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NAME

VideoControl
Modify the operation of a ViewPort's ColorMap (V36)

VideoControlTags
varargs stub for VideoControl (V36)

SYNOPSIS

error = VideoControl( cm , tags )
d0 a0 a1

ULONG VideoControl( struct ColorMap *, struct TagItem * );

error= VideoControlTags(cm, tags,...);

FUNCTION

Process the commands in the VideoControl command TagItem buffer using cm as the target, with respect to its "attached" ViewPort.

viewport commands:

VTAG_ATTACH_CM [_SET | _GET] - set/get attached viewport
VTAG_VIEWPORTEXTRA [_SET | _GET] - set/get attached vp_extra
VTAG_NORMAL_DISP [_SET | _GET] - set/get DisplayInfoHandle
(natural mode)
VTAG_COERCE_DISP [_SET | _GET] - set/get DisplayInfoHandle
(coerced mode)
VTAG_PF1_BASE [_SET | _GET] - set/get color base for
first playfield. (V39)
VTAG_PF2_BASE [_SET | _GET] - set/get color base for
second playfield. (V39)
VTAG_SPODD_BASE [_SET | _GET] - set/get color base for odd
sprites. (V39)
VTAG_SPEVEN_BASE [_SET | _GET] - set/get color base for even
sprites. (V39)
VTAG_BORDERSPRITE [_SET | _GET] - on/off/inquire sprites in
borders. (V39)
VTAG_SPRITERESN [_SET | _GET] - set/get sprite resolution
(legal values are SPRITERESN_ECS/_140NS/_70NS/_35NS.
see graphics/view.h) (V39)
VTAG_PF1_TO_SPRITEPRI [_SET | _GET] - set/get playfield1 priority
with respect to sprites (V39)
VTAG_PF2_TO_SPRITEPRI [_SET | _GET] - set/get playfield2 priority
with respect to sprites (V39)
(These two require that the ColorMap is attached to a ViewPort to be
effective).

genlock commands:

VTAG_BORDERBLANK [_SET | _CLR | _GET] - on/off/inquire blanking
VTAG_BORDERNOTRANS [_SET | _CLR | _GET] - on/off/inquire notransparency
VTAG_CHROMAKEY [_SET | _CLR | _GET] - on/off/inquire chroma mode
VTAG_BITPLANEKEY [_SET | _CLR | _GET] - on/off/inquire bitplane mode
VTAG_CHROMA_PEN [_SET | _CLR | _GET] - set/clr/get chromakey pen #
VTAG_CHROMA_PLANE [_SET | | _GET] - set/get bitplanekey plane #

control commands:

VTAG_IMMEDIATE
normally, VideoControl changes do not occur until the next MakeVPort. Using this tag, some changes can be made to happen immediately. The tag data is a pointer to a longword flag variable which will be cleared if all changes happened immediately. See the example. (V39)

VTAG_FULLPALETTE_xxx
[_SET | _CLR | _GET] enable/disable loading of all colors in the copper list. Normally, graphics will only load the color which are necessary for the viewport, based upon the screen depth and mode. In order to use the color palette banking features, you may need to use this tag to tell graphics to load ALL colors, regardless of screen depth. (V39)

VC_IntermediateCLUpdate
see next

VC_IntermediateCLUpdate_Query
When set, graphics will update the intermediate copper lists on colour changes. When FALSE, graphics won't update the intermediate copperlists, so ScrollVPort(), ChangeVPBitMap() and colour loading functions will be faster. This value is TRUE by default. (V40)

VC_NoColorPaletteLoad
see next

VC_NoColorPaletteLoad_Query
When set, only colour 0 will be loaded for this ViewPort, hence the inter-ViewPort gap will be smaller. The colours for this ViewPort are inherited from the next higher ViewPort. The results are undefined if this is the first or only ViewPort in the display, and undefined when used in conjunction with VTAG_FULLPALETTE (!?!). This value is FALSE by default. (V40)

VC_DUALPF_Disable
see next

VC_DUALPF_Disable_Query
When set, disables the setting of the dual-playfield bit in bplcon0. When used with a dual-playfield mode screen, this allows using separate scroll and bitmaps for the odd and even bitplanes, without going through the normal dual-playfield priority and palette selection. With appropriate palette setup, this can be used for transparency effects, etc.

copper commands

VTAG_USERCLIP_xxx
[_SET | _CLR | _GET] - on/off/inquire clipping of UserCopperList at bottom edge of ColorMap->cm_vp (defaults to off)

buffer commands:

VTAG_NEXTBUF_CM
link to more VTAG commands

VTAG_END_CM
terminate command buffer

batch mode commands:

(if you want your videocontrol taglist to be processed in "batch"

mode, that is, at the next MakeVPort() for the ColorMap->cm_vp; you may install a static list of videocontrol TagItems into the ColorMap with the BATCH_ITEMS_SET command; and then enable/disable batch mode processing of those items via the BATCH_CM control command)

VTAG_BATCH_CM_xxx
[_SET | _CLR | _GET] - on/off/inquire batch mode

VTAG_BATCH_ITEMS_ xxx - [_SET | _ADD | _GET] - set/add/get batched TagLists

private commands (used internally by intuition - do not call):

VTAG_VPMODEID_xxx
[_SET | _CLR | _GET] - force GetVPModeID() return

INPUTS

cm
pointer to struct ColorMap obtained via GetColorMap().

tags
pointer to a table of videocontrol tagitems.

RESULT

error
NULL if no error occurred in the control operation. (non-NULL if bad colormap pointer, no tagitems or bad tag)

The operating characteristics of the ColorMap and its attached ViewPort are modified. The result will be incorporated into the ViewPort when its copper lists are reassembled via MakeVPort().

Note that you must NOT change colors in the viewport (via SetRGB4(), LoadRGB4(), SetRGB4(), etc.) after changing any of the color palette offsets (VTAG_PF1_BASE, etc), without first remaking the ViewPort.

NOTES

Sprite resolutions is controlled by two sets of tags, SPRITERESN and DEFSPRITERESN. If you don't set the sprite resolution, it will follow the intuition-controlled "default" sprite resolution. Setting the sprite resolution to one of the SPRITERESN_ values will allow the application to override intuition's control of it.

This function will modify the contents of the TagList you pass to it by changing _GET tags to the corresponding _SET or _CLR tag. The exceptions to this rule are documented as such above (such as VTAG_IMMEDIATE).

The new tags added for V40 have the prefix VC_ instead of VTAG_. These tags work in the same manner as all other tags in the system, and will not be modified by VideoControl().

EXAMPLE

must_remake=-1;
error=VideoControl(myvp->ColorMap,VTAG_BORDERBLANK_SET,-1,
(GFXBase->lib_Version>=39)?VTAG_IMMEDIATE:TAG_IGNORE,
&must_remake);
if (must_remake) { MakeVPort(myview,myvp); MrgCop(myview); }

EXAMPLE

struct TagItem VCTags[] =
{
{VTAG_BORDERBLANK_GET, NULL},
{VTAG_SPRITERESN_SET, SPRITERESN_35NS},
{TAG_DONE, NULL},
};
BOOL bblank = FALSE;

if (VideoControl(cm, VCTags) == NULL)
{
bblank = (VCTags[0].ti_Tag == VTAG_BORDERBLANK_SET);
}

EXAMPLE

struct TagItem VCTags[] =
{
{VC_NoColorPaletteLoad_Query, NULL},
{TAG_DONE},
};
ULONG query;

VCTags[0].ti_Data = (ULONG)&query;
if (VideoControl(cm, VCTags) == NULL)
{
printf("Palette loading is %s\n", (query ? "off" : "on"));
}

BUGS

VTAG_SPRITERESN_GET and VTAG_DEFSPRITERESN_GET returned 0xff instead of -1 for the default sprite resolution under V45 and below.

SEE ALSO

<graphics/videocontrol.h>, GetColorMap(), FreeColorMap()