+ //tunsweep = SIN(nframes) >> 4;
+
+ if((bnstate & BN_RT) && tunsweep > -31) tunsweep--;
+ if((bnstate & BN_LT) && tunsweep < 31) tunsweep++;
+
+ flip = tunsweep < 0;
+ tunturn = abs(tunsweep) & 0x1f;
+
+ zoffs = num_vbl;
+ uoffs = (flip ? -num_vbl : num_vbl) >> 1;
+
+ top = vram[backbuf];
+ bot = vram[backbuf] + 159 * 240 / 2;
+ tunptr = tunmap + tunturn * 9600;
+
+ if(flip) {
+ tunptr += 240/2;
+ for(i=0; i<80; i++) {
+ for(j=0; j<240/2; j++) {
+ tun = *--tunptr;
+
+ angle = TUN_U(tun >> 16);
+ depth = TUN_V(tun >> 16);
+ shade = depth >> 7;
+ tx = ~(angle - uoffs) & 0x1f;
+ ty = ((depth >> 1) + zoffs) & 0x1f;
+ pptop = TEXEL(tx, ty, shade);
+ tx = (angle + uoffs) & 0x1f;
+ ppbot = TEXEL(tx, ty, shade);
+
+ angle = TUN_U(tun);
+ depth = TUN_V(tun);
+ shade = depth >> 7;
+ tx = ~(angle - uoffs) & 0x1f;
+ ty = ((depth >> 1) + zoffs) & 0x1f;
+ pptop |= (uint16_t)TEXEL(tx, ty, shade) << 8;
+ tx = (angle + uoffs) & 0x1f;
+ ppbot |= (uint16_t)TEXEL(tx, ty, shade) << 8;
+
+ *top++ = pptop;
+ *bot++ = ppbot;
+ }
+ bot -= 240;
+ tunptr += 240;
+ }
+ } else {
+ for(i=0; i<80; i++) {
+ for(j=0; j<240/2; j++) {
+ tun = *tunptr++;
+
+ angle = TUN_U(tun);
+ depth = TUN_V(tun);
+ shade = depth >> 7;
+ tx = (angle - uoffs) & 0x1f;
+ ty = ((depth >> 1) + zoffs) & 0x1f;
+ pptop = TEXEL(tx, ty, shade);
+ tx = ~(angle + uoffs) & 0x1f;
+ ppbot = TEXEL(tx, ty, shade);
+
+ angle = TUN_U(tun >> 16);
+ depth = TUN_V(tun >> 16);
+ shade = depth >> 7;
+ tx = (angle - uoffs) & 0x1f;
+ ty = ((depth >> 1) + zoffs) & 0x1f;
+ pptop |= (uint16_t)TEXEL(tx, ty, shade) << 8;
+ tx = ~(angle + uoffs) & 0x1f;
+ ppbot |= (uint16_t)TEXEL(tx, ty, shade) << 8;
+
+ *top++ = pptop;
+ *bot++ = ppbot;