Unify coordinate systems with canonical WoW world coordinates

Centralizes all coordinate conversions in core/coordinates.hpp with
proper canonical WoW coords (+X=North, +Y=West, +Z=Up). Fixes critical
tile calculation bug that was loading wrong surrounding tiles during
terrain streaming, and fixes position sync sending ADT-raw format
instead of canonical coordinates to the server.

include/core/coordinates.hpp

@@ -0,0 +1,83 @@
+#pragma once
+
+#include <glm/glm.hpp>
+#include <algorithm>
+#include <cmath>
+#include <utility>
+
+namespace wowee::core::coords {
+
+inline constexpr float TILE_SIZE = 533.33333f;
+inline constexpr float ZEROPOINT = 32.0f * TILE_SIZE;
+
+// ---- Canonical WoW world coordinate system (per-map) ----
+//   +X = North,  +Y = West,  +Z = Up (height)
+//   Origin (0,0,0) is the center of the 64x64 tile grid.
+//   Full extent: ±17066.66656 in X and Y.
+//
+// ---- Engine rendering coordinate system ----
+//   renderX = wowY (west),  renderY = wowX (north),  renderZ = wowZ (up)
+//   Terrain vertices (MCNK) are stored directly in this space.
+//
+// ---- ADT file placement coordinate system ----
+//   Used by MDDF (doodads) and MODF (WMOs) records in ADT files.
+//   Range [0, 34133.333] with center at ZEROPOINT (17066.666).
+//   adtY = height; adtX/adtZ are horizontal.
+
+// Convert between canonical WoW and engine rendering coordinates (just swap X/Y).
+inline glm::vec3 canonicalToRender(const glm::vec3& wow) {
+    return glm::vec3(wow.y, wow.x, wow.z);
+}
+
+inline glm::vec3 renderToCanonical(const glm::vec3& render) {
+    return glm::vec3(render.y, render.x, render.z);
+}
+
+// ADT file placement data (MDDF/MODF) -> engine rendering coordinates.
+inline glm::vec3 adtToWorld(float adtX, float adtY, float adtZ) {
+    return glm::vec3(
+        -(adtZ - ZEROPOINT),   // renderX = ZP - adtZ  (= wowY)
+        -(adtX - ZEROPOINT),   // renderY = ZP - adtX  (= wowX)
+        adtY                    // renderZ = adtY       (= wowZ)
+    );
+}
+
+inline glm::vec3 adtToWorld(const glm::vec3& adt) {
+    return adtToWorld(adt.x, adt.y, adt.z);
+}
+
+// Engine rendering coordinates -> ADT file placement data.
+inline glm::vec3 worldToAdt(float renderX, float renderY, float renderZ) {
+    return glm::vec3(
+        ZEROPOINT - renderY,   // adtX = ZP - renderY  (= ZP - wowX)
+        renderZ,               // adtY = renderZ       (= wowZ, height)
+        ZEROPOINT - renderX    // adtZ = ZP - renderX  (= ZP - wowY)
+    );
+}
+
+inline glm::vec3 worldToAdt(const glm::vec3& world) {
+    return worldToAdt(world.x, world.y, world.z);
+}
+
+// Engine rendering coordinates -> ADT tile indices.
+// Returns (tileX, tileY) matching ADT filename: Map_{tileX}_{tileY}.adt
+// Uses canonical formula: tileN = floor(32 - wowN / TILE_SIZE)
+inline std::pair<int, int> worldToTile(float renderX, float renderY) {
+    // renderY = wowX (north), renderX = wowY (west)
+    int tileX = static_cast<int>(std::floor(32.0f - renderY / TILE_SIZE));
+    int tileY = static_cast<int>(std::floor(32.0f - renderX / TILE_SIZE));
+    tileX = std::clamp(tileX, 0, 63);
+    tileY = std::clamp(tileY, 0, 63);
+    return {tileX, tileY};
+}
+
+// Canonical WoW coordinates -> ADT tile indices.
+inline std::pair<int, int> canonicalToTile(float wowX, float wowY) {
+    int tileX = static_cast<int>(std::floor(32.0f - wowX / TILE_SIZE));
+    int tileY = static_cast<int>(std::floor(32.0f - wowY / TILE_SIZE));
+    tileX = std::clamp(tileX, 0, 63);
+    tileY = std::clamp(tileY, 0, 63);
+    return {tileX, tileY};
+}
+
+} // namespace wowee::core::coords