LYGIA Shader Library

Use:

<mat3> lookAt(<vec3> forward, <vec3> up)

<mat3> lookAt(<vec3> eye, <vec3> target, <vec3> up)

<mat3> lookAt(<vec3> eye, <vec3> target, <float> roll)

<mat3> lookAt(<vec3> forward)

Check it on Github

#ifndef FNC_LOOKAT
#define FNC_LOOKAT

mat3 lookAt(vec3 forward, vec3 up) {
    vec3 zaxis = normalize(forward);
#if defined(LOOK_AT_RIGHT_HANDED)
    vec3 xaxis = normalize(cross(zaxis, up));
    vec3 yaxis = cross(xaxis, zaxis);
#else
    vec3 xaxis = normalize(cross(up, zaxis));
    vec3 yaxis = cross(zaxis, xaxis);
#endif
    return mat3(xaxis, yaxis, zaxis);
}

mat3 lookAt(vec3 eye, vec3 target, vec3 up) {
    vec3 forward = normalize(target - eye);
    return lookAt(forward, up);
}

mat3 lookAt(vec3 eye, vec3 target, float roll) {
    vec3 up = vec3(sin(roll), cos(roll), 0.0);
    return lookAt(eye, target, up);
}

mat3 lookAt(vec3 forward) {
    return lookAt(forward, vec3(0.0, 1.0, 0.0));
}

#endif

Use:

<float3x3> lookAt(<float3> forward, <float3> up)

<float3x3> lookAt(<float3> target, <float3> eye, <float3> up)

<float3x3> lookAt(<float3> target, <float3> eye, <float> roll)

<float3x3> lookAt(<float3> forward)

Check it on Github

#ifndef FNC_LOOKAT
#define FNC_LOOKAT

float3x3 lookAt(float3 forward, float3 up) {
    float3 zaxis = normalize(forward);
#if defined (LOOK_AT_RIGHT_HANDED)
    float3 xaxis = normalize(cross(zaxis, up));
    float3 yaxis = cross(xaxis, zaxis);
#else
    float3 xaxis = normalize(cross(up, zaxis));
    float3 yaxis = cross(zaxis, xaxis);
#endif
    float3x3 m;
    m._m00_m10_m20 = xaxis;
    m._m01_m11_m21 = yaxis;
    m._m02_m12_m22 = zaxis;
    return m;
}

float3x3 lookAt(float3 eye, float3 target, float3 up) {
    float3 forward = normalize(target - eye);
    return lookAt(forward, up);
}

float3x3 lookAt(float3 eye, float3 target, float roll) {
    float3 up = float3(sin(roll), cos(roll), 0.0);
    return lookAt(eye, target, up);
}

float3x3 lookAt(float3 forward) {
    return lookAt(forward, float3(0.0, 1.0, 0.0));
}

#endif

Use:

<mat3> lookAt(<float3> forward, <float3> up)

<mat3> lookAt(<float3> eye, <float3> target, <float3> up)

<mat3> lookAt(<float3> eye, <float3> target, <float> rolle)

<mat3> lookAt(<float3> forward)

Check it on Github

#ifndef FNC_LOOKAT
#define FNC_LOOKAT

mat3 lookAt(float3 forward, float3 up) {
    float3 zaxis = normalize(forward);
#if defined(LOOK_AT_RIGHT_HANDED)
    float3 xaxis = normalize(cross(zaxis, up));
    float3 yaxis = cross(xaxis, zaxis);
#else
    float3 xaxis = normalize(cross(up, zaxis));
    float3 yaxis = cross(zaxis, xaxis);
#endif
    return mat3(xaxis, yaxis, zaxis);
}

mat3 lookAt(float3 eye, float3 target, float3 up) {
    float3 zaxis = normalize(target - eye);
    float3 xaxis = normalize(cross(zaxis, up));
    float3 yaxis = cross(zaxis, xaxis);
    return mat3(xaxis, yaxis, zaxis);
}

mat3 lookAt(float3 eye, float3 target, float roll) {
    float3 up = float3(sin(roll), cos(roll), 0.0);
    float3 zaxis = normalize(target - eye);
    float3 xaxis = normalize(cross(zaxis, up));
    float3 yaxis = normalize(cross(xaxis, zaxis));
    return mat3(xaxis, yaxis, zaxis);
}

mat3 lookAt(float3 forward) {
    return lookAt(forward, float3(0.0, 1.0, 0.0));
}

#endif