Maths
[Main]

Defines
#define	oslAbs(x)   (((x)<0)?(-(x)):(x))
#define	oslMin(x, y)   (((x)<(y))?(x):(y))
#define	oslMax(x, y)   (((x)>(y))?(x):(y))
#define	oslMinMax(x, min, max)   ((x) < (max) ? ((x) > (min) ? (x) : (min)) : (max))
#define	oslNumberof(n)   (sizeof(n)/sizeof(*(n)))
Functions
float	oslSin (float angle, float dist)
float	oslCos (float angle, float dist)
int	oslSini (int angle, int dist)
int	oslCosi (int angle, int dist)
int	oslGetNextPower2 (int val)

---

Detailed Description

Main OSLib section. Contains the main routines to initialize and terminate the library.

---

Define Documentation

#define oslAbs

(

x

)

(((x)<0)?(-(x)):(x))

Returns the absolute value of a number (that is, the positive part of the number).

//Prints 2
oslPrintf("%i", oslAbs(2));
//Prints 2 as well (the minus sign is ignored in an absolute value)
oslPrintf("%i", oslAbs(-2));

#define oslMin	(	x,
		y		)	(((x)<(y))?(x):(y))

Returns the smallest value between the two.

#define oslMax	(	x,
		y		)	(((x)>(y))?(x):(y))

Returns the greatest value between the two.

//Move the object 1 pixel to the left but make sure it will never go beyond the left corner of the screen.
posX = oslMax(posX - 1, 0);

#define oslMinMax	(	x,
		min,
		max		)	((x) < (max) ? ((x) > (min) ? (x) : (min)) : (max))

Returns a value clamped between a minimum and maximum.

int addColor(int colValue, int addValue)                        {
        //We add addValue to colValue, but we must check the color component is always between 0 and 255.
        colValue = oslMinMax(colValue + addValue, 0, 255);
        return colValue;
}

#define oslNumberof

(

n

)

(sizeof(n)/sizeof(*(n)))

Returns the number of objects in an array.

OSL_VIRTUALFILENAME ram_files[] =               {
        {"ram:/file1.jpg", (void*)file1_jpg, file1_jpg_size, &VF_MEMORY},
        {"ram:/file2.png", (void*)file2_png, file2_png_size, &VF_MEMORY},
};

//This will display 2, as 2 elements are contained in the table ram_files.
oslPrintf("%i", oslNumberof(ram_files));

---

Function Documentation

float oslSin	(	float	angle,
		float	dist
	)

Calculates the sine of an angle in degrees multiplicated by a radius. Returns the result as a float. oslSin and oslCos use the VFPU to compute the result, and thus it's very fast and very precise.

Parameters:

	angle	Angle in degrees (360° means a full circle)
	dist	Radius of the circle

Returns:

sin(angle * PI / 180) * dist

//Character coordinates
float cX, cY;
//Character speed
float cSpeed;
//Character angle
float cAngle;

//Move the character depending on its instant speed and angle
cX += oslCos(cAngle, cSpeed);
//In mathematics, positive y coordinates are directed upwards, in informatics it's directed
//downwards, as if we were writing on a sheet of paper, so we need to substract the sine.
cY -= oslSin(cAngle, cSpeed);

float oslCos	(	float	angle,
		float	dist
	)

Calculates the cosine of an angle in degrees multiplicated by a radius. Returns the result as a float.

Parameters:

	angle	Angle in degrees (360° means a full circle)
	dist	Radius of the circle

Returns:

cos(angle * PI / 180) * dist

int oslSini	(	int	angle,
		int	dist
	)

Returns the sine of an angle in degrees (0 to 360) multiplicated by an integer radius. Returns the result as an integer. These routines use a precalculated lookup table to compute the result. Don't think oslSini and oslCosi are much faster than oslSin and oslCos, it's not the case.

//This code draws a line in a circle which has a radius of 20 pixels. You can play with the angle to move the line.
int angle = 40, radius = 20;
//Draw our line. Same remark as for oslSin applies.
oslDrawLine(240, 136, 240 + oslCosi(angle, radius), 136 - oslSini(angle, radius));

int oslCosi	(	int	angle,
		int	dist
	)

Returns the cosine of an angle in degrees (0 to 360) multiplicated by an integer radius. Returns the result as an integer.

int oslGetNextPower2

(

int

val

)

Returns the next (upper) power of two of a number.

//Prints 256, as 256 = 2^8 (2^7 = 128, too low).
oslPrintf("%i", oslGetNextPower2(200);