RISC OS Programmers Reference Manuals : Sprite Plot Actions

Introduction and Overview

The sprite plot action is a bit field allowing the caller to specify the manner of the sprite plotting. It is used on a number of OS_SpriteOp calls, in particular :

Put sprite (28)
Put sprite at user co-ords (32)
Paint sprite scaled (52)
Plot sprite transformed (56)
Tile sprite scaled (65)

Technical Details

The following bits are used within the plot action :

Bit(s)

Meaning

0-2

Plot action (see PRM 1-753):

Value	Meaning
0	Overwrite
1	OR
2	AND
3	EOR
4	Invert
5	No-effect
6	AND-NOT
7	OR-NOT

Use mask if set, otherwise ignore mask data if present. See PRM 1-753

Use palette entries rather than translation table if suitable. See PRM 5a-117

Wide Translation Table has been used if set, otherwise 8 bit translation is present. See PRM 5a-118

Use dithering to more accurately match colours if set, otherwise the fastest rendering method will be used. See PRM 5a-118

Colour-mapping function is provided rather than a translation table if set. See ColourMapping of deep sprites

8-15

Translucency level (see Translucent sprite operation):

Value	Meaning
0	Solid image
255	No effect, or close to no effect
1-254	Other values linearly represent translucency levels between these extremes, but may be quantised by the rendering implementation in SpriteExtend or other acceleration systems

16-31

Reserved, must be 0

Sprite Plot Actions

Introduction and Overview

Technical Details

Initial version

PRM-in-XML version