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#ifndef __FT_TRIGONOMETRY_H__
#define __FT_TRIGONOMETRY_H__
FT_BEGIN_HEADER
/***************************************************************************
*
* @section: computations
*
*/
/***************************************************************************
*
* @type: FT_Angle
*
* @description:
* this type is used to model angle values in FreeType. Note that
* the angle is a 16.16 fixed float value expressed in _degrees_
*/
typedef FT_Fixed FT_Angle;
/***************************************************************************
*
* @macro: FT_ANGLE_PI
*
* @description:
* the angle pi expressed in @FT_Angle units
*/
#define FT_ANGLE_PI (180L << 16)
/***************************************************************************
*
* @macro: FT_ANGLE_2PI
*
* @description:
* the angle 2pi expressed in @FT_Angle units
*/
#define FT_ANGLE_2PI (FT_ANGLE_PI*2)
/***************************************************************************
*
* @macro: FT_ANGLE_PI2
*
* @description:
* the angle pi/2 expressed in @FT_Angle units
*/
#define FT_ANGLE_PI2 (FT_ANGLE_PI/2)
/***************************************************************************
*
* @macro: FT_ANGLE_PI4
*
* @description:
* the angle pi/4 expressed in @FT_Angle units
*/
#define FT_ANGLE_PI4 (FT_ANGLE_PI/4)
/***************************************************************************
*
* @function: FT_Sin
*
* @description:
* return the sinus of a given angle in fixed point format
*
* @input:
* angle :: input angle
*
* @return:
* sinus value
*
* @note:
* if you need both the sinus and cosinus for a given angle, you'd
* better use the function @FT_Vector_Unit
*/
FT_EXPORT(FT_Fixed) FT_Sin( FT_Angle angle );
/***************************************************************************
*
* @function: FT_Cos
*
* @description:
* return the cosinus of a given angle in fixed point format
*
* @input:
* angle :: input angle
*
* @return:
* cosinus value
*
* @note:
* if you need both the sinus and cosinus for a given angle, you'd
* better use the function @FT_Vector_Unit
*/
FT_EXPORT(FT_Fixed) FT_Cos( FT_Angle angle );
/***************************************************************************
*
* @function: FT_Tan
*
* @description:
* return the tangent of a given angle in fixed point format
*
* @input:
* angle :: input angle
*
* @return:
* tangent value
*/
FT_EXPORT(FT_Fixed) FT_Tan( FT_Angle angle );
/***************************************************************************
*
* @function: FT_Atan2
*
* @description:
* return the arc-tangent corresponding to a given vector (x,y) in
* the 2d plane
*
* @input:
* x :: horizontal vector coordinate
* y :: vertical vector coordinate
*
* @return:
* arc-tangent value (i.e. angle)
*/
FT_EXPORT(FT_Angle) FT_Atan2( FT_Fixed x, FT_Fixed y );
/***************************************************************************
*
* @function: FT_Vector_Unit
*
* @description:
* return the unit vector corresponding to a given angle. After the call,
* the value of "vec.x" will be "sin(theta)", and the value of "vec.y"
* will be "cos(angle)"
*
* this function is useful to retrieve both the sinus and cosinus
* of a given angle quickly
*
* @input:
* vec :: address of target vector
* angle :: address of angle
*/
FT_EXPORT(void) FT_Vector_Unit( FT_Vector* vec,
FT_Angle angle );
/***************************************************************************
*
* @function: FT_Vector_Rotate
*
* @description:
* rotate a given vector by a given angle
*
* @input:
* vec :: address of target vector
* angle :: address of angle
*/
FT_EXPORT(void) FT_Vector_Rotate( FT_Vector* vec,
FT_Angle angle );
/***************************************************************************
*
* @function: FT_Vector_Length
*
* @description:
* returns the length of a given vector
*
* @input:
* vec :: address of target vector
*
* @return:
* vector length, expressed in the same units that the original
* vector coordinates !!
*/
FT_EXPORT(FT_Fixed) FT_Vector_Length( FT_Vector* vec );
/***************************************************************************
*
* @function: FT_Vector_Normalize
*
* @description:
* normalize a given vector (i.e. compute the equivalent unit vector)
*
* @input:
* vec :: address of target vector
*/
FT_EXPORT(void) FT_Vector_Normalize( FT_Vector* vec );
/***************************************************************************
*
* @function: FT_Vector_Polarize
*
* @description:
* compute both the length and angle of a given vector
*
* @input:
* vec :: address of source vector
*
* @output:
* length :: vector length
* angle :: vector angle
*/
FT_EXPORT(void) FT_Vector_Polarize( FT_Vector* vec,
FT_Fixed *length,
FT_Angle *angle );
/* */
FT_END_HEADER
#endif /* __FT_TRIGONOMETRY_H__ */
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