[core] desc.node: Use node's Python executable to call meshroom_compute

If `pythonExecutable` has not been explicitly set in the node's
description, then the default `python` will be used. Otherwise, the
one set in the description will be used.

`_MESHROOM_COMPUTE_EXE` is removed since it is now impossible to
determine it outside of the node.

Author: cbentejac

meshroom/core/desc/node.py

@@ -17,7 +17,6 @@
 
 _MESHROOM_ROOT = Path(meshroom.__file__).parent.parent.as_posix()
 _MESHROOM_COMPUTE = (Path(_MESHROOM_ROOT) / "bin" / "meshroom_compute").as_posix()
-_MESHROOM_COMPUTE_EXE = f"python {_MESHROOM_COMPUTE}"
 
 
 class MrNodeType(enum.Enum):
@@ -272,15 +271,18 @@ def getMrNodeType(self):
         return MrNodeType.NODE
 
     def processChunkInEnvironment(self, chunk):
-        meshroomComputeCmd = f"{_MESHROOM_COMPUTE_EXE} \"{chunk.node.graph.filepath}\" --node {chunk.node.name} --extern --inCurrentEnv"
+        meshroomComputeCmd = f"{chunk.node.nodeDesc.pythonExecutable} {_MESHROOM_COMPUTE}" + \
+                             f" \"{chunk.node.graph.filepath}\" --node {chunk.node.name}" + \
+                              " --extern --inCurrentEnv"
 
         if len(chunk.node.getChunks()) > 1:
             meshroomComputeCmd += f" --iteration {chunk.range.iteration}"
 
         runtimeEnv = chunk.node.nodeDesc.plugin.runtimeEnv
         cmdPrefix = chunk.node.nodeDesc.plugin.commandPrefix
         cmdSuffix = chunk.node.nodeDesc.plugin.commandSuffix
-        self.executeChunkCommandLine(chunk, cmdPrefix + meshroomComputeCmd + cmdSuffix, env=runtimeEnv)
+        self.executeChunkCommandLine(chunk, cmdPrefix + meshroomComputeCmd + cmdSuffix,
+                                     env=runtimeEnv)
 
 
 class CommandLineNode(BaseNode):