Math: Difference between revisions
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== CMath::sinoid == | == CMath::sinoid == | ||
Approximates sine for | Approximates sine for the given input <tt>float a1</tt>. This function is typically inlined. | ||
<syntaxhighlight lang="cpp"> | <syntaxhighlight lang="cpp"> |
Revision as of 04:29, 12 April 2017
CMath::split
Given an input of float xf, assign the integer part to int xi, and the fractional (radix) part to float xr.
void CMath::split(float xf, float *xr, int *xi) {
if (xf <= 0.0f) {
*xi = xf - 1;
*xr = xf - *xi;
} else {
*xi = xf;
*xr = xf - *xi;
}
}
CMath::sinoid
Approximates sine for the given input float a1. This function is typically inlined.
double CMath::sinoid(float a1) {
int xi;
float xr;
float v1 = (a1 * M_1_PI) - 0.5;
CMath::split(v1, &xr, &xi);
double result = 1.0 - xr * ((6.0 - 4.0 * xr) * xr);
if (xi & 1) {
result = -result;
}
return result;
}
CMath::cosoid
Approximates cosine for the given input float a1. This function is typically inlined.
double CMath::cosoid(float a1) {
int xi;
float xr;
float v1 = a1 * M_1_PI;
CMath::split(v1, &xr, &xi);
double result = 1.0 - xr * ((6.0 - 4.0 * xr) * xr);
if (xi & 1) {
result = -result;
}
return result;
}