On 14/10/2013 22:06, bearophile wrote:
Spacen Jasset:
const float pi = 3.14159265f;
float dx = cast(float)(Clock.currSystemTick.length %
(TickDuration.ticksPerSec * 10)) / (TickDuration.ticksPerSec * 10);
float xRot = sin(dx * pi * 2) * 0.4f + pi / 2;
float yRot = cos(dx * pi * 2) * 0.4f;
float yCos = cos(yRot);
float ySin = sin(yRot);
float xCos = cos(xRot);
float xSin = sin(xRot);
float ox = 32.5f + dx * 64;
float oy = 32.5f;
float oz = 32.5f;
for (int x = 0; x < width; ++x) {
float ___xd = cast(float)(x - width / 2) / height;
for (int y = 0; y < height; ++y) {
float __yd = cast(float)(y - height / 2) / height;
float __zd = 1;
The performance difference between the DMD and GDC compile is kind of
expected for FP-heavy code. Also try the new LDC2 compiler (ldmd2 for
the same compilation switches) that sometimes is better than GDC.
More comments:
- There is a PI in std.math (but it's not a float);
- Add immutable/const to every variable that doesn't need to change.
This is a good habit like washing your hands before eating;
- "for (int x = 0; x < width; ++x)" ==> "foreach (immutable x; 0 ..
width)";
- I suggest to avoid many leading/trailing newlines in identifier names;
- It's probably worth replacing all those "float" with another name,
like "FP" and then define "alias FP = float;" at the beginning. So you
can see how much performance you lose/gain using floats/doubles. In many
cases in my code there is no difference, but float are less precise.
Floats can be useful when you have many of them, in a struct or array.
Floats can also be useful when you call certain numerical functions that
compute their result by approximation, but on some CPUs sin/cos are not
among those functions.
Bye,
bearophile
Thank you. I may take up some of those suggestions. It was a direct port
of some c++ hence the style.
