render: export TriStrip and TriFan to the drivers

Rather than perform an intermediate copy and expand the strip and the
fan into a triangle list (thereby tripling the number of edges that the
driver needs to process), allow the backend to hook directly into the
appropriate Composite function.

In order to extend the PictureScreen, without needlessly bumping the
ABI, we move the existing copy implementations to mipict.c and assign
those by default. To notify the ddx that the new entry points are
available, we introduce PICTURE_SCREEN_VERSION.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Aaron Plattner <aplattner@nvidia.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/render/mipict.c b/render/mipict.c
index 9a44c2729..0b86bee34 100644
--- a/render/mipict.c
+++ b/render/mipict.c
@@ -569,6 +569,64 @@ miRenderPixelToColor (PictFormatPtr format,
     }
 }
 
+void
+miTriStrip (CARD8	    op,
+	    PicturePtr	    pSrc,
+	    PicturePtr	    pDst,
+	    PictFormatPtr  maskFormat,
+	    INT16	    xSrc,
+	    INT16	    ySrc,
+	    int		    npoints,
+	    xPointFixed    *points)
+{
+    xTriangle           *tris, *tri;
+    int                 ntri;
+
+    ntri = npoints - 2;
+    tris = malloc(ntri * sizeof (xTriangle));
+    if (!tris)
+        return;
+
+    for (tri = tris; npoints >= 3; npoints--, points++, tri++)
+    {
+        tri->p1 = points[0];
+        tri->p2 = points[1];
+        tri->p3 = points[2];
+    }
+    CompositeTriangles (op, pSrc, pDst, maskFormat, xSrc, ySrc, ntri, tris);
+    free(tris);
+}
+
+void
+miTriFan (CARD8		op,
+	  PicturePtr	pSrc,
+	  PicturePtr	pDst,
+	  PictFormatPtr	maskFormat,
+	  INT16		xSrc,
+	  INT16		ySrc,
+	  int		npoints,
+	  xPointFixed	*points)
+{
+    xTriangle		*tris, *tri;
+    xPointFixed		*first;
+    int			ntri;
+
+    ntri = npoints - 2;
+    tris = malloc(ntri * sizeof (xTriangle));
+    if (!tris)
+	return;
+
+    first = points++;
+    for (tri = tris; npoints >= 3; npoints--, points++, tri++)
+    {
+	tri->p1 = *first;
+	tri->p2 = points[0];
+	tri->p3 = points[1];
+    }
+    CompositeTriangles (op, pSrc, pDst, maskFormat, xSrc, ySrc, ntri, tris);
+    free(tris);
+}
+
 Bool
 miPictureInit (ScreenPtr pScreen, PictFormatPtr formats, int nformats)
 {
@@ -602,5 +660,8 @@ miPictureInit (ScreenPtr pScreen, PictFormatPtr formats, int nformats)
     ps->AddTraps	= 0;			/* requires DDX support */
     ps->AddTriangles	= 0;			/* requires DDX support */
 
+    ps->TriStrip	= miTriStrip; /* converts call to CompositeTriangles */
+    ps->TriFan		= miTriFan;
+
     return TRUE;
 }