bg rotation

diff --git a/src/gamescr.c b/src/gamescr.c
index 39ed733..ec4f353 100644 (file)
--- a/src/gamescr.c
+++ b/src/gamescr.c
@@ -78,10 +78,13 @@ void gamescr(void)
        }
 }
 
+static int32_t bgmat[4];
+static int32_t bgx, bgy;
+
 __attribute__((noinline, target("arm"), section(".iwram")))
 static void draw_tunnel(void)
 {
-       static int uoffs;
+       static short uoffs;
        int i, j, tx, ty, angle, depth, zoffs;
        uint16_t pptop, ppbot;
        uint16_t *top, *bot;
@@ -92,6 +95,13 @@ static void draw_tunnel(void)
        if(bnstate & BN_LT) uoffs++;
        if(bnstate & BN_RT) uoffs--;
 
+       bgmat[0] = COS(uoffs) << 1;
+       bgmat[1] = -SIN(uoffs) << 1;
+       bgmat[2] = SIN(uoffs) << 1;
+       bgmat[3] = COS(uoffs) << 1;
+       bgx = (120 << 8) - bgmat[0] * 120 + bgmat[1] * -80;
+       bgy = (80 << 8) - bgmat[2] * 120 + bgmat[3] * -80;
+
        top = vram[backbuf];
        bot = vram[backbuf] + 159 * 240 / 2;
        tunptr = tunmap;
@@ -109,18 +119,22 @@ static void draw_tunnel(void)
 
                        angle = tun & 0xff;
                        depth = (tun >> 8) & 0xff;
-                       tx = ((angle >> 1) + uoffs) & 0x1f;
+//                     tx = ((angle >> 1) - uoffs) & 0x1f;
+                       tx = (angle >> 1) & 0x1f;
                        ty = ((depth >> 1) + zoffs) & 0x1f;
                        pptop = tex[(ty << 5) + tx];
-                       tx = ~((angle >> 1) - uoffs) & 0x1f;
+//                     tx = ~((angle >> 1) + uoffs) & 0x1f;
+                       tx = ~(angle >> 1) & 0x1f;
                        ppbot = tex[(ty << 5) + tx];
 
                        angle = (tun >> 16) & 0xff;
                        depth = (tun >> 24) & 0xff;
-                       tx = ((angle >> 1) + uoffs) & 0x1f;
+//                     tx = ((angle >> 1) - uoffs) & 0x1f;
+                       tx = (angle >> 1) & 0x1f;
                        ty = ((depth >> 1) + zoffs) & 0x1f;
                        pptop |= (uint16_t)tex[(ty << 5) + tx] << 8;
-                       tx = ~((angle >> 1) - uoffs) & 0x1f;
+//                     tx = ~((angle >> 1) + uoffs) & 0x1f;
+                       tx = ~(angle >> 1) & 0x1f;
                        ppbot |= (uint16_t)tex[(ty << 5) + tx] << 8;
 
                        *top++ = pptop;
@@ -137,6 +151,13 @@ static void vblank(void)
        int16_t mat[4];
        static short gate_speed;
 
+       REG_BG2PA = bgmat[0];
+       REG_BG2PB = bgmat[1];
+       REG_BG2PC = bgmat[2];
+       REG_BG2PD = bgmat[3];
+       REG_BG2X = bgx;
+       REG_BG2Y = bgy;
+
        bnstate = ~REG_KEYINPUT;
        if(bnstate & BN_DPAD) {
                if(gate_speed < 5) {