diff options
Diffstat (limited to 'src/mesa/swrast/s_aatriangle.c')
| -rw-r--r-- | src/mesa/swrast/s_aatriangle.c | 89 |
1 files changed, 51 insertions, 38 deletions
diff --git a/src/mesa/swrast/s_aatriangle.c b/src/mesa/swrast/s_aatriangle.c index 83f145ca9fd..5f0a5c76012 100644 --- a/src/mesa/swrast/s_aatriangle.c +++ b/src/mesa/swrast/s_aatriangle.c @@ -1,8 +1,8 @@ -/* $Id: s_aatriangle.c,v 1.19 2001/09/19 20:30:44 kschultz Exp $ */ +/* $Id: s_aatriangle.c,v 1.20 2001/11/13 00:26:39 brianp Exp $ */ /* * Mesa 3-D graphics library - * Version: 3.5 + * Version: 4.0.1 * * Copyright (C) 1999-2001 Brian Paul All Rights Reserved. * @@ -142,27 +142,43 @@ static GLfloat compute_coveragef(const GLfloat v0[3], const GLfloat v1[3], const GLfloat v2[3], GLint winx, GLint winy) { -#define B 0.125 + /* Given a position [0,3]x[0,3] return the sub-pixel sample position. + * Contributed by Ray Tice. + * + * Jitter sample positions - + * - average should be .5 in x & y for each column + * - each of the 16 rows and columns should be used once + * - the rectangle formed by the first four points + * should contain the other points + * - the distrubition should be fairly even in any given direction + * + * The pattern drawn below isn't optimal, but it's better than a regular + * grid. In the drawing, the center of each subpixel is surrounded by + * four dots. The "x" marks the jittered position relative to the + * subpixel center. + */ +#define POS(a, b) (0.5+a*4+b)/16 static const GLfloat samples[16][2] = { /* start with the four corners */ - { 0.00+B, 0.00+B }, - { 0.75+B, 0.00+B }, - { 0.00+B, 0.75+B }, - { 0.75+B, 0.75+B }, + { POS(0, 2), POS(0, 0) }, + { POS(3, 3), POS(0, 2) }, + { POS(0, 0), POS(3, 1) }, + { POS(3, 1), POS(3, 3) }, /* continue with interior samples */ - { 0.25+B, 0.00+B }, - { 0.50+B, 0.00+B }, - { 0.00+B, 0.25+B }, - { 0.25+B, 0.25+B }, - { 0.50+B, 0.25+B }, - { 0.75+B, 0.25+B }, - { 0.00+B, 0.50+B }, - { 0.25+B, 0.50+B }, - { 0.50+B, 0.50+B }, - { 0.75+B, 0.50+B }, - { 0.25+B, 0.75+B }, - { 0.50+B, 0.75+B } + { POS(1, 1), POS(0, 1) }, + { POS(2, 0), POS(0, 3) }, + { POS(0, 3), POS(1, 3) }, + { POS(1, 2), POS(1, 0) }, + { POS(2, 3), POS(1, 2) }, + { POS(3, 2), POS(1, 1) }, + { POS(0, 1), POS(2, 2) }, + { POS(1, 0), POS(2, 1) }, + { POS(2, 1), POS(2, 3) }, + { POS(3, 0), POS(2, 0) }, + { POS(1, 3), POS(3, 0) }, + { POS(2, 2), POS(3, 2) } }; + const GLfloat x = (GLfloat) winx; const GLfloat y = (GLfloat) winy; const GLfloat dx0 = v1[0] - v0[0]; @@ -226,28 +242,25 @@ static GLint compute_coveragei(const GLfloat v0[3], const GLfloat v1[3], const GLfloat v2[3], GLint winx, GLint winy) { - /* NOTE: 15 samples instead of 16. - * A better sample distribution could be used. - */ + /* NOTE: 15 samples instead of 16. */ static const GLfloat samples[15][2] = { /* start with the four corners */ - { 0.00+B, 0.00+B }, - { 0.75+B, 0.00+B }, - { 0.00+B, 0.75+B }, - { 0.75+B, 0.75+B }, + { POS(0, 2), POS(0, 0) }, + { POS(3, 3), POS(0, 2) }, + { POS(0, 0), POS(3, 1) }, + { POS(3, 1), POS(3, 3) }, /* continue with interior samples */ - { 0.25+B, 0.00+B }, - { 0.50+B, 0.00+B }, - { 0.00+B, 0.25+B }, - { 0.25+B, 0.25+B }, - { 0.50+B, 0.25+B }, - { 0.75+B, 0.25+B }, - { 0.00+B, 0.50+B }, - { 0.25+B, 0.50+B }, - /*{ 0.50, 0.50 },*/ - { 0.75+B, 0.50+B }, - { 0.25+B, 0.75+B }, - { 0.50+B, 0.75+B } + { POS(1, 1), POS(0, 1) }, + { POS(2, 0), POS(0, 3) }, + { POS(0, 3), POS(1, 3) }, + { POS(1, 2), POS(1, 0) }, + { POS(2, 3), POS(1, 2) }, + { POS(3, 2), POS(1, 1) }, + { POS(0, 1), POS(2, 2) }, + { POS(1, 0), POS(2, 1) }, + { POS(2, 1), POS(2, 3) }, + { POS(3, 0), POS(2, 0) }, + { POS(1, 3), POS(3, 0) } }; const GLfloat x = (GLfloat) winx; const GLfloat y = (GLfloat) winy; |