correct tunnel curving

[gbajam21] / src / gamescr.c

diff --git a/src/gamescr.c b/src/gamescr.c
index ec4f353..7da593a 100644 (file)
--- a/src/gamescr.c
+++ b/src/gamescr.c
@@ -24,6 +24,10 @@ static uint16_t oam[4 * MAX_SPR];
 static short x = 120, y = 80;
 static unsigned char rot;
 
+static int32_t bgmat[4];
+static int32_t bgx, bgy;
+static int32_t tunrot;
+
 void gamescr(void)
 {
        int i;
@@ -78,69 +82,86 @@ 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 short uoffs;
-       int i, j, tx, ty, angle, depth, zoffs;
+       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;
 
-       zoffs = nframes;
+       //tunsweep = SIN(nframes) >> 4;
 
-       if(bnstate & BN_LT) uoffs++;
-       if(bnstate & BN_RT) uoffs--;
+       if((bnstate & BN_RT) && tunsweep > -31) tunsweep--;
+       if((bnstate & BN_LT) && tunsweep < 31) tunsweep++;
 
-       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;
+       flip = tunsweep < 0;
+       tunturn = abs(tunsweep) & 0x1f;
+
+       zoffs = nframes;
+
+       uoffs = flip ? -nframes : nframes;
 
        top = vram[backbuf];
        bot = vram[backbuf] + 159 * 240 / 2;
-       tunptr = tunmap;
-       for(i=0; i<80; i++) {
-#ifdef VBLBAR
-               top++;
-               bot++;
-               tunptr++;
-
-               for(j=1; j<240/2; j++) {
-#else
-               for(j=0; j<240/2; j++) {
-#endif
-                       tun = *tunptr++;
-
-                       angle = tun & 0xff;
-                       depth = (tun >> 8) & 0xff;
-//                     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) & 0x1f;
-                       ppbot = tex[(ty << 5) + tx];
-
-                       angle = (tun >> 16) & 0xff;
-                       depth = (tun >> 24) & 0xff;
-//                     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) & 0x1f;
-                       ppbot |= (uint16_t)tex[(ty << 5) + tx] << 8;
-
-                       *top++ = pptop;
-                       *bot++ = ppbot;
+       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);
+
+                               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;
+               }
+       } else {
+               for(i=0; i<80; i++) {
+                       for(j=0; j<240/2; j++) {
+                               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;
+                       }
+                       bot -= 240;
                }
-               bot -= 240;
        }
 }
 
@@ -151,13 +172,6 @@ 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) {
@@ -180,13 +194,14 @@ static void vblank(void)
        if(bnstate & BN_A) rot -= 2;
        if(bnstate & BN_B) rot += 2;
 
+
        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);