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, 2 insertions, 2 deletions

diff --git a/src/modules/montage/montage.c b/src/modules/montage/montage.c
index 13c8a36..e6f6ef1 100644
--- a/src/modules/montage/montage.c
+++ b/src/modules/montage/montage.c
@@ -144,14 +144,14 @@ static int montage_fragment_tile(const til_fb_fragment_t *fragment, unsigned til
 	xoff = x * tile_width;
 	yoff = y * tile_height;
 
-	res_fragment->buf = (void *)fragment->buf + (yoff * fragment->pitch) + (xoff * 4);
+	res_fragment->buf = fragment->buf + (yoff * fragment->pitch) + xoff;
 	res_fragment->x = 0;					/* fragment is a new frame */
 	res_fragment->y = 0;					/* fragment is a new frame */
 	res_fragment->width = MIN(fragment->width - xoff, tile_width);
 	res_fragment->height = MIN(fragment->height - yoff, tile_height);
 	res_fragment->frame_width = res_fragment->width;	/* fragment is a new frame */
 	res_fragment->frame_height = res_fragment->height;	/* fragment is a new frame */
-	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;