The document discusses optimizing game performance by addressing the roles of artists and programmers in improving visual elements without sacrificing efficiency. Key performance issues include reducing draw calls, minimizing alpha blending, and utilizing compressed textures. Best practices suggested include working closely with technical artists, self-education, and employing engineering standards to enhance overall performance.

1. Adding more visuals to the game
without affecting performance
by Dmytro Vovk

2. PERFORMANCE

3. Performance
• Why it matters?!

6. Performance
• Is a shared responsibility of both artists and
programmers.

7. Good Enough
• Don’t do more that it’s needed

8. TECHNICAL TIPS FOR ART

9. Technical Artist
• Is a bridge between you and a programmers.
• They are usually responsible for technical side
of art and a performance.
• Availability of TA in your team doesn’t mean,
that you don’t have to understand tech.

10. Performance Killers
• Draw calls
• Alpha blending
• Huge textures

11. Draw Call
• A command to GPU to render a set of vertices
(mesh) with specified state – i.e. textures,
shader, blend mode

12. Draw Call
• Employ texture atlases – a set of small
textures combined into big one
• Merge static meshes into one

13. Texture Atlas

15. Alpha Blending
• Is the process of combining an image with a
background to create the appearance of
partial or full transparency.
• Most common blend mode in 2D games.
• Most common source of performance
problems also 

16. Alpha Blending
• Alpha blending makes impossible to utilize
some hardware optimizations, so it requires
both visible and invisible pixels to be
processed.
• In extreme cases this can be an order of
magnitude slower

17. Alpha Blending
• The majority of 2D games do not use
translucent geometry i.e. alpha value of every
pixel in textures is either 0 or 255.

18. Alpha Blending
• So the pixels with alpha equal to 0 will not
contribute to resulting image at all, but they
still have to be processed
• And the pixels with alpha equal to 255 will
replace any pixel that existed in the
background image before, but it still requires
those replaced pixels to be processed.

19. Alpha Blending
• So sprites with huge transparent areas will
affect performance a lot.
• This can be solved with a “proper” art

20. Alpha Blending
• Replace sprite quads with more complex
geometry:

21. Alpha Blending
• Split geometry into two meshes – one alpha
blended (blue), one – opaque (red):

23. Textures
• Textures are the biggest resources in the
games.
• Apps are bound by 50 Mb app size limit.
• The amount of available GPU memory can be
even lower on a low end device

24. Textures
• RGB8 texture will occupy the same amount of
memory as RGBA8 on most devices.
• Try to lower textures precision – RGB565
instead of RGB888, RGBA5551 instead of
RGBA8888, etc.
• Compressed textures are more preferred
though.

25. Compressed Textures
• A texture compressed with a special lossy
algorithm optimized for GPU.
• PNG is a lossless compressed image format.
Why do you have to use something else?

26. Texture VS File Compression
• On a disk:
PNG (600Kb): PVRTCDXTETC (128Kb):

27. Texture VS File Compression
• In RAM:
PNG (1Mb): PVRTCDXTETC (128Kb):

28. Texture VS File Compression
• In VRAM:
PNG (1Mb): PVRTCDXTETC (128Kb):

29. Compressed Textures
• So compressed textures are preferable since
they are:
– Smaller, allow you to have more textures in the
game;
– Internally optimized for GPU;
– Faster to uploadstream to GPU;
– Faster to render;
• They are not always applicable for 2D games


30. Key Action Points
• Reduce the number of draw calls
• Avoid alpha blended geometry as much as
possible
• Try to compress your textures

31. Best practices
• Employ engineering best practices:
– Introduce Definition of Done. DoD is a checklist of
valuable activities;
– Introduce a Sign Off process;
– Talk to your TA, talk to other TA’s;
– Talk to your programmers;
– Self educate.

32. BONUS

33. Alpha test
– Alpha test effects performance heavily;
– Use alpha blend instead;
– If you still need to use alpha test, try to mimic it
with geometry

34. Alpha test
• If it’s too hard to avoid alpha test with
tessellated geometry, try to localize it into as
small region, as possible*

35. Alpha test
• All engines allow you to control the draw
order of your geometry. To get the best
performance possible, try do draw you
geometry in this order:
– Opaque geometry;
– Alpha tested geometry;
– Alpha blended geometry;