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.

5 files changed, 7 insertions, 8 deletions

diff --git a/src/modules/blinds/blinds.c b/src/modules/blinds/blinds.c
index c0ae079..9996d8a 100644
--- a/src/modules/blinds/blinds.c
+++ b/src/modules/blinds/blinds.c
@@ -67,7 +67,7 @@ static inline void draw_blind_horizontal(til_fb_fragment_t *fragment, unsigned r
 	unsigned	height = roundf(t * (float)row_height);
 
 	for (unsigned y = 0; y < height; y++)
-		memset(fragment->buf + ((row * row_height) + y ) * (fragment->pitch >> 2), 0xff, fragment->width * 4);
+		memset(fragment->buf + ((row * row_height) + y ) * fragment->pitch, 0xff, fragment->width * 4);
 }
 
 
@@ -78,7 +78,7 @@ static inline void draw_blind_vertical(til_fb_fragment_t *fragment, unsigned col
 	unsigned	width = roundf(t * (float)column_width);
 
 	for (unsigned y = 0; y < fragment->height; y++)
-		memset(fragment->buf + y * (fragment->pitch >> 2) + column * column_width, 0xff, width * 4);
+		memset(fragment->buf + y * fragment->pitch + column * column_width, 0xff, width * 4);
 }
 
 
diff --git a/src/modules/julia/julia.c b/src/modules/julia/julia.c
index fb3bdae..4b3cd73 100644
--- a/src/modules/julia/julia.c
+++ b/src/modules/julia/julia.c
@@ -155,7 +155,7 @@ static void julia_render_fragment(void *context, unsigned ticks, unsigned cpu, t
 			*buf = colors[julia_iter(real, imag, ctxt->creal, ctxt->cimag, sizeof(colors) / sizeof(*colors), ctxt->threshold)];
 		}
 
-		buf = ((void *)buf) + fragment->stride;
+		buf += fragment->stride;
 	}
 }
 
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;
diff --git a/src/modules/plasma/plasma.c b/src/modules/plasma/plasma.c
index 81540c5..0a6b1e5 100644
--- a/src/modules/plasma/plasma.c
+++ b/src/modules/plasma/plasma.c
@@ -156,7 +156,7 @@ static void plasma_render_fragment(void *context, unsigned ticks, unsigned cpu,
 			*buf = color2pixel(&c);
 		}
 
-		buf = ((void *)buf) + fragment->stride;
+		buf += fragment->stride;
 	}
 }
 
diff --git a/src/modules/roto/roto.c b/src/modules/roto/roto.c
index 5409970..65b3400 100644
--- a/src/modules/roto/roto.c
+++ b/src/modules/roto/roto.c
@@ -240,11 +240,10 @@ static void roto_render_fragment(void *context, unsigned ticks, unsigned cpu, ti
 			x_sin_r += sin_r;
 		}
 
-		buf = ((void *)buf) + fragment->stride;
+		buf += fragment->stride;
 		y_cos_r += cos_r;
 		y_sin_r += sin_r;
 	}
-
 }