Automatic Software Occlusion Culling for Massive Streaming Worlds

SAMPO LAPPALAINENUMBRA SOFTWARE

• FOUNDED IN 2007• BASED IN HELSINKI, FINLAND• 11 EMPLOYEES• SPECIALIZING IN OCCLUSION

CULLING• LONG HISTORY IN VISIBILITY

SOLUTIONS• TWO DOZEN SHIPPED

GAMES USE UMBRA• SEVERAL UMBRA 3 –

POWERED GAMES RELEASING IN Q4 2013 AND IN 2014

PREVIOUS METHODS

• PVS– SLOW TO COMPUTE– STATIC

• OCCLUSION QUERIES– GPU SYNCHRONIZATION

• MANUALLY PLACED PORTALS OR OCCLUDERS- MANUAL WORK- VERY HARD TO MODEL OUTDOOR AREAS ACCURATELY

DESIGN CONSTRAINTS

• BOUNDED TIME• BOUNDED MEMORY• AUTOMATIC• FAST CONTENT ITERATION• ARBITRARY SCENE SIZE

WHAT IS VISIBILITY

• SET OF LINES IN SPACE• ACCURATE REPRESENTATION OF VISIBILITY IN POLYGON

SOUP IS VERY COMPLEX O(N^5)

• CONSERVATIVE VISIBILITY

• REASONING ABOUT SPACE• TOPOLOGICAL REPRESENTATION

WORKFLOWCONTENT PIPELINE RUNTIME

VISIBLE OBJECTS

VISIBILITY DATA

POLYGON SOUP

VOXELS

CELLS AND

PORTALS

VIEW TREE• CONSTRUCT VIEW TREE FROM

VOXELS

HIERARCHICAL OCCLUDER DATA

• SAME DATA IN LOWER RESOLUTION

TOME OF VISIBILITY

TOME

STREAMING BLOCKS• COMPUTE

DATA FOR EACH SUB-REGION

STREAMINGBLOCK

STREAMINGBLOCK

STREAMINGBLOCK

STREAMINGBLOCK

STREAMINGBLOCK

RUNTIME

STREAMING• CHOOSE THE

SET OF STREAMING BLOCKS NEEDED

STREAMINGBLOCK

STREAMINGBLOCK

STREAMINGBLOCK

STREAMINGBLOCK

STREAMING• COMBINE INTO

A TOME OF VISIBILITY

TOME

VISIBILITY QUERY• VISIBLE OBJECTS AND DEPTH BUFFER FROM THE

TOMETOME

VISIBILITY QUERY1. FIND

STARTING CELL FROM VIEW TREE

VISIBILITY QUERY2. RASTERIZE

PORTAL GRAPH

HIERARCHICAL OCCLUDER DATA

3. SELECT RESOLUTION BASED ON DISTANCE

DEPTH BUFFER

TEST OBJECTS3. OBJECT VISIBILITY

DYNAMIC OCCLUDERS

PREDICTED CAMERA

RECAP

Demo

Demo2-3 min?

Demo2-3 min?

Demo2-3 min?

Demo2-3 min?

CONCLUSIONS AND FUTURE WORK

CONCLUSIONS

• DATA STRUCTURE FOR SPATIAL REASONING IN POLYGON SOUP

• VOXELS AND AUTOMATIC PORTAL GENERATION

OTHER USE CASES

• SHADOW CASTER CULLING• GAME LOGIC• AUDIO OCCLUSION• LIGHTING

FUTURE WORK

• GENERATE DATA AT RUNTIME• AUTOMATED LEVEL ANALYSIS• COMPUTE SHADER VERSION• OTHER USE CASES FOR SPATIAL

REASONING

Thank You and Q&A

TOME

INFO@UMBRASOFTWARE.COM