InitHEADmain

1 files changed, 71 insertions, 0 deletions

diff --git a/Homework/cs5410/bbiy/src/systems/grid.js b/Homework/cs5410/bbiy/src/systems/grid.js
new file mode 100644
index 0000000..6d4cf84
--- /dev/null
+++ b/Homework/cs5410/bbiy/src/systems/grid.js
@@ -0,0 +1,71 @@
+game.system.Grid = (entitiesGrid) => {
+  let gridWidth = game.canvas.width / game.config.xDim;
+  let gridHeight = game.canvas.height / game.config.yDim;
+
+  const gameCoordsToGrid = ({ x, y }) => {
+    return { x: Math.floor((x+gridWidth/2) / game.canvas.width * game.config.yDim), y: Math.floor((y+gridHeight/2) / game.canvas.height * game.config.yDim) };
+  };
+
+  const gridCoordsToGame = ({ x, y }) => {
+    return { x: x * gridWidth, y: y * gridHeight };
+  };
+
+  const rebuildGrid = (entities) => {
+    let changedIds = new Set();
+    entities.map(entity => {
+      const { x, y } = entity.components.gridPosition;
+      if (!entitiesGrid[y][x].has(entity.id)) {
+        changedIds.add(entity.id);
+      }
+    });
+    entitiesGrid.forEach((row) => row.forEach((entitiesInCell) => {
+      for (let id of entitiesInCell.keys()) {
+        if (changedIds.has(id)) {
+          entitiesInCell.delete(id);
+        }
+      }
+    }));
+    changedIds.forEach(id => {
+      // TODO: Figure out why we HAVE to use game.entities rather than entities
+      // Hint: it breaks when changing a level in the menu
+      const entity = game.entities[id];
+      const { x, y } = entity.components.gridPosition;
+      entitiesGrid[y][x].set(entity.id, entity);
+    });
+  };
+
+  const update = (_elapsedTime, entities, changedIds) => {
+    gridEntities = Object.keys(entities).filter((x) => entities[x].hasComponent("gridPosition")).map((x) => entities[x]);
+    const thisChangedIds = new Set();
+    gridEntities.map((entity) => {
+      if (entity.hasComponent("appearance")) {
+        entity.components.appearance.width = gridWidth;
+        entity.components.appearance.height = gridHeight;
+      }
+      if (entity.hasComponent("gridPosition")) {
+        const oldGridCoords = entity.components.gridPosition;
+        if (entity.hasComponent("position")) {
+          const gameCoords = gridCoordsToGame(entity.components.gridPosition);
+          if (Math.abs(entity.components.position.x - gameCoords.x) >= gridWidth/2 || Math.abs(entity.components.position.y - gameCoords.y) >= gridHeight/2) {
+            entity.components.gridPosition = gameCoordsToGrid(entity.components.position);
+            if (entity.hasComponent("momentum")) {
+              entity.removeComponent("momentum");
+            }
+          }
+        }
+        if (!entity.hasComponent("position") || !equivalence(entity.components.gridPosition, oldGridCoords)) {
+          entity.components.position = {
+            ...entity.components.position,
+            ...gridCoordsToGame(entity.components.gridPosition)
+          };
+          thisChangedIds.add(entity.id);
+        }
+      }
+    });
+    rebuildGrid(gridEntities);
+    return thisChangedIds;
+  };
+
+
+  return { gameCoordsToGrid, gridCoordsToGame, update, gridWidth, gridHeight };
+};