//// Includes
////
-#include "direction.h"
#include "square.h"
+int8_t DirectionTable[64][64];
-////
-//// Local definitions
-////
-namespace {
+static SquareDelta direction(Square orig, Square dest) {
- const SquareDelta directionToDelta[] = {
- DELTA_E, DELTA_W, DELTA_N, DELTA_S, DELTA_NE, DELTA_SW, DELTA_NW, DELTA_SE
+ const SquareDelta directions[] = {
+ DELTA_E, DELTA_N, DELTA_NE, DELTA_NW, DELTA_W, DELTA_S, DELTA_SW, DELTA_SE
};
- bool reachable(Square orig, Square dest, SignedDirection dir) {
-
- SquareDelta delta = directionToDelta[dir];
- Square from = orig;
- Square to = from + delta;
- while (to != dest && square_distance(to, from) == 1 && square_is_ok(to))
- {
- from = to;
- to += delta;
- }
- return (to == dest && square_distance(from, to) == 1);
- }
-
-}
-
-
-////
-//// Variables
-////
+ Square from, to;
-uint8_t DirectionTable[64][64];
-uint8_t SignedDirectionTable[64][64];
+ for (int idx = 0; idx < 8; idx++)
+ {
+ from = orig;
+ to = from + directions[idx];
+ while (to != dest && square_distance(to, from) == 1 && square_is_ok(to))
+ {
+ from = to;
+ to += directions[idx];
+ }
-////
-//// Functions
-////
+ if (to == dest && square_distance(from, to) == 1)
+ return directions[idx];
+ }
+ return DELTA_NONE;
+}
void init_direction_table() {
for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
- {
- DirectionTable[s1][s2] = uint8_t(DIR_NONE);
- SignedDirectionTable[s1][s2] = uint8_t(SIGNED_DIR_NONE);
- if (s1 == s2)
- continue;
-
- for (SignedDirection d = SIGNED_DIR_E; d != SIGNED_DIR_NONE; d++)
- {
- if (reachable(s1, s2, d))
- {
- SignedDirectionTable[s1][s2] = uint8_t(d);
- DirectionTable[s1][s2] = uint8_t(d / 2);
- break;
- }
- }
- }
+ DirectionTable[s1][s2] = uint8_t(direction(s1, s2));
}