Transcript PowerPoint Template

Graphics
Using Vertex Shader in
DirectX 8.1
강신진
2002. 02. 05
cgvr.korea.ac.kr
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Graphics Lab @ Korea University
Overview
CGVR

What is Vertex Programming?
 Vertex Programming Assembly Language
 Sample Programs

Instruction Set
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Graphics Lab @ Korea University
Graphics
What is Vertex
Programming?
Part 1
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Graphics Lab @ Korea University
Traditional Rendering Pipeline

CGVR
Traditional Graphics Pipeline
transform &
lighting
setup
rasterizer
texture
blending
frame-buffer
anti-aliasing
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Graphics Lab @ Korea University
Vertex Shader Rendering
Pipeline
transform &
lighting
CGVR
Vertex
Program
setup
rasterizer
texture
blending
SetVertexShader()
frame-buffer
anti-aliasing
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Switch from standard T&L mode
to
Vertex Program mode
Graphics Lab @ Korea University
What is Possible?
CGVR

Complete control of transform and lighting HW
 Complex vertex operations accelerated in HW
 Custom vertex lighting
 Custom skinning and blending
 Custom texture coordinate generation
 Custom texture matrix operations
 Custom vertex computations of your choice
 Offloading vertex computations frees up CPU
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Graphics Lab @ Korea University
What is Possible?

CGVR
Custom transform, lighting, and skinning
Directional Light
Keyframe Interpolation
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Bump Point Lighting
Graphics Lab @ Korea University
Vertex Programming
Conceptual Overview
Vertex
Attributes
CGVR
Program
Parameters
16x4 registers
Vertex
Program
128 instructions
Read-only
96x4 registers
Temporary
Registers
Read/Write-able
12x4 registers
Vertex
Output
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Graphics Lab @ Korea University
Vertex Programming
Conceptual Overview
Vertex Attribute
Registers
CGVR
Program
Parameter
Registers
v[0] v[1] … v[15]
r
Vertex
Program
w
Vertex Result
Registers
oPos, oD0
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r
c[0] c[1] … c[95]
r/w
Temporary
Registers
R0 R1 … R10 R11
A0.x
Address Register
Graphics Lab @ Korea University
Sample Code

CGVR
Position & Constant Color
reg c0
reg c4-7
reg c8
reg v0
reg v5
= (0,0.5,1.0,2.0)
= WorldViewProj matrix
= constant color
= position ( 4x1 vector )
= diffuse color
const char SimpleVertexShader0[] =“
vs.1.0
//Shader version 1.0
m4x4 oPos , v0, c4
//emit projected position
mov oD0, c8
//Diffuse color = c8”
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Graphics Lab @ Korea University
What is Vertex Programming?

CGVR
Vertex Program





Assembly language interface to T&L unit
GPU instruction set to perform all vertex math
Reads an untransformed, unlit vertex
Creates a transformed vertex
Optionally creates




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Lights a vertex
Creates texture coordinates
Creates fog coordinates
Creates point sizes
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Graphics Lab @ Korea University
What is Vertex Programming?

CGVR
Vertex Program

Does not create or delete vertices


No topological information provided


1 vertex in and 1 vertex out
No edge, face, nor neighboring vertex info
Dynamically loadable
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Graphics Lab @ Korea University
Graphics
Vertex Programming
Assembly Language
Part 2
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Graphics Lab @ Korea University
Assembly Language Format
CGVR
Instruction Format:
Opcode
Instruction
name
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dst, [-]s0 [,[-]s1 [,[-]s2]]; #comment
Destination Source0
Register
Register
14
Source1
Register
Source2
Register
Graphics Lab @ Korea University
Assembly Language Format
CGVR
Instruction Format:
Opcode
Instruction
name
dst, [-]s0 [,[-]s1 [,[-]s2]]; #comment
Destination Source0
Register
Register
Source2
Register
R1
Example:
MOV
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Source1
Register
15
r1, r2
R2
x
y
z
w
x
y
z
w
Graphics Lab @ Korea University
Assembly Example
CGVR
Simple Example:
MOV
R1, R2;
before
R1
0.0
0.0
0.0
0.0
after
R2
x
y
7.0
z
3.0
6.0
w
2.0
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R1
x
y
7.0
z
3.0
6.0
w
2.0
R2
x
y
7.0
z
3.0
6.0
w
2.0
x
y
z
w
Graphics Lab @ Korea University
Assembly Example
CGVR
Source registers can be negated:
MOV
R1, -R2;
before
R1
0.0
0.0
0.0
0.0
after
R2
x
y
7.0
z
3.0
6.0
w
2.0
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R1
x
y
-7.0
z
-3.0
-6.0
w
-2.0
R2
x
y
7.0
z
3.0
6.0
w
2.0
x
y
z
w
Graphics Lab @ Korea University
Masking
CGVR
Destination register can mask which components
are written to…
R1

write all components
R1.x

write only x component
R1.xw

write only x, w components
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Graphics Lab @ Korea University
Masking
CGVR
Destination register masking:
MOV
R1.xw, -R2;
before
R1
0.0
0.0
0.0
0.0
after
R2
x
y
7.0
z
3.0
6.0
w
2.0
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R1
x
y
-7.0
z
0.0
0.0
w
-2.0
R2
x
y
7.0
z
3.0
6.0
w
2.0
x
y
z
w
Graphics Lab @ Korea University
All Instructions
CGVR
There are 17 instructions in total
• ARL
• MOV
• MUL
• ADD
• MAD
• RCP
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• RSQ
• DP3
• DP4
• DST
• MIN
• MAX
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• SLT
• SGE
• EXP
• LOG
• LIT
Graphics Lab @ Korea University
Graphics
Sample Program
Part 3
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Graphics Lab @ Korea University
Vertex Shader Frame Work in
DX 8.1






CGVR
Step 1: Declare the vertex data
Step 2: Design the shader functionality
Step 3: Check for vertex shader support
Step 4: Declare the shader registers
Step 5: Create the shader
Step 6: Render the output pixels
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Graphics Lab @ Korea University
Vertex Shader Frame Work in
DX 8.1






CGVR
Step 1: Declare the vertex data
Step 2: Design the shader functionality
Step 3: Check for vertex shader support
Step 4: Declare the shader registers
Step 5: Create the shader
Step 6: Render the output pixels
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Graphics Lab @ Korea University
Step 1

CGVR
Declare the vertex data
struct CUSTOMVERTEX { FLOAT x, y, z; DWORD diffuseColor; };
#define D3DFVF_CUSTOMVERTEX
(D3DFVF_XYZ|D3DFVF_DIFFUSE)
CUSTOMVERTEX g_Vertices[]= {
{ -1.0f, -1.0f, 0.0f, 0xffff0000 },
{ +1.0f, -1.0f, 0.0f, 0xff00ff00 },
{ +1.0f, +1.0f, 0.0f, 0xff0000ff },
{ -1.0f, +1.0f, 0.0f, 0xffffff00 }, };
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Graphics Lab @ Korea University
Vertex Shader Frame Work in
DX 8.1






CGVR
Step 1: Declare the vertex data
Step 2: Design the shader functionality
Step 3: Check for vertex shader support
Step 4: Declare the shader registers
Step 5: Create the shader
Step 6: Render the output pixels
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Graphics Lab @ Korea University
Basic Instruction (Step 2)
CGVR
DP3: Three-Component Dot Product
Function:
Computes the three-component (x,y,z) dot
product of two source vectors and replicates the
result across the destination register.
Syntax:
DP3
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dest, src0, src1;
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Graphics Lab @ Korea University
Basic Instruction (Step 2)
CGVR
DP3 Example:
DP3
R1, R6, R6;
before
after
R1
R6
R1
R6
0.0
3.0
14.0
3.0
z
0.0
0.0
2.0
1.0
z
14.0
14.0
2.0
1.0
w
0.0
1.0
w
14.0
1.0
x
y
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x
y
Graphics Lab @ Korea University
Sample Code – 1 (Step 2)

CGVR
Position & Diffuse Color
reg c0
reg c4-7
reg c8
reg v0
reg v5
= (0,0.5,1.0,2.0)
= WorldViewProj matrix
= constant color
= position ( 4x1 vector )
= diffuse color
const char SimpleVertexShader1[] =“
vs.1.0
//Shader version 1.0
dp4 oPos.x , v0, c4
//emit projected x position
dp4 oPos.y , v0, c5
//emit projected y position
dp4 oPos.z , v0, c6
//emit projected z position
dp4 oPos.w , v0, c7
//emit projected w position
mov oD0, v5
//Diffuse color = vertex color ”
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Graphics Lab @ Korea University
Sample Code – 2 (Step 2)

CGVR
Position & Texture
reg c0
reg c4-7
reg c8
reg v0
reg v5
reg v7
= (0,0.5,1.0,2.0)
= WorldViewProj matrix
= constant color
= position ( 4x1 vector )
= diffuse color
= texcoords ( 2x1 vector )
const char SimpleVertexShader2[] =“
vs.1.0
//Shader version 1.0
dp4 oPos.x , v0, c4
//emit projected x position
dp4 oPos.y , v0, c5
//emit projected y position
dp4 oPos.z , v0, c6
//emit projected z position
dp4 oPos.w , v0, c7
//emit projected w position
mov oT0.xy , v7
//copy texcoords”
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Graphics Lab @ Korea University
Sample Code – 3 (Step 2)

CGVR
Position & Lighting
reg c0
reg c4-7
reg c8
reg v0
reg v5
reg v7
= (0,0.5,1.0,2.0)
= WorldViewProj matrix
= constant color
= position ( 4x1 vector )
= diffuse color
= texcoords ( 2x1 vector )
const char SimpleVertexShader3[] =
vs.1.0
//Shader version 1.0
dp4 oPos.x, v0, c4
//emit projected x position
dp4 oPos.y, v0, c5
//emit projected y position
dp4 oPos.z, v0, c6
//emit projected z position
dp4 oPos.w, v0, c7
//emit projected w position
dp3 r0.x,
v3, c12
//N dot L in world space
mul oD0, r0.x , v5
//Calculate color intensity
mov oT0.xy , v7
//copy texcoords
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Graphics Lab @ Korea University
Vertex Shader Frame Work in
DX 8.1






CGVR
Step 1: Declare the vertex data
Step 2: Design the shader functionality
Step 3: Check for vertex shader support
Step 4: Declare the shader registers
Step 5: Create the shader
Step 6: Render the output pixels
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Graphics Lab @ Korea University
Step 3

CGVR
Check for vertex shader support
D3DCAPS8 caps;
m_pd3dDevice->GetDeviceCaps(&caps);
if( D3DSHADER_VERSION_MAJOR( caps.VertexShaderVersio
n ) < 1 ) return E_FAIL;
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Graphics Lab @ Korea University
Vertex Shader Frame Work in
DX 8.1






CGVR
Step 1: Declare the vertex data
Step 2: Design the shader functionality
Step 3: Check for vertex shader support
Step 4: Declare the shader registers
Step 5: Create the shader
Step 6: Render the output pixels
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Graphics Lab @ Korea University
Step 4

CGVR
Declare the shader registers
DWORD dwDecl[] = { D3DVSD_STREAM(0),
D3DVSD_REG(D3DVSDE_POSITION, D3DVSDT_FLOAT3),
D3DVSD_REG( D3DVSDE_DIFFUSE, D3DVSDT_D3DCOLOR ),
D3DVSD_END() };
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Graphics Lab @ Korea University
Vertex Shader Frame Work in
DX 8.1






CGVR
Step 1: Declare the vertex data
Step 2: Design the shader functionality
Step 3: Check for vertex shader support
Step 4: Declare the shader registers
Step 5: Create the shader
Step 6: Render the output pixels
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Graphics Lab @ Korea University
Step 5

CGVR
Create the shader
TCHAR strPath[512];
LPD3DXBUFFER pCode;
DXUtil_FindMediaFile( strPath, _T("VertexShader.vsh") );
D3DXAssembleShaderFromFile( strPath, 0, NULL, &pCode,
NULL );
m_pd3dDevice->CreateVertexShader( dwDecl, (DWORD*)pCode>GetBufferPointer(), &m_hVertexShader, 0 )))
pCode->Release();
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Graphics Lab @ Korea University
Vertex Shader Frame Work in
DX 8.1






CGVR
Step 1: Declare the vertex data
Step 2: Design the shader functionality
Step 3: Check for vertex shader support
Step 4: Declare the shader registers
Step 5: Create the shader
Step 6: Render the output pixels
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Graphics Lab @ Korea University
Step 6

CGVR
Render the output pixels
m_pd3dDevice->SetVertexShaderConstant( 0, &mat, 4 );
float color[4] = {0,1,0,0};
m_pd3dDevice->SetVertexShaderConstant( 4, &color, 1 );
m_pd3dDevice->SetStreamSource( 0, m_pQuadVB,
sizeof(CUSTOMVERTEX) );
m_pd3dDevice->SetVertexShader( m_hVertexShader );
m_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLEFAN, 0, 2 );
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Graphics Lab @ Korea University
Demo Program
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CGVR
Graphics Lab @ Korea University
Performance
CGVR
For Optimal performance
• Be clever
• Exploit vector parallelism
• (Ex. 4 scalar adds with a vector add)
• Swizzle and negate away
• (no performance penalty for doing so)
• Use LIT and DST effectively
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Graphics Lab @ Korea University
Summary – Vertex Programs

Increased programmability




CGVR
Customizable engine for transform, lighting,
texture coordinate generation, and more.
Facilitates setup for per-fragment shading.
Allows animation/deformation through key-frame
interpolation and skinning.
Accelerated in Future Generation GPUs

Offloads CPU tasks to GPU yielding higher
performance.
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Graphics Lab @ Korea University
Graphics
The Instruction Set
Appendix
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Graphics Lab @ Korea University
All Instructions
CGVR
There are 17 instructions in total
• ARL
• MOV
• MUL
• ADD
• MAD
• RCP
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• RSQ
• DP3
• DP4
• DST
• MIN
• MAX
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• SLT
• SGE
• EXP
• LOG
• LIT
Graphics Lab @ Korea University
RCP
CGVR
RCP: Reciprocal
Function:
Inverts the value of the source and replicates
the result across the destination register.
Syntax:
RCP dest, src0.C;
where ‘C’ is x, y, z, or w
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Graphics Lab @ Korea University
RCP
CGVR
RCP Example:
RCP
R1, R2.w;
before
after
R1
R2
R1
R2
0.0
7.0
0.5
7.0
z
0.0
0.0
3.0
6.0
z
0.5
0.5
3.0
6.0
w
0.0
2.0
w
0.5
2.0
x
y
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x
y
Graphics Lab @ Korea University
RSQ
CGVR
RSQ: Reciprocal Square Root
Function:
Computes the inverse square root of the
absolute value of the source scalar and replicates
the result across the destination register.
Syntax:
RSQ dest, src0.C;
where ‘C’ is x, y, z, or w
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Graphics Lab @ Korea University
RSQ
CGVR
RSQ Example:
RSQ
R1.x, R5.x;
before
after
R1
R5
R1
R5
0.0
-4.0
0.5
-4.0
z
0.0
0.0
3.0
7.0
z
0.0
0.0
3.0
7.0
w
0.0
9.0
w
0.0
9.0
x
y
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x
y
Graphics Lab @ Korea University
SLT
CGVR
SLT: Set On Less Than
Function:
Performs a component-wise assignment of
either 1.0 or 0.0. 1.0 is assigned if the value
of the first source is less than the value of the
second. Otherwise, 0.0 is assigned.
Syntax:
SLT
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dest, src0, src1;
48
Graphics Lab @ Korea University
SLT
CGVR
SLT Example:
SLT
R1, R2, R3;
before
after
R1
R2
R3
0.0
7.0
2.0
z
0.0
0.0
3.0
6.0
2.1
5.0
w
0.0
2.0
7.0
x
y
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R1
R2
R3
0.0
7.0
2.0
z
0.0
0.0
3.0
6.0
2.1
5.0
w
1.0
2.0
7.0
x
y
Graphics Lab @ Korea University
LIT
CGVR
LIT: Light Coefficients
Function:
Computes ambient, diffuse, and specular
lighting coefficients from a diffuse dot product, a
specular dot product, and a specular power.
Assumes:
src0.x = diffuse dot product
src0.y = specular dot product
src0.w = power
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(N • L)
(N • H)
(m)
Graphics Lab @ Korea University
LIT
CGVR
LIT: Light Coefficients
Syntax:
LIT dest, src0
Result:
dest.x = 1.0
dest.y = CLAMP(src0.x, 0, 1)
= CLAMP(N • L, 0, 1)
dest.z = (see next slide…)
dest.w = 1.0
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(ambient coeff.)
(diffuse coeff.)
(specular coeff.)
Graphics Lab @ Korea University
LIT
CGVR
LIT: Light Coefficients
Result:
(Recall: src0.x  N • L)
if ( src0.x > 0.0 )
dest.z = (MAX(src0.y,0))(ECLAMP(src0.w,-128,128))
= (MAX(N • H,0))m
where m in (-128,128)
otherwise,
dest.z = 0.0
(dest.z is specular coeff. as defined by OpenGL)
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Graphics Lab @ Korea University
LIT
CGVR
LIT Example:
LIT
R1, R7;
before
after
R1
R7
R1
R7
0.0
0.3
1.0
0.3
z
0.0
0.0
0.8
0.0
(specular) z
0.3
0.64
0.8
0.0
w
0.0
2.0
w
1.0
2.0
x
y
(ambient) x
(diffuse) y
(Good to 8+ bits)
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Graphics Lab @ Korea University