mmath.h File Reference

#include <math.h>

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Macros
#define	FloatToInt(F)   lrintf((F))
#define	GL_SQRT(X)   sqrt(X)
#define	NORMALIZE_3FV(V)

Functions
float	gl_sqrt (float x)
void	gl_init_math (void)

Macro Definition Documentation

FloatToInt

#define FloatToInt

(

F

)

lrintf((F))

Definition at line 56 of file mmath.h.

GL_SQRT

#define GL_SQRT

(

X

)

sqrt(X)

Definition at line 63 of file mmath.h.

NORMALIZE_3FV

#define NORMALIZE_3FV

(

V

)

Value:

{                           \
   GLfloat len;                     \
   len = GL_SQRT(V[0]*V[0]+V[1]*V[1]+V[2]*V[2]);    \
   if (len>0.0001F) {                   \
      len = 1.0F / len;                 \
      V[0] *= len;                  \
      V[1] *= len;                  \
      V[2] *= len;                  \
   }                            \
}

Definition at line 68 of file mmath.h.

Function Documentation

gl_init_math()

void gl_init_math

(

void

)

Definition at line 140 of file mmath.c.

{
   static GLboolean initialized = GL_FALSE;
 
   if (!initialized) {
      init_sqrt();
 
 
      initialized = GL_TRUE;
   }
}

Referenced by gl_create_context().

gl_sqrt()

float gl_sqrt

(

float

x

)

Definition at line 104 of file mmath.c.

{
#ifdef FAST_MATH
   unsigned int *num = (unsigned int *)&x;
                                /* to access the bits of a float in C
                                 * we must misuse pointers */
                                                        
   short e;                     /* the exponent */
   if (x == 0.0F) return 0.0F;  /* check for square root of 0 */
   e = (*num >> 23) - 127;      /* get the exponent - on a SPARC the */
                                /* exponent is stored with 127 added */
   *num &= 0x7fffff;            /* leave only the mantissa */
   if (e & 0x01) *num |= 0x800000;
                                /* the exponent is odd so we have to */
                                /* look it up in the second half of  */
                                /* the lookup table, so we set the   */
                                /* high bit                                */
   e >>= 1;                     /* divide the exponent by two */
                                /* note that in C the shift */
                                /* operators are sign preserving */
                                /* for signed operands */
   /* Do the table lookup, based on the quaternary mantissa,
    * then reconstruct the result back into a float
    */
   *num = ((sqrttab[*num >> 16]) << 16) | ((e + 127) << 23);
   return x;
#else
   return sqrt(x);
#endif
}