porting voxscape to gba

[gbajam22] / src / util.h

diff --git a/src/util.h b/src/util.h
index 3bbafbd..f719b17 100644 (file)
--- a/src/util.h
+++ b/src/util.h
@@ -29,8 +29,14 @@ void present(int buf);               /* defined in src/pc/main.c */
 
 extern int16_t sinlut[];
 
-#define SIN(x) sinlut[(x) & 0xff]
-#define COS(x) sinlut[((x) + 64) & 0xff]
+#define SINLUT_BITS            8
+#define SINLUT_SIZE            (1 << SINLUT_BITS)
+
+#define SIN(angle) \
+       ((int32_t)sinlut[((angle) >> (16 - SINLUT_BITS)) & (SINLUT_SIZE - 1)] << 1)
+
+#define COS(angle) \
+       ((int32_t)sinlut[(((angle) >> (16 - SINLUT_BITS)) + (SINLUT_SIZE / 4)) & (SINLUT_SIZE - 1)] << 1)
 
 int iwram_brk(void *addr);
 void *iwram_sbrk(intptr_t delta);