// Internal type definitions for GDI3D
// Pasi Paavola 1993

#ifndef __INTERN__
#define __INTERN__


// Structure, which is included in every 3D output window as extra words

typedef struct tagG3WND {
    LOCALHANDLE hParams;        // Handle of the local memory block containing
                                //  window specific data
    int iError;                 // Last error code
    } G3WND;

typedef G3WND NEAR * NPG3WND;
typedef G3WND FAR * LPG3WND;

// Position indexes for G3 window extra words

#define HPARPOS 0
#define IERRPOS 2

// Transformation matrix type coefficients

#define TM_TRANS  (0x0001)
#define TM_SCALE  (0x0002)
#define TM_ROTATE (0x0004)

// Structure, which holds all the current 3D parameters for the window

typedef struct tagG3PARAMS {
    double CosTheta, SinTheta;  // Viewpoint data is presented in spherical
    double r;                   //  coordinates (r, theta, fi defined as usual).
    double CosFi, SinFi;        //  Only sines and cosines and the needed
    double CtCf, CtSf;          //  combination (e.g. CtCf) terms  of the
    double StSf, StCf;          //  angles are saved for the sake of speed
                                //  (explicit presentations are not needed).

    double VPx, VPy, VPz;       // Viewpoint data explicitly in cartesian
                                //  coordinates

    double d, S1, S2;           // Three related parameters where d is the
                                //  distance of the viewing plane center
                                //  from the origin of the world coordinate
                                //  system and S1 and S2 are the halves of
                                //  the viewing plane width and height
                                //  respectively

    double dS1, dS2;            // d/S1 and d/S2 to speed up calculations

    int cx, cy;                 // Center coordinates for the viewport
    int hw, hh;                 // Half width and height of the viewport
                                // Default: Whole window

    int iTrFlag;                // Flag to indicate the current
                                //  transformation type. If it is
                                //  0, then no transformations are
                                //  applied. If it is nonzero, it is a
                                //  bitwise OR'ed combination of the TM_-
                                //  prefixed constants defined above.

    double M11, M12, M13, M14;  // Transformation matrix elements.
    double M21, M22, M23, M24;  //  Mij is the element on the row i and
    double M31, M32, M33, M34;  //  column j. Transformed point is multiplied
                                //  from left by the transformation matrix.

    } G3PARAMS;

typedef G3PARAMS NEAR * NPG3PARAMS;
typedef G3PARAMS FAR * LPG3PARAMS;

#endif // __INTERN__