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.
