40 lines
1.3 KiB
C
40 lines
1.3 KiB
C
/**
|
|
* Copyright (c) 2025 Dominic Masters
|
|
*
|
|
* This software is released under the MIT License.
|
|
* https://opensource.org/licenses/MIT
|
|
*/
|
|
|
|
#include "worldunit.h"
|
|
#include "assert/assert.h"
|
|
|
|
void worldChunkPosAdd(worldchunkpos_t *pos, worldsubtile_t amt) {
|
|
assertNotNull(pos, "Position pointer cannot be NULL");
|
|
|
|
/*
|
|
int32_t sum = (int32_t)pos->subtile + (int32_t)amt;
|
|
int32_t shifted = sum + 128; // may be negative or large
|
|
int32_t carry = div_floor(shifted, 256); // tiles to add (can be neg)
|
|
int32_t rem = mod_floor(shifted, 256); // 0..255
|
|
int32_t new_sub = rem - 128; // back to [-128,127]
|
|
|
|
pos->subtile = (int8_t)new_sub;
|
|
pos->tile = (uint8_t)((int32_t)pos->tile + carry); // wrap mod 256
|
|
*/
|
|
|
|
int32_t shiftedTotal = (int32_t)pos->subtile + (int32_t)amt + 128;
|
|
int32_t tileCarry = shiftedTotal >> 8; // divide by 256
|
|
int32_t wrappedSubtile = shiftedTotal - (tileCarry << 8);
|
|
pos->subtile = (int8_t)(wrappedSubtile - 128);
|
|
pos->tile = (uint8_t)(pos->tile + (uint8_t)tileCarry);
|
|
}
|
|
|
|
|
|
|
|
float_t worldChunkPosToF32(worldchunkpos_t pos, const uint8_t tileSize) {
|
|
const float scaleFactor = (float)tileSize * (1.0f / 256.0f);
|
|
return (
|
|
(float)pos.tile * (float)tileSize + ((float)pos.subtile + 128.0f) *
|
|
scaleFactor
|
|
);
|
|
} |