fmath.h

Go to the documentation of this file.

/* KallistiOS ##version##

   dc/fmath.h
   Copyright (C) 2001 Andrew Kieschnick
   Copyright (C) 2013, 2014 Lawrence Sebald

*/

#ifndef __DC_FMATH_H
#define __DC_FMATH_H

#include <sys/cdefs.h>
__BEGIN_DECLS

#include <arch/types.h>
#include <dc/fmath_base.h>

/**
    \file   dc/fmath.h
    \brief  Inline functions for the DC's special math instructions
    \author Andrew Kieschnick
    \author Lawrence Sebald
*/

/* Sigh... C99 treats inline stuff a lot differently than traditional GCC did,
   so we need to take care of that... */
#if __STDC_VERSION__ >= 199901L
#define __FMINLINE static inline
#elif __GNUC__
#define __FMINLINE extern inline
#else
/* Uhm... I guess this is the best we can do? */
#define __FMINLINE static
#endif

/**
    \brief  Floating point inner product.
    \return v1 dot v2 (inner product)
*/
__FMINLINE float fipr(float x, float y, float z, float w,
                      float a, float b, float c, float d) {
    return __fipr(x, y, z, w, a, b, c, d);
}

/**
    \brief  Floating point inner product w/self (square of vector magnitude)
    \return v1 dot v1 (square of magnitude)
*/
__FMINLINE float fipr_magnitude_sqr(float x, float y, float z, float w) {
    return __fipr_magnitude_sqr(x, y, z, w);
}

/**
    \brief Floating point sine
    \param r a floating point number between 0 and 2*PI
    \return sin(r), where r is [0..2*PI]
*/
__FMINLINE float fsin(float r) {
    return __fsin(r);
}

/**
    \brief Floating point cosine
    \param r a floating point number between 0 and 2*PI
    \return cos(r), where r is [0..2*PI]
*/
__FMINLINE float fcos(float r) {
    return __fcos(r);
}

/**
    \brief Floating point tangent
    \param r a floating point number between 0 and 2*PI
    \return tan(r), where r is [0..2*PI]
*/
__FMINLINE float ftan(float r) {
    return __ftan(r);
}

/**
    \brief Integer sine
    \param d an integer between 0 and 65535
    \return sin(d), where d is [0..65535]
*/
__FMINLINE float fisin(int d) {
    return __fisin(d);
}

/**
    \brief Integer cosine
    \param d an integer between 0 and 65535
    \return cos(d), where d is [0..65535]
*/
__FMINLINE float ficos(int d) {
    return __ficos(d);
}

/**
    \brief Integer tangent
    \param d an integer between 0 and 65535
    \return tan(d), where d is [0..65535]
*/
__FMINLINE float fitan(int d) {
    return __fitan(d);
}

/**
    \brief Floating point square root
    \return sqrt(f)
*/
__FMINLINE float fsqrt(float f) {
    return __fsqrt(f);
}

/**
    \return 1.0f / sqrt(f)
*/
__FMINLINE float frsqrt(float f) {
    return __frsqrt(f);
}

/** \brief  Calculate the sine and cosine of a value in degrees.

    This function uses the fsca instruction to calculate an approximation of the
    sine and cosine of the input value.

    \param  f               The value to calculate the sine and cosine of.
    \param  s               Storage for the returned sine value.
    \param  c               Storage for the returned cosine value.
*/
__FMINLINE void fsincos(float f, float *s, float *c) {
    __fsincos(f, *s, *c);
}

/** \brief  Calculate the sine and cosine of a value in radians.

    This function uses the fsca instruction to calculate an approximation of the
    sine and cosine of the input value.

    \param  f               The value to calculate the sine and cosine of.
    \param  s               Storage for the returned sine value.
    \param  c               Storage for the returned cosine value.
*/
__FMINLINE void fsincosr(float f, float *s, float *c) {
    __fsincosr(f, *s, *c);
}

/** \brief  Calculate the offset color value for a set of bumpmap parameters.

    This function calculates the value to be placed into the oargb value for the
    use of bumpmapping on a polygon. The angles specified should be expressed in
    radians and within the limits specified for the individual parameter.

    \param  h               Weighting value in the range [0, 1] for how defined
                            the bumpiness of the surface should be.
    \param  t               Spherical elevation angle in the range [0, pi/2]
                            between the surface and the lighting source. A value
                            of pi/2 implies that the light is directly overhead.
    \param  q               Spherical rotation angle in the range [0, 2*pi]
                            between the surface and the lighting source.
    \return                 32-bit packed value to be used as an offset color on
                            the surface to be bump mapped.

    \note   For more information about how bumpmapping on the PVR works, refer
            to <a href="https://google.com/patents/US6819319">US Patent
            6,819,319</a>, which describes the algorithm implemented in the
            hardware (specifically look at Figures 2 and 3, along with the
            description in the Detailed Description section).
    \note   Thanks to Fredrik Ehnbom for figuring this stuff out and posting it
            to the mailing list back in 2005!
*/
__FMINLINE uint32 pvr_pack_bump(float h, float t, float q) {
    uint8 hp = (uint8)(h * 255.0f);
    uint8 k1 = ~hp;
    uint8 k2 = (uint8)(hp * __fsin(t));
    uint8 k3 = (uint8)(hp * __fcos(t));
    uint8 qp = (uint8)((q / (2 * F_PI)) * 255.0f);


    return (k1 << 24) | (k2 << 16) | (k3 << 8) | qp;
}

/* Make sure we declare the non-inline versions for C99 and non-gcc. Why they'd
   ever be needed, since they're inlined above, who knows? I guess in case
   someone tries to take the address of one of them? */
/** \cond */
#if __STDC_VERSION__ >= 199901L || !defined(__GNUC__)
extern float fipr(float x, float y, float z, float w, float a, float b, float c,
                  float d);
extern float fipr_magnitude_sqr(float x, float y, float z, float w);
extern float fsin(float r);
extern float fcos(float r);
extern float ftan(float r);
extern float fisin(int d);
extern float ficos(int d);
extern float fitan(int d);
extern float fsqrt(float f);
extern float frsqrt(float f);
extern void fsincos(float f, float *s, float *c);
extern void fsincosr(float f, float *s, float *c);
#endif /* __STDC_VERSION__ >= 199901L || !defined(__GNUC__) */
/** \endcond */

__END_DECLS

#endif  /* __DC_FMATH_H */