Virtual Textures Dealing with Enormous Texture-Based Resources

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Anders Scheel Nielsen 1

Virtual Textures

Dealing with Enormous Texture-Based Resources

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Real life problems

Problems:

• Limited amount of resources (avg. 256 MB) • Large variation in system resources

• Maximum texture sizes from: fra 2048 x 2048 til 8192 x 8192 • Atomic Resource

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Real life problems

Problems:

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Real life problems

Problems:

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Real life problems

Problems:

Solution for ’large’ models:

• Repeating textures • Blending

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Static handling of Texture budget

Using too much memory?

• Permanently reduce the texture resolution

• Load lower mip map levels

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Static handling of Texture budget

Using too much memory?

• Permanently reduce the texture resolution

• Load lower mip map levels

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Static handling of Texture budget

Using too much memory?

• Permanently reduce the texture resolution

• Load lower mip map levels

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Static handling of Texture budget

Using too much memory?

• Permanently reduce the texture resolution

• Load lower mip map levels

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Observations

Large Textures

• All ’points’ in a surface can be truly unique

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Observations

Large Textures

• Artists can add all the details to the texture they want

Texture loading with higher granularity

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Observations

Large Textures

• Artists can add all the details to the texture they want

Load Textures Runtime:

• Artists/developers: No headaches from keeping texture budgets! • Smoother scaling for different hardware configurations

• Artists can (in theory) work in arbitrary resolution

Texture loading with higher granularity

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Calculation of visible tiles

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Barrett’s Fragment shader

1 float mipmapLevel = calcMipmapLevel(uv * textureSize);

2 float2 tilePos = floor(uv * indirectionSize);

3 tilePos /= 256.0;

4 float2 tilePos_low = frac(tilePos);

5 float2 tilePos_high = floor(tilePos);

6 color.bg = floor(tilePos_low * 256.0 + 0.5)/255.0;

7 color.r = (tilePos_high.x + tilePos_high.y * 16)/255.0;

8 color.a = (mipmapLevel + textureId * 16)/255.0;

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10 float calcTextureMipmapLevel(float2 uv) {

11 float2 dtdx = dFdx(uv);

12 float2 dtdy = dFdy(uv);

13 float2 dtex = dtdx*dtdx + dtdy*dtdy;

14 float minDelta = max(dtex.x,dtex.y);

15 float miplevel = max(0.5 * log2(minDelta), 0.0);

16 return miplevel;

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Barrett’s Fragment shader

1 float mipmapLevel = calcMipmapLevel(uv * textureSize);

2 float2 tilePos = floor(uv * indirectionSize); 3 tilePos /= 256.0;

4 float2 tilePos_low = frac(tilePos);

5 float2 tilePos_high = floor(tilePos);

6 color.bg = floor(tilePos_low * 256.0 + 0.5)/255.0;

7 color.r = (tilePos_high.x + tilePos_high.y * 16)/255.0;

8 color.a = (mipmapLevel + textureId * 16)/255.0;

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10 float calcTextureMipmapLevel(float2 uv) {

11 float2 dtdx = dFdx(uv);

12 float2 dtdy = dFdy(uv);

13 float2 dtex = dtdx*dtdx + dtdy*dtdy;

14 float minDelta = max(dtex.x,dtex.y);

15 float miplevel = max(0.5 * log2(minDelta), 0.0);

16 return miplevel;

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TD-texture

Texture usage:

• 5 texture types

• 4096 x 4096

• Usage: 80 MB

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TD-texture

Texture usage:

• 5 texture types

• 4096 x 4096

• Usage: 80 MB

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TD-texture

1 color = tex2D(tdTexture, vertexIn.uv * coordScale);

2 color.w = tex2Dbias(tdTexture, vertexIn.uv, mipBias +

Texture usage:

• 5 texture types

• 4096 x 4096

• Usage: 80 MB

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Tilbagelæsning

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Which tiles to load first?

• Screen area prioritized

• Based on error metric:

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Which tiles to discard?

• First In First Out

• Least Frequently Used • Least Recently Used

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Visual Results

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Resultater

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Diskussion

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The demo

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The demo

Virtual Textures:

• Efficient handling of giant textures:

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The demo

Virtual Textures:

Demo: 128k x 128k, theoretical: 2M x 2M (16 TB) • Texture usage for a 20 GB texture: 17 MB

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The demo

Virtual Textures:

Demo: 128k x 128k, theoretical: 2M x 2M (16 TB)

• Frame rate: 150-200 FPS (8800GT)

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Future work

Prediction of visible tiles

• Camera vector • A priori map

Virtuel Terrain

• Height map as a Virtual Texture

Other uses than games

• Browsing pictures

• Google Earth’ish applications

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Contributions

• Calculating visible tiles at greater precision with 2 lines of code

• Simple, but effective tile prediction method

• New strategies for prioritizing tiles

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Thank you!

Andreas Bærentzen

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DTU

Carsten Kjær

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Dalux

Daniel Povlsen

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Aptocore

Martin Mittring

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CryTek

GmbH

Sean Barrett

Per Rasmussen

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Media

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Reading tiles from media

• Maximizing throughput MPixels/s:

• Compression = more MPixels/s

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Reading tiles from media

• Maximizing throughput MPixels/s:

• Compression = more MPixels/s

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Reading tiles from media

• Maximizing throughput MPixels/s:

• Compression = more MPixels/s

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Reading tiles from media

• Maximizing throughput MPixels/s:

• Compression = more MPixels/s

• Texture Layout on media: minimizing seek time

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Diskussion 1

Ulemper ved metoden:

Transparente objekter

• Et ekstra prepass

Antal unikke teksturer

• Pakke flere teksturer i ét VT

• 8 bit tile-position

Kvalitetstab pga. manglende tekstur

• Højere teksturkomprimering

• Fjern visuel pops

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Diskussion 2

Hastighedstab pga. indirection

• men mindre state change • Genbrug

Filtrering

• Manuel i shader • Border padding

• Hardwareunderstøttelse

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Backup: SVT

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Tilbagelæsning

Tilbagelæsning fra grafikkort til systemhukommelse

• Grundlag for metoden er tilbagelæsning til

systemhukommelsen

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Backup: SVT

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Backup: Teksturrepetition

Introduktion Litteratur Metode Resultater Diskussion Konklusion

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Tekstur

Teksturrepetition Introduktion Litteratur Metode Resultater Diskussion Konklusion

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Teksturrepetition

Introduktion Litteratur Metode Resultater Konklusion

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Teksturrepetition

Introduktion Introduktion Litteratur Metode Resultater Konklusion

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Teksturrepetition

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Teksturrepetition

Introduktion Introduktion Litteratur Metode Resultater Konklusion

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Teksturrepetition

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Resultater: Tekstur download

Resultater Introduktion Litteratur Metode Resultater Diskussion Konklusion

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Resultater: Tekstur download

Introduktion Litteratur Metode Resultater Diskussion Konklusion