## digitalmars.D.learn - Hopefully a simple question...

- WhatMeWorry (19/19) Jan 13 I'm converting some C++ and glm code to D and gl3n. And I'm
- kinke (9/11) Jan 13 The C++ source disagrees:
- Nicholas Wilson (7/26) Jan 13 If you're doing game dev stuff I'd highly recommend using/taking

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

Jan 13

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.

Jan 13

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? ThanksIf 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

Jan 13