llcamera.h

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#ifndef LL_CAMERA_H
#define LL_CAMERA_H


#include "llmath.h"
#include "llcoordframe.h"
#include "llplane.h"

const F32 DEFAULT_FIELD_OF_VIEW         = 60.f * DEG_TO_RAD;
const F32 DEFAULT_ASPECT_RATIO          = 640.f / 480.f;
const F32 DEFAULT_NEAR_PLANE            = 0.25f;
const F32 DEFAULT_FAR_PLANE             = 64.f; // far reaches across two horizontal, not diagonal, regions

const F32 MAX_FIELD_OF_VIEW = F_PI;
const F32 MAX_ASPECT_RATIO      = 50.0f;
const F32 MAX_NEAR_PLANE        = 10.f;
const F32 MAX_FAR_PLANE         = 100000.0f; //1000000.0f; // Max allowed. Not good Z precision though.
const F32 MAX_FAR_CLIP          = 512.0f;

const F32 MIN_FIELD_OF_VIEW = 0.1f;
const F32 MIN_ASPECT_RATIO      = 0.02f;
const F32 MIN_NEAR_PLANE        = 0.1f;
const F32 MIN_FAR_PLANE         = 0.2f;

static const LLVector3 X_AXIS(1.f,0.f,0.f);
static const LLVector3 Y_AXIS(0.f,1.f,0.f);
static const LLVector3 Z_AXIS(0.f,0.f,1.f);

static const LLVector3 NEG_X_AXIS(-1.f,0.f,0.f);
static const LLVector3 NEG_Y_AXIS(0.f,-1.f,0.f);
static const LLVector3 NEG_Z_AXIS(0.f,0.f,-1.f);


// An LLCamera is an LLCoorFrame with a view frustum.
// This means that it has several methods for moving it around 
// that are inherited from the LLCoordFrame() class :
//
// setOrigin(), setAxes()
// translate(), rotate()
// roll(), pitch(), yaw()
// etc...


class LLCamera
:       public LLCoordFrame
{
public:
        enum {
                PLANE_LEFT = 0,
                PLANE_RIGHT = 1,
                PLANE_BOTTOM = 2,
                PLANE_TOP = 3,
                PLANE_NUM = 4
        };
        enum {
                PLANE_LEFT_MASK = (1<<PLANE_LEFT),
                PLANE_RIGHT_MASK = (1<<PLANE_RIGHT),
                PLANE_BOTTOM_MASK = (1<<PLANE_BOTTOM),
                PLANE_TOP_MASK = (1<<PLANE_TOP),
                PLANE_ALL_MASK = 0xf
        };
        enum {
                HORIZ_PLANE_LEFT = 0,
                HORIZ_PLANE_RIGHT = 1,
                HORIZ_PLANE_NUM = 2
        };
        enum {
                HORIZ_PLANE_LEFT_MASK = (1<<HORIZ_PLANE_LEFT),
                HORIZ_PLANE_RIGHT_MASK = (1<<HORIZ_PLANE_RIGHT),
                HORIZ_PLANE_ALL_MASK = 0x3
        };

protected:
        F32 mView;                                      // angle between top and bottom frustum planes in radians.
        F32 mAspect;                            // width/height
        S32 mViewHeightInPixels;        // for ViewHeightInPixels() only
        F32 mNearPlane;
        F32 mFarPlane;
        LLPlane mLocalPlanes[4];
        F32 mFixedDistance;                     // Always return this distance, unless < 0
        LLVector3 mFrustCenter;         // center of frustum and radius squared for ultra-quick exclusion test
        F32 mFrustRadiusSquared;
        
        LLPlane mWorldPlanes[PLANE_NUM];
        LLPlane mHorizPlanes[HORIZ_PLANE_NUM];

        typedef struct 
        {
                LLPlane p;
                U8 mask;
        } frustum_plane;
        frustum_plane mAgentPlanes[7];  //frustum planes in agent space a la gluUnproject (I'm a bastard, I know) - DaveP
                                                                        
        U32 mPlaneCount;  //defaults to 6, if setUserClipPlane is called, uses user supplied clip plane in

        LLVector3 mWorldPlanePos;               // Position of World Planes (may be offset from camera)
public:
        LLVector3 mAgentFrustum[8];  //8 corners of 6-plane frustum
        F32     mFrustumCornerDist;             //distance to corner of frustum against far clip plane
        
public:
        LLCamera();
        LLCamera(F32 z_field_of_view, F32 aspect_ratio, S32 view_height_in_pixels, F32 near_plane, F32 far_plane);

        void setUserClipPlane(LLPlane plane);
        void disableUserClipPlane();
        U8 calcPlaneMask(const LLPlane& plane);
        void setView(F32 new_view);
        void setViewHeightInPixels(S32 height);
        void setAspect(F32 new_aspect);
        void setNear(F32 new_near);
        void setFar(F32 new_far);

        F32 getView() const                                                     { return mView; }                               // vertical FOV in radians
        S32 getViewHeightInPixels() const                       { return mViewHeightInPixels; }
        F32 getAspect() const                                           { return mAspect; }                             // width / height
        F32 getNear() const                                                     { return mNearPlane; }                  // meters
        F32 getFar() const                                                      { return mFarPlane; }                   // meters
        
        F32 getYaw() const
        {
                return atan2f(mXAxis[VY], mXAxis[VX]);
        }
        F32 getPitch() const
        {
                F32 xylen = sqrtf(mXAxis[VX]*mXAxis[VX] + mXAxis[VY]*mXAxis[VY]);
                return atan2f(mXAxis[VZ], xylen);
        }

        const LLPlane& getWorldPlane(S32 index) const   { return mWorldPlanes[index]; }
        const LLVector3& getWorldPlanePos() const               { return mWorldPlanePos; }
        
        // Copy mView, mAspect, mNearPlane, and mFarPlane to buffer.
        // Return number of bytes copied.
        size_t writeFrustumToBuffer(char *buffer) const;

        // Copy mView, mAspect, mNearPlane, and mFarPlane from buffer.
        // Return number of bytes copied.
        size_t readFrustumFromBuffer(const char *buffer);
        void calcAgentFrustumPlanes(LLVector3* frust);
        // Returns 1 if partly in, 2 if fully in.
        // NOTE: 'center' is in absolute frame.
        S32 sphereInFrustumOld(const LLVector3 &center, const F32 radius) const;
        S32 sphereInFrustum(const LLVector3 &center, const F32 radius) const;
        S32 pointInFrustum(const LLVector3 &point) const { return sphereInFrustum(point, 0.0f); }
        S32 sphereInFrustumFull(const LLVector3 &center, const F32 radius) const { return sphereInFrustum(center, radius); }
        S32 AABBInFrustum(const LLVector3 &center, const LLVector3& radius);
        S32 AABBInFrustumNoFarClip(const LLVector3 &center, const LLVector3& radius);

        //does a quick 'n dirty sphere-sphere check
        S32 sphereInFrustumQuick(const LLVector3 &sphere_center, const F32 radius); 

        // Returns height of object in pixels (must be height because field of view
        // is based on window height).
        F32 heightInPixels(const LLVector3 &center, F32 radius ) const;

        // return the distance from pos to camera if visible (-distance if not visible)
        F32 visibleDistance(const LLVector3 &pos, F32 rad, F32 fudgescale = 1.0f, U32 planemask = PLANE_ALL_MASK) const;
        F32 visibleHorizDistance(const LLVector3 &pos, F32 rad, F32 fudgescale = 1.0f, U32 planemask = HORIZ_PLANE_ALL_MASK) const;
        void setFixedDistance(F32 distance) { mFixedDistance = distance; }
        
        friend std::ostream& operator<<(std::ostream &s, const LLCamera &C);

protected:
        void calculateFrustumPlanes();
        void calculateFrustumPlanes(F32 left, F32 right, F32 top, F32 bottom);
        void calculateFrustumPlanesFromWindow(F32 x1, F32 y1, F32 x2, F32 y2);
        void calculateWorldFrustumPlanes();
};


#endif

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