diff options
| author | Keith Packard <keithp@keithp.com> | 2008-03-18 15:15:40 -0700 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2008-11-24 13:24:39 -0800 |
| commit | 97ab0c6eff870b52c0383b63a78cec49059b2545 (patch) | |
| tree | b2f6c25a95b2cd18dd94cfefc40d2cedb01d5645 /render/matrix.c | |
| parent | 6d3a9e40a4b9ec455af11cce31e4aa616c93db32 (diff) | |
When converting from double to fixed, round carefully.
This reduces the matrix representation error after inverting a
transformation matrix (although it doesn't eliminate it entirely).
Perhaps we should extend Render to include 64-bit floating point transforms...
Diffstat (limited to 'render/matrix.c')
| -rw-r--r-- | render/matrix.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/render/matrix.c b/render/matrix.c index 6e502057c..0d5d96267 100644 --- a/render/matrix.c +++ b/render/matrix.c @@ -72,9 +72,9 @@ PictureTransformPoint3d (PictTransformPtr transform, return FALSE; result.vector[j] = (xFixed) v; } + *vector = result; if (!result.vector[2]) return FALSE; - *vector = result; return TRUE; } @@ -286,7 +286,8 @@ from_doubles (PictTransformPtr t, double m[3][3]) double d = m[j][i]; if (d < -32767.0 || d > 32767.0) return FALSE; - t->matrix[j][i] = pixman_double_to_fixed (d); + d = d * 65536.0 + 0.5; + t->matrix[j][i] = (xFixed) floor (d); } return TRUE; } @@ -294,7 +295,7 @@ from_doubles (PictTransformPtr t, double m[3][3]) static Bool invert (double r[3][3], double m[3][3]) { - double det, norm; + double det; int i, j; static int a[3] = { 2, 2, 1 }; static int b[3] = { 1, 0, 0 }; |