Same-plane splitting reftest

wrench/reftests/split/reftest.list

@@ -9,3 +9,6 @@
 #== cross.yaml cross-ref.yaml #TODO: investigate sub-pixel differences
 == ordering.yaml ordering-ref.yaml
 fuzzy(1,20) == near-plane.yaml near-plane.png
+# Note: on windows the image is rendered at a slightly different spot.
+# similarly, a lot of tests in "transform" are non-windows. TODO: investigate
+platform(linux,mac) fuzzy(1,20) == same-plane.yaml same-plane.png

wrench/reftests/split/same-plane.yaml

@@ -0,0 +1,33 @@
+# This test has a number of rectangles placed on the same transformed preserve3d plane.
+# The expected result is that the rectangles are rendered in the order they are listed.
+# This can fail if the primitives are considered outside of the main plane due
+# to floating point precision issues in plane-splitting and transformation.
+---
+root:
+  items:
+    -
+      type: "stacking-context"
+      transform: rotate-y(30) rotate-x(75) translate(-100, 100, 0)
+      transform-style: preserve-3d
+      perspective: 400
+      items:
+        -
+          bounds: [0, 0, 450, 300]
+          type: rect
+          color: 0 255 0 1.0000
+        - type: stacking-context
+          bounds: [0, 0, 600, 600]
+          transform: translate(200, 0, 0)
+          items:
+            -
+              bounds: [-200, 0, 150, 300]
+              type: rect
+              color: 255 0 0 1.0000
+        - type: stacking-context
+          bounds: [0, 0, 600, 600]
+          transform: rotate-z(90)
+          items:
+            -
+              bounds: [0, 200, 150, 200]
+              type: rect
+              color: 0 0 255 1.0000