/**
* intersectsCircleMapTile: This method checks whether a circle intersects a specified map tile.
* Pre: The map tile must exist. Post: A boolean will be returned indicating whether the shapes
* collide (true) or do not collide (false)
*/
private static boolean intersectsCircleMapTile(
double circleX, double circleY, double circleRadius, int mapX, int mapY) {
// Distance from circle center to map tile center (non-negative)
double dCircleTileDistanceX = Math.abs(circleX - (mapX + 0.5));
double dCircleTileDistanceY = Math.abs(circleY - (mapY + 0.5));
// Case: no intersection when the circle's bounding box does not intersect the tile's bounding
// box.
if (dCircleTileDistanceX > (0.5 + circleRadius)) {
return false;
}
if (dCircleTileDistanceY > (0.5 + circleRadius)) {
return false;
}
// Case: Intersection when the circle's center lies inside the box
if (dCircleTileDistanceX <= 0.5) {
return true;
}
if (dCircleTileDistanceY <= 0.5) {
return true;
}
// Case: Intersection if an identical circle placed on the map-tile's corners intersects the
// original circle. //Variable left squared to save processor speed.
double dCornerCircleIntersectionDistance =
(dCircleTileDistanceX - 0.5) * (dCircleTileDistanceX - 0.5)
+ (dCircleTileDistanceY - 0.5) * (dCircleTileDistanceY - 0.5);
return (dCornerCircleIntersectionDistance <= circleRadius * circleRadius);
}
/**
* valueInBoundsY: This method returns the closest value within the y-coordinates of the map. Pre:
* The map must exist. Post: Returns the closest value to the parameters that is in the
* y-coordinates.
*/
public static int valueInBoundsY(int value) {
return Math.max(Math.min(dngCurrentDungeon.iDungeonYSize, value), 0);
}
/**
* moveEntity: This method moves an entity and checks the potential move for collisions. Pre: The
* game must have been initialized. The entity at the index must not be null. Post: The entity
* will have been moved accordingly.
*/
public static void moveEntity(int iEntityID) {
boolean bXHandled = false;
boolean bYHandled = false;
boolean bCollidesWithWalls = handleEntity(iEntityID).collidesWithWalls();
// X and Y displacements of the entity, provided that there will be no collisions.
double dEntityXShift =
Math.sin(handleEntity(iEntityID).getMovementDirection())
* handleEntity(iEntityID).dMovementMagnitude;
double dEntityYShift =
(-1)
* Math.cos(handleEntity(iEntityID).getMovementDirection())
* handleEntity(iEntityID).dMovementMagnitude;
// The pre-movement xposition, yposition, and circle radius.
double dCurrentXPos = handleEntity(iEntityID).getXPos();
double dCurrentYPos = handleEntity(iEntityID).getYPos();
double dCurrentSize = handleEntity(iEntityID).getSize();
// Hypothetical post-movement coordinates of the circle's bounding box
double dNewXPosCenter = dCurrentXPos + dEntityXShift;
double dNewXPosRight = dNewXPosCenter + dCurrentSize;
double dNewXPosLeft = dNewXPosCenter - dCurrentSize;
double dNewYPosCenter = dCurrentYPos + dEntityYShift;
double dNewYPosTop = dNewYPosCenter - dCurrentSize;
double dNewYPosBot = dNewYPosCenter + dCurrentSize;
// Handling right-way movement
if (dNewXPosCenter < dngCurrentDungeon.getXSize() - dCurrentSize) {
if (dEntityXShift > 0 && !bXHandled && bCollidesWithWalls) { // Entity is moving right
rightMovingCollisions:
for (int iuP1 = (int) dNewXPosLeft; iuP1 <= (int) dNewXPosRight; iuP1 += 1) {
for (int iuP2 = valueInBoundsY((int) (dCurrentYPos - dCurrentSize));
iuP2 <= valueInBoundsY((int) (dCurrentYPos + dCurrentSize));
iuP2 += 1) {
if (!isWalkable(handleTile(iuP1, iuP2).getTileType())) {
if (intersectsCircleMapTile(dNewXPosCenter, dCurrentYPos, dCurrentSize, iuP1, iuP2)) {
dEntityXShift =
Math.max(
(iuP1 - dCurrentXPos) - (dCurrentSize + DISTANCE_TO_KEEP_FROM_WALL), 0);
break rightMovingCollisions;
}
}
}
}
bXHandled = true;
}
} else {
dEntityXShift = 0;
}
// Handling left-way movement
if (dNewXPosCenter > 0 + dCurrentSize) {
if (dEntityXShift < 0 && !bXHandled && bCollidesWithWalls) { // Entity is moving left
leftMovingCollisions:
for (int iuP1 = (int) dNewXPosRight; iuP1 >= (int) dNewXPosLeft; iuP1 -= 1) {
for (int iuP2 = valueInBoundsY((int) (dCurrentYPos - dCurrentSize));
iuP2 <= valueInBoundsY((int) (dCurrentYPos + dCurrentSize));
iuP2 += 1) {
if (!isWalkable(handleTile(iuP1, iuP2).getTileType())) {
if (intersectsCircleMapTile(dNewXPosCenter, dCurrentYPos, dCurrentSize, iuP1, iuP2)) {
dEntityXShift =
Math.min(
(iuP1 + 1 - dCurrentXPos) + (dCurrentSize + DISTANCE_TO_KEEP_FROM_WALL), 0);
break leftMovingCollisions;
}
}
}
}
bXHandled = true;
}
} else {
dEntityXShift = 0;
}
// Handling down-way movement
if (dNewYPosCenter < dngCurrentDungeon.getYSize() - dCurrentSize) {
if (dEntityYShift > 0 && !bYHandled && bCollidesWithWalls) { // Entity is moving down
downMovingCollisions:
for (int iuP1 = (int) dNewYPosTop; iuP1 <= (int) dNewYPosBot; iuP1 += 1) {
for (int iuP2 = valueInBoundsX((int) (dCurrentXPos - dCurrentSize));
iuP2 <= valueInBoundsX((int) (dCurrentXPos + dCurrentSize));
iuP2 += 1) {
if (!isWalkable(handleTile(iuP2, iuP1).getTileType())) {
if (intersectsCircleMapTile(dCurrentXPos, dNewYPosCenter, dCurrentSize, iuP2, iuP1)) {
dEntityYShift =
Math.max(
(iuP1 - dCurrentYPos) - (dCurrentSize + DISTANCE_TO_KEEP_FROM_WALL), 0);
break downMovingCollisions;
}
}
}
}
bYHandled = true;
}
} else {
dEntityYShift = 0;
}
// Handling up-way movement
if (dNewYPosCenter > 0 + dCurrentSize) {
if (dEntityYShift < 0 && !bYHandled && bCollidesWithWalls) { // Entity is moving up
upMovingCollisions:
for (int iuP1 = (int) dNewYPosBot; iuP1 >= (int) dNewYPosTop; iuP1 -= 1) {
for (int iuP2 = valueInBoundsX((int) (dCurrentXPos - dCurrentSize));
iuP2 <= valueInBoundsX((int) (dCurrentXPos + dCurrentSize));
iuP2 += 1) {
if (!isWalkable(handleTile(iuP2, iuP1).getTileType())) {
if (intersectsCircleMapTile(dCurrentXPos, dNewYPosCenter, dCurrentSize, iuP2, iuP1)) {
dEntityYShift =
Math.min(
(iuP1 + 1 - dCurrentYPos) + (dCurrentSize + DISTANCE_TO_KEEP_FROM_WALL), 0);
break upMovingCollisions;
}
}
}
}
bYHandled = true;
}
} else {
dEntityYShift = 0;
}
dNewXPosCenter = dCurrentXPos + dEntityXShift;
dNewYPosCenter = dCurrentYPos + dEntityYShift;
if (handleEntity(iEntityID).collidesWithEntities()) {
for (int iuP1 = 0; iuP1 < entveCurrentEntities.size(); iuP1++) {
if (iuP1 != iEntityID) {
if (handleEntity(iuP1).collidesWithEntities()) {
double distance =
(dNewXPosCenter - handleEntity(iuP1).getXPos())
* (dNewXPosCenter - handleEntity(iuP1).getXPos())
+ (dNewYPosCenter - handleEntity(iuP1).getYPos())
* (dNewYPosCenter - handleEntity(iuP1).getYPos());
if (distance
< (dCurrentSize + handleEntity(iuP1).getSize())
* (dCurrentSize + handleEntity(iuP1).getSize())) {
dEntityXShift = 0;
dEntityYShift = 0;
}
}
}
}
}
// Moves the character by shifting their X and Y coordinates.
handleEntity(iEntityID).shiftXPos(dEntityXShift);
handleEntity(iEntityID).shiftYPos(dEntityYShift);
}