driver.video.types¶

Shared video subsystem data types and function pointer signatures.

Overview¶

This unit defines all foundational types for the video subsystem. It is depended upon by every video driver and the front-end driver.video unit. No executable code is present; the unit consists entirely of type and constant declarations.

Dependencies¶

(none — foundational video unit)

Types¶

VideoBuffer¶

VideoBuffer = uint32;

A raw physical or virtual framebuffer address treated as an opaque 32-bit value.

TVideoBuffer¶

Describes a single framebuffer (front or back):

Field	Type	Description
`Initialized`	`boolean`	Whether this buffer has been configured
`Location`	`pointer`	Base address of the framebuffer
`BitsPerPixel`	`uint8`	Colour depth (8, 16, 24, or 32)
`Width`	`uint32`	Horizontal resolution in pixels
`Height`	`uint32`	Vertical resolution in pixels

Function Pointer Types¶

Type	Signature	Description
`FDrawPixel`	`procedure(Buffer: PVideoBuffer; X, Y: uint32; Pixel: TRGB32)`	Draw a single pixel
`FFlush`	`procedure(Front, Back: PVideoBuffer)`	Copy back buffer to front buffer
`FDrawLine`	`procedure(Buffer: PVideoBuffer; X1, Y1, X2, Y2: uint32; Pixel: TRGB32)`	Draw a line
`FDrawRect`	`procedure(Buffer: PVideoBuffer; X, Y, W, H: uint32; Pixel: TRGB32)`	Draw a rectangle outline
`FFillRect`	`procedure(Buffer: PVideoBuffer; X, Y, W, H: uint32; Pixel: TRGB32)`	Fill a rectangle

TDrawRoutines¶

Groups all drawing function pointers into a single record. An instance of this record is embedded in TVideoInterface and populated by the active BPP-specific driver module during init.

TVideoInterface¶

The central video state record:

Field	Type	Description
`DefaultBuffer`	`PVideoBuffer`	Active draw target (points to back buffer when double buffering is enabled)
`FrontBuffer`	`TVideoBuffer`	The visible (front) framebuffer
`BackBuffer`	`TVideoBuffer`	The off-screen (back) framebuffer
`DrawRoutines`	`TDrawRoutines`	Currently active drawing function pointers

Callback Types¶

Type	Description
`FEnableDriver`	Called when a named video driver is enabled; receives `PVideoInterface`
`FRegisterDriver`	Registers a driver identifier and its enable callback
`FInitDriver`	Driver initialisation callback signature