diff options
Diffstat (limited to 'src/mesa/swrast')
| -rw-r--r-- | src/mesa/swrast/s_texfilter.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/mesa/swrast/s_texfilter.c b/src/mesa/swrast/s_texfilter.c index 3fc554c5a2..1aa2bcaf74 100644 --- a/src/mesa/swrast/s_texfilter.c +++ b/src/mesa/swrast/s_texfilter.c @@ -135,8 +135,11 @@ lerp_rgba_3d(GLfloat result[4], GLfloat a, GLfloat b, GLfloat c, /** - * If A is a signed integer, A % B doesn't give the right value for A < 0 - * (in terms of texture repeat). Just casting to unsigned fixes that. + * Used for GL_REPEAT wrap mode. Using A % B doesn't produce the + * right results for A<0. Casting to A to be unsigned only works if B + * is a power of two. Adding a bias to A (which is a multiple of B) + * avoids the problems with A < 0 (for reasonable A) without using a + * conditional. */ #define REMAINDER(A, B) (((A) + (B) * 1024) % (B)) |