keronprint.blogg.se - august 2022

Glm permute vector swizzle how to#

class _swizzle : public _swizzle_base2 _swizzle Provided is to access the attributes after swizzle according to the index, pay attention to the difference and the difference between _swizzle_base0::elem.Ĥ. In other words, when vec3.zy = vec2(2,1), _swizzle_base2::operator=(vecType const&) is actually called The above method provides the set attribute, _swizzle_base2::operator/=(vecType const& ) _swizzle_base2::operator*=(vecType const& ) _swizzle_base2::operator-=(vecType const& ) _swizzle_base2::operator+=(vecType const& ) _swizzle_base2::operator=(vecType const& ) When DUPLICATE_ELEMENTS is 0, that is, there are no identical elements and set attributes. _swizzle_base2 specializes with DUPLICATE_ELEMENTS(0,1) In fact, when the attributes of swizzle have the same elem, there is only the get attribute, because the behavior of vec3.yxy = (1,2,3) is uncertain when it is assigned.

class _swizzle_base2 : public _swizzle_base1 _swizzle_base2ĭUPLICATE_ELEMENTS: This parameter refers to whether the attributes of swizzle are the same, such as: vec3.yxy That is to say, when we use vec2 v2 = v3.xz, we actually call _swizzle_base1::operator()() to construct a vec2.Īccording to N being 2, 3 to construct a VecType of 2 elem or 3 elem swizzle.ģ. _swizzle_base1 is specialized with the number of N, mainly to provide the get attribute for the swizzle attribute. class _swizzle_base1 : public _swizzle_base0 _swizzle_base1Į0, E1, E2: the index of each elem of Swizzle

class _swizzle_base0 _swizzle_base0, as the bottom class of swizzle, only provides the elem interface, and uses i to get the i-th element.Ģ.

Use macros to turn attributes into methods.

For example, we cannot use attributes like xz (interval) and zy (reverse order).

Using the characteristics of union can make multiple "names" use the same memory area, but the above method does not achieve the Swizzle we want very well.

We may be able to think of using uion+struct to achieve.

Glm permute vector swizzle how to#

We can easily write a vec class with two or three attributes in C++, but how to make vec also support the above syntax to mix attributes?.When writing gl shader, I found that vec in the syntax of glsl can support arbitrary mixed attributes like the following syntax.