates the transform matrix.
static void	bgSetRotateScale (int id, int angle, s32 sx, s32 sy)
	Sets the rotation and scale of the background and update background control registers.
static void	bgSetScale (int id, s32 sx, s32 sy)
	Sets the scale of the specified background.
static void	bgSetScroll (int id, int x, int y)
	Sets the scroll hardware to the specified location.
static void	bgSetScrollf (int id, s32 x, s32 y)
	Sets the scroll hardware to the specified location (fixed point).
static void	bgSetTileBase (int id, unsigned int base)
	Sets the background map base.
static void	bgShow (int id)
	Shows the current background via the display control register.
void	bgUpdate (void)
	Must be called once per frame to update scroll/scale/and rotation of backgrounds.
static void	bgWrapOff (int id)
	turns wrap off for a background. has no effect on text backgrounds, which are always wrapped.
static void	bgWrapOn (int id)
	turns wrap on for a background. has no effect on text backgrounds, which are always wrapped.

---

Enumeration Type Documentation

enum BgSize

Allowed background Sizes The lower 16 bits of these defines can be used directly to set the background control register bits.

Enumerator:

BgSize_R_128x128	128 x 128 pixel rotation background
BgSize_R_256x256	256 x 256 pixel rotation background
BgSize_R_512x512	512 x 512 pixel rotation background
BgSize_R_1024x1024	1024 x 1024 pixel rotation background
BgSize_T_256x256	256 x 256 pixel text background
BgSize_T_512x256	512 x 256 pixel text background
BgSize_T_256x512	256 x 512 pixel text background
BgSize_T_512x512	512 x 512 pixel text background
BgSize_ER_128x128	128 x 128 pixel extended rotation background
BgSize_ER_256x256	256 x 256 pixel extended rotation background
BgSize_ER_512x512	512 x 512 pixel extended rotation background
BgSize_ER_1024x1024	1024 x 1024 extended pixel rotation background
BgSize_B8_128x128	128 x 128 pixel 8 bit bitmap background
BgSize_B8_256x256	256 x 256 pixel 8 bit bitmap background
BgSize_B8_512x256	512 x 256 pixel 8 bit bitmap background
BgSize_B8_512x512	512 x 512 pixel 8 bit bitmap background
BgSize_B8_1024x512	1024 x 512 pixel 8 bit bitmap background
BgSize_B8_512x1024	512 x 1024 pixel 8 bit bitmap background
BgSize_B16_128x128	128 x 128 pixel 16 bit bitmap background
BgSize_B16_256x256	256 x 256 pixel 16 bit bitmap background
BgSize_B16_512x256	512 x 512 pixel 16 bit bitmap background
BgSize_B16_512x512	1024 x 1024 pixel 16 bit bitmap background

enum BgType

Allowed background types, used in bgInitMain and bgInitSub.

Enumerator:

BgType_Text8bpp	8bpp Tiled background with 16 bit tile indexes and no allowed rotation or scaling
BgType_Text4bpp	4bpp Tiled background with 16 bit tile indexes and no allowed rotation or scaling
BgType_Rotation	Tiled background with 8 bit tile indexes Can be scaled and rotated.
BgType_ExRotation	Tiled background with 16 bit tile indexes Can be scaled and rotated.
BgType_Bmp8	Bitmap background with 8 bit color values which index into a 256 color palette.
BgType_Bmp16	Bitmap background with 16 bit color values of the form aBBBBBGGGGGRRRRR (if 'a' is set the pixel will be rendered...if not the pixel will be transparent).

---

Function Documentation

static void bgClearControlBits	(	int	id,
		u16	bits
	)			[inline, static]

Clears the specified bits from the backgrounds control register.

Parameters:

	id	background id returned from bgInit or bgInitSub
	bits	sets the specified bits to clear in the backgrounds control register

static u16* bgGetGfxPtr

(

int

id

)

[inline, static]

Gets a pointer to the background graphics.

Parameters:

id

background id returned from bgInit or bgInitSub

Returns:

A pointer to the tile graphics or bitmap graphics

Examples:

Graphics/Backgrounds/256_color_bmp/source/main.cpp, Graphics/Backgrounds/all_in_one/source/advanced.cpp, Graphics/Backgrounds/all_in_one/source/basic.cpp, Graphics/Backgrounds/all_in_one/source/handmade.cpp, Graphics/Backgrounds/all_in_one/source/scrolling.cpp, Graphics/Backgrounds/Double_Buffer/source/main.cpp, and Graphics/Backgrounds/rotation/source/main.cpp.

static int bgGetMapBase

(

int

id

)

[inline, static]

Gets the current map base for the supplied background.

Parameters:

id

background id returned from bgInit or bgInitSub

Returns:

background map base

Note:

this is the integer offset of the base not a pointer to the map

Examples:

Graphics/Backgrounds/Double_Buffer/source/main.cpp.

static u16* bgGetMapPtr

(

int

id

)

[inline, static]

Gets a pointer to the background map.

Parameters:

id

background id returned from bgInit or bgInitSub

Returns:

A pointer to the map

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp, Graphics/Backgrounds/all_in_one/source/basic.cpp, Graphics/Backgrounds/all_in_one/source/handmade.cpp, and Graphics/Backgrounds/all_in_one/source/scrolling.cpp.

static int bgGetPriority

(

int

id

)

[inline, static]

Gets the background priority.

Parameters:

id

background id returned from bgInit or bgInitSub

Returns:

background priority

static int bgGetTileBase

(

int

id

)

[inline, static]

Gets the background tile base.

Parameters:

id

background id returned from bgInit or bgInitSub

Returns:

background tile base

static void bgHide

(

int

id

)

[inline, static]

Hides the current background via the display control register.

Parameters:

id

background id returned from bgInit or bgInitSub

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp.

static int bgInit	(	int	layer,
		BgType	type,
		BgSize	size,
		int	mapBase,
		int	tileBase
	)			[inline, static]

Initializes a background on the main display Sets up background control register with specified settings and defaults to 256 color mode for tiled backgrounds. Sets the rotation/scale attributes for rot/ex rot backgrounds to 1:1 scale and 0 angle of rotation.

Parameters:

	layer	background hardware layer to init. Must be 0 - 3
	type	the type of background to init
	size	the size of the background
	mapBase	the 2k offset into vram the tile map will be placed --OR-- the 16k offset into vram the bitmap data will be placed for bitmap backgrounds
	tileBase	the 16k offset into vram the tile graphics data will be placed

Returns:

the background id to be used in the supporting functions

Note:

tileBase is unused for bitmap backgrounds

Examples:

Graphics/Backgrounds/16bit_color_bmp/source/template.cpp, Graphics/Backgrounds/256_color_bmp/source/main.cpp, Graphics/Backgrounds/all_in_one/source/advanced.cpp, Graphics/Backgrounds/all_in_one/source/basic.cpp, Graphics/Backgrounds/all_in_one/source/handmade.cpp, Graphics/Backgrounds/all_in_one/source/scrolling.cpp, Graphics/Backgrounds/Double_Buffer/source/main.cpp, and Graphics/Backgrounds/rotation/source/main.cpp.

static int bgInitSub	(	int	layer,
		BgType	type,
		BgSize	size,
		int	mapBase,
		int	tileBase
	)			[inline, static]

Initializes a background on the sub display Sets up background control register with specified settings and defaults to 256 color mode for tiled backgrounds. Sets the rotation/scale attributes for rot/ex rot backgrounds to 1:1 scale and 0 angle of rotation.

Parameters:

	layer	background hardware layer to init. Must be 0 - 3
	type	the type of background to init
	size	the size of the background
	mapBase	the 2k offset into vram the tile map will be placed --OR-- the 16k offset into vram the bitmap data will be placed for bitmap backgrounds
	tileBase	the 16k offset into vram the tile graphics data will be placed

Returns:

the background id to be used in the supporting functions

Note:

tileBase is unused for bitmap backgrounds

Examples:

Graphics/3D/3D_Both_Screens/source/template.c.

static void bgMosaicDisable

(

int

id

)

[inline, static]

Disables mosaic on the specified background.

Parameters:

id

background id returned from bgInit or bgInitSub

static void bgMosaicEnable

(

int

id

)

[inline, static]

Enables mosaic on the specified background.

Parameters:

id

background id returned from bgInit or bgInitSub

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp.

static void bgRotate	(	int	id,
		int	angle
	)			[inline, static]

Rotates the background counter clockwise by the specified angle. (this rotation is cumulative).

Parameters:

	id	background id returned from bgInit or bgInitSub
	angle	the angle of counter clockwise rotation (-32768 to 32767)

static void bgScroll	(	int	id,
		int	dx,
		int	dy
	)			[inline, static]

Scrolls the background by the specified relative values.

Parameters:

	id	background id returned from bgInit or bgInitSub
	dx	horizontal scroll
	dy	vertical scroll

Note:

while valid for text backgrounds the fractional part will be ignored

static void bgScrollf	(	int	id,
		s32	dx,
		s32	dy
	)			[inline, static]

Scrolls the background by the specified relative values (fixed point).

Parameters:

	id	background id returned from bgInit or bgInitSub
	dx	the 8 bits fractional fixed point horizontal scroll
	dy	the 8 bits fractional fixed point vertical scroll

Note:

while valid for text backgrounds the fractional part will be ignored

static void bgSet	(	int	id,
		int	angle,
		s32	sx,
		s32	sy,
		s32	scrollX,
		s32	scrollY,
		s32	rotCenterX,
		s32	rotCenterY
	)			[inline, static]

Sets the rotation and scale of the background and update background control registers.

Parameters:

	id	background id returned from bgInit or bgInitSub
	angle	the angle of counter clockwise rotation (-32768 to 32767)
	sx	the 24.8 bit fractional fixed point inverse horizontal scaling to apply
	sy	the 24.8 bit fractional fixed point inverse vertical scaling to apply
	scrollX	the 24.8 bit fractional fixed point horizontal scroll to apply
	scrollY	the 24.8 bit fractional fixed point vertical scroll to apply
	rotCenterX	the 24.8 bit fractional fixed point center of rotation x component
	rotCenterY	the 24.8 bit fractional fixed point center of rotation y component

static void bgSetAffineMatrixScroll	(	int	id,
		int	hdx,
		int	vdx,
		int	hdy,
		int	vdy,
		int	scrollx,
		int	scrolly
	)			[inline, static]

directly sets the affine matrix and scroll registers of a background.

With this, you have more freedom to set the matrix, but it might be more difficult to use if you're not used to affine transformation matrix. This will ignore (but not erase) any values set using the bg rotating, scaling or center functions.

Parameters:

	id	The id returned by bgInit or bgInitSub.
	hdx	The change in x per horizontal pixel.
	vdx	The change in x per vertical pixel.
	hdy	The change in y per horizontal pixel.
	vdy	The change in y per vertical pixel.
	scrollx	The horizontal scroll/offset value of the background.
	scrolly	The vertical scroll/offset value of the background.

static void bgSetCenter	(	int	id,
		int	x,
		int	y
	)			[inline, static]

Sets the center of rotation for the supplied background.

Parameters:

	id	background id returned from bgInit or bgInitSub
	x	center x
	y	center y

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp, and Graphics/Backgrounds/rotation/source/main.cpp.

static void bgSetCenterf	(	int	id,
		s32	x,
		s32	y
	)			[inline, static]

Sets the center of rotation for the supplied background (fixed point).

Parameters:

	id	background id returned from bgInit or bgInitSub
	x	the 8 bits fractional center x
	y	the 8 bits fractional center y

Note:

while valid for text backgrounds the fractional part will be ignored

static vuint16* bgSetControlBits	(	int	id,
		u16	bits
	)			[inline, static]

allows direct access to background control for the chosen layer, returns a pointer to the current control bits

Parameters:

	id	background id returned from bgInit or bgInitSub
	bits	sets the specified bits to set in the backgrounds control register

Returns:

a pointer to the appropriate background control register

Examples:

Graphics/Backgrounds/all_in_one/source/scrolling.cpp.

static void bgSetMapBase	(	int	id,
		unsigned int	base
	)			[inline, static]

Sets the background map base.

Parameters:

	id	background id returned from bgInit or bgInitSub
	base	the 2k offset into vram for the backgrounds tile map or the 16k offset for bitmap graphics

Examples:

Graphics/Backgrounds/Double_Buffer/source/main.cpp.

static void bgSetMosaic	(	unsigned int	dx,
		unsigned int	dy
	)			[inline, static]

Sets the horizontal and vertical mosaic values for all backgrounds.

Parameters:

	dx	horizontal mosaic value (between 0 and 15)
	dy	vertical mosaic value (between 0 and 15)

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp.

static void bgSetMosaicSub	(	unsigned int	dx,
		unsigned int	dy
	)			[inline, static]

Sets the horizontal and vertical mosaic values for all backgrounds (Sub Display).

Parameters:

	dx	horizontal mosaic value (between 0 and 15)
	dy	vertical mosaic value (between 0 and 15)

static void bgSetPriority	(	int	id,
		unsigned int	priority
	)			[inline, static]

Sets the background priority.

Parameters:

	id	background id returned from bgInit or bgInitSub
	priority	background priority (0-3), higher level priority will result in background rendering on top of lower level

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp.

static void bgSetRotate	(	int	id,
		int	angle
	)			[inline, static]

Sets the rotation angle of the specified background and updates the transform matrix.

Parameters:

	id	background id returned from bgInit or bgInitSub
	angle	the angle of counter clockwise rotation (0 to 511)

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp.

static void bgSetRotateScale	(	int	id,
		int	angle,
		s32	sx,
		s32	sy
	)			[inline, static]

Sets the rotation and scale of the background and update background control registers.

Parameters:

	id	background id returned from bgInit or bgInitSub
	angle	the angle of counter clockwise rotation (-32768 to 32767)
	sx	the 24.8 bit fractional fixed point horizontal scaling to apply
	sy	the 24.8 bit fractional fixed point vertical scaling to apply

Examples:

Graphics/Backgrounds/rotation/source/main.cpp, and Graphics/Printing/rotscale_text/source/main.c.

static void bgSetScale	(	int	id,
		s32	sx,
		s32	sy
	)			[inline, static]

Sets the scale of the specified background.

Parameters:

	id	background id returned from bgInit or bgInitSub
	sx	the 24.8 bit fractional fixed point horizontal scaling to apply
	sy	the 24.8 bit fractional fixed point vertical scaling to apply

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp.

static void bgSetScroll	(	int	id,
		int	x,
		int	y
	)			[inline, static]

Sets the scroll hardware to the specified location.

Parameters:

	id	background id returned from bgInit or bgInitSub
	x	the horizontal scroll
	y	the vertical scroll

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp, Graphics/Backgrounds/all_in_one/source/scrolling.cpp, Graphics/Backgrounds/rotation/source/main.cpp, and Graphics/Printing/rotscale_text/source/main.c.

static void bgSetScrollf	(	int	id,
		s32	x,
		s32	y
	)			[inline, static]

Sets the scroll hardware to the specified location (fixed point).

Parameters:

	id	background id returned from bgInit or bgInitSub
	x	the 8 bits fractional fixed point horizontal scroll
	y	the 8 bits fractional fixed point vertical scroll

Note:

while valid for text backgrounds the fractional part will be ignored

static void bgSetTileBase	(	int	id,
		unsigned int	base
	)			[inline, static]

Sets the background map base.

Parameters:

	id	background id returned from bgInit or bgInitSub
	base	the 16k offset into vram for the backgrounds tile map ignored for bitmap graphics

static void bgShow

(

int

id

)

[inline, static]

Shows the current background via the display control register.

Parameters:

id

background id returned from bgInit or bgInitSub

Examples:

Graphics/Backgrounds/all_in_one/source/advanced.cpp.

static void bgWrapOff

(

int

id

)

[inline, static]

turns wrap off for a background. has no effect on text backgrounds, which are always wrapped.

Parameters:

id

background id returned from bgInit or bgInitSub

static void bgWrapOn

(

int

id

)

[inline, static]

turns wrap on for a background. has no effect on text backgrounds, which are always wrapped.

Parameters:

id

background id returned from bgInit or bgInitSub