From: John Tsiombikas <nuclear@member.fsf.org>
Date: Tue, 20 Apr 2021 10:35:14 +0000 (+0300)
Subject: 16bit LUT
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=gbajam21;a=commitdiff_plain;h=f6bf5b7710b9a695ddaef0ad929796a4e151268e

16bit LUT
---

diff --git a/src/gamescr.c b/src/gamescr.c
index 452709c..8d5f344 100644
--- a/src/gamescr.c
+++ b/src/gamescr.c
@@ -80,10 +80,10 @@ void gamescr(void)
 		present(backbuf);
 
 		tunrot = nframes;
-		bgmat[0] = (COS(tunrot) * 280) >> 8;
-		bgmat[1] = (-SIN(tunrot) * 280) >> 8;
-		bgmat[2] = (SIN(tunrot) * 280) >> 8;
-		bgmat[3] = (COS(tunrot) * 280) >> 8;
+		bgmat[0] = (COS(tunrot) * 140) >> 8;
+		bgmat[1] = (-SIN(tunrot) * 140) >> 8;
+		bgmat[2] = (SIN(tunrot) * 140) >> 8;
+		bgmat[3] = (COS(tunrot) * 140) >> 8;
 		bgx = (120 << 8) - bgmat[0] * 120 + bgmat[1] * -80;
 		bgy = (80 << 8) - bgmat[2] * 120 + bgmat[3] * -80;
 
@@ -101,7 +101,7 @@ static void draw_tunnel(void)
 
 	zoffs = nframes;
 
-	uoffs = tunrot;
+	uoffs = tunrot >> 1;
 
 	top = vram[backbuf] + 20;
 	bot = vram[backbuf] + 159 * 240 / 2 + 20;
@@ -182,10 +182,10 @@ static void vblank(void)
 	spr_oam(oam, 0, 512 + 256, x - 64, y - 64, SPR_256COL | SPR_SZ64 | SPR_DBLSZ |
 			SPR_ROTSCL | SPR_ROTSCL_SEL(0));
 
-	mat[0] = COS(rot) << 1;
-	mat[1] = -SIN(rot) << 1;
-	mat[2] = SIN(rot) << 1;
-	mat[3] = COS(rot) << 1;
+	mat[0] = COS(rot);
+	mat[1] = -SIN(rot);
+	mat[2] = SIN(rot);
+	mat[3] = COS(rot);
 	spr_transform(oam, 0, mat);
 
 
diff --git a/src/util.h b/src/util.h
index 5181ba1..789e63e 100644
--- a/src/util.h
+++ b/src/util.h
@@ -20,7 +20,7 @@
 		((uint16_t*)CRAM_BG_ADDR)[idx] = (uint16_t)(r) | ((uint16_t)(g) << 5) | ((uint16_t)(b) << 10); \
 	} while(0)
 
-extern int8_t sinlut[];
+extern int16_t sinlut[];
 
 #define SIN(x)	sinlut[(x) & 0xff]
 #define COS(x)	sinlut[((x) + 64) & 0xff]
diff --git a/tools/lutgen.c b/tools/lutgen.c
index c3f003a..70d7641 100644
--- a/tools/lutgen.c
+++ b/tools/lutgen.c
@@ -10,7 +10,7 @@ int main(void)
 	puts("sinlut:");
 	for(i=0; i<256; i++) {
 		float x = sin((float)i / 128.0f * M_PI);
-		printf("\t.byte %d\n", (int)(x * 127.5f - 0.5f));
+		printf("\t.short %d\n", (int)(x * 256.0f));
 	}
 	return 0;
 }