diff options
| -rw-r--r-- | src/mesa/swrast/s_aatriangle.c | 46 |
1 files changed, 28 insertions, 18 deletions
diff --git a/src/mesa/swrast/s_aatriangle.c b/src/mesa/swrast/s_aatriangle.c index d3d44d4e54..1b179bc613 100644 --- a/src/mesa/swrast/s_aatriangle.c +++ b/src/mesa/swrast/s_aatriangle.c @@ -1,4 +1,4 @@ -/* $Id: s_aatriangle.c,v 1.28 2003/01/22 15:03:09 brianp Exp $ */ +/* $Id: s_aatriangle.c,v 1.29 2003/01/25 18:57:13 brianp Exp $ */ /* * Mesa 3-D graphics library @@ -213,30 +213,40 @@ compute_coveragef(const GLfloat v0[3], const GLfloat v1[3], for (i = 0; i < stop; i++) { const GLfloat sx = x + samples[i][0]; const GLfloat sy = y + samples[i][1]; - const GLfloat fx0 = sx - v0[0]; - const GLfloat fy0 = sy - v0[1]; - const GLfloat fx1 = sx - v1[0]; - const GLfloat fy1 = sy - v1[1]; - const GLfloat fx2 = sx - v2[0]; - const GLfloat fy2 = sy - v2[1]; /* cross product determines if sample is inside or outside each edge */ - GLfloat cross0 = (dx0 * fy0 - dy0 * fx0); - GLfloat cross1 = (dx1 * fy1 - dy1 * fx1); - GLfloat cross2 = (dx2 * fy2 - dy2 * fx2); + GLfloat cross = (dx0 * (sy - v0[1]) - dy0 * (sx - v0[0])); /* Check if the sample is exactly on an edge. If so, let cross be a * positive or negative value depending on the direction of the edge. */ - if (cross0 == 0.0F) - cross0 = dx0 + dy0; - if (cross1 == 0.0F) - cross1 = dx1 + dy1; - if (cross2 == 0.0F) - cross2 = dx2 + dy2; - if (cross0 < 0.0F || cross1 < 0.0F || cross2 < 0.0F) { - /* point is outside triangle */ + if (cross == 0.0F) + cross = dx0 + dy0; + if (cross < 0.0F) { + /* sample point is outside first edge */ insideCount -= 1.0F; stop = 16; } + else { + /* sample point is inside first edge */ + cross = (dx1 * (sy - v1[1]) - dy1 * (sx - v1[0])); + if (cross == 0.0F) + cross = dx1 + dy1; + if (cross < 0.0F) { + /* sample point is outside second edge */ + insideCount -= 1.0F; + stop = 16; + } + else { + /* sample point is inside first and second edges */ + cross = (dx2 * (sy - v2[1]) - dy2 * (sx - v2[0])); + if (cross == 0.0F) + cross = dx2 + dy2; + if (cross < 0.0F) { + /* sample point is outside third edge */ + insideCount -= 1.0F; + stop = 16; + } + } + } } if (stop == 4) return 1.0F; |