static glm::mat4 Util_SetViewMatrix(EERIE_TRANSFORM &transform) {
Vec3f vFrom(transform.pos.x, -transform.pos.y, transform.pos.z);
Vec3f vTout(0.0f, 0.0f, 1.0f);
Vec3f vView;
rotPoint(&vTout, &vView, transform);
Vec3f up(0.f, 1.f, 0.f);
Vec3f vWorldUp;
rotPoint(&up, &vWorldUp, transform);
return Util_LookAt(vFrom, vView, vWorldUp);
}
void Util_SetViewMatrix(glm::mat4x4 &mat, EERIE_TRANSFORM &transform) {
Vec3f vFrom(transform.pos.x, -transform.pos.y, transform.pos.z);
Vec3f vTout(0.0f, 0.0f, 1.0f);
Vec3f vView;
vView.y = -(vTout.z * transform.xsin);
vView.z = -(vTout.z * transform.xcos);
vView.x = (vView.z * transform.ysin);
vView.z = -(vView.z * transform.ycos);
Vec3f vWorldUp(0.f, 1.f, 0.f);
// Normalize the z basis vector
float fLength = glm::length(vView);
if (fLength < 1e-6f)
return;
// Get the dot product, and calculate the projection of the z basis
// vector onto the up vector. The projection is the y basis vector.
float fDotProduct = glm::dot(vWorldUp, vView);
Vec3f vUp = vWorldUp - vView * fDotProduct;
// If this vector has near-zero length because the input specified a
// bogus up vector, let's try a default up vector
if(1e-6f > (fLength = glm::length(vUp)))
{
vUp = Vec3f_Y_AXIS - vView * vView.y;
// If we still have near-zero length, resort to a different axis.
if(1e-6f > (fLength = glm::length(vUp)))
{
vUp = Vec3f_Z_AXIS - vView * vView.z;
if(1e-6f > (fLength = glm::length(vUp)))
return;
}
}
// Normalize the y basis vector
vUp /= fLength;
// The x basis vector is found simply with the cross product of the y
// and z basis vectors
Vec3f vRight = glm::cross(vUp, vView);
// Start building the matrix. The first three rows contains the basis
// vectors used to rotate the view to point at the lookat point
mat[0][0] = vRight.x;
mat[0][1] = vUp.x;
mat[0][2] = vView.x;
mat[1][0] = vRight.y;
mat[1][1] = vUp.y;
mat[1][2] = vView.y;
mat[2][0] = vRight.z;
mat[2][1] = vUp.z;
mat[2][2] = vView.z;
// Do the translation values (rotations are still about the eyepoint)
mat[3][0] = -glm::dot(vFrom, vRight);
mat[3][1] = -glm::dot(vFrom, vUp);
mat[3][2] = -glm::dot(vFrom, vView);
mat[3][3] = 1.0f;
}
