diff options
Diffstat (limited to 'src/mesa/swrast/s_aaline.c')
| -rw-r--r-- | src/mesa/swrast/s_aaline.c | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/src/mesa/swrast/s_aaline.c b/src/mesa/swrast/s_aaline.c index 89df853233c..f60233c3aca 100644 --- a/src/mesa/swrast/s_aaline.c +++ b/src/mesa/swrast/s_aaline.c @@ -1,4 +1,4 @@ -/* $Id: s_aaline.c,v 1.7 2001/03/28 21:37:24 brianp Exp $ */ +/* $Id: s_aaline.c,v 1.8 2001/04/10 15:46:51 brianp Exp $ */ /* * Mesa 3-D graphics library @@ -120,10 +120,18 @@ compute_plane(GLfloat x0, GLfloat y0, GLfloat x1, GLfloat y1, const GLfloat b = pz * py; const GLfloat c = px * px + py * py; const GLfloat d = -(a * x0 + b * y0 + c * z0); - plane[0] = a; - plane[1] = b; - plane[2] = c; - plane[3] = d; + if (a == 0.0 && b == 0.0 && c == 0.0 && d == 0.0) { + plane[0] = 0.0; + plane[1] = 0.0; + plane[2] = 1.0; + plane[3] = 0.0; + } + else { + plane[0] = a; + plane[1] = b; + plane[2] = c; + plane[3] = d; + } #endif } @@ -141,7 +149,7 @@ constant_plane(GLfloat value, GLfloat plane[4]) static INLINE GLfloat solve_plane(GLfloat x, GLfloat y, const GLfloat plane[4]) { - GLfloat z = (plane[3] + plane[0] * x + plane[1] * y) / -plane[2]; + const GLfloat z = (plane[3] + plane[0] * x + plane[1] * y) / -plane[2]; return z; } @@ -155,8 +163,11 @@ solve_plane(GLfloat x, GLfloat y, const GLfloat plane[4]) static INLINE GLfloat solve_plane_recip(GLfloat x, GLfloat y, const GLfloat plane[4]) { - GLfloat z = -plane[2] / (plane[3] + plane[0] * x + plane[1] * y); - return z; + const GLfloat denom = plane[3] + plane[0] * x + plane[1] * y; + if (denom == 0.0) + return 0.0; + else + return -plane[2] / denom; } |