I'm converting some C++ and glm code to D and gl3n.  And I'm stumped at the following line.


GLboolean CheckCollision(BallObject &one, GameObject &two) // AABB - Circle collision
{
    // Get center point circle first
    glm::vec2 center(one.Position + one.Radius);
    . . .
}

one.Position is a vec2 (x and y) whereas Radius is a GLfloat

// my D code statement

vec2 center2 = one.position + one.radius;   // D code with gl3n

returns Error: incompatible types for ((one.position) + (one.radius)): 'Vector!(float, 2)' and 'float'

I agree with the D code. A vec and scalar can't be added together.  So why (or how) is the glm code working?


I looked at https://github.com/g-truc/glm project source, but I'm not even sure where to start?

Thanks

On Friday, 13 January 2017 at 16:56:43 UTC, WhatMeWorry wrote:
> A vec and scalar can't be added together.  So why (or how) is the glm code working?

The C++ source disagrees: https://github.com/g-truc/glm/blob/master/glm/detail/type_vec2.hpp#L219
It works via operator overloading, and adding a scalar simply means adding it to all vector components.

In your case, you may get away by simply using the types in `core.simd`, such as `float2` instead of your `Vector` template. Otherwise, D operator overloading is way more elegant in D than in C++, see https://dlang.org/spec/operatoroverloading.html.

On Friday, 13 January 2017 at 16:56:43 UTC, WhatMeWorry wrote:
> I'm converting some C++ and glm code to D and gl3n.  And I'm stumped at the following line.
>
>
> GLboolean CheckCollision(BallObject &one, GameObject &two) // AABB - Circle collision
> {
>     // Get center point circle first
>     glm::vec2 center(one.Position + one.Radius);
>     . . .
> }
>
> one.Position is a vec2 (x and y) whereas Radius is a GLfloat
>
> // my D code statement
>
> vec2 center2 = one.position + one.radius;   // D code with gl3n
>
> returns Error: incompatible types for ((one.position) + (one.radius)): 'Vector!(float, 2)' and 'float'
>
> I agree with the D code. A vec and scalar can't be added together.  So why (or how) is the glm code working?
>
>
> I looked at https://github.com/g-truc/glm project source, but I'm not even sure where to start?
>
> Thanks

If you're doing game dev stuff I'd highly recommend using/taking a look at
https://github.com/d-gamedev-team/ and in particular using https://github.com/d-gamedev-team/gfm/ as your math library.

It appears to support what you want https://github.com/d-gamedev-team/gfm/blob/master/math/gfm/math/vector.d#L53-59