Support fetching effect instances and classes from the project

Author: einarf

demosys/effects/effect.py

@@ -1,4 +1,4 @@
-from typing import Any
+from typing import Any, Type
 
 from pyrr import Matrix33, Matrix44, Vector3, matrix44
 from rocket.tracks import Track
@@ -126,6 +126,24 @@ def get_data(self, label) -> Any:
         """
         return self._project.get_data(label)
 
+    def get_effect(self, label) -> 'Effect':
+        """
+        Get an effect instance by label
+
+        :param label: Label for the data file
+        :return: The requested effect instance
+        """
+        return self._project.get_effect(label)
+
+    def get_effect_class(self, effect_name, package_name=None) -> Type['Effect']:
+        """
+        Get an effect class.
+
+        :param effect_name: Name of the effect class
+        :param package_name: (optional) The package this effect belongs to
+        """
+        return self._project.get_effect_class(effect_name, package_name=package_name)
+
     # Utility methods for matrices
 
     def create_projection(self, fov=75.0, near=1.0, far=100.0, ratio=None):

demosys/effects/registry.py

@@ -59,7 +59,7 @@ def add_package(self, name):
         package.load()
 
         self.packages.append(package)
-        self.package_map[package.path] = package
+        self.package_map[package.name] = package
 
         # Load effect package dependencies
         self.polulate(package.effect_packages)
@@ -193,6 +193,12 @@ def load_resource_module(self):
                 "Effect dependencies module '{}': 'effect_packages' is of type {} instead of a list".format(
                     name, type(self.effects)))
 
+    def __str__(self):
+        return "<{} {}>".format(self.__class__.__name__, self.name)
+
+    def __repr__(self):
+        return str(self)
+
 
 class EffectError(Exception):
     pass

demosys/project/base.py

@@ -92,6 +92,9 @@ def _add_resource_descriptions_to_pools(self, meta_list):
     def get_effect(self, label):
         return self._get_resource(label, self._effects, "effect")
 
+    def get_effect_class(self, class_name, package_name=None):
+        return effects.find_effect_class(class_name, package_name=package_name)
+
     def get_scene(self, label):
         return self._get_resource(label, self._scenes, "scene")
 

examples/textrenderer/effects.py

@@ -2,7 +2,6 @@
 import os
 
 from demosys.effects import effect
-from demosys.effects.text.effects import TextRenderer2D
 
 
 class TextRendererEffect(effect.Effect):
@@ -13,6 +12,8 @@ def __init__(self):
         with open(os.path.join(os.path.dirname(__file__), 'sample.txt'), 'r') as fd:
             lines = fd.readlines()
 
+        TextRenderer2D = self.get_effect_class('TextRenderer2D', package_name='demosys.effects.text')
+
         self.renderer = TextRenderer2D(
             (105, len(lines)),
             text_lines=lines,

examples/textwriter/effects.py

@@ -2,7 +2,6 @@
 import os
 
 from demosys.effects import effect
-from demosys.effects.text.effects import TextWriter2D
 
 
 class TextWriterEffect(effect.Effect):
@@ -13,6 +12,8 @@ def __init__(self):
         with open(os.path.join(os.path.dirname(__file__), 'sample.txt'), 'r') as fd:
             lines = fd.readlines()
 
+        TextWriter2D = self.get_effect_class('TextWriter2D', package_name='demosys.effects.text')
+
         self.writer = TextWriter2D(
             (105, len(lines)),
             aspect_ratio=self.window.aspect_ratio,