This talks about some topics we need to know before designing our rendering engine, and it describes the graphics pipeline how to handle 3D objects drawing.

1. XPEC
Senior software engineer
Ellison Mu
2012.9.20
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2.  Game Platforms
 3D EngineArchitecture
 Graphics Pipeline
 Q&A
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3. Console
• PS3
• XBOX 360
• Wii
Desktop
• Windows
• Linux
• Mac OSX
Handheld
Device
• NDS, N3DS
• PSP,Vita
• iPhone/iPad
• Android devices
Web
Browser
• IE:ActiveX
• Chrome,
FireFox,
Safori…: NPAPI
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4. 4

5. Target platform?
Tools pipeline?
Programming language?
Game design?
Reach or Rich?
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6. Decide
model
format
Scene
management
Draw surface
Render
module
Material
system
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7. 7

8.  As possible as minimize draw surface
 View frustum culling
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9.  As possible as minimize draw surface
 Tree hierarchy
▪ BSP
▪ Quad-Tree
▪ Oct-Tree
▪ KD-Tree
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10. 10

11.  As possible as minimize draw surface
 Preprocess visibility determination
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12. 12

13.  As possible as minimize draw surface
 Preprocess visibility determination
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14. Vertex
buffer
Index
buffer
Material
• Texture
• Render state
• Shader
Execute
draw call
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15.  Different platform provides different render
API
 DirectX
 OpenGL
 OpenGL ES
 Customized API
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16. Non-platform-dependency codes
Render Layer Game Logic
Scene
Manager
Abstract
layer
Platform
dependency
codes
Software
development
kit
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17. 17
Vertex
Index
Stream
3D API
Commands
Assembled
Primitives
Pixel
Updates
Pixel
Location
Stream
Programmable
Fragment
Processor
Transformed
Vertices
Programmable
Vertex
Processor
GPU
Front End
Primitive
Assembly
Frame
Buffer
Raster
Operations
Rasterization
and
Interpolation
3D API:
OpenGL or
Direct3D
3D
Application
Or Game
Pre-transformed
Vertices
Pre-transformed
Fragments
Transformed
Fragments
GPU
Command&
DataStream
CPU-GPU Boundary (AGP/PCIe)
Programmable pipeline

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19. 19
(x, y, z)
(r, g, b,a)
(Nx,Ny,Nz)
(tx, ty,[tz])
(tx, ty)
(tx, ty)
Vertex Image F(x,y) = (r,g,b,a)
Material
properties*

20.  Without indexing
 With indexing
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21.  Vertices mapped from object space to world
space
 M = model transformation (scene)
 V = view transformation (camera)
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X’
Y’
Z’
W’
X
Y
Z
1M *V *

22.  Operate on a vertex to transform it into the
viewport space
 The viewport is two-dimensional: however,
vertex z-value is retained for depth testing.
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23.  All primitives are now converted to
fragments.
 Data type change !Vertices to fragments
 The rasterizer produces a stream of
fragments.
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Fragment attributes:
(r,g,b,a)
(x,y,z,w)
(tx,ty), …

24. 24
Color R G B A
Position X Y Z W
Texture
coordinates
X Y [Z] -
Texture
coordinates
X Y [Z] -
…
Interpolated from
vertex information
X Y Z W
Input: Fragment
Attributes

25.  Color(v) = emissive + ambient + diffuse +
specular
 Each term in the right hand side is a function
of the vertex color, position, normal and
material properties.
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26.  Each fragment undergoes a series of tests.
 Scissor
 Alpha
 Stencil
 Depth
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27.  Blending: pixels are accumulated into final
framebuffer storage
new-val = pixel-value op old-val
new-val = SrcColor * A + DstColor * B
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28. 28
Fragment
Processor
Vertex
Processor
GPU
Front End
Primitive
Assembly
Raster
Operations
Rasterization
and
Interpolation

29.  Lock index buffer, vertex buffer, texture
 Create device, index buffer, vertex buffer,
texture
 Destroy device, index buffer, vertex buffer,
texture
 VaildateDevice
 Present
 Command buffer is full
 Query::GetData
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30.  Group similar material
 Avoid redundant state change
 Adv:
 Reduce probability of full command buffer
 Separate transparent / Opaque objects
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31.  Static / Dynamic type
 Share buffer is better
 Large buffer is better
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32. Thank you for attending
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