Features: set captured image resolution, set camera target, set camera position

examples/demo.ipynb

@@ -417,7 +417,9 @@
   },
   {
    "cell_type": "markdown",
-   "metadata": {},
+   "metadata": {
+    "tags": []
+   },
    "source": [
     "## Cart-Pole\n",
     "\n",
@@ -453,6 +455,47 @@
     "    time.sleep(0.01)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Let's set the camera position to above left of the cartpole:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "vis.jupyter_cell()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "vis.set_cam_pos([0.6, -1.0, 1.0])"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Let's change the focus to the leftmost 'l' character:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "vis.set_cam_target([0.0, -1.0, 0.0])"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,
@@ -477,9 +520,9 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.5.2"
+   "version": "3.9.13"
   }
  },
  "nbformat": 4,
- "nbformat_minor": 2
+ "nbformat_minor": 4
 }

src/meshcat/commands.py

@@ -44,12 +44,36 @@ def lower(self):
             u"matrix": list(self.matrix.T.flatten())
         }
 
-class CaptureImage:
+
+class SetCamTarget:
+    """Set the camera target point."""
+    __slots__ = ["value"]
+    def __init__(self, pos):
+        self.value = pos
 
     def lower(self):
         return {
+            u"type": "set_target",
+            u"path": "",
+            u"value": list(self.value)
+        }
+
+
+class CaptureImage:
+
+    def __init__(self, xres=None, yres=None):
+        self.xres = xres
+        self.yres = yres
+
+    def lower(self):
+        data = {
             u"type": u"capture_image"
         }
+        if self.xres:
+            data[u"xres"] = self.xres
+        if self.yres:
+            data[u"yres"] = self.yres
+        return data
 
 
 class Delete:

src/meshcat/geometry.py

@@ -427,7 +427,7 @@ def __init__(self, contents, mesh_format):
 
     def lower(self, object_data):
         return {
-            u"type": u"_meshfile",
+            u"type": u"_meshfile_geometry",
             u"uuid": self.uuid,
             u"format": self.mesh_format,
             u"data": self.contents

src/meshcat/servers/zmqserver.py

@@ -259,6 +259,9 @@ def handle_zmq(self, frames):
             self.zmq_socket.send(self.web_url.encode("utf-8"))
         elif cmd == "wait":
             self.ioloop.add_callback(self.wait_for_websockets)
+        elif cmd == "set_target":
+            self.forward_to_websockets(frames)
+            self.zmq_socket.send(b"ok")
         elif cmd == "capture_image":
             if len(self.websocket_pool) > 0:
                 self.forward_to_websockets(frames)  # on_message callback should handle the pb

src/meshcat/visualizer.py

@@ -8,7 +8,7 @@
 
 
 from .path import Path
-from .commands import SetObject, SetTransform, Delete, SetProperty, SetAnimation, CaptureImage
+from .commands import SetObject, SetTransform, Delete, SetProperty, SetAnimation, CaptureImage, SetCamTarget
 from .geometry import MeshPhongMaterial
 from .servers.zmqserver import start_zmq_server_as_subprocess
 
@@ -68,8 +68,8 @@ def get_scene(self):
         # we receive the HTML as utf-8-encoded, so decode here
         return self.zmq_socket.recv().decode('utf-8')
 
-    def get_image(self):
-        cmd_data = CaptureImage().lower()
+    def get_image(self, w, h):
+        cmd_data = CaptureImage(w, h).lower()
         self.zmq_socket.send_multipart([
             cmd_data["type"].encode("utf-8"),
             "".encode("utf-8"),
@@ -157,9 +157,22 @@ def set_property(self, key, value):
     def set_animation(self, animation, play=True, repetitions=1):
         return self.window.send(SetAnimation(animation, play=play, repetitions=repetitions))
 
-    def get_image(self):
+    def set_cam_target(self, value):
+        """Set camera target (in right-handed coordinates (x,y,z))."""
+        v = list(value)
+        v[1], v[2] = v[2], -v[1]  # convert to left-handed (x,z,-y)
+        return self.window.send(SetCamTarget(v))
+
+    def set_cam_pos(self, value):
+        """Set camera position (in right-handed coordinates (x,y,z))."""
+        path = "/Cameras/default/rotated/<object>"
+        v = list(value)
+        v[1], v[2] = v[2], -v[1]  # convert to left-handed (x,z,-y)
+        return self[path].set_property("position", v)
+
+    def get_image(self, w=None, h=None):
         """Save an image"""
-        return self.window.get_image()
+        return self.window.get_image(w, h)
 
     def delete(self):
         return self.window.send(Delete(self.path))