From 69cfef46beafe0ee7cc5122ef01d88adea8e62f4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sigrid=20Solveig=20Hafl=C3=ADnud=C3=B3ttir?=
 <ftrvxmtrx@gmail.com>
Date: Sat, 25 Dec 2021 22:42:34 +0100
Subject: [PATCH] ppu_palette: rewrite for more readability

---
 src/devices/ppu.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/devices/ppu.c b/src/devices/ppu.c
index 603ca47..9dae9d9 100644
--- a/src/devices/ppu.c
+++ b/src/devices/ppu.c
@@ -40,13 +40,14 @@ static Uint8 font[][8] = {
 void
 ppu_palette(Ppu *p, Uint8 *addr)
 {
-	int i;
-	for(i = 0; i < 4; ++i) {
+	int i, shift;
+	for(i = 0, shift = 4; i < 4; ++i, shift ^= 4) {
 		Uint8
-			r = (*(addr + i / 2) >> (!(i % 2) << 2)) & 0x0f,
-			g = (*(addr + 2 + i / 2) >> (!(i % 2) << 2)) & 0x0f,
-			b = (*(addr + 4 + i / 2) >> (!(i % 2) << 2)) & 0x0f;
-		p->palette[i] = 0xff000000 | (r << 20) | (r << 16) | (g << 12) | (g << 8) | (b << 4) | b;
+			r = (addr[0 + i / 2] >> shift) & 0x0f,
+			g = (addr[2 + i / 2] >> shift) & 0x0f,
+			b = (addr[4 + i / 2] >> shift) & 0x0f;
+		p->palette[i] = 0x0f000000 | r << 16 | g << 8 | b;
+		p->palette[i] |= p->palette[i] << 4;
 	}
 	p->fg.changed = p->bg.changed = 1;
 }