2007

2 0 0 8

2008 1

i

...................................................................................................

I ........................................................................................................ 1

1.1 ..................................................................................... 1

1.1.1 ................................................ 1

1.1.1.1 .................................................... 3

1.1.2 ............................................................................. 6

1.1.3 ...................................................... 8

1.2 ..................................................................................... 10

II ............................................................................................... 12

2.1 ..................................................................................... 12

2.1.1 .............................................................................. 12

2.1.2 .................................................................... 14

2.2 ..................................................................................... 15

2.2.1 ............................................................... 15

2.2.2 ............................................................ 16

III .................... 18

3.1 ..................................................................... 18

3.1.1 ......................................................................... 20

3.1.2 .............................................................................. 21

3.1.3 .................................................................. 23

IV ..................... 25

4.1 ....................................................................... 25

4.1.1 .................................................................................. 26

4.2 ......................................................................... 29

V ......................................................................................... 32

5.1 ................................ 32

5.2 ..................... 36

VI ...................................................................................................... 40

ii

6.1 ......................................................... 40

6.2 ............................................... 40

.................................................................................................... 42

ABSTRACT.............................................................................................. 47

iii

1-1 ................................... 3

1-2 ..................................................... 5

1-3 LOD ................................ 8

1-4 .............................................................................. 9

3-1 ............................................................................ 19

3-2 ................................................................ 21

3-3 ............................................................................. 22

3-4 ...................................................... 24

4-1 ...................................................................... 27

5-1 ......................................................................... 33

5-2 ..................................................... 34

5-3 ................................................. 35

5-4 .......................................................... 36

5-5 .............................................................................. 38

5-6 .......................................................... 39

iv

5-1 ............................................................

34

5-2 ............................................................ 37

4-1 ..................................................................

28

4-2 ........................................................... 31

4-1 ......................................................................................... 29

v

(GPU)

(rasterization) CAD

(visibility culling)

(shadow map) .

CAD

,

(arrangement) .

,

(directed distance field) GPU ,

(fast marching method)

(outer envelope) .

(self-shadow)

GPU (occlusion query) (ray-tracing)

.

3

CAD , 70%

, nVIDIA GeForce 7900GX2 Dual

vi

AMD Athlon 64 2.6GHz PC 6.5 .

1024 1024 (height map)

nVIDIA GeForce 6800 AMD Athlon 64 2.2GHz PC 7.32

.

1

I

1.1

1.1.1

,

(animation), (virtual reality)

. 3

. 3

(GPU)

, GPU

. PC GPU

TV,

, .

3 3 .

(application stage), (geometry stage),

(rasterization stage)[35].

, 3D .

2

(transformation) . (primitive)

.

(frame buffer)

.

1990 1 GPU

. 1990 2000 2 GPU

. 2000 3 GPU

(pixel shader)

(vertex shader) .

GPU

. GPU

cg[35], HLSL[36], GLSL[37] C

(shading language) ( 1-1).

(unified shader) GPU

[38].

3

1-1

1.1.1.1

GPU

, (interpolation) , (texture)

.

(fragment) . 1-2 GPU

. (scissor test)

.

(alpha test) .

4

.

.

(stencil test) . (stencil buffer)

. (depth test, Z test) .

(depth buffer)

.

, ,

. GPU

(occlusion query) .

.

. GL_LEQUAL

0 (occluder)

.

0 , .

(color buffer)

(alpha blending) .

5

(depth buffering)

.

1-2

6

1.1.2

, ,

.

.

(model simplification)[11], LOD(level of detail) [14],

(visibility culling)[16] .

.

CAD CAD

,

.

.

,

.

7

.

.

, [15].

8

1.1.3

(terrain) , , GIS(geographic information

system), (flight simulation)

.

2 .

.

LOD

[41] . LOD

( 1-

3).

1-3

LOD [41]

9

,

( 1-4)[19].

(shadow map)[20], (ray-

tracing)[28,29], (shadow polygon)[30], (shadow

volume)[31] .

.

.

.

1-4

. () ()

[39]

10

1.2

GPU

.

CAD

. , GPU

(bounding box)

,

.

.

,

.

. ,

GL_GREATER

. 1

11

.

(image precision) .

.

cg

.

12

II

2.1

2.1.1

(visibility)

, , [3].

[16].

,

.

.

. (back-face culling)

, (viewing-

frustum culling) .

[2,13].

(potentially visible set, PVS) [6,18]. PVS

13

(conservative visibility) .

PVS

[5]. PVS

[4],

[7], [8] .

3

[1,9,17,18].

Ernst [15]

3 .

,

.

Monte Carlo

,

.

14

2.1.2

(open cell) (decomposition)

[10].

, 3 ( log +

log ) [10].

(vertical decomposition) ,

, , Davenport-Schinzel .

3

.

15

2.2

Woo

[19]. (image

precision method) (object presicion method)

.

2.2.1

(depth image)

[20].

GPU [21,22].

(aliasing)

. (edge) ,

(perspective aliasing) (projective aliasing)

[23].

. . Reeves

(percentage closer-filtering)

[24]. Brabec

16

[25].

(adaptive shadow map) [26].

.

[27].

(perspective

shadow map) [23].

(ray-

tracing) . PCs

[28,29].

GPU

[38].

2.2.2

. Blinn

(shadow polygon)

17

[30].

.

(shadow volume)

[31].

.

. BSP

[32,33].

. Heidmann

[34].

18

III

GPU

.

CAD

.

, GPU ,

.

, .

3.1

( 3-1).

19

.

.

,

[12].

3 .

1 GPU

. 2

3-1

: 5 2

c1, c2, c3, c4 .

, .

20

.

3

, .

3.1.1

(distance field) 3 ( )

, .

(directed distance field)

x-, x+, y-, y+, z-, z+ .

,

2 .

,

. GPU

2 . ,

( 3-2).

21

2

.

,

.

3.1.2

,

.

3-2

: A

D

A .

B A

.

22

/ .

(front) (front

propagation) ( 3-3).

3

, ' (K)',

' (T)', ' (F)' ,

.

T. /

, .

:

3-3

23

1.

K . P .

2. P Q . Q K

, P P Q

. P Q

. Q Q

. Q .

3. 1-2

.

/ .

3.1.3

,

/ ( 3-3).

.

( 3-4),

.

24

4

.

,

,

.

3-4

: A, C

.

25

IV

GPU

.

.

GPU

.

. 1

GPU

,

. 2

.

4.1

,

26

. (directional light),

(spot light), (point light)

.

4.1.1

,

.

(

4-1). GPU

.

.

GL_LEQUAL 0

(occluder) .

0 ,

.

GL_GREATER

27

. 1

.

( 4-1).

4-1

: A C

. B

h

.

28

glDepthMask(GL_FALSE);

glDepthFunc(GL_GREATER);

for (int X=0; X < MAP_SIZE; X += STEP_SIZE )

for (int Y=0; Y < MAP_SIZE; Y += STEP_SIZE )

{

int x, y, z;

x = X;

y = Y;

z = Height(pHeightMap, X, Y );

glBeginOcclusionQueryNV(occlusionQueries[0]);

glBegin (GL_LINES);

glVertex3i(x, y, z);

glVertex3f( lightPosition[0], lightPosition[1], lightPosition[2] );

glEnd();

glEndOcclusionQueryNV();

glGetOcclusionQueryuivNV(occlusionQueries[0],

GL_PIXEL_COUNT_NV, &pixelCount);

if(pixelCount >= 1) fprintf(opFile_shadow, "%d\n", 1);

else if (pixelCount == 0 ) fprintf(opFile_shadow, "%d\n", 0);

}

glDepthMask(GL_TRUE);

glDepthFunc(GL_LEQUAL);

4-1

:

.

29

4.2

. (diffuse)

(specular)

( 4-1).

= + +

= + + ( )

ambient intensity

N surface normal L light source direction

H = (L+V)/|L+V|

V view direction

4-1

3D cg

(cg vertex program)

( 4-4).

30

void VertexLight(float4 position : POSITION,

float3 normal : NORMAL,

out float4 oPosition : POSITION,

out float4 color : COLOR,

uniform float4x4 modelViewProj,

uniform float3 globalAmbient,

uniform float3 lightColor,

float3 lightPosition,

float3 eyePosition,

float3 Ka,

float3 Kd,

float 3 Ks,

float shininess )

{

oPosition = mul(modelViewProj, position);

float3 P = position.xyz;

float3 N = normal;

float3 ambient = Ka * globalAmbient;

float3 L = normalize(lightPosition - P);

float diffuseLight = max(dot(N, L), 0);

float3 diffuse = Kd * lightColor * diffuseLight;

float3 V = normalize(eyePosition - P);

float3 H = normalize(L + V);

float specularLight = pow(max(dot(N, H), 0), shininess);

if (diffuseLight

31

color.xyz = ambient + diffuse + specular;

color.w = 1;

}

4-2

: Kd

Ks , (ambient)

.

32

V

GPU

.

, , .

5.1

Microsoft

Visual C++.Net OpenGL, OpenSG , nVIDIA

GeForce 7900 GX2 Dual AMD Athlon 64 2.6GHz

PC .

( 5-1).

33

5-1

. (). 247 , 3 ().

7177 , 2 7

5-2, 5-3 ,

, (

) . 247

, 3

128 175 71%

. 7177 , 2 7

64

5915 82% ( 5-1).

34

(247 ,

3 )

128 175 71% 3.42 0.05

256 170 69% 6.59 0.10

(7177 ,

2 7 )

64 5915 82% 1.85 0.05

128 4611 64% 4.26 0.40

5-1

5-2

. () 64 ()

128

35

5-3

.

. () 128 () 128

() 256

36

5.2

Microsoft Visual

C++.Net OpenGL , cg ,

nVIDIA GeForce 6800 AMD Athlon 64 2.2GHz

PC .

256 256, 512 512, 1024 1024 (

5-4).

5-4

5-5, 5-6 ,

, , ,

37

. 256 256

0.50 , 512 512 1.81 , 1024 1024

7.32 CPU

5 ( 5-2).

CPU

GPU

256 2.39 0.50

512 9.56 1.81

1024 38.24 7.32

5-2

0

10

20

30

40

50

256 512 1024

(

)

GPU

CPU

38

5-5

. () () ()

39

5-6

. () () (

) ()

40

VI

6.1

.

(visibility ordering) .

GPU

.

.

6.2

GPU

, CPU

41

.

(view frustum culling) ,

(vertex buffer object) (shadow ray

optimization), (multi-resolution)

.

42

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46

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47

ABSTRACT

This dissertation addresses how one can exploit the fast rasterization

and visibility functions available in graphics hardware (GPU) for efficient

visibility culling for large CAD model and shadow generation for a large

terrain model.

The goal of our visibility culling is to remove the invisible triangles of a

CAD model, consisting of millions of triangles, when the camera is located

outside of the given model. We pose this problem as arrangement

computation, and the arrangement of the given model is approximated by

generating the directed distance field of the given model by using GPU

and finding the outer envelope by fast marching method. From our

experimentation, we could cull away more than 70% of hidden geometry

by using our algorithm, taking 6.3 seconds on nVIDIA GeForce 7900GX2

for a large CAD model consisting of three millions of triangles.

Furthermore, we also compute shadow map for a large terrain model by

combining ray tracing with GPU-supported occlusion query. The shadow

map generation took 7.31 seconds for 10242 height map on nVIDIA

GeForce 6800.

48

,

.

, , , , ,

, , , , ,

, , .

, , , ,

,

.

Virtual Builders

, VB .

,

, , VR ,

.

,

, .

, .

49

, . ...

, .

.

. .