correct tunnel curving

diff --git a/src/gamescr.c b/src/gamescr.c
index aef4966..7da593a 100644 (file)
--- a/src/gamescr.c
+++ b/src/gamescr.c
@@ -85,59 +85,83 @@ void gamescr(void)
 __attribute__((noinline, target("arm"), section(".iwram")))
 static void draw_tunnel(void)
 {
-       int i, j, tx, ty, angle, depth, zoffs, uoffs, flip;
-       int tunsweep;
+       int i, j, tx, ty, angle, depth, zoffs, uoffs, flip, tunturn;
+       static int tunsweep;
        uint16_t pptop, ppbot;
        uint16_t *top, *bot;
        uint32_t tun, *tunptr;
 
-       tunsweep = (SIN(nframes) >> 2) + 64;
-       if(tunsweep > 127) tunsweep = 127;
+       //tunsweep = SIN(nframes) >> 4;
 
-       flip = tunsweep >= 64;
+       if((bnstate & BN_RT) && tunsweep > -31) tunsweep--;
+       if((bnstate & BN_LT) && tunsweep < 31) tunsweep++;
 
-       tunsweep = (tunsweep & 0x3f);
-       if(tunsweep >= 32) tunsweep = 63 - tunsweep;
+       flip = tunsweep < 0;
+       tunturn = abs(tunsweep) & 0x1f;
 
        zoffs = nframes;
 
-       uoffs = tunrot >> 1;
+       uoffs = flip ? -nframes : nframes;
 
        top = vram[backbuf];
        bot = vram[backbuf] + 159 * 240 / 2;
-       tunptr = tunmap + tunsweep * 9600;
-       if(flip) tunptr += 240/2;
-       for(i=0; i<80; i++) {
-               for(j=0; j<240/2; j++) {
-                       if(flip) {
+       tunptr = tunmap + tunturn * 9600;
+
+       if(flip) {
+               tunptr += 240/2;
+               for(i=0; i<80; i++) {
+                       for(j=0; j<240/2; j++) {
                                tun = *--tunptr;
                                tun = (tun >> 16) | (tun << 16);
-                       } else {
-                               tun = *tunptr++;
-                       }
 
-                       angle = tun & 0xff;
-                       depth = (tun >> 8) & 0xff;
-                       tx = ((angle >> 1) - uoffs) & 0x1f;
-                       ty = ((depth >> 1) + zoffs) & 0x1f;
-                       pptop = tex[(ty << 5) + tx];
-                       tx = ~((angle >> 1) + uoffs) & 0x1f;
-                       ppbot = tex[(ty << 5) + tx];
-
-                       angle = (tun >> 16) & 0xff;
-                       depth = (tun >> 24) & 0xff;
-                       tx = ((angle >> 1) - uoffs) & 0x1f;
-                       ty = ((depth >> 1) + zoffs) & 0x1f;
-                       pptop |= (uint16_t)tex[(ty << 5) + tx] << 8;
-                       tx = ~((angle >> 1) + uoffs) & 0x1f;
-                       ppbot |= (uint16_t)tex[(ty << 5) + tx] << 8;
-
-                       *top++ = pptop;
-                       *bot++ = ppbot;
+                               angle = tun & 0xff;
+                               depth = (tun >> 8) & 0xff;
+                               tx = ~((angle >> 1) - uoffs) & 0x1f;
+                               ty = ((depth >> 1) + zoffs) & 0x1f;
+                               pptop = tex[(ty << 5) + tx];
+                               tx = ((angle >> 1) + uoffs) & 0x1f;
+                               ppbot = tex[(ty << 5) + tx];
+
+                               angle = (tun >> 16) & 0xff;
+                               depth = (tun >> 24) & 0xff;
+                               tx = ~((angle >> 1) - uoffs) & 0x1f;
+                               ty = ((depth >> 1) + zoffs) & 0x1f;
+                               pptop |= (uint16_t)tex[(ty << 5) + tx] << 8;
+                               tx = ((angle >> 1) + uoffs) & 0x1f;
+                               ppbot |= (uint16_t)tex[(ty << 5) + tx] << 8;
+
+                               *top++ = pptop;
+                               *bot++ = ppbot;
+                       }
+                       bot -= 240;
+                       tunptr += 240;
                }
-               bot -= 240;
+       } else {
+               for(i=0; i<80; i++) {
+                       for(j=0; j<240/2; j++) {
+                               tun = *tunptr++;
 
-               if(flip) tunptr += 240;
+                               angle = tun & 0xff;
+                               depth = (tun >> 8) & 0xff;
+                               tx = ((angle >> 1) - uoffs) & 0x1f;
+                               ty = ((depth >> 1) + zoffs) & 0x1f;
+                               pptop = tex[(ty << 5) + tx];
+                               tx = ~((angle >> 1) + uoffs) & 0x1f;
+                               ppbot = tex[(ty << 5) + tx];
+
+                               angle = (tun >> 16) & 0xff;
+                               depth = (tun >> 24) & 0xff;
+                               tx = ((angle >> 1) - uoffs) & 0x1f;
+                               ty = ((depth >> 1) + zoffs) & 0x1f;
+                               pptop |= (uint16_t)tex[(ty << 5) + tx] << 8;
+                               tx = ~((angle >> 1) + uoffs) & 0x1f;
+                               ppbot |= (uint16_t)tex[(ty << 5) + tx] << 8;
+
+                               *top++ = pptop;
+                               *bot++ = ppbot;
+                       }
+                       bot -= 240;
+               }
        }
 }
 

diff --git a/tools/tungen.c b/tools/tungen.c
index 49b3f16..f480758 100644 (file)
--- a/tools/tungen.c
+++ b/tools/tungen.c
@@ -102,7 +102,7 @@ invalopt:   fprintf(stderr, "invalid argument: %s\n", argv[i]);
                        if(fabs(r - prev_r) < 0.05) continue;
 
                        for(j=0; j<UDIV; j++) {
-                               float u = (float)j / (float)(UDIV - 1);
+                               float u = (float)j / (float)UDIV;
                                float theta = 2.0f * u * M_PI;
 
                                int x = (int)(cos(theta) * r - z) + xsz / 2;