[Glamor] [PATCH] Fallback to pixman when trapezoid mask is big.

[junyan.he at linux.intel.com]

From: Junyan He <junyan.he at linux.intel.com>

 The trapezoid generating speed of the shader is relatively
 slower when the trapezoid area is big. We fallback when
 the trapezoid's width and height is bigger enough.
 The big traps number will also slow down the render because
 of the VBO size. We fallback if ntrap > 256

Signed-off-by: Junyan He <junyan.he at linux.intel.com>
---
 src/glamor_priv.h      |   2 +-
 src/glamor_trapezoid.c | 104 +++++++++++++++++++++++++++++++++++--------------
 2 files changed, 75 insertions(+), 31 deletions(-)

diff --git a/src/glamor_priv.h b/src/glamor_priv.h
index 11d09c4..1830b56 100644
--- a/src/glamor_priv.h
+++ b/src/glamor_priv.h
@@ -1016,7 +1016,7 @@ glamor_composite_rectangles(CARD8	 op,
 
 #define GLAMOR_PIXMAP_DYNAMIC_UPLOAD
 #define GLAMOR_GRADIENT_SHADER
-//#define GLAMOR_TRAPEZOID_SHADER
+#define GLAMOR_TRAPEZOID_SHADER
 #define GLAMOR_TEXTURED_LARGE_PIXMAP 1
 #define WALKAROUND_LARGE_TEXTURE_MAP
 #if 0
diff --git a/src/glamor_trapezoid.c b/src/glamor_trapezoid.c
index 7813d82..7bb75f5 100644
--- a/src/glamor_trapezoid.c
+++ b/src/glamor_trapezoid.c
@@ -36,6 +36,28 @@
 #include "mipict.h"
 #include "fbpict.h"
 
+static xFixed
+_glamor_linefixedX (xLineFixed *l, xFixed y, Bool ceil)
+{
+	xFixed dx = l->p2.x - l->p1.x;
+	xFixed_32_32 ex = (xFixed_32_32) (y - l->p1.y) * dx;
+	xFixed dy = l->p2.y - l->p1.y;
+	if (ceil)
+		ex += (dy - 1);
+	return l->p1.x + (xFixed) (ex / dy);
+}
+
+static xFixed
+_glamor_linefixedY (xLineFixed *l, xFixed x, Bool ceil)
+{
+	xFixed dy = l->p2.y - l->p1.y;
+	xFixed_32_32 ey = (xFixed_32_32) (x - l->p1.x) * dy;
+	xFixed dx = l->p2.x - l->p1.x;
+	if (ceil)
+		ey += (dx - 1);
+	return l->p1.y + (xFixed) (ey / dx);
+}
+
 #ifdef GLAMOR_TRAPEZOID_SHADER
 
 #define GLAMOR_VERTEX_TOP_BOTTOM  (GLAMOR_VERTEX_SOURCE + 1)
@@ -72,28 +94,6 @@ _glamor_lines_crossfixedY (xLineFixed *l, xLineFixed *r)
 	return 0xFFFFFFFF;
 }
 
-static xFixed
-_glamor_linefixedX (xLineFixed *l, xFixed y, Bool ceil)
-{
-	xFixed dx = l->p2.x - l->p1.x;
-	xFixed_32_32 ex = (xFixed_32_32) (y - l->p1.y) * dx;
-	xFixed dy = l->p2.y - l->p1.y;
-	if (ceil)
-		ex += (dy - 1);
-	return l->p1.x + (xFixed) (ex / dy);
-}
-
-static xFixed
-_glamor_linefixedY (xLineFixed *l, xFixed x, Bool ceil)
-{
-	xFixed dy = l->p2.y - l->p1.y;
-	xFixed_32_32 ey = (xFixed_32_32) (x - l->p1.x) * dy;
-	xFixed dx = l->p2.x - l->p1.x;
-	if (ceil)
-		ey += (dx - 1);
-	return l->p1.y + (xFixed) (ey / dx);
-}
-
 static Bool
 point_inside_trapezoid(int point[2], xTrapezoid * trap, xFixed cut_y)
 {
@@ -1601,6 +1601,45 @@ glamor_create_mask_picture(ScreenPtr screen,
 	return picture;
 }
 
+static int
+_glamor_trapezoid_bounds (int ntrap, xTrapezoid *traps, BoxPtr box)
+{
+	box->y1 = MAXSHORT;
+	box->y2 = MINSHORT;
+	box->x1 = MAXSHORT;
+	box->x2 = MINSHORT;
+	int has_large_trapezoid = 0;
+
+	for (; ntrap; ntrap--, traps++) {
+		INT16 x1, y1, x2, y2;
+
+		if (!xTrapezoidValid(traps))
+			continue;
+		y1 = xFixedToInt (traps->top);
+		if (y1 < box->y1)
+			box->y1 = y1;
+
+		y2 = xFixedToInt (xFixedCeil (traps->bottom));
+		if (y2 > box->y2)
+			box->y2 = y2;
+
+		x1 = xFixedToInt (min (_glamor_linefixedX (&traps->left, traps->top, FALSE),
+		                  _glamor_linefixedX (&traps->left, traps->bottom, FALSE)));
+		if (x1 < box->x1)
+			box->x1 = x1;
+
+		x2 = xFixedToInt (xFixedCeil (max (_glamor_linefixedX (&traps->right, traps->top, TRUE),
+		                  _glamor_linefixedX (&traps->right, traps->bottom, TRUE))));
+		if (x2 > box->x2)
+			box->x2 = x2;
+
+		if (!has_large_trapezoid && (x2 - x1) > 256 && (y2 - y1) > 32)
+			has_large_trapezoid = 1;
+	}
+
+	return has_large_trapezoid;
+}
+
 /**
  * glamor_trapezoids will first try to create a trapezoid mask using shader,
  * if failed, miTrapezoids will generate trapezoid mask accumulating in
@@ -1621,6 +1660,7 @@ _glamor_trapezoids(CARD8 op,
 	PixmapPtr pixmap;
 	pixman_image_t *image = NULL;
 	int ret = 0;
+	int has_large_trapezoid;
 
 	/* If a mask format wasn't provided, we get to choose, but behavior should
 	 * be as if there was no temporary mask the traps were accumulated into.
@@ -1638,10 +1678,10 @@ _glamor_trapezoids(CARD8 op,
 		return TRUE;
 	}
 
-	miTrapezoidBounds(ntrap, traps, &bounds);
+	has_large_trapezoid = _glamor_trapezoid_bounds(ntrap, traps, &bounds);
 	DEBUGF("The bounds for all traps is: bounds.x1 = %d, bounds.x2 = %d, "
-	       "bounds.y1 = %d, bounds.y2 = %d\n", bounds.x1, bounds.x2,
-	       bounds.y1, bounds.y2);
+	       "bounds.y1 = %d, bounds.y2 = %d, ---- ntrap = %d\n", bounds.x1,
+	       bounds.x2, bounds.y1, bounds.y2, ntrap);
 
 	if (bounds.y1 >= bounds.y2 || bounds.x1 >= bounds.x2)
 		return TRUE;
@@ -1666,16 +1706,20 @@ _glamor_trapezoids(CARD8 op,
 	   When the depth is not 1, AA is needed and we use a shader to generate
 	   a temp mask pixmap.
 	 */
-	if(mask_format->depth == 1) {
+	if (mask_format->depth == 1) {
 		ret = _glamor_trapezoids_with_shader(op, src, dst, mask_format,
 		                                     x_src, y_src, ntrap, traps);
 		if(ret)
 			return TRUE;
 	} else {
-		/*  The precise mode is that we sample the trapezoid on the centre points of
-		    an (2*n+1)x(2*n-1) subpixel grid. It is computationally expensive in shader
-		    and we use inside area ratio to replace it if the polymode == Imprecise. */
-		if(dst->polyMode == PolyModeImprecise) {
+		if (has_large_trapezoid || ntrap > 256) {
+			/* The shader speed is relative slower than pixman when generating big chunk
+			   trapezoid mask. We fallback to pixman to improve the performance. */
+			;
+		} else if (dst->polyMode == PolyModeImprecise) {
+			/*  The precise mode is that we sample the trapezoid on the centre points of
+			    an (2*n+1)x(2*n-1) subpixel grid. It is computationally expensive in shader
+			    and we use inside area ratio to replace it if the polymode == Imprecise. */
 			picture = glamor_create_mask_picture(screen, dst, mask_format,
 			          width, height, 1);
 			if (!picture)
-- 
1.7.11.2