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→Investigations on update_camera()
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== The role of "x_gl_mat1" == | == The role of "x_gl_mat1" == | ||
The following section of code assembles the matrix "x_view", which is a subset of "x_gl_mat1". The matrix "x_gl_mat1" consists of multiple translations, | The following section of code assembles the matrix "x_view", which is a subset of "x_gl_mat1". The matrix "x_gl_mat1" consists of multiple translations, scales and one rotation operation. | ||
{{Code|Section of axes::properties::update_camera ()"|<syntaxhighlight lang="C" style="font-size:13px"> | {{Code|Section of axes::properties::update_camera ()"|<syntaxhighlight lang="C" style="font-size:13px"> | ||
// Unit length vector for direction of view "f" | // Unit length vector for direction of view "f" and up vector "UP" | ||
ColumnVector F (c_center), f (F), UP (c_upv); | ColumnVector F (c_center), f (F), UP (c_upv); | ||
normalize (f); | normalize (f); | ||
normalize (UP); | normalize (UP); | ||
// Scale "UP" vector, so that norm(f x UP) becomes 1 | |||
if (std::abs (dot (f, UP)) > 1e-15) | |||
{ | |||
double fa = 1 / sqrt (1 - f(2)*f(2)); | |||
scale (UP, fa, fa, fa); | |||
} | |||
// Calculate the vector rejection UP onto f | // Calculate the vector rejection UP onto f | ||