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...
---
 render/matrix.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/render/matrix.c b/render/matrix.c
index 6e50205..0d5d962 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 };
-- 
1.5.6.5

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