Started on simple deferred renderer

Author: einarf

TODO.md

@@ -4,7 +4,7 @@
 Find more efficient OpenGL bindings. ModernGL (https://pypi.python.org/pypi/ModernGL) 
 don't have a binary distribution for darwin.
 
-- Runtime re-loading of shaders
+- Framebuffer Blitting
 - Properly verify all settings
 - Make EffectControllers
   - TrackSystemEffectController

demosys/deferred/__init__.py

@@ -0,0 +1 @@
+from .renderer import DeferredRenderer  # noqa

demosys/deferred/renderer.py

@@ -0,0 +1,50 @@
+from demosys.opengl import FBO
+from demosys.opengl import Texture
+from OpenGL import GL
+
+
+class DeferredRenderer:
+
+    def __init__(self, width, height, gbuffer=None, lightbuffer=None):
+        self.gbuffer = gbuffer
+        self.lightbuffer = lightbuffer
+
+        # FIXME: We might want double buffering here as well
+        # Create geometry buffer if not supplied
+        if not self.gbuffer:
+            self.gbuffer = FBO()
+            # RGBA color attachment
+            self.gbuffer.add_color_attachment(
+                Texture.create_2d(width=width, height=height,
+                                  internal_format=GL.GL_RGBA8, format=GL.GL_RGBA,
+                                  min_filter=GL.GL_NEAREST, mag_filter=GL.GL_NEAREST,
+                                  wrap_s=GL.GL_CLAMP_TO_EDGE, wrap_t=GL.GL_CLAMP_TO_EDGE)
+            )
+            # 16 bit RGB float buffer for normals
+            self.gbuffer.add_color_attachment(
+                Texture.create_2d(width=width, height=height,
+                                  format=GL.GL_RGB, internal_format=GL.GL_RGB16F, type=GL.GL_FLOAT,
+                                  min_filter=GL.GL_NEAREST, mag_filter=GL.GL_NEAREST,
+                                  wrap_s=GL.GL_CLAMP_TO_EDGE, wrap_t=GL.GL_CLAMP_TO_EDGE)
+            )
+            # 24 bit depth, 8 bit stencil
+            self.gbuffer.set_depth_attachment(
+                Texture.create_2d(width=width, height=height,
+                                  internal_format=GL.GL_DEPTH24_STENCIL8, format=GL.GL_DEPTH_COMPONENT,
+                                  min_filter=GL.GL_NEAREST, mag_filter=GL.GL_NEAREST,
+                                  wrap_s=GL.GL_CLAMP_TO_EDGE, wrap_t=GL.GL_CLAMP_TO_EDGE, wrap_r=GL.GL_CLAMP_TO_EDGE)
+            )
+        if not self.lightbuffer:
+            self.lightbuffer = FBO()
+            # 8 bit light accumulation buffer
+            self.lightbuffer.add_color_attachment(
+                Texture.create_2d(width=width, height=height,
+                                  internal_format=GL.GL_RED, format=GL.GL_RED, type=GL.GL_UNSIGNED_BYTE,
+                                  min_filter=GL.GL_NEAREST, mag_filter=GL.GL_NEAREST,
+                                  wrap_s=GL.GL_CLAMP_TO_EDGE, wrap_t=GL.GL_CLAMP_TO_EDGE)
+            )
+            # Attach the same depth buffer as the geometry buffer
+            self.lightbuffer.set_depth_attachment(self.gbuffer.depth_buffer)
+
+    def render_geometry(self):
+        pass