sna/gen6: Special case spans with no transform

As the no transform is a special case of affine, we were attempting to
deference the NULL transform in order to determine if it was a simple
no-rotation matrix. As the operation is extremely simple, add a special
case vertex program to speed it up.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 42 insertions, 2 deletions

diff --git a/src/sna/gen6_render.c b/src/sna/gen6_render.c
index 38d7f96d..c7d4e7b3 100644
--- a/src/sna/gen6_render.c
+++ b/src/sna/gen6_render.c
@@ -2603,6 +2603,44 @@ gen6_emit_composite_spans_solid(struct sna *sna,
 }
 
 fastcall static void
+gen6_emit_composite_spans_identity(struct sna *sna,
+				   const struct sna_composite_spans_op *op,
+				   const BoxRec *box,
+				   float opacity)
+{
+	float *v;
+	union {
+		struct sna_coordinate p;
+		float f;
+	} dst;
+
+	float sx = op->base.src.scale[0];
+	float sy = op->base.src.scale[1];
+	int16_t tx = op->base.src.offset[0];
+	int16_t ty = op->base.src.offset[1];
+
+	v = sna->render.vertex_data + sna->render.vertex_used;
+	sna->render.vertex_used += 3*5;
+
+	dst.p.x = box->x2;
+	dst.p.y = box->y2;
+	v[0] = dst.f;
+	v[1] = (box->x2 + tx) * sx;
+	v[7] = v[2] = (box->y2 + ty) * sy;
+	v[13] = v[8] = v[3] = opacity;
+	v[9] = v[4] = 1;
+
+	dst.p.x = box->x1;
+	v[5] = dst.f;
+	v[11] = v[6] = (box->x1 + tx) * sx;
+
+	dst.p.y = box->y1;
+	v[10] = dst.f;
+	v[12] = (box->y1 + ty) * sy;
+	v[14] = 0;
+}
+
+fastcall static void
 gen6_emit_composite_spans_simple(struct sna *sna,
 				 const struct sna_composite_spans_op *op,
 				 const BoxRec *box,
@@ -2795,9 +2833,11 @@ gen6_render_composite_spans(struct sna *sna,
 	gen6_composite_alpha_gradient_init(sna, &tmp->base.mask);
 
 	tmp->prim_emit = gen6_emit_composite_spans_primitive;
-	if (tmp->base.src.is_solid)
+	if (tmp->base.src.is_solid) {
 		tmp->prim_emit = gen6_emit_composite_spans_solid;
-	else if (tmp->base.is_affine) {
+	} else if (tmp->base.src.transform == NULL) {
+		tmp->prim_emit = gen6_emit_composite_spans_identity;
+	} else if (tmp->base.is_affine) {
 		if (tmp->base.src.transform->matrix[0][1] == 0 &&
 		    tmp->base.src.transform->matrix[1][0] == 0) {
 			tmp->base.src.scale[0] /= tmp->base.src.transform->matrix[2][2];