radeon/exa: fallback for non-affine transforms

We need to implement a texture lookup with perspective
divide for non-affine transforms.  For now just fallback.
Should fix:
https://bugs.freedesktop.org/show_bug.cgi?id=31799
although it appears either EXA or the xserver gets this
wrong too.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/radeon_exa.c b/src/radeon_exa.c
index 503d569b..9c40da79 100644
--- a/src/radeon_exa.c
+++ b/src/radeon_exa.c
@@ -174,6 +174,18 @@ Bool RADEONGetPixmapOffsetPitch(PixmapPtr pPix, uint32_t *pitch_offset)
 	return RADEONGetOffsetPitch(pPix, bpp, pitch_offset, offset, pitch);
 }
 
+/**
+ * Returns whether the provided transform is affine.
+ *
+ * transform may be null.
+ */
+Bool radeon_transform_is_affine(PictTransformPtr t)
+{
+	if (t == NULL)
+		return TRUE;
+	return t->matrix[2][0] == 0 && t->matrix[2][1] == 0;
+}
+
 #if X_BYTE_ORDER == X_BIG_ENDIAN
 
 static unsigned long swapper_surfaces[6];