+ world.frame ^= 0x1;
+ }
+
+ // Fish ticks
+ if( world.simulating )
+ {
+ while( world.sim_frame < (int)((vg_time-world.sim_start)*2.0f) )
+ {
+ vg_info( "frame: %u\n", world.sim_frame );
+
+ for( int i = 0; i < arrlen( world.io ); i ++ )
+ {
+ struct cell_terminal *term = &world.io[ i ];
+ int posx = term->id % world.w;
+ int posy = (term->id - posx)/world.w;
+ int is_input = world.data[ term->id ].state & FLAG_INPUT;
+
+ if( is_input )
+ {
+ if( world.sim_frame < arrlen( term->conditions ) )
+ {
+ struct fish *fish = &world.fishes[world.num_fishes++];
+ fish->pos[0] = posx;
+ fish->pos[1] = posy;
+ fish->alive = 1;
+ fish->payload = term->conditions[world.sim_frame];
+
+ int can_spawn = 0;
+
+ v2i dirs[] = {{1,0},{-1,0},{0,-1}};
+ for( int j = 0; j < vg_list_size(dirs); j ++ )
+ {
+ v2i target;
+ if( world.data[ (posy+dirs[j][1])*world.w + posx+dirs[j][0] ].water[ world.frame & 0x1 ] )
+ {
+ fish->dir[0] = dirs[j][0];
+ fish->dir[1] = dirs[j][1];
+ can_spawn = 1;
+ break;
+ }
+ }
+
+ if( !can_spawn )
+ world.num_fishes--;
+ }
+ }
+ }
+
+ for( int i = 0; i < world.num_fishes; i ++ )
+ {
+ struct fish *fish = &world.fishes[i];
+ struct cell *cell_current = pcell( fish->pos );
+
+ if( !fish->alive )
+ continue;
+
+ // Apply to output
+ if( cell_current->state & FLAG_OUTPUT )
+ {
+ for( int j = 0; j < arrlen( world.io ); j ++ )
+ {
+ struct cell_terminal *term = &world.io[j];
+
+ if( term->id == fish->pos[1]*world.w + fish->pos[0] )
+ {
+ term->recv[ term->recv_count ++ ] = fish->payload;
+ break;
+ }
+ }
+
+ fish->alive = 0;
+ continue;
+ }
+
+ if( !(cell_current->water[ world.frame & 0x1 ] || cell_current->state & (FLAG_INPUT)) )
+ {
+ fish->alive = 0;
+ }
+ else
+ {
+ if( cell_current->state & FLAG_SPLIT )
+ {
+ // Flip flop L/R
+ fish->dir[0] = cell_current->state&FLAG_FLIP_FLOP?1:-1;
+ fish->dir[1] = 0;
+
+ cell_current->state ^= FLAG_FLIP_FLOP;
+ }
+ else if( cell_current->state & FLAG_MERGER )
+ {
+ // Can only move up
+ fish->dir[0] = 0;
+ fish->dir[1] = -1;
+ }
+ else
+ {
+ struct cell *cell_next = pcell( (v2i){ fish->pos[0]+fish->dir[0], fish->pos[1]+fish->dir[1] } );
+ if( !cell_next->water[ world.frame & 0x1 ] )
+ {
+ // Try other directions for valid
+ v2i dirs[] = {{1,0},{-1,0},{0,-1}};
+ vg_info( "Trying some other directions...\n" );
+
+ for( int j = 0; j < vg_list_size(dirs); j ++ )
+ {
+ if( (dirs[j][0] == -fish->dir[0]) && (dirs[j][1] == -fish->dir[1]) )
+ continue;
+
+ if( pcell( (v2i){ fish->pos[0]+dirs[j][0], fish->pos[1]+dirs[j][1] } )->water[ world.frame & 0x1 ] )
+ {
+ fish->dir[0] = dirs[j][0];
+ fish->dir[1] = dirs[j][1];
+ }
+ }
+ }
+ }
+
+ fish->pos[0] += fish->dir[0];
+ fish->pos[1] += fish->dir[1];
+ }
+ }
+
+ world.sim_frame ++;
+ }