Outline of Portalrendering2 project

- Vector mathematics
  - Quaternions
  - Planes

- 2D polygon (TRIANGLE) rendering
  - With texture mapping
  - With perspective correction

- Multi-sided polygon rendering
  - Tesselation

- Viewport
  - Frustum, created from 2D edgepoints
  - Pixel buffer (float vectors)
  - Z buffer
  - Prespective projection algorithms

- 3D polygon rendering
  - Discard polygons that are facing opposite way
  - Clip against view frustum (set of planes)
  - Prespective projection

- Scene rendering, part 1
  - Go through all polygons in the current sector
     - Project and clip
     - If the polygon is a portal, recurse using the 2D points as a frustum
     - If the polygon is not a portal, add it to one of the four draw-lists
  - Sort draw-lists: 0 = non-overlapping polygons (classic portal rendering), no sorting;
                     1 = Z-buffer polygons, nearest first
                     2 = Translucent polygons, farthest first
                     3 = Overlay polygons, farthest first
  - For each multi-sided polygon in the draw-list, render them.

- Scene rendering, part 2: Projection
  - Compose the pixel map from carefully selected and cropped view plates
  - Each view plate is rendered as in part 1

- Final step: HDR
  - Calculate brightness value for each pixel using current GlobalBrightness
  - Calculate an overall illumination value using a weighted average of the per-pixel brightness values
  - Adjust the GlobalBrightness using this illumination value
  - Calculate the average difference between brightness of previous and current frame
  - Calculate an “aggressivity” value using that difference
  - Calculate a per-pixel “ideal brightness” value, using current brightness, current overall illumination value and aggressiveness
  - Create two blurred-down versions of the per-pixel “ideal brightness” maps
  - Create a per-pixel brightness target map using a weighted average of previous frame brightness target map and the three “ideal brightness” maps
  - Render the picture by multiplying original pixels with the per-pixel brightness map and the GlobalBrightness; clamping with saturation and rendering with dithering.