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#include "global.h"
void guLookAtF(f32 mf[4][4], f32 xEye, f32 yEye, f32 zEye, f32 xAt, f32 yAt, f32 zAt, f32 xUp, f32 yUp, f32 zUp) {
f32 length;
f32 xLook;
f32 yLook;
f32 zLook;
f32 xRight;
f32 yRight;
f32 zRight;
guMtxIdentF(mf);
xLook = xAt - xEye;
yLook = yAt - yEye;
zLook = zAt - zEye;
length = -1.0 / sqrtf(SQ(xLook) + SQ(yLook) + SQ(zLook));
xLook *= length;
yLook *= length;
zLook *= length;
xRight = yUp * zLook - zUp * yLook;
yRight = zUp * xLook - xUp * zLook;
zRight = xUp * yLook - yUp * xLook;
length = 1.0 / sqrtf(SQ(xRight) + SQ(yRight) + SQ(zRight));
xRight *= length;
yRight *= length;
zRight *= length;
xUp = yLook * zRight - zLook * yRight;
yUp = zLook * xRight - xLook * zRight;
zUp = xLook * yRight - yLook * xRight;
length = 1.0 / sqrtf(SQ(xUp) + SQ(yUp) + SQ(zUp));
xUp *= length;
yUp *= length;
zUp *= length;
mf[0][0] = xRight;
mf[1][0] = yRight;
mf[2][0] = zRight;
mf[3][0] = -(xEye * xRight + yEye * yRight + zEye * zRight);
mf[0][1] = xUp;
mf[1][1] = yUp;
mf[2][1] = zUp;
mf[3][1] = -(xEye * xUp + yEye * yUp + zEye * zUp);
mf[0][2] = xLook;
mf[1][2] = yLook;
mf[2][2] = zLook;
mf[3][2] = -(xEye * xLook + yEye * yLook + zEye * zLook);
mf[0][3] = 0;
mf[1][3] = 0;
mf[2][3] = 0;
mf[3][3] = 1;
}
void guLookAt(Mtx* m, f32 xEye, f32 yEye, f32 zEye, f32 xAt, f32 yAt, f32 zAt, f32 xUp, f32 yUp, f32 zUp) {
f32 mf[4][4];
guLookAtF(mf, xEye, yEye, zEye, xAt, yAt, zAt, xUp, yUp, zUp);
guMtxF2L((MtxF*)mf, m);
}
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