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The /tests/pc folder is now /tests/pcx86 (to be consistent with the associated emulator)

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This commit is contained in:
Jeff Parsons 2016-08-09 11:48:09 -07:00
commit 663343a1ad
68 changed files with 24 additions and 16 deletions
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131
tests/pc/vga/L42-1.C
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@ -1,131 +0,0 @@
/* Function to draw an antialiased line from (X0,Y0) to (X1,Y1), using an
* antialiasing approach published by Xiaolin Wu in the July 1991 issue of
* Computer Graphics. Requires that the palette be set up so that there
* are NumLevels intensity levels of the desired drawing color, starting at
* color BaseColor (100% intensity) and followed by (NumLevels-1) levels of
* evenly decreasing intensity, with color (BaseColor+NumLevels-1) being 0%
* intensity of the desired drawing color (black). This code is suitable for
* use at screen resolutions, with lines typically no more than 1K long; for
* longer lines, 32-bit error arithmetic must be used to avoid problems with
* fixed-point inaccuracy. No clipping is performed in DrawWuLine; it must be
* performed either at a higher level or in the DrawPixel function.
* Tested with Borland C++ in C compilation mode and the small model.
*/
extern void DrawPixel(int, int, int);
/* Wu antialiased line drawer.
* (X0,Y0),(X1,Y1) = line to draw
* BaseColor = color # of first color in block used for antialiasing, the
* 100% intensity version of the drawing color
* NumLevels = size of color block, with BaseColor+NumLevels-1 being the
* 0% intensity version of the drawing color
* IntensityBits = log base 2 of NumLevels; the # of bits used to describe
* the intensity of the drawing color. 2**IntensityBits==NumLevels
*/
void DrawWuLine(int X0, int Y0, int X1, int Y1, int BaseColor, int NumLevels, unsigned int IntensityBits)
{
unsigned int IntensityShift, ErrorAdj, ErrorAcc;
unsigned int ErrorAccTemp, Weighting, WeightingComplementMask;
int DeltaX, DeltaY, Temp, XDir;
/* Make sure the line runs top to bottom */
if (Y0 > Y1) {
Temp = Y0; Y0 = Y1; Y1 = Temp;
Temp = X0; X0 = X1; X1 = Temp;
}
/* Draw the initial pixel, which is always exactly intersected by
the line and so needs no weighting */
DrawPixel(X0, Y0, BaseColor);
if ((DeltaX = X1 - X0) >= 0) {
XDir = 1;
} else {
XDir = -1;
DeltaX = -DeltaX; /* make DeltaX positive */
}
/* Special-case horizontal, vertical, and diagonal lines, which
require no weighting because they go right through the center of
every pixel */
if ((DeltaY = Y1 - Y0) == 0) {
/* Horizontal line */
while (DeltaX-- != 0) {
X0 += XDir;
DrawPixel(X0, Y0, BaseColor);
}
return;
}
if (DeltaX == 0) {
/* Vertical line */
do {
Y0++;
DrawPixel(X0, Y0, BaseColor);
} while (--DeltaY != 0);
return;
}
if (DeltaX == DeltaY) {
/* Diagonal line */
do {
X0 += XDir;
Y0++;
DrawPixel(X0, Y0, BaseColor);
} while (--DeltaY != 0);
return;
}
/* Line is not horizontal, diagonal, or vertical */
ErrorAcc = 0; /* initialize the line error accumulator to 0 */
/* # of bits by which to shift ErrorAcc to get intensity level */
IntensityShift = 16 - IntensityBits;
/* Mask used to flip all bits in an intensity weighting, producing the
result (1 - intensity weighting) */
WeightingComplementMask = NumLevels - 1;
/* Is this an X-major or Y-major line? */
if (DeltaY > DeltaX) {
/* Y-major line; calculate 16-bit fixed-point fractional part of a
pixel that X advances each time Y advances 1 pixel, truncating the
result so that we won't overrun the endpoint along the X axis */
ErrorAdj = ((unsigned long) DeltaX << 16) / (unsigned long) DeltaY;
/* Draw all pixels other than the first and last */
while (--DeltaY) {
ErrorAccTemp = ErrorAcc; /* remember currrent accumulated error */
ErrorAcc += ErrorAdj; /* calculate error for next pixel */
if (ErrorAcc <= ErrorAccTemp) {
/* The error accumulator turned over, so advance the X coord */
X0 += XDir;
}
Y0++; /* Y-major, so always advance Y */
/* The IntensityBits most significant bits of ErrorAcc give us the
intensity weighting for this pixel, and the complement of the
weighting for the paired pixel */
Weighting = ErrorAcc >> IntensityShift;
DrawPixel(X0, Y0, BaseColor + Weighting);
DrawPixel(X0 + XDir, Y0, BaseColor + (Weighting ^ WeightingComplementMask));
}
/* Draw the final pixel, which is always exactly intersected by the line
and so needs no weighting */
DrawPixel(X1, Y1, BaseColor);
return;
}
/* It's an X-major line; calculate 16-bit fixed-point fractional part of a
pixel that Y advances each time X advances 1 pixel, truncating the
result to avoid overrunning the endpoint along the X axis */
ErrorAdj = ((unsigned long) DeltaY << 16) / (unsigned long) DeltaX;
/* Draw all pixels other than the first and last */
while (--DeltaX) {
ErrorAccTemp = ErrorAcc; /* remember currrent accumulated error */
ErrorAcc += ErrorAdj; /* calculate error for next pixel */
if (ErrorAcc <= ErrorAccTemp) {
/* The error accumulator turned over, so advance the Y coord */
Y0++;
}
X0 += XDir; /* X-major, so always advance X */
/* The IntensityBits most significant bits of ErrorAcc give us the
intensity weighting for this pixel, and the complement of the
weighting for the paired pixel */
Weighting = ErrorAcc >> IntensityShift;
DrawPixel(X0, Y0, BaseColor + Weighting);
DrawPixel(X0, Y0 + 1, BaseColor + (Weighting ^ WeightingComplementMask));
}
/* Draw the final pixel, which is always exactly intersected by the line
and so needs no weighting */
DrawPixel(X1, Y1, BaseColor);
}