On 8 August 2012 07:54, F i L <witte2...@gmail.com> wrote:
> F i L wrote:
>
>> Okay, that makes a lot of sense and is inline with what I was reading
>> last night about FPU/SSE assembly code. However I'm also a bit confused. At
>> some point, like in your hightmap example, I'm going to need to do
>> arithmetic work on single vector components. Is there some sort of SSE
>> arithmetic/shuffle instruction which uses "masking" that I should use to
>> isolate and manipulate components?
>>
>> If not, and manipulating components is just bad for performance reasons,
>> then I've figured out a solution to my original concern. By using this code:
>>
>> @property @trusted pure nothrow
>> {
>> auto ref x(T:float4)(auto ref T v) { return v.ptr[0]; }
>> auto ref y(T:float4)(auto ref T v) { return v.ptr[1]; }
>> auto ref z(T:float4)(auto ref T v) { return v.ptr[2]; }
>> auto ref w(T:float4)(auto ref T v) { return v.ptr[3]; }
>>
>> void x(T:float4)(ref float4 v, float val) { v.ptr[0] = val; }
>> void y(T:float4)(ref float4 v, float val) { v.ptr[1] = val; }
>> void z(T:float4)(ref float4 v, float val) { v.ptr[2] = val; }
>> void w(T:float4)(ref float4 v, float val) { v.ptr[3] = val; }
>> }
>>
>> I am able to perform arithmetic on single components:
>>
>> auto vec = Vectors.float4(x, y, 0, 1); // factory
>> vec.x += scalar; // += components
>>
>> again, I'll abandon this approach if there's a better way to manipulate
>> single components, like you mentioned above. I'm just not aware of how to
>> do that using SSE instructions alone. I'll do more research, but would
>> appreciate any insight you can give.
>>
>
>
> Okay, disregard this. I see you where talking about your function in
> std.simd (setY), and I'm referring to that for an example of the
> appropriate vector functions.
>
>_<
