fix broken headless rendering

Author: einarf

demosys/context/base.py

@@ -105,4 +105,4 @@ def set_default_viewport(self):
 
         # How much positive or negative y padding
         blank_space = self.buffer_height - expected_height
-        self.ctx.screen.viewport = (0, blank_space // 2, self.buffer_width, expected_height)
+        self.fbo.viewport = (0, blank_space // 2, self.buffer_width, expected_height)

demosys/context/glfw.py

@@ -66,6 +66,7 @@ def __init__(self):
         # Create mederngl context from existing context
         self.ctx = moderngl.create_context()
         self.fbo = FBO()
+        self.fbo.ctx = self.ctx
         self.fbo.fbo = self.ctx.screen
         self.fbo.default_framebuffer = True
         context.WINDOW = self

demosys/context/headless.py

@@ -1,6 +1,6 @@
 import moderngl
-from demosys.conf import settings
-from demosys.conf import ImproperlyConfigured
+from demosys import context
+from demosys.conf import ImproperlyConfigured, settings
 from demosys.opengl.fbo import FBO
 
 from .base import Window
@@ -19,7 +19,16 @@ def __init__(self):
 
         self._close = False
         self.ctx = moderngl.create_standalone_context()
-        self.screenbuffer = FBO.create((self.width, self.height), depth=True)
+
+        self.fbo = FBO()
+        self.fbo.ctx = self.ctx
+        self.fbo.fbo = self.ctx.framebuffer(
+            color_attachments=self.ctx.texture((self.width, self.height), 4),
+            depth_attachment=self.ctx.depth_texture((self.width, self.height)),
+        )
+        # self.fbo.default_framebuffer = True
+        context.WINDOW = self
+        self.set_default_viewport()
 
     def draw(self, current_time, frame_time):
         super().draw(current_time, frame_time)
@@ -28,7 +37,7 @@ def draw(self, current_time, frame_time):
             self.close()
 
     def use(self):
-        self.screenbuffer.use(stack=False)
+        self.fbo.use(stack=False)
 
     def should_close(self):
         return self._close