diff options
| author | Dylan Baker <dylan.c.baker@intel.com> | 2020-04-30 12:40:56 -0700 |
|---|---|---|
| committer | Marge Bot <eric+marge@anholt.net> | 2020-06-30 21:43:22 +0000 |
| commit | fde25a6ed94409eca4e6b47f73774356314095d9 (patch) | |
| tree | cc73f428385711a21007cbd6a1c51ee90465d6f6 | |
| parent | 2e5b2145068223bbe0b4a8cb1ffb2f26e2fb6527 (diff) | |
mesa/swrast: use logf2 instead of util_fast_log2
The fast version is apparently not accurate enough. I wrote a very
simply test program that called logf2 and the old LOG2 function 100000
times. Across that the two functions had very similar run times, neither
appeared meaningfully faster, so the optimization of bringing back yet
another way to calculate log2f seems pointless.
Fixes: bd4e769515345a6b20562310334bc828c0bb6605
("replace LOG2 with util_fast_log2")
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/2856
Reviewed-by: Matt Turner <mattst88@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5406>
| -rw-r--r-- | src/mesa/swrast/s_span.c | 4 | ||||
| -rw-r--r-- | src/mesa/swrast/s_texfilter.c | 2 |
2 files changed, 3 insertions, 3 deletions
diff --git a/src/mesa/swrast/s_span.c b/src/mesa/swrast/s_span.c index 2eb22539a0f..dcb2db01e6d 100644 --- a/src/mesa/swrast/s_span.c +++ b/src/mesa/swrast/s_span.c @@ -426,7 +426,7 @@ _swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy, GLfloat x = sqrtf(dudx * dudx + dvdx * dvdx); GLfloat y = sqrtf(dudy * dudy + dvdy * dvdy); GLfloat rho = MAX2(x, y); - GLfloat lambda = util_fast_log2(rho); + GLfloat lambda = log2f(rho); return lambda; } @@ -453,7 +453,7 @@ _swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy, maxU = MAX2(dsdx2, dsdy2) * texW; maxV = MAX2(dtdx2, dtdy2) * texH; rho = MAX2(maxU, maxV); - lambda = util_fast_log2(rho); + lambda = logf2(rho); return lambda; } #endif diff --git a/src/mesa/swrast/s_texfilter.c b/src/mesa/swrast/s_texfilter.c index 381eb343812..28bd57be8a1 100644 --- a/src/mesa/swrast/s_texfilter.c +++ b/src/mesa/swrast/s_texfilter.c @@ -1961,7 +1961,7 @@ sample_lambda_2d_aniso(struct gl_context *ctx, /* note: we need to have Pmin=sqrt(Pmin2) here, but we can avoid * this since 0.5*log(x) = log(sqrt(x)) */ - lod = 0.5f * util_fast_log2(Pmin2); + lod = 0.5f * log2f(Pmin2); if (adjustLOD) { /* from swrast/s_texcombine.c _swrast_texture_span */ |