llvowlsky.h

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#ifndef LL_VOWLSKY_H
#define LL_VOWLSKY_H

#include "llviewerobject.h"

class LLVOWLSky : public LLStaticViewerObject {
private:
        static const F32 DISTANCE_TO_STARS;

        // anything less than 3 makes it impossible to create a closed dome.
        static const U32 MIN_SKY_DETAIL;
        // anything bigger than about 180 will cause getStripsNumVerts() to exceed 65535.
        static const U32 MAX_SKY_DETAIL;

        inline static U32 getNumStacks(void);
        inline static U32 getNumSlices(void);
        inline static U32 getFanNumVerts(void);
        inline static U32 getFanNumIndices(void);
        inline static U32 getStripsNumVerts(void);
        inline static U32 getStripsNumIndices(void);
        inline static U32 getStarsNumVerts(void);
        inline static U32 getStarsNumIndices(void);

public:
        LLVOWLSky(const LLUUID &id, const LLPCode pcode, LLViewerRegion *regionp);

        void initSunDirection(LLVector3 const & sun_direction,
                LLVector3 const & sun_angular_velocity);

        /*virtual*/ BOOL                 idleUpdate(LLAgent &agent, LLWorld &world, const F64 &time);
        /*virtual*/ BOOL                 isActive(void) const;
        /*virtual*/ LLDrawable * createDrawable(LLPipeline *pipeline);
        /*virtual*/ BOOL                 updateGeometry(LLDrawable *drawable);

        void drawStars(void);
        void drawDome(void);
        void resetVertexBuffers(void);
        
        void cleanupGL();
        void restoreGL();

private:
        // a tiny helper function for controlling the sky dome tesselation.
        static F32 calcPhi(U32 i);

        // helper function for initializing the stars.
        void initStars();

        // helper function for building the fan vertex buffer.
        static void buildFanBuffer(LLStrider<LLVector3> & vertices,
                                                           LLStrider<LLVector2> & texCoords,
                                                           LLStrider<U16> & indices);

        // helper function for building the strips vertex buffer.
        // note begin_stack and end_stack follow stl iterator conventions,
        // begin_stack is the first stack to be included, end_stack is the first
        // stack not to be included.
        static void buildStripsBuffer(U32 begin_stack, U32 end_stack,
                                                                  LLStrider<LLVector3> & vertices,
                                                                  LLStrider<LLVector2> & texCoords,
                                                                  LLStrider<U16> & indices);

        // helper function for updating the stars colors.
        void updateStarColors();

        // helper function for updating the stars geometry.
        BOOL updateStarGeometry(LLDrawable *drawable);

private:
        LLPointer<LLVertexBuffer>                                       mFanVerts;
        std::vector< LLPointer<LLVertexBuffer> >        mStripsVerts;
        LLPointer<LLVertexBuffer>                                       mStarsVerts;

        std::vector<LLVector3>  mStarVertices;                          // Star verticies
        std::vector<LLColor4>   mStarColors;                            // Star colors
        std::vector<F32>                mStarIntensities;                       // Star intensities
};

#endif // LL_VOWLSKY_H

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