Callback hack

Before we figure out how to defer loading resources properly

Author: einarf

demosys/resources/__init__.py

@@ -5,8 +5,6 @@
 from .data import data
 from .data import Data  # noqa
 
-ON_LOAD_FUNCS = []
-
 __all__ = [
     'shaders',
     'textures',
@@ -16,24 +14,55 @@
     'Data',
     'load',
     'count',
+    'on_load',
     'on_loaded',
+    'loading_complete',
 ]
 
 
+class States:
+    on_loaded_funcs = []
+    on_load_funcs = []
+    loaded = False
+
+    @classmethod
+    def sort_callbacks(cls):
+        cls.on_load_funcs = sorted(cls.on_load_funcs, key=lambda x: x[0])
+        cls.on_loaded_funcs = sorted(cls.on_loaded_funcs, key=lambda x: x[0])
+
+
 def load():
+    States.sort_callbacks()
+
+    for func in reversed(States.on_load_funcs):
+        func[1]()
+
     scenes.load()
     shaders.load()
     textures.load()
     tracks.load()
     data.load()
 
-    for func in ON_LOAD_FUNCS:
-        func()
+    States.loaded = True
+    for func in reversed(States.on_loaded_funcs):
+        func[1]()
 
 
 def count():
     return shaders.count + textures.count
 
 
-def on_loaded(func):
-    ON_LOAD_FUNCS.append(func)
+def loading_complete():
+    return States.loaded
+
+
+def on_load(func, priority=0):
+    States.on_load_funcs.append((priority, func))
+
+
+def on_loaded(func, priority=0):
+    if loading_complete():
+        func()
+        return
+
+    States.on_loaded_funcs.append((priority, func))

demosys/resources/data.py

@@ -68,7 +68,7 @@ def get(self, name, create=False, cls=Data) -> Data:
         key = name.lower()
 
         data_file = self.file_map.get(key)
-        if not data_file:
+        if not data_file and create:
             data_file = cls(name)
             self.files.append(data_file)
             self.file_map[key] = data_file

demosys/text/renderer2d.py

@@ -2,11 +2,18 @@
 
 import moderngl
 from demosys.opengl import FBO, VAO
-from demosys.resources import shaders
+from demosys import resources
 
 from .writer2d import TextWriter2D
 
 
+def on_load():
+    resources.shaders.get('demosys/text/view_renderer_texture.glsl', create=True)
+
+
+resources.on_load(on_load, priority=100)
+
+
 class TextRenderer2D(TextWriter2D):
 
     def __init__(self, area, text_lines=None, texture_height=64):
@@ -15,16 +22,16 @@ def __init__(self, area, text_lines=None, texture_height=64):
         :param size: Text size
         :param text: Initial text
         """
-        super().__init__(area, text_lines=text_lines)
         self._texture_height = texture_height
         self._texture_width = 0
 
         self._quad = self._create_vao()
-        # self._quad = geometry.quad_fs()
-        self._quad_shader = shaders.get('demosys/text/view_renderer_texture.glsl', create=True)
+        self._quad_shader = resources.shaders.get('demosys/text/view_renderer_texture.glsl', create=True)
         self._fbo = None
+        super().__init__(area, text_lines=text_lines)
 
     def _post_load(self):
+        print("TextRenderer2D._post_load")
         super()._post_load()
         self._texture_width = int(
             round(self._meta.char_aspect_wh * self._texture_height * self.area[0] / self.area[1], 0)

demosys/text/writer2d.py

@@ -2,11 +2,19 @@
 
 import moderngl
 from demosys.opengl import VAO, TextureArray
-from demosys.resources import data, shaders, textures
+from demosys import resources
 from pyrr import matrix44
 
 from .base import BaseText, Meta
 
+def on_load():
+    resources.textures.get('demosys/text/VeraMono.png', cls=TextureArray, layers=190, create=True)
+    resources.shaders.get('demosys/text/textwriter2d.glsl', create=True)
+    resources.data.get('demosys/text/meta.json', create=True)
+
+
+resources.on_load(on_load, priority=100)
+
 
 class TextWriter2D(BaseText):
 
@@ -25,13 +33,13 @@ def __init__(self, area, text_lines=None, aspect_ratio=1.0):
         self.aspect_ratio = aspect_ratio
 
         self._vao = None
-        self._texture = textures.get('demosys/text/VeraMono.png', cls=TextureArray, layers=190, create=True)
-        self._shader = shaders.get('demosys/text/textwriter2d.glsl', create=True)
-        self._config = data.get('demosys/text/meta.json', create=True)
+        self._texture = resources.textures.get('demosys/text/VeraMono.png', cls=TextureArray, layers=190, create=True)
+        self._shader = resources.shaders.get('demosys/text/textwriter2d.glsl', create=True)
+        self._config = resources.data.get('demosys/text/meta.json', create=True)
 
         self._string_buffer = None
 
-        data.on_loaded(self._post_load)
+        resources.on_loaded(self._post_load, priority=99)
 
     def _post_load(self):
         """Parse font metadata after resources are loaded"""

examples/textrenderer/effect.py

@@ -5,7 +5,7 @@
 from demosys.text import TextRenderer2D
 
 
-class TextEffect(effect.Effect):
+class TextRendererEffect(effect.Effect):
 
     def __init__(self):
         super().__init__()

examples/textwriter/effect.py

@@ -5,7 +5,7 @@
 from demosys.text import TextWriter2D
 
 
-class TextEffect(effect.Effect):
+class TextWriterEffect(effect.Effect):
 
     def __init__(self):
         super().__init__()