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1994-03-30
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SuperVGA S3 BGI driver
Version 1.6
March 30, 1994
Revisions:
1.5 - August 28, 1993
1.1 - May 20, 1993
1.05 - January 28, 1993
1.0 - June 28, 1992
This is the latest version of my SuperVGA S3 BGI driver. All functions
have been implemented, but there may still be bugs.
o Apparently there is a problem with using putimage at addresses >64k
(The driver will put up a solid block instead of the image)
Note: Palette functions, and the mouse cursor will not work with this driver.
Paging is not yet implemented
Using the driver in the 256 and 16 color modes is similar to using the
standard SuperVGA 256 and 16 color drivers. See the files NOTES[256|16].SVG
Using the S3 driver in 32768 color mode:
Implementing the 32768 color driver involved several hacks, as
the BGI interface only supports 8-bit color values, but the driver
needed support for 15-bit color values. The procedures that needed
to be changed were those that accepted color values, (SetColor,
SetFillStyle, SetFillPattern, PutPixel and Floodfill) and those
that return color values (GetColor and GetPixel).
As the HiColor modes do not support palettes, I decided to use
the SetRgbPalette call to set colors, as it accepts values for the
R,G and B components of the color.
The format of a pixel in the HiColor modes is:
-Byte 1- -Byte 0-
xRRRRRGG GGGBBBBB
Several new functions are defined to make the color selection easier.
In addition, the macro RGB(rv,gv,bv) has been defined. It packs
the R, G and B values into the format described above and returns the
combined color.
* RealDrawColor(); - Sets the current drawing color.
Usage:
setcolor(RealDrawColor(RGB(rval,gval,bval)); - HiColor modes
setcolor(RealDrawColor(cval)); - (suggested for any other driver)
* RealFillColor(); - Sets the current fill color.
Usage:
setfillstyle(fillstyle,RealFillColor(RGB(rval,gval,bval)));
setfillstyle(fillstyle,RealFillColor(cval));
setfillpattern(fillpat,RealFillColor(RGB(rval,gval,bval)));
setfillpattern(fillpat,RealFillColor(cval));
* RealColor(); - For putpixel, sets the color of the pixel
- For floodfill, sets the color of the boundary
putpixel(x,y,RealColor(RGB(rval,gval,bval)));
putpixel(x,y,RealColor(cval));
floodfill(x,y,RealColor(RGB(rval,gval,bval)));
floodfill(x,y,RealColor(cval));
* GetPixel normally only returns an 8-bit value. However, the
value returned from the BGI driver is a 16-bit value in DX (the
BGI kernel loads the value into AX and clears the upper 8 bits),
so to read the value of a pixel:
In Pascal:
Color := getpixel(x,y);
inline($89/$56/<Color); (* Loads 15-bit color value *)
In C:
Color = getpixel(x,y);
Color = _DX;
o Mouse code hooks added (1.05)
o Fixed text clipping at right and bottom edges (1.1)
o Added compile-time support for 8x8, 8x14, or 8x16 bitmap fonts (1.1)
o Fixed detection so it should work with newer S3 cards (1.1)
o Drivers now have compile-time support for BGI version 3.0.
Supports protected mode with Borland Pascal 7.0 (1.5)
o Fixed lockup bug (1.6)