sforman
/
Thun
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Alpha blend font FTW!

This commit is contained in:
Simon Forman 2023-02-26 11:21:18 -08:00
parent 2680d8ce1b
commit 84f163b71c
1 changed files with 12 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
implementations/uvm-ncc/xerblin.c
View File

@ -20,12 +20,21 @@ draw_char(u8 ch, u64 dest_x, u64 dest_y)
for (size_t x = 0; x < font_width; ++x) {
for (size_t y = 0; y < font_height; ++y) {
u32* pix_ptr = dest + x + FRAME_WIDTH * y;
u32 dest_pixel = *pix_ptr;
u32 pixel = character_data[x + font_width * y];
if (!(pixel >> 24)) { // no alpha
u8 alpha = pixel >> 24;
if (!alpha) { // no alpha
continue;
}
*pix_ptr = pixel;
if (0xFF == alpha) {
*pix_ptr = pixel;
continue;
}
u32 dest_pixel = *pix_ptr;
u8 unalpha = 0xFF - alpha;
u8 red = (((dest_pixel >> 16) & 255) * unalpha + ((pixel >> 16) & 255) * alpha) / 0xff;
u8 green = (((dest_pixel >> 8) & 255) * unalpha + ((pixel >> 8) & 255) * alpha) / 0xff;
u8 blue = ((dest_pixel & 255) * unalpha + (pixel & 255) * alpha) / 0xff;
*pix_ptr = (alpha << 24) | (red << 16) | (green << 8) | blue;
}
}
}