etnaviv: masks with no RGB are not component alpha

Masks with no RGB components but have their component alpha property
set are not component alpha because there are no components present to
specify the alpha of each channel.  Treat these as standard masks.

Signed-off-by: Russell King <rmk@armlinux.org.uk>

1 files changed, 20 insertions, 3 deletions

diff --git a/etnaviv/etnaviv_render.c b/etnaviv/etnaviv_render.c
index e95b7f5..20dbba2 100644
--- a/etnaviv/etnaviv_render.c
+++ b/etnaviv/etnaviv_render.c
@@ -638,7 +638,7 @@ static int etnaviv_accel_composite_masked(PicturePtr pSrc, PicturePtr pMask,
 
 	mask_op = etnaviv_composite_op[PictOpInReverse];
 
-	if (pMask->componentAlpha) {
+	if (pMask->componentAlpha && PICT_FORMAT_RGB(pMask->format)) {
 		/* Only PE2.0 can do component alpha blends. */
 		if (!VIV_FEATURE(etnaviv->conn, chipMinorFeatures0, 2DPE20))
 			goto fallback;
@@ -750,11 +750,29 @@ static Bool etnaviv_accel_reduce_mask(struct etnaviv_blend_op *final_blend,
 {
 	uint32_t colour;
 
+	/* Deal with component alphas first */
+	if (pMask->componentAlpha && PICT_FORMAT_RGB(pMask->format)) {
+		/*
+		 * The component alpha operation is (for C in R,G,B,A):
+		 *  dst.C = tV.C * Fa(OP) + dst.C * Fb(OP)
+		 *   where tV.C = src.C * mask.C, tA.C = src.A * mask.C
+		 *   and Fa(OP) is the alpha factor based on dst.A
+		 *   and Fb(OP) is the alpha factor based on tA.C
+		 */
+		/* If the mask is solid white, the IN has no effect. */
+		if (etnaviv_pict_solid_argb(pMask, &colour)) {
+			if (colour == 0xffffffff)
+				return TRUE;
+		}
+
+		return FALSE;
+	}
+
 	/*
 	 * If the mask has no alpha, then the alpha channel is treated
 	 * as constant 1.0.  This makes the IN operation redundant.
 	 */
-	if (!PICT_FORMAT_A(pMask->format) && !pMask->componentAlpha)
+	if (!PICT_FORMAT_A(pMask->format))
 		return TRUE;
 
 	/*
@@ -786,7 +804,6 @@ static Bool etnaviv_accel_reduce_mask(struct etnaviv_blend_op *final_blend,
 	 * format must not have an alpha channel.
 	 */
 	if (op == PictOpOver &&
-	    !pMask->componentAlpha &&
 	    !PICT_FORMAT_A(pDst->format) &&
 	    etnaviv_pict_solid_argb(pMask, &colour)) {
 		uint32_t src_alpha_mode;