axmol/cocos/2d/renderer/Frustum.cpp

#include "Frustum.h"
#include "platform/CCCommon.h"

#include <stdlib.h>

NS_CC_BEGIN

ViewTransform::ViewTransform()
{
    _position = {0, 0, 0};
    _focus = {0, 0, -1};
    _up = {0, 1, 0 };
    _dirty = true;
    kmMat4Identity(&_matrix);
}

ViewTransform::~ViewTransform()
{
}

void ViewTransform::Init(const kmVec3 &pos, const kmVec3 &focus, const kmVec3 &up)
{
    _position = pos;
    _focus = focus;
    _up = up;
    _dirty = true;
}

void ViewTransform::LazyAdjust() const
{
    if(!_dirty) return;
    kmVec3Subtract(&_adjustDir, &_focus, &_position);
    kmVec3Normalize(&_adjustDir, &_adjustDir);
    
    kmVec3Cross(&_adjustRight, &_adjustDir, &_up);
    kmVec3Normalize(&_adjustRight, &_adjustRight);
    
    kmVec3Cross(&_adjustUp, &_adjustRight, &_adjustDir);
    kmVec3Normalize(&_adjustUp, &_adjustUp);
    
    _dirty = false;
}

const kmVec3& ViewTransform::getDirection() const
{
    LazyAdjust();
    return _adjustDir;
}

const kmVec3& ViewTransform::getRight() const
{
    LazyAdjust();
    return _adjustRight;
}

const kmVec3& ViewTransform::getUp() const
{
    LazyAdjust();
    return _adjustUp;
}

AABB::AABB(const kmVec3& min, const kmVec3& max)
{
    _min = min;
    _max = max;
    if(_min.x > _max.x)
    {
        CCLOG("_min.x is greater than _max.x, it will be swapped!");
        float temp = _min.x; _min.x = _max.x; _max.x = temp;
    }
    if(_min.y > _max.y)
    {
        CCLOG("_min.y is greater than _max.y, it will be swapped!");
        float temp = _min.y; _min.y = _max.y; _max.y = temp;
    }
    if(_min.z > _max.z)
    {
        CCLOG("_min.z is greater than _max.z, it will be swapped!");
        float temp = _min.z; _min.z = _max.z; _max.z = temp;
    }
}

AABB::~AABB()
{
}

kmVec3 AABB::getCenter() const
{
    kmVec3 result;
    
    kmVec3Add(&result, &_min, &_max);
    kmVec3Scale(&result, &result, 0.5f);
    return result;
}

float AABB::getDimensionX() const
{
    return _max.x - _min.x;
}

float AABB::getDimensionY() const
{
    return _max.y - _min.y;
}

float AABB::getDimensionZ() const
{
    return _max.z - _min.z;
}

kmVec3 AABB::getPositivePoint(const kmVec3& direction) const
{
    kmVec3 result = _max;
    if( direction.x < 0 ) result.x = _min.x;
    if( direction.y < 0 ) result.y = _min.y;
    if( direction.z < 0 ) result.z = _min.z;
    
    return result;
}

const AABB& AABB::expand(const kmVec3& point)
{
    if(point.x > _max.x) _max.x = point.x;
    if(point.y > _max.y) _max.y = point.y;
    if(point.z > _max.z) _max.z = point.z;

    if(point.x < _min.x) _min.x = point.x;
    if(point.y < _min.y) _min.y = point.y;
    if(point.z < _min.z) _min.z = point.z;
    
    return *this;
}

kmVec3 AABB::getNegativePoint(const kmVec3& direction) const
{
    kmVec3 result = _min;
    if( direction.x < 0 ) result.x = _max.x;
    if( direction.y < 0 ) result.y = _max.y;
    if( direction.z < 0 ) result.z = _max.z;
    
    return result;
}

Frustum::Frustum()
{
}

Frustum::~Frustum()
{
}

void Frustum::setupProjectionOrthogonal(const cocos2d::ViewTransform &view, float width, float height, float near, float far)
{
    kmVec3 cc = view.getPosition();
    kmVec3 cDir = view.getDirection();
    kmVec3 cRight = view.getRight();
    kmVec3 cUp = view.getUp();
    
    kmVec3Normalize(&cDir, &cDir);
    kmVec3Normalize(&cRight, &cRight);
    kmVec3Normalize(&cUp, &cUp);
    
    //near
    {
        kmVec3 point;
        kmVec3 normal;
        normal = cDir;
        kmVec3Scale(&point, &cDir, near);
        kmVec3Add(&point, &point, &cc);
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::NEAR], &point, &normal);
    }
    
    //far
    {
        kmVec3 point;
        kmVec3 normal;
        kmVec3Scale(&normal, &cDir, -1);
        kmVec3Scale(&point, &cDir, far);
        kmVec3Add(&point, &point, &cc);
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::FAR], &point, &normal);
    }
    
    //left
    {
        kmVec3 point;
        kmVec3 normal;
        normal = cRight;
        kmVec3Scale(&point, &cRight, -width * 0.5);
        kmVec3Add(&point, &point, &cc);
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::LEFT], &point, &normal);
    }
    
    //right
    {
        kmVec3 point;
        kmVec3 normal;
        kmVec3Scale(&normal, &cRight, -1);
        kmVec3Scale(&point, &cRight, width * 0.5);
        kmVec3Add(&point, &point, &cc);
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::RIGHT], &point, &normal);
    }
    
    //bottom
    {
        kmVec3 point;
        kmVec3 normal;
        normal = cUp;
        kmVec3Scale(&point, &cUp, -height * 0.5);
        kmVec3Add(&point, &point, &cc);
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::BOTTOM], &point, &normal);
    }
    
    //top
    {
        kmVec3 point;
        kmVec3 normal;
        kmVec3Scale(&normal, &cUp, -1);
        kmVec3Scale(&point, &cUp, height * 0.5);
        kmVec3Add(&point, &point, &cc);
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::TOP], &point, &normal);
    }
}

void Frustum::setupProjectionPerspective(const ViewTransform& view, float left, float right, float top, float bottom, float near, float far)
{
    kmVec3 cc = view.getPosition();
    kmVec3 cDir = view.getDirection();
    kmVec3 cRight = view.getRight();
    kmVec3 cUp = view.getUp();
    
    kmVec3Normalize(&cDir, &cDir);
    kmVec3Normalize(&cRight, &cRight);
    kmVec3Normalize(&cUp, &cUp);
    
    kmVec3 nearCenter;
    kmVec3 farCenter;
    
    kmVec3Scale(&nearCenter, &cDir, near);
    kmVec3Add(&nearCenter, &nearCenter, &cc);
    
    kmVec3Scale(&farCenter, &cDir, far);
    kmVec3Add(&farCenter, &farCenter, &cc);
    
    //near
    {
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::NEAR], &nearCenter, &cDir);
    }
    
    //far
    {
        kmVec3 normal;
        kmVec3Scale(&normal, &cDir, -1);
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::FAR], &farCenter, &normal);
    }
    
    //left
    {
        kmVec3 point;
        kmVec3Scale(&point, &cRight, left);
        kmVec3Add(&point, &point, &nearCenter);
        
        kmVec3 normal;
        kmVec3Subtract(&normal, &point, &cc);
        kmVec3Cross(&normal, &normal, &cUp);
        kmVec3Normalize(&normal, &normal);
        
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::LEFT], &point, &normal);
    }
    
    //right
    {
        kmVec3 point;
        kmVec3Scale(&point, &cRight, right);
        kmVec3Add(&point, &point, &nearCenter);
        
        kmVec3 normal;
        kmVec3Subtract(&normal, &point, &cc);
        kmVec3Cross(&normal, &cUp, &normal);
        kmVec3Normalize(&normal, &normal);
        
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::RIGHT], &point, &normal);
    }
    
    //bottom
    {
        kmVec3 point;
        kmVec3Scale(&point, &cUp, bottom);
        kmVec3Add(&point, &point, &nearCenter);
        
        kmVec3 normal;
        kmVec3Subtract(&normal, &point, &cc);
        kmVec3Cross(&normal, &cRight, &normal);
        kmVec3Normalize(&normal, &normal);
        
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::BOTTOM], &point, &normal);
    }
    
    //top
    {
        kmVec3 point;
        kmVec3Scale(&point, &cUp, top);
        kmVec3Add(&point, &point, &nearCenter);
        
        kmVec3 normal;
        kmVec3Subtract(&normal, &point, &cc);
        kmVec3Cross(&normal, &normal, &cRight);
        kmVec3Normalize(&normal, &normal);
        
        kmPlaneFromPointNormal(&_frustumPlanes[FrustumPlane::TOP], &point, &normal);
    }
    
}

void Frustum::setupProjectionPerspectiveFov(const ViewTransform& view, float fov, float ratio, float near, float far)
{
    float width = 2 * near * tan(fov * 0.5);
    float height = width/ratio;
    setupProjectionPerspective(view, -width/2, width/2, height/2, -height/2, near, far);
}

void Frustum::setupFromMatrix(const kmMat4 &view, const kmMat4 &projection)
{
    kmMat4 mvp;
    kmMat4Multiply(&mvp, &projection, &view);
    
    kmMat4ExtractPlane(&_frustumPlanes[FrustumPlane::NEAR], &mvp, KM_PLANE_NEAR);
    kmMat4ExtractPlane(&_frustumPlanes[FrustumPlane::FAR], &mvp, KM_PLANE_FAR);
    kmMat4ExtractPlane(&_frustumPlanes[FrustumPlane::LEFT], &mvp, KM_PLANE_LEFT);
    kmMat4ExtractPlane(&_frustumPlanes[FrustumPlane::RIGHT], &mvp, KM_PLANE_RIGHT);
    kmMat4ExtractPlane(&_frustumPlanes[FrustumPlane::BOTTOM], &mvp, KM_PLANE_BOTTOM);
    kmMat4ExtractPlane(&_frustumPlanes[FrustumPlane::TOP], &mvp, KM_PLANE_TOP);
}

Frustum::IntersectResult Frustum::intersectPoint(const kmVec3 &point) const
{
    int indexFirst = static_cast<int>(FrustumPlane::NEAR);
    int indexNumber = static_cast<int>(FrustumPlane::NUMBER);
    
    for(int planeIndex = indexFirst; planeIndex < indexNumber; ++planeIndex)
    {
        if(kmPlaneDotCoord(&_frustumPlanes[static_cast<FrustumPlane>(planeIndex)], &point) < 0)
            return IntersectResult::OUTSIDE;
    }
    return IntersectResult::INSIDE;
}

Frustum::IntersectResult Frustum::intersectAABB(const AABB& aabb) const
{
    IntersectResult result = IntersectResult::INSIDE;
    int indexFirst = static_cast<int>(FrustumPlane::NEAR);
    int indexNumber = static_cast<int>(FrustumPlane::NUMBER);
    
    for(int planeIndex = indexFirst; planeIndex < indexNumber; ++planeIndex)
    {
        kmPlane plane = _frustumPlanes[static_cast<FrustumPlane>(planeIndex)];
        kmVec3 normal = {plane.a, plane.b, plane.c};
        kmVec3Normalize(&normal, &normal);
        kmVec3 positivePoint = aabb.getPositivePoint(normal);
        kmVec3 negativePoint = aabb.getNegativePoint(normal);
        
        if(kmPlaneDotCoord(&plane, &positivePoint) < 0)
            return IntersectResult::OUTSIDE;
        if(kmPlaneDotCoord(&plane, &negativePoint) < 0)
            result = IntersectResult::INTERSECT;
    }
    
    return result;
}

Frustum::IntersectResult Frustum::intersectSphere(const kmVec3& center, float radius) const
{
    IntersectResult result = IntersectResult::INSIDE;
    int indexFirst = static_cast<int>(FrustumPlane::NEAR);
    int indexNumber = static_cast<int>(FrustumPlane::NUMBER);
    
    for(int planeIndex = indexFirst; planeIndex < indexNumber; ++planeIndex)
    {
        kmPlane plane = _frustumPlanes[static_cast<FrustumPlane>(planeIndex)];
        kmVec3 normal = {plane.a, plane.b, plane.c};
        
        float distance = kmPlaneDotCoord(&plane, &center);
        distance = distance / kmVec3Length(&normal);
        
        if(distance < -radius) return IntersectResult::OUTSIDE;
        if(distance <= radius && distance >= -radius) result = IntersectResult::INTERSECT;
    }
    
    return result;
}

NS_CC_END