Allow height-field elevation data to be specified in XML.

PiperOrigin-RevId: 602374498
Change-Id: I2d3364d68876a35799b24aca1051e2f5aebdda75

test/user/testdata/hfield_png.xml

@@ -0,0 +1,12 @@
+<mujoco>
+  <asset>
+    <hfield name="hfield" file="hfield.png" size="0.5 0.5 0.05 0.1"/>
+    <texture name="hfield" type="2d" file="hfield.png"/>
+    <material name="hfield" texture="hfield"/>
+  </asset>
+
+  <worldbody>
+    <light pos="-.4 .6 1"/>
+    <geom type="hfield" hfield="hfield" pos="-.4 .6 .05" material="hfield"/>
+  </worldbody>
+</mujoco>

test/user/testdata/hfield_xml.xml

@@ -0,0 +1,22 @@
+<mujoco>
+  <asset>
+    <hfield name="J" size="0.9 1.1 .2 .1" nrow="12" ncol="10" elevation="
+            0 0 0 0 0 0 0 0 0 0
+            0 0 0 0 0 0 0 0 0 0
+            0 0 0 0 0 0 1 1 0 0
+            0 0 0 0 0 0 1 1 0 0
+            0 0 0 0 0 0 1 1 0 0
+            0 0 0 0 0 0 1 1 0 0
+            0 0 0 0 0 0 1 1 0 0
+            0 0 1 1 0 0 1 1 0 0
+            0 0 1 1 1 1 1 1 0 0
+            0 0 1 1 1 1 1 0 0 0
+            0 0 0 0 0 0 0 0 0 0
+            0 0 0 0 0 0 0 0 0 0"/>
+  </asset>
+
+  <worldbody>
+    <light pos="0 0 1"/>
+    <geom type="hfield" hfield="J"/>
+  </worldbody>
+</mujoco>

test/user/testdata/png_hfield.xml

@@ -1,9 +0,0 @@
-<mujoco>
-  <asset>
-    <hfield name="hfield" file="hfield.png" size="0.5 0.5 1 0.1"/>
-  </asset>
-
-  <worldbody>
-    <geom type="hfield" hfield="hfield" pos="-.4 .6 .05"/>
-  </worldbody>
-</mujoco>