diff options
| author | Brian Paul <brianp@vmware.com> | 2009-03-17 10:28:32 -0600 |
|---|---|---|
| committer | Brian Paul <brianp@vmware.com> | 2009-03-17 10:28:32 -0600 |
| commit | c334ce273e946733928339b1c7f9a02ccdef1b4b (patch) | |
| tree | bcd4db01fc727f99e38f2159169cf8b1bf419da6 | |
| parent | 1eee1bac1f6d911e6124daafc9b9291666d91cef (diff) | |
swrast: use better _swrast_compute_lambda() function
The MAX-based function can produce values that are non-monotonic for a span
which causes glitches in texture filtering. The sqrt-based one avoids that.
This is perhaps slightly slower than before, but the difference
probably isn't noticable given we're doing software mipmap filtering.
Issue reported by Nir Radian <nirr@horizonsemi.com>
| -rw-r--r-- | src/mesa/swrast/s_span.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/src/mesa/swrast/s_span.c b/src/mesa/swrast/s_span.c index 5e1f412d6b..15a783b236 100644 --- a/src/mesa/swrast/s_span.c +++ b/src/mesa/swrast/s_span.c @@ -442,11 +442,10 @@ _swrast_span_interpolate_z( const GLcontext *ctx, SWspan *span ) * Compute mipmap LOD from partial derivatives. * This the ideal solution, as given in the OpenGL spec. */ -#if 0 -static GLfloat -compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy, - GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH, - GLfloat s, GLfloat t, GLfloat q, GLfloat invQ) +GLfloat +_swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy, + GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH, + GLfloat s, GLfloat t, GLfloat q, GLfloat invQ) { GLfloat dudx = texW * ((s + dsdx) / (q + dqdx) - s * invQ); GLfloat dvdx = texH * ((t + dtdx) / (q + dqdx) - t * invQ); @@ -458,13 +457,13 @@ compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy, GLfloat lambda = LOG2(rho); return lambda; } -#endif /** * Compute mipmap LOD from partial derivatives. * This is a faster approximation than above function. */ +#if 0 GLfloat _swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy, GLfloat dqdx, GLfloat dqdy, GLfloat texW, GLfloat texH, @@ -485,6 +484,7 @@ _swrast_compute_lambda(GLfloat dsdx, GLfloat dsdy, GLfloat dtdx, GLfloat dtdy, lambda = LOG2(rho); return lambda; } +#endif /** |