I've been trying to create a dynamic light effect with cocos2d-x, but I cannot find a good tutorial for the 4.0 version.
For the context, I'm developping a top-down game for as a personnal project. The light would spread directly in front of the player like a flash-light, lighting every object in front of him and "colliding" with the walls and entities
The Shader hint
I've found multiple repos creating a custom light effect with cocos2d-x, but they all use the 3.0 version. The 4.0 version changed how the OpenGL code is managed in the Cocos backend.
Here's the repos I've found :
- https://github.com/CodeAndWeb/cocos2d-x-dynamic-lighting
- https://github.com/zerodarkzone/Cocos2d-x-lights
- https://github.com/wantnon2/EffectNodes-for-cocos2dx
I've also read the Cocos2d-x Gitbook which explains what exactly changed in the CCSprite file. Since I'm a beginner to Cocos2d-x and shader rendering, I did not understand what I had to change to make the old repos work ..
The polygon hint
I tried to create a VisionZone that would be a Cocos2d-x Node. The node would have a physic body colliding with the walls. On collision, the shape would update and adapt its shape.
Here's what the code would look like :
VisionZone.h
class VisionZone : public Node {
public:
static std::vector<Vec2> sm_shapeCollisionPoints;
static VisionZone *create(Vec2 origin, int visionDetail);
bool init() override;
void update(float delta) override;
void UpdateWithPlayer(Vec2 playerPos);
private:
void CreateNewPhysicBody(std::vector<Vec2> &points);
void UpdateShapeAndRedraw();
static bool IsInLine(Vec2 segmentStart, Vec2 segmentEnd, Vec2 point);
void CompareWithContactPoints();
void Rotate();
std::vector<Vec2> m_nonCollidedSegmentsEnds;
std::vector<Vec2> m_collidedSegmentsEnds;
Vec2 m_origin;
DrawNode *m_pVisionZoneDrawer;
int m_visionDetail;
VisionZone.cpp
std::vector<Vec2> VisionZone::sm_shapeCollisionPoints = {};
VisionZone *VisionZone::create(Vec2 origin, int visionDetail) {
auto *_obj = new(std::nothrow) VisionZone();
if (_obj && _obj->init()) {
_obj->m_origin = origin;
_obj->m_visionDetail = visionDetail;
int mid = std::floor(_obj->m_visionDetail * 0.5);
for (int i = -(mid); i <= mid; i++) {
_obj->m_nonCollidedSegmentsEnds.emplace_back(
static_cast<float>(_obj->m_origin.x + float(i) * 1.3f), _obj->m_origin.y + 300
);
}
_obj->m_collidedSegmentsEnds = _obj->m_nonCollidedSegmentsEnds;
std::vector<Vec2> _points = _obj->m_nonCollidedSegmentsEnds;
_points.emplace_back(_obj->m_origin);
_obj->CreateNewPhysicBody(_points);
} else
CC_SAFE_DELETE(_obj);
return _obj;
}
bool VisionZone::init() {
if (!Node::init()) return false;
m_pVisionZoneDrawer = DrawNode::create();
m_pVisionZoneDrawer->setPosition(m_origin);
assert(m_pVisionZoneDrawer);
addChild(m_pVisionZoneDrawer);
return true;
}
void VisionZone::update(float delta) {
Node::update(delta);
CompareWithContactPoints();
Rotate();
UpdateShapeAndRedraw();
}
void VisionZone::UpdateWithPlayer(Vec2 playerPos) {
m_origin = playerPos;
setPosition(m_origin);
}
void VisionZone::CreateNewPhysicBody(std::vector<Vec2> &points) {
points.push_back(m_origin);
PhysicsBody *_body = PhysicsBody::createEdgePolygon(
&points.front(),
int(points.size()),
PHYSICSBODY_MATERIAL_DEFAULT,
1
);
_body->setCategoryBitmask(vision_zone_collision_bitmask);
_body->setCollisionBitmask(map_collision_bitmask);
_body->setContactTestBitmask(true);
_body->setDynamic(false);
setPhysicsBody(_body);
}
bool VisionZone::IsInLine(Vec2 segmentStart, Vec2 segmentEnd, Vec2 point) {
float _startToPoint = sqrt(pow((segmentStart.x - point.x), 2) + pow((segmentStart.y - point.y), 2));
float _pointToEnd = sqrt(pow((point.x - segmentEnd.x), 2) + pow((point.y - segmentEnd.y), 2));
float _startToEnd = sqrt(pow((segmentStart.x - segmentEnd.x), 2) + pow((segmentStart.y - segmentEnd.y), 2));
return (_startToPoint + _pointToEnd == _startToEnd);
}
void VisionZone::CompareWithContactPoints() {
if (sm_shapeCollisionPoints.empty()) {
m_collidedSegmentsEnds = {m_origin, m_nonCollidedSegmentsEnds.front(), m_nonCollidedSegmentsEnds.back()};
return;
}
for (Vec2 &_nonCollidedEnd: m_nonCollidedSegmentsEnds) {
for (Vec2 &_contactPoint: sm_shapeCollisionPoints) {
if (IsInLine(m_origin, _nonCollidedEnd, _contactPoint)) {
Vec2 _midPoint = (m_nonCollidedSegmentsEnds.front() + m_nonCollidedSegmentsEnds.back()) / 2;
if (IsInLine(m_nonCollidedSegmentsEnds.front(), _midPoint, _contactPoint)) {
m_collidedSegmentsEnds = {
m_origin, sm_shapeCollisionPoints.front(), sm_shapeCollisionPoints.back(),
m_nonCollidedSegmentsEnds.back()
};
} else if (IsInLine(_midPoint, m_nonCollidedSegmentsEnds.back(), _contactPoint)) {
m_collidedSegmentsEnds = {
m_origin, m_nonCollidedSegmentsEnds.front(), sm_shapeCollisionPoints.front(),
sm_shapeCollisionPoints.back()
};
}
}
}
}
}
void VisionZone::Rotate() {
float _distanceX = InputManager::GetCursorPosX() - getPositionX();
float _distanceY = InputManager::GetCursorPosY() - getPositionY();
float _angle = atan2(_distanceY, _distanceX) * 180.f / static_cast<float>(M_PI);
setRotation(_angle);
}
void VisionZone::UpdateShapeAndRedraw() {
PhysicsShape *_newShape = getPhysicsBody()->addShape(PhysicsShapePolygon::create(
m_collidedSegmentsEnds.data(), int(m_collidedSegmentsEnds.size()))
);
assert(_newShape);
m_pVisionZoneDrawer->clear();
m_pVisionZoneDrawer->drawSolidPoly(
&m_collidedSegmentsEnds.front(),
m_collidedSegmentsEnds.size(),
Color4F(1.f, 0.94, 0.7, 1)
);
}
CollisionManager.cpp
#include "CollisionManager.h"
#include "Utility/Bitmasks.h"
USING_NS_CC;
EventListenerPhysicsContact *CollisionManager::m_contactListener = nullptr;
void CollisionManager::Init() {
m_contactListener = EventListenerPhysicsContact::create();
m_contactListener->onContactBegin = [](PhysicsContact &contact) { return ContactBeginCallback(contact); };
m_contactListener->onContactSeparate = [](PhysicsContact &contact) { return ContactSeparateCallback(contact); };
}
bool CollisionManager::ContactBeginCallback(PhysicsContact &contact) {
PhysicsBody *_bodyA = contact.getShapeA()->getBody();
PhysicsBody *_bodyB = contact.getShapeB()->getBody();
const bool visionAndWallCondition = ((_bodyA->getCategoryBitmask() == vision_zone_collision_bitmask &&
_bodyB->getCategoryBitmask() == map_collision_bitmask) ||
(_bodyB->getCategoryBitmask() == vision_zone_collision_bitmask &&
_bodyA->getCategoryBitmask() == map_collision_bitmask));
if (visionAndWallCondition) {
for (Vec2 _p: contact.getContactData()->points) VisionZone::sm_shapeCollisionPoints.push_back(_p);
return true;
}
return false;
}
bool CollisionManager::ContactSeparateCallback(PhysicsContact &contact) {
PhysicsBody *_bodyA = contact.getShapeA()->getBody();
PhysicsBody *_bodyB = contact.getShapeB()->getBody();
const bool visionAndWallCondition = ((_bodyA->getCategoryBitmask() == vision_zone_collision_bitmask &&
_bodyB->getCategoryBitmask() == map_collision_bitmask) ||
(_bodyB->getCategoryBitmask() == vision_zone_collision_bitmask &&
_bodyA->getCategoryBitmask() == map_collision_bitmask));
if (visionAndWallCondition) {
VisionZone::sm_shapeCollisionPoints.clear();
return true;
}
return false;
}
GameLayer.cpp
bool GameLayer::init() {
if (!Layer::init()) return false;
CollisionManager::Init();
_eventDispatcher->addEventListenerWithSceneGraphPriority(CollisionManager::GetContactListener(), this);
// ... SOME CODE ... //
m_visionZone = VisionZone::create(player->getPosition(), 100);
addChild(m_visionZone, 1);
return true;
}
void GameLayer::update(float delta) {
Node::update(delta);
m_visionZone->UpdateWithPlayer(m_player->getPosition());
}
I am not sure about this method though ... I feels like it is not optimal at all ?
Really curious to have some feedback on this, thanks in advance, sorry for the quantity of code :)
Let me know if you need more informations, code or links
