til_fb: til_fb_fragment_t.{pitch,stride} uint32_t units

Originally it seemed sensible to make these units of bytes, for
flexibility reasons.

But it's advantageous for everything to be able to assume pixels
are always 4-byte/32-bit aligned.  Having the stride/pitch be in
bytes of units made it theoretically possible to produce
unaligned rows of pixels, which would break that assumption.

I don't think anything was ever actually producing such things,
and I've added some asserts to the {sdl,drm}_fb.c page
acquisition code to go fatal on such pages.

This change required going through all the modules and get rid of
their uint32_t vs. void* dances and other such 1-byte vs. 4-byte
scaling arithmetic.

Code is simpler now, and probably faster in some cases.  And now
allows future work to just assume things cna always occur 4-bytes
at a time without concern for unaligned accesses.

1 files changed, 3 insertions, 4 deletions

diff --git a/src/til_fb.c b/src/til_fb.c
index 5a6a956..eb14e27 100644
--- a/src/til_fb.c
+++ b/src/til_fb.c
@@ -395,12 +395,11 @@ int til_fb_fragment_slice_single(const til_fb_fragment_t *fragment, unsigned n_f
 {
 	unsigned	slice = fragment->height / n_fragments;
 	unsigned	yoff = slice * number;
-	unsigned	pitch;
 
 	if (yoff >= fragment->height)
 		return 0;
 
-	res_fragment->buf = ((void *)fragment->buf) + yoff * fragment->pitch;
+	res_fragment->buf = fragment->buf + yoff * fragment->pitch;
 	res_fragment->x = fragment->x;
 	res_fragment->y = yoff;
 	res_fragment->width = fragment->width;
@@ -436,14 +435,14 @@ int til_fb_fragment_tile_single(const til_fb_fragment_t *fragment, unsigned tile
 	xoff = x * tile_size;
 	yoff = y * tile_size;
 
-	res_fragment->buf = (void *)fragment->buf + (yoff * fragment->pitch) + (xoff * 4);
+	res_fragment->buf = fragment->buf + (yoff * fragment->pitch) + (xoff);
 	res_fragment->x = fragment->x + xoff;
 	res_fragment->y = fragment->y + yoff;
 	res_fragment->width = MIN(fragment->width - xoff, tile_size);
 	res_fragment->height = MIN(fragment->height - yoff, tile_size);
 	res_fragment->frame_width = fragment->frame_width;
 	res_fragment->frame_height = fragment->frame_height;
-	res_fragment->stride = fragment->stride + ((fragment->width - res_fragment->width) * 4);
+	res_fragment->stride = fragment->stride + (fragment->width - res_fragment->width);
 	res_fragment->pitch = fragment->pitch;
 	res_fragment->number = number;
 	res_fragment->cleared = fragment->cleared;