float MathUtils::atan2f(float y, float x)
{
// MSDN docs appear to state that Infinity is in the domain for atan2f, but
// that does not appear to be true. So implement the whole mess here.
// Easy cases are handled by the libc function.
if (isFiniteAndNonzerof(y) && isFiniteAndNonzerof(x))
return ::atan2f(y, x);
if (isNaNf(x)) return x;
if (isNaNf(y)) return y;
if (isInfinitef(y))
{
if (!isInfinitef(x))
return (y > 0 ? (PI_f / 2) : -(PI_f / 2));
float r = (x > 0 ? (PI_f / 4) : (3 * PI_f / 4));
return (y > 0 ? r : -r);
}
else if (y != 0)
{
if (x == 0)
return (y > 0 ? (PI_f / 2) : -(PI_f / 2));
assert(isInfinite(x));
float r = (x > 0 ? 0.0f : PI_f);
return (y > 0 ? r : -r);
}
else // y == 0
{
int32_t zx = isZerof(x);
int32_t zy = isZerof(y);
float r = (x > 0 || zx == 1) ? 0 : PI_f;
return (zy > 0) ? r : -r;
}
}
void matrixx_t::load(const matrixf_t& rhs) {
GLfixed* xp = m;
GLfloat const* fp = rhs.elements();
unsigned int i = 16;
do {
const GLfloat f = *fp++;
*xp++ = isZerof(f) ? 0 : gglFloatToFixed(f);
} while (--i);
}
void matrixf_t::rotate(GLfloat a, GLfloat x, GLfloat y, GLfloat z)
{
matrixf_t rotation;
GLfloat* r = rotation.m;
GLfloat c, s;
r[3] = 0; r[7] = 0; r[11]= 0;
r[12]= 0; r[13]= 0; r[14]= 0; r[15]= 1;
a *= GLfloat(M_PI / 180.0f);
sincosf(a, &s, &c);
if (isOnef(x) && isZerof(y) && isZerof(z)) {
r[5] = c; r[10]= c;
r[6] = s; r[9] = -s;
r[1] = 0; r[2] = 0;
r[4] = 0; r[8] = 0;
r[0] = 1;
} else if (isZerof(x) && isOnef(y) && isZerof(z)) {
r[0] = c; r[10]= c;
r[8] = s; r[2] = -s;
r[1] = 0; r[4] = 0;
r[6] = 0; r[9] = 0;
r[5] = 1;
} else if (isZerof(x) && isZerof(y) && isOnef(z)) {
r[0] = c; r[5] = c;
r[1] = s; r[4] = -s;
r[2] = 0; r[6] = 0;
r[8] = 0; r[9] = 0;
r[10]= 1;
} else {
const GLfloat len = sqrtf(x*x + y*y + z*z);
if (!isOnef(len)) {
const GLfloat recipLen = reciprocalf(len);
x *= recipLen;
y *= recipLen;
z *= recipLen;
}
const GLfloat nc = 1.0f - c;
const GLfloat xy = x * y;
const GLfloat yz = y * z;
const GLfloat zx = z * x;
const GLfloat xs = x * s;
const GLfloat ys = y * s;
const GLfloat zs = z * s;
r[ 0] = x*x*nc + c; r[ 4] = xy*nc - zs; r[ 8] = zx*nc + ys;
r[ 1] = xy*nc + zs; r[ 5] = y*y*nc + c; r[ 9] = yz*nc - xs;
r[ 2] = zx*nc - ys; r[ 6] = yz*nc + xs; r[10] = z*z*nc + c;
}
multiply(rotation);
}
