hvdblit.h File Reference

Interface for HVD element blitters. More...

Data Structures
struct	HVD_raster_layout
	Layout of an HVD element raster buffer. More...
struct	HVD_raster_offsets
	Structure defining the offsets to apply to an eHVD blit operation. More...

Typedefs
typedef int	HVD_data_format
	Type of HVD raster data represented.
typedef struct HVD_raster_layout	HVD_raster_layout
	Layout of an HVD element raster buffer. More...
typedef void()	HVD_blitter_fn(const HVD_raster_layout *dest, const HVD_raster_layout *src, const HVD_raster_layout *mask, const HVD_raster_offsets *offsets)
	Type of the HVD element blitter function. More...

Enumerations
enum	{ HVD_DATA_PIXELS , HVD_DATA_MASK0 , HVD_DATA_ALPHA , HVD_DATA_RLE }
	Values for HVD_data_format. More...

Functions
HVD_blitter_fn *	HVD_get_blitter (const HVD_raster_layout *dest, const HVD_raster_layout *src, const HVD_raster_layout *mask)
	Get an HVD element blitter function suitable for blitting the raster layouts specified. More...
HqBool	HVD_blit_offsets (const HVD_raster_layout *dest, const HVD_raster_layout *src, int32 xoffset, int32 yoffset, HVD_raster_offsets *offsets)
	Calculate the size and offsets of the intersection of the destination raster and the source element. More...

Detailed Description

Interface for HVD element blitters.

Typedef Documentation

HVD_blitter_fn

typedef void() HVD_blitter_fn(const HVD_raster_layout *dest, const HVD_raster_layout *src, const HVD_raster_layout *mask, const HVD_raster_offsets *offsets)

Type of the HVD element blitter function.

The blitter function is selected by HVD_get_blitter(), using raster layout descriptions for the destination, source, and mask. The blitter function should be passed the same raster layout descriptions to do its work.

The blitter function copies a rectangle of raster data from a source raster into a destination raster at a specified device space (x,y) offset, applying a mask or alpha channel to the pixels.

The source raster rectangle will be clipped to the boundary of the destination raster.

Parameters

[in]	dest	The destination raster address and layout. The destination raster layout must be compatible with the source layout.
[in]	src	The source raster address and layout. The source raster layout must be compatible with the destination layout. The source raster layout must either have the same number of channels as the mask raster layout, or the mask raster layout must have one channel (which will be used to determine the application of all channels for each pixel).
[in]	mask	The mask raster address and layout. The source raster layout must either have the same number of channels as the mask raster layout, or the mask raster layout must have one channel (which will be used to determine the application of all channels for each pixel). For the common HVD ContoneMask case, the source data can be set as format HVD_DATA_MASK0 and the mask pointer may be NULL; or the mask address can be identical to the source pointer.
[in]	offsets	The intersection size, and offset from the destination and source rasters of the intersection, as computed by HVD_blit_offsets().

HVD_raster_layout

typedef struct HVD_raster_layout HVD_raster_layout

Layout of an HVD element raster buffer.

This type is used to represent the source, destination, and mask for blitting HVD elements. The raster layouts are used to discover optimised blitters to perform the blitting, and to inform the blitter of the layout and addresses of the raster buffers.

Enumeration Type Documentation

anonymous enum

anonymous enum

Values for HVD_data_format.

Enumerator
HVD_DATA_PIXELS	Data represents pixels. This is the normal format for raster destination and source.
HVD_DATA_MASK0	Data represents a mask. Do not apply pixels with minimum value (0, or maximum value values_per_channel-1 if the mask is inverted) to the destination.
HVD_DATA_ALPHA	Data represents an alpha mask with Normal combining.
HVD_DATA_RLE	Data represents an RLE stream.

Function Documentation

HVD_blit_offsets()

HqBool HVD_blit_offsets	(	const HVD_raster_layout *	dest,
		const HVD_raster_layout *	src,
		int32	xoffset,
		int32	yoffset,
		HVD_raster_offsets *	offsets
	)

Calculate the size and offsets of the intersection of the destination raster and the source element.

Parameters

[in]	dest	The destination raster layout, as previously passed to HVD_get_blitter().
[in]	src	The source raster layout, as previously passed to HVD_get_blitter().
[in]	xoffset	The X offset of the source raster layout relative to the destination raster. This may be negative.
[in]	yoffset	The Y offset of the source raster layout relative to the destination raster. This may be negative.
[out]	offsets	The width and height of the destination/source intersection, together with the offset from the source raster and the offset from the destination raster.

Return values

TRUE	If the intersection of the destination and source rasters is not degenerate.
FALSE	If the intersection of the destination and source rasters is degenerate.

HVD_get_blitter()

HVD_blitter_fn* HVD_get_blitter	(	const HVD_raster_layout *	dest,
		const HVD_raster_layout *	src,
		const HVD_raster_layout *	mask
	)

Get an HVD element blitter function suitable for blitting the raster layouts specified.

The blitter function should be passed the same raster layout descriptions as this function uses for selection.

For the common HVD ContoneMask case, the source data can be set as format HVD_DATA_MASK0 and the mask pointer may be NULL; or the mask address can be identical to the source pointer.

Parameters

[in]	dest	The destination raster address and layout.
[in]	src	The source raster address and layout.
[in]	mask	The mask raster address and layout. If this is NULL and the source data format is not HVD_DATA_MASK0, the blit operation overwrites all pixels intersected by the source and destination rasters.

Returns

A blitter function pointer, or NULL if the layouts are incompatible or no blitter function exists for the operation specified.