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trident: reworked Bresenham line drawing. It's better, but I'm still not convinced it's completely accurate.

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mahlemiut 2014-10-09 02:32:51 +00:00
parent 3b23f9c85e
commit eadd1b3ac6
1 changed files with 23 additions and 19 deletions
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42
src/emu/bus/isa/trident.c
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@ -1487,32 +1487,36 @@ void trident_vga_device::accel_line()
// TGUI_SRC_XY(dmin-dmaj,dmin);
// TGUI_DEST_XY(x,y);
// TGUI_DIM_XY(dmin+e,len);
INT16 dx = abs(tri.accel_source_x - tri.accel_source_y);
INT16 dy = abs(tri.accel_source_y);
INT16 err = (tri.accel_dim_x - tri.accel_source_y);
INT16 dx = tri.accel_source_y - tri.accel_source_x;
INT16 dy = tri.accel_source_y;
INT16 err = tri.accel_dim_x + tri.accel_source_y;
int sx = (tri.accel_drawflags & 0x0200) ? -1 : 1;
int sy = (tri.accel_drawflags & 0x0100) ? -1 : 1;
int count = 0;
INT16 temp;
int x,y,z;
if(tri.accel_drawflags & 0x0400)
x = tri.accel_dest_x;
y = tri.accel_dest_y;
WRITEPIXEL(x,y,col);
for(z=0;z<tri.accel_dim_y;z++)
{
temp = dx; dx = dy; dy = temp;
}
for(;;)
{
WRITEPIXEL(tri.accel_dest_x,tri.accel_dest_y,col);
if (count > tri.accel_dim_y) break;
count++;
if((err*2) > -dy)
if(tri.accel_drawflags & 0x0400)
y += sy;
else
x += sx;
if(err > 0)
{
err -= dy;
tri.accel_dest_x += sx;
if(tri.accel_drawflags & 0x0400)
x += sx;
else
y += sy;
WRITEPIXEL(x,y,col);
err += (dy-dx);
}
if((err*2) < dx)
else
{
err += dx;
tri.accel_dest_y += sy;
WRITEPIXEL(x,y,col);
err += dy;
}
}
}