gl2 shading language

GL2 Shading LanguageGL2 Shading Language

Bill Licea-KaneBill Licea-Kane

ATI Research, Inc.ATI Research, Inc.

[email protected]@ati.com

GL2 Shading LanguageGL2 Shading LanguageBack to the futureBack to the future


““As far as generating pictures from data is As far as generating pictures from data is concerned, we feel the display processor should concerned, we feel the display processor should be a specialized device, capable only of generating be a specialized device, capable only of generating pictures from read-only representations in core.”pictures from read-only representations in core.”

Myer and Sutherland, On the Design of Display Processors.Communications of the ACM, Volume 11 Number 6, June, 1968



• June 30, 1992June 30, 1992– OpenGL 1.0 Final Draft publishedOpenGL 1.0 Final Draft published

• June 30, 1992June 30, 1992– OpenGL 1.0 Final Draft publishedOpenGL 1.0 Final Draft published



““OpenGL does not provide a programming language. OpenGL does not provide a programming language. Its function may be controlled by turning operations Its function may be controlled by turning operations on or off or specifying parameters to operations, but on or off or specifying parameters to operations, but the rendering algorithms are essentially fixed. One the rendering algorithms are essentially fixed. One reason for this decision is that, for performance reason for this decision is that, for performance reasons, graphics hardware is usually designed to reasons, graphics hardware is usually designed to apply certain operations in a specific order; replacing apply certain operations in a specific order; replacing these operations with arbitrary algorithms is usually these operations with arbitrary algorithms is usually infeasible.infeasible. Programmability would conflict with Programmability would conflict with keeping the API close to the hardware and thus with keeping the API close to the hardware and thus with the goal of maximum performance.”the goal of maximum performance.”

Segal and Akeley, Segal and Akeley, The Design of the OpenGL Graphics The Design of the OpenGL Graphics InterfaceInterface, 1994, 1994



• August 23, 1993August 23, 1993– First OpenGL 1.0 implementation First OpenGL 1.0 implementation

shipsships

• August 23, 1993August 23, 1993– First OpenGL 1.0 implementation First OpenGL 1.0 implementation

shipsships



[email protected] (William C. Archibald) writes:[email protected] (William C. Archibald) writes:

|> 1)Quite a few modern rendering techniques and renderers|> 1)Quite a few modern rendering techniques and renderers|> support shader function calls at arbitrary points|> support shader function calls at arbitrary points|> across a surface being rendered. ... What I would|> across a surface being rendered. ... What I would|> _like_ to do is call the shader at visible|> _like_ to do is call the shader at visible|> (front-facing) points. Is there _any_ way to do|> (front-facing) points. Is there _any_ way to do|> this kind of thing in OpenGL?|> this kind of thing in OpenGL?

Not with the current API. One could extend OpenGL in this Not with the current API. One could extend OpenGL in this manner...manner...

Akeley, comp.graphics.opengl posting, 13 Oct 1993Akeley, comp.graphics.opengl posting, 13 Oct 1993

GL2 Shading LanguageGL2 Shading LanguageBack to the presentBack to the present

GL2 Shading LanguageGL2 Shading LanguageBack to the presentBack to the present

• February 27, 2003February 27, 2003– arb-gl2 workgroup publishesarb-gl2 workgroup publishes

Draft OpenGL Shading LanguageDraft OpenGL Shading Language– End construction zoneEnd construction zone

• February 27, 2003February 27, 2003– arb-gl2 workgroup publishesarb-gl2 workgroup publishes

Draft OpenGL Shading LanguageDraft OpenGL Shading Language– End construction zoneEnd construction zone

GL2 Shading LanguageGL2 Shading LanguageTodayToday


• How we replace Fixed FunctionHow we replace Fixed Function• Review Shading LanguageReview Shading Language• Shading Language examplesShading Language examples• Procedural Shader demoProcedural Shader demo


OpenGLOpenGLFixed Function VertexFixed Function Vertex

TransformTransform[MVP],[MV],[MV][MVP],[MV],[MV]-T-T

LightinLightingg

[0,1][0,1]

[0,1][0,1]

TexgenTexgen TextureTextureMatrixMatrixnn

ColorColorSecondaryColSecondaryColoror

TexCoordTexCoordnn

EdgeFlagEdgeFlag

NormalNormal

Vertex Vertex (object)(object)

TexCoordTexCoordnn

EdgeFlagEdgeFlag

Vertex (eye)Vertex (eye)

Vertex (clip)Vertex (clip)

Front&BackFront&BackColorColor

Front&BackFront&BackSecondaryColSecondaryColoror

GL2 Vertex ProcessorGL2 Vertex Processor

TemporariesTemporaries

VertexVertexShaderShader

UniformUniform


TexCoordTexCoordnn

EdgeFlagEdgeFlag

NormalNormal

Vertex Vertex (object)(object)

TexCoordTexCoordnn

EdgeFlagEdgeFlag

Vertex (eye)Vertex (eye)

Vertex (clip)Vertex (clip)



GL2 Vertex ProcessorGL2 Vertex ProcessorNamesNames

VertexVertex

ClipVertexClipVertex

PositionPosition



UniformUniform


MultiTexCoorMultiTexCoorddnn

EdgeFlagEdgeFlag

NormalNormal

TexCoord[TexCoord[nn]]

EdgeFlagEdgeFlag



GL2 Vertex ProcessorGL2 Vertex ProcessorAdd Fog CoordinateAdd Fog Coordinate

VertexVertex


PositionPosition



UniformUniform


MultiTexCoorMultiTexCoorddnn

EdgeFlagEdgeFlag

NormalNormal


EdgeFlagEdgeFlag



FogCoordFogCoord FogFragCoordFogFragCoord

GL2 Vertex ProcessorGL2 Vertex ProcessorGeneralize InputGeneralize Input

AttributeAttributenn

Attribute1Attribute1



PositionPosition




UniformUniform

EdgeFlagEdgeFlag EdgeFlagEdgeFlag




……

FogFragCoordFogFragCoord

GL2 Vertex ProcessorGL2 Vertex ProcessorGeneralize OutputGeneralize Output

VaryingVaryingnn

Varying1Varying1

Varying0Varying0

Varying2Varying2

……





EdgeFlagEdgeFlag



UniformUniformClipVertexClipVertex

PositionPosition

EdgeFlagEdgeFlag

……

GL2 Vertex ProcessorGL2 Vertex ProcessorAdditional OutputAdditional Output

VaryingVaryingnn

Varying1Varying1

Varying0Varying0

Varying2Varying2……





EdgeFlagEdgeFlag



UniformUniformClipVertexClipVertex

PositionPosition

EdgeFlagEdgeFlag

PointSizePointSize

……

GL2 Vertex LimitsGL2 Vertex LimitsActive Attributes (16 Active Attributes (16

vec4)vec4)





EdgeFlagEdgeFlag



UniformUniform

EdgeFlagEdgeFlag

……

VaryingVaryingnn

Varying1Varying1

Varying0Varying0



PositionPosition

PointSizePointSize

GL2 Vertex LimitsGL2 Vertex LimitsUniform (512 words)Uniform (512 words)





EdgeFlagEdgeFlag



UniformUniform

EdgeFlagEdgeFlag

……

VaryingVaryingnn

Varying1Varying1

Varying0Varying0



PositionPosition

PointSizePointSize

GL2 Vertex LimitsGL2 Vertex LimitsVarying (32 floats)Varying (32 floats)





EdgeFlagEdgeFlag



UniformUniform

EdgeFlagEdgeFlag

……

VaryingVaryingnn

Varying1Varying1

Varying0Varying0



PositionPosition

PointSizePointSize

GL2 Vertex LimitsGL2 Vertex LimitsInstructions (Virtual)Instructions (Virtual)





EdgeFlagEdgeFlag



UniformUniform

EdgeFlagEdgeFlag

……

VaryingVaryingnn

Varying1Varying1

Varying0Varying0



PositionPosition

PointSizePointSize

GL2 Vertex LimitsGL2 Vertex LimitsTemporaries (Virtual)Temporaries (Virtual)





EdgeFlagEdgeFlag



UniformUniform

EdgeFlagEdgeFlag

……

VaryingVaryingnn

Varying1Varying1

Varying0Varying0



PositionPosition

PointSizePointSize

GL2 Vertex LimitsGL2 Vertex LimitsTexture Units (1)Texture Units (1)





EdgeFlagEdgeFlag



UniformUniform

EdgeFlagEdgeFlag

TextureTexture

……

VaryingVaryingnn

Varying1Varying1

Varying0Varying0



PositionPosition

PointSizePointSize


PositionPosition

EdgeFlagEdgeFlag

VaryingVaryingnn


PositionPosition

EdgeFlagEdgeFlag

VaryingVaryingnn

OpenGLOpenGLFixed Function Fixed Function RasterizationRasterization

PrimitivePrimitiveAssemblyAssembly

FlatshadeFlatshade

Culling orCulling orClippingClipping

FaceFaceProcessingProcessing

VaryingVaryingnn

CoordCoord

PointPointLineLine

PolygonPolygonRasterizationRasterization

Pixel Pixel RectangleRectangle

BitmapBitmapRasterizationRasterization


PositionPosition

EdgeFlagEdgeFlag

VaryingVaryingnn

RasterPosRasterPos

VaryingVaryingnn

FrontFacing

ColorColor

Coord

Depth

OpenGLOpenGLFixed Function FragmentFixed Function Fragment

TexTexnn

TETEnn

SuSumm

FogFog[0,1][0,1]

Coord

FrontFacing

ColorColor

SecondaryColSecondaryColoror


zz (|zzee|,f )

Depth

GL2 Fragment ProcessorGL2 Fragment Processor


FrontFacing

zz (|zzee|,f )

Coord

FrontFacing

ColorColor

Coord

ColorColor

SecondaryColSecondaryColoror

Depth Depth


FragmenFragmentt

ShaderShader

UniformUniform TextureTexture

GL2 Fragment ProcessorGL2 Fragment ProcessorNamesNames


FrontFacing

FogFragCoord

FragCoord

FrontFacing

FragColorFragColor

FragCoord

Color0Color0

Color1Color1

FragDepth FragDepth


FragmenFragmentt

ShaderShader


GL2 Fragment ProcessorGL2 Fragment ProcessorGeneralize InputGeneralize Input

FrontFacing

FragCoord

FrontFacing

FragColorFragColor

FragCoord

FragDepth FragDepth


FragmenFragmentt

ShaderShader


VaryingVaryingnn

Varying1Varying1

Varying0Varying0

Varying2Varying2

……

GL2 Fragment LimitsGL2 Fragment LimitsUniforms (64 words)Uniforms (64 words)

FrontFacing

FragCoord

FrontFacing

FragColorFragColor

FragCoord

FragDepth FragDepth


FragmenFragmentt

ShaderShader


VaryingVaryingnn

Varying1Varying1

Varying0Varying0

Varying2Varying2

……

GL2 Fragment LimitsGL2 Fragment LimitsVarying (32 floats)Varying (32 floats)

FrontFacing

FragCoord

FrontFacing

FragColorFragColor

FragCoord

FragDepth FragDepth


FragmenFragmentt

ShaderShader


VaryingVaryingnn

Varying1Varying1

Varying0Varying0

Varying2Varying2

……

GL2 Fragment LimitsGL2 Fragment LimitsInstructions (virtual)Instructions (virtual)

FrontFacing

FragCoord

FrontFacing

FragColorFragColor

FragCoord

FragDepth FragDepth


FragmenFragmentt

ShaderShader


VaryingVaryingnn

Varying1Varying1

Varying0Varying0

Varying2Varying2

……

GL2 Fragment LimitsGL2 Fragment LimitsTemporaries (virtual)Temporaries (virtual)

FrontFacing

FragCoord

FrontFacing

FragColorFragColor

FragCoord

FragDepth FragDepth


FragmenFragmentt

ShaderShader


VaryingVaryingnn

Varying1Varying1

Varying0Varying0

Varying2Varying2

……

GL2 Fragment LimitsGL2 Fragment LimitsTexture Units (2)Texture Units (2)

FrontFacing

FragCoord

FrontFacing

FragColorFragColor

FragCoord

FragDepth FragDepth


FragmenFragmentt

ShaderShader


VaryingVaryingnn

Varying1Varying1

Varying0Varying0

Varying2Varying2

……

GL2 Fragment LimitsGL2 Fragment LimitsFragment Output (fixed)Fragment Output (fixed)

FrontFacing

FragCoord

FrontFacing

FragColorFragColor

FragCoord

FragDepth FragDepth


FragmenFragmentt

ShaderShader


VaryingVaryingnn

Varying1Varying1

Varying0Varying0

Varying2Varying2

……

GL2 Shading LanguageGL2 Shading LanguagePreprocessor directivesPreprocessor directivesGL2 Shading LanguageGL2 Shading LanguagePreprocessor directivesPreprocessor directives

##

#define#define

#undef#undef

#if#if

#ifdef#ifdef

#ifndef#ifndef

#else#else

#elif#elif

#endif#endif

##

#define#define

#undef#undef

#if#if

#ifdef#ifdef

#ifndef#ifndef

#else#else

#elif#elif

#endif#endif

#error#error

#pragma optimize(on|off)#pragma optimize(on|off)

#pragma debug(on|off)#pragma debug(on|off)

#line line #line line filefile

__LINE____LINE__

__FILE____FILE__

__VERSION____VERSION__

// comment// comment

/* comment *//* comment */

#error#error

#pragma optimize(on|off)#pragma optimize(on|off)

#pragma debug(on|off)#pragma debug(on|off)

#line line #line line filefile

__LINE____LINE__

__FILE____FILE__

__VERSION____VERSION__

// comment// comment

/* comment *//* comment */

GL2 Shading LanguageGL2 Shading LanguageTypesTypes


• voidvoid

• float vec2 vec3 vec4float vec2 vec3 vec4

• mat2 mat3 mat4mat2 mat3 mat4

• int ivec2 ivec3 ivec4int ivec2 ivec3 ivec4

• bool bvec2 bvec3 bvec4bool bvec2 bvec3 bvec4

• samplersamplernnD samplerCube D samplerCube samplerShadowsamplerShadownnDD

• voidvoid

• float vec2 vec3 vec4float vec2 vec3 vec4

• mat2 mat3 mat4mat2 mat3 mat4

• int ivec2 ivec3 ivec4int ivec2 ivec3 ivec4

• bool bvec2 bvec3 bvec4bool bvec2 bvec3 bvec4

• samplersamplernnD samplerCube D samplerCube samplerShadowsamplerShadownnDD



• struct (with some minor restrictions)struct (with some minor restrictions)

– No qualifiersNo qualifiers

– No bit fieldsNo bit fields

– No forward referencesNo forward references

– No in-place definitionsNo in-place definitions

– No anonymous structuresNo anonymous structures

• struct (with some minor restrictions)struct (with some minor restrictions)

– No qualifiersNo qualifiers

– No bit fieldsNo bit fields

– No forward referencesNo forward references

– No in-place definitionsNo in-place definitions

– No anonymous structuresNo anonymous structures



• arrays ( with some minor restrictions)arrays ( with some minor restrictions)

– one dimensionalone dimensional

– size is integral constant expressionsize is integral constant expression

– can declare unsized array, but…can declare unsized array, but…

– specify size and type of array ONCEspecify size and type of array ONCE

– any basic type and structany basic type and struct

– NO initialization at declarationNO initialization at declaration

• arrays ( with some minor restrictions)arrays ( with some minor restrictions)

– one dimensionalone dimensional

– size is integral constant expressionsize is integral constant expression

– can declare unsized array, but…can declare unsized array, but…

– specify size and type of array ONCEspecify size and type of array ONCE

– any basic type and structany basic type and struct

– NO initialization at declarationNO initialization at declaration

GL2 Shading LanguageGL2 Shading LanguageReserved TypesReserved Types

GL2 Shading LanguageGL2 Shading LanguageReserved TypesReserved Types

• half hvec2 hvec3 hvec4half hvec2 hvec3 hvec4

• fixed fvec2 fvec3 fvec4fixed fvec2 fvec3 fvec4

• double dvec2 dvec3 dvec4double dvec2 dvec3 dvec4

• sampler2DRect sampler3DRectsampler2DRect sampler3DRect

• half hvec2 hvec3 hvec4half hvec2 hvec3 hvec4

• fixed fvec2 fvec3 fvec4fixed fvec2 fvec3 fvec4

• double dvec2 dvec3 dvec4double dvec2 dvec3 dvec4

• sampler2DRect sampler3DRectsampler2DRect sampler3DRect

GL2 Shading LanguageGL2 Shading LanguageScopeScope

GL2 Shading LanguageGL2 Shading LanguageScopeScope

• globalglobal

– outside functionoutside function

– shared globals must be same typeshared globals must be same type

• local (nested)local (nested)

– within function definitionwithin function definition

– within functionwithin function

– within compound statementwithin compound statement

• globalglobal

– outside functionoutside function

– shared globals must be same typeshared globals must be same type

• local (nested)local (nested)

– within function definitionwithin function definition

– within functionwithin function

– within compound statementwithin compound statement

GL2 Shading LanguageGL2 Shading LanguageType QualifiersType Qualifiers

GL2 Shading LanguageGL2 Shading LanguageType QualifiersType Qualifiers

• constconst

• attributeattribute

• uniformuniform

• varyingvarying

• (default)(default)

• constconst

• attributeattribute

• uniformuniform

• varyingvarying

• (default)(default)

GL2 Shading LanguageGL2 Shading LanguageOperatorsOperators


• grouping: ()grouping: ()

• array subscript: []array subscript: []

• function call and constructor: ()function call and constructor: ()

• field selector and swizzle: .field selector and swizzle: .

• postfix: ++ --postfix: ++ --

• prefix: ++ -- + - !prefix: ++ -- + - !

• grouping: ()grouping: ()

• array subscript: []array subscript: []

• function call and constructor: ()function call and constructor: ()

• field selector and swizzle: .field selector and swizzle: .

• postfix: ++ --postfix: ++ --

• prefix: ++ -- + - !prefix: ++ -- + - !



• binary: * / + -binary: * / + -

• relational: < <= > >=relational: < <= > >=

• equality: == != equality: == !=

• logical: && ^^ ||logical: && ^^ ||

• selection: ?:selection: ?:

• assignment: = *= /= += -=assignment: = *= /= += -=

• binary: * / + -binary: * / + -

• relational: < <= > >=relational: < <= > >=

• equality: == != equality: == !=

• logical: && ^^ ||logical: && ^^ ||

• selection: ?:selection: ?:

• assignment: = *= /= += -=assignment: = *= /= += -=

GL2 Shading LanguageGL2 Shading LanguageReserved OperatorsReserved Operators

GL2 Shading LanguageGL2 Shading LanguageReserved OperatorsReserved Operators

• prefix: ~ prefix: ~

• binary: %binary: %

• bitwise: << >> & ^ |bitwise: << >> & ^ |

• assignment: %= <<= >>= &= ^= |=assignment: %= <<= >>= &= ^= |=

• prefix: ~ prefix: ~

• binary: %binary: %

• bitwise: << >> & ^ |bitwise: << >> & ^ |

• assignment: %= <<= >>= &= ^= |=assignment: %= <<= >>= &= ^= |=

GL2 Shading LanguageGL2 Shading LanguageConstructorsConstructors

GL2 Shading LanguageGL2 Shading LanguageConstructorsConstructors

• float()float()

• int()int()

• bool()bool()

• vec2() vec3() vec4()vec2() vec3() vec4()

• mat2() mat3() mat4()mat2() mat3() mat4()

• float()float()

• int()int()

• bool()bool()

• vec2() vec3() vec4()vec2() vec3() vec4()

• mat2() mat3() mat4()mat2() mat3() mat4()

GL2 Shading LanguageGL2 Shading LanguageScalar ConstructorsScalar Constructors

GL2 Shading LanguageGL2 Shading LanguageScalar ConstructorsScalar Constructors

float f; int i; bool b;float f; int i; bool b;

float( b)float( b) // b=true?1.0:0.0;// b=true?1.0:0.0;

int( b)int( b) // b=true?1:0;// b=true?1:0;

bool( b)bool( b) // identity// identity

float( i)float( i) // int to float// int to float

int( i)int( i) // identity// identity

bool( i)bool( i) // i!=0?true:false;// i!=0?true:false;

float( f)float( f) // identity// identity

int( f)int( f) // float to int// float to int

bool( f)bool( f) // f!=0.0?true:false;// f!=0.0?true:false;

GL2 Shading LanguageGL2 Shading LanguageVector ConstructorsVector Constructors

GL2 Shading LanguageGL2 Shading LanguageVector ConstructorsVector Constructors

vec2 v2; vec3 v3; vec4 v4;vec2 v2; vec3 v3; vec4 v4;

vec2( 1.0 ,2.0)vec2( 1.0 ,2.0)

vec3( 0.0 ,0.0 ,1.0)vec3( 0.0 ,0.0 ,1.0)

vec4( 1.0 ,0.5 ,0.0 ,1.0)vec4( 1.0 ,0.5 ,0.0 ,1.0)

vec4( 1.0)vec4( 1.0) // all 1.0// all 1.0

vec4( v2 ,v2)vec4( v2 ,v2) // different...// different...

vec4( v3 ,1.0)vec4( v3 ,1.0) // ...types// ...types

vec2( v4)vec2( v4)

float( v4)float( v4)

GL2 Shading LanguageGL2 Shading LanguageMatrix ConstructorsMatrix Constructors

GL2 Shading LanguageGL2 Shading LanguageMatrix ConstructorsMatrix Constructors

vec4 v4; mat4 m4;vec4 v4; mat4 m4;

mat4( 1.0, 2.0, 3.0, 4.0, mat4( 1.0, 2.0, 3.0, 4.0,

5.0, 6.0, 7.0, 8.0, 5.0, 6.0, 7.0, 8.0,

9.0, 10., 11., 12., 9.0, 10., 11., 12.,

13., 14., 15., 16.) 13., 14., 15., 16.) // row major// row major

mat4( v4, v4, v4, v4)mat4( v4, v4, v4, v4)

mat4( 1.0)mat4( 1.0) // identity matrix// identity matrix

mat3( m4)mat3( m4) // upper 3x3// upper 3x3

vec4( m4)vec4( m4) // 1st column// 1st column

float( m4) float( m4) // upper 1x1// upper 1x1

GL2 Shading LanguageGL2 Shading LanguageStructure ConstructorsStructure ConstructorsGL2 Shading LanguageGL2 Shading LanguageStructure ConstructorsStructure Constructors

struct light {struct light {

float intensity;float intensity;

vec3 position;vec3 position;

}}

light headLight = light( 0.2light headLight = light( 0.2

,vec3( 0.0 ,0.0, 1.0));,vec3( 0.0 ,0.0, 1.0));

// same as// same as

light headLight;light headLight;

headLight.intensity = 0.2;headLight.intensity = 0.2;

headLight.position = vec3( 0.0 ,0.0, 1.0);headLight.position = vec3( 0.0 ,0.0, 1.0);

GL2 Shading LanguageGL2 Shading LanguageComponentsComponents

GL2 Shading LanguageGL2 Shading LanguageComponentsComponents

• component accessor for vectorscomponent accessor for vectors– xyzw rgba stpq [i]xyzw rgba stpq [i]

• component accessor for matricescomponent accessor for matrices

– [i] [i][j][i] [i][j]

• component accessor for vectorscomponent accessor for vectors– xyzw rgba stpq [i]xyzw rgba stpq [i]

• component accessor for matricescomponent accessor for matrices

– [i] [i][j][i] [i][j]

GL2 Shading LanguageGL2 Shading LanguageVector componentsVector components

GL2 Shading LanguageGL2 Shading LanguageVector componentsVector components

vec2 v2;vec2 v2;

vec3 v3;vec3 v3;

vec4 v4;vec4 v4;

v2.xv2.x // is a float// is a float

v2.zv2.z // // wrong: component undefined for typewrong: component undefined for type

v4.rgbav4.rgba // is a vec4// is a vec4

v4.stpv4.stp // is a vec3// is a vec3

v4.bv4.b // is a float// is a float

v4.xyv4.xy // is a vec2// is a vec2

v4.xgp v4.xgp // // wrong: mismatched component setswrong: mismatched component sets

GL2 Shading LanguageGL2 Shading LanguageVector components (r-Vector components (r-

value)value)

GL2 Shading LanguageGL2 Shading LanguageVector components (r-Vector components (r-

value)value)vec2 v2;vec2 v2;

vec3 v3;vec3 v3;

vec4 v4;vec4 v4;

v4.wzyxv4.wzyx // swizzles, is a vec4// swizzles, is a vec4

v4.bgrav4.bgra // swizzles, is a vec4// swizzles, is a vec4

v4.xxxxv4.xxxx // smears x, is a vec4// smears x, is a vec4

v4.xxxv4.xxx // smears x, is a vec3// smears x, is a vec3

v4.yyxxv4.yyxx // duplicates x and y, is a vec4// duplicates x and y, is a vec4

v2.yyyyv2.yyyy // // wrong: too many components for typewrong: too many components for type

GL2 Shading LanguageGL2 Shading LanguageVector components (l-Vector components (l-

value)value)

GL2 Shading LanguageGL2 Shading LanguageVector components (l-Vector components (l-

value)value)vec4 v4 = vec4( 1.0, 2.0, 3.0, 4.0);vec4 v4 = vec4( 1.0, 2.0, 3.0, 4.0);

v4.xw = vec2( 5.0, 6.0);v4.xw = vec2( 5.0, 6.0); // (5.0, 2.0, 3.0, 6.0)// (5.0, 2.0, 3.0, 6.0)

v4.wx = vec2( 7.0, 8.0);v4.wx = vec2( 7.0, 8.0); // (8.0, 2.0, 3.0, 7.0)// (8.0, 2.0, 3.0, 7.0)

v4.xx = vec2( 9.0,10.0);v4.xx = vec2( 9.0,10.0); // // wrong: x used twicewrong: x used twice

v4.yz = 11.0;v4.yz = 11.0; // // wrong: type mismatchwrong: type mismatch

v4.yz = vec2( 12.0 ); v4.yz = vec2( 12.0 ); // (8.0,12.0,12.0, 7.0)// (8.0,12.0,12.0, 7.0)

GL2 Shading LanguageGL2 Shading LanguageVector components Vector components

(array)(array)

GL2 Shading LanguageGL2 Shading LanguageVector components Vector components

(array)(array)vec4 v4 = vec4( 1.0, 2.0, 3.0, 4.0);vec4 v4 = vec4( 1.0, 2.0, 3.0, 4.0);

float f;float f;

int i;int i;

f = v4[0];f = v4[0]; // 1.0// 1.0

f = v4[3]; f = v4[3]; // 4.0// 4.0

f = v4[4]; f = v4[4]; // // undefinedundefined

// ...// ...

f = v4[i+1]; f = v4[i+1]; // defined for -1<i<3// defined for -1<i<3

GL2 Shading LanguageGL2 Shading LanguageMatrix components Matrix components

(array)(array)

GL2 Shading LanguageGL2 Shading LanguageMatrix components Matrix components

(array)(array)mat4 m4;mat4 m4;

m4[1] = vec4(2.0);m4[1] = vec4(2.0); // 2nd column = 2.0// 2nd column = 2.0

m4[0][0] = 1.0; m4[0][0] = 1.0; // upper 1x1 = 1.0// upper 1x1 = 1.0

m4[4][4] = 3.0; m4[4][4] = 3.0; // // undefinedundefined

GL2 Shading LanguageGL2 Shading LanguageComponents (arrays)Components (arrays)

GL2 Shading LanguageGL2 Shading LanguageComponents (arrays)Components (arrays)

vec3 v3[2];vec3 v3[2];

mat3 m3[2];mat3 m3[2];

v3[0]v3[0] // is a vec3// is a vec3

v3[0][0]v3[0][0] // is a float// is a float

V3[0].xV3[0].x // is a float // is a float

m3[0]m3[0] // is a mat3// is a mat3

m3[0][0]m3[0][0] // is a vec3, 1st column// is a vec3, 1st column

m3[0][0][0]m3[0][0][0] // is a float, upper 1x1// is a float, upper 1x1

// :-(// :-(

GL2 Shading LanguageGL2 Shading LanguageVector and Matrix Vector and Matrix

OperationsOperations

GL2 Shading LanguageGL2 Shading LanguageVector and Matrix Vector and Matrix

OperationsOperationsmat4 m4,n4;mat4 m4,n4;

vec4 v4vec4 v4

v4 * m4v4 * m4 // is a vec4// is a vec4

m4 * n4m4 * n4 // is a mat4// is a mat4

GL2 Shading LanguageGL2 Shading LanguageFlow-control (scalar)Flow-control (scalar)

GL2 Shading LanguageGL2 Shading LanguageFlow-control (scalar)Flow-control (scalar)

• expression ? trueExpression : expression ? trueExpression : falseExpressionfalseExpression

• if, if-elseif, if-else• for, while, do-whilefor, while, do-while• return, break, continuereturn, break, continue• discard (fragment only)discard (fragment only)

• expression ? trueExpression : expression ? trueExpression : falseExpressionfalseExpression

• if, if-elseif, if-else• for, while, do-whilefor, while, do-while• return, break, continuereturn, break, continue• discard (fragment only)discard (fragment only)

GL2 Shading LanguageGL2 Shading LanguageUser-defined functionsUser-defined functionsGL2 Shading LanguageGL2 Shading LanguageUser-defined functionsUser-defined functions

• Call by value-returnCall by value-return• in out inout keywordsin out inout keywords• Function overloadingFunction overloading• One return value (can be any type)One return value (can be any type)• Scope rules same as CScope rules same as C

• Call by value-returnCall by value-return• in out inout keywordsin out inout keywords• Function overloadingFunction overloading• One return value (can be any type)One return value (can be any type)• Scope rules same as CScope rules same as C

GL2 Shading LanguageGL2 Shading LanguageBuilt-in Vertex SpecialBuilt-in Vertex SpecialGL2 Shading LanguageGL2 Shading LanguageBuilt-in Vertex SpecialBuilt-in Vertex Special

vec4 gl_Position; vec4 gl_Position; // must be written// must be written

vec4 gl_ClipPosition; vec4 gl_ClipPosition; // may be written// may be written

float gl_PointSize; float gl_PointSize; // may be written// may be written

GL2 Shading LanguageGL2 Shading LanguageBuilt-in Fragment SpecialBuilt-in Fragment SpecialGL2 Shading LanguageGL2 Shading Language

Built-in Fragment SpecialBuilt-in Fragment Specialbool gl_FrontFacing; bool gl_FrontFacing; // may be read// may be read

float gl_FragColor; float gl_FragColor; // may be written// may be written

float gl_FragDepth; float gl_FragDepth; // may be read/written// may be read/written

float gl_FragStencil; float gl_FragStencil; // may be read/written// may be read/written

vec4 gl_FragDatavec4 gl_FragDatan; n; // may be written// may be written

vec4 gl_FragCoord; vec4 gl_FragCoord; // may be read// may be read

vec4 gl_FBColor; vec4 gl_FBColor; // may be read// may be read

float gl_FBDepth; float gl_FBDepth; // may be read // may be read

float gl_FBStencil; float gl_FBStencil; // may be read// may be read

vec4 gl_FBDatavec4 gl_FBDatan; n; // may be read// may be read

GL2 Shading LanguageGL2 Shading LanguageBuilt-in AttributesBuilt-in Attributes

GL2 Shading LanguageGL2 Shading LanguageBuilt-in AttributesBuilt-in Attributes

// Vertex Attributes, p. 19// Vertex Attributes, p. 19

attribute vec4 gl_Vertex;attribute vec4 gl_Vertex;

attribute vec3 gl_Normal;attribute vec3 gl_Normal;

attribute vec4 gl_Color;attribute vec4 gl_Color;

attribute vec4 gl_SecondaryColor;attribute vec4 gl_SecondaryColor;

attribute vec4 gl_MultiTexCoordattribute vec4 gl_MultiTexCoordnn;;

attribute float gl_FogCoord;attribute float gl_FogCoord;

GL2 Shading LanguageGL2 Shading LanguageUser-defined AttributesUser-defined AttributesGL2 Shading LanguageGL2 Shading LanguageUser-defined AttributesUser-defined Attributes

attribute vec3 myTangent;attribute vec3 myTangent;

attribute vec3 myBinormal;attribute vec3 myBinormal;

attribute float myTemperature;attribute float myTemperature;

attribute float myPressure;attribute float myPressure;

attribute float myRainfall;attribute float myRainfall;

attribute float myTime;attribute float myTime;

// etc...// etc...

GL2 Shading LanguageGL2 Shading LanguageBuilt-in ConstantsBuilt-in Constants

GL2 Shading LanguageGL2 Shading LanguageBuilt-in ConstantsBuilt-in Constants

// Implementation dependent constants// Implementation dependent constants

// Minimum Maximums// Minimum Maximums

const int gl_MaxLights = 8;const int gl_MaxLights = 8;

const int gl_MaxClipPlanes = 6;const int gl_MaxClipPlanes = 6;

const int gl_MaxTextureUnits = 2;const int gl_MaxTextureUnits = 2;

const int gl_MaxTextureCoordsARB = 2;const int gl_MaxTextureCoordsARB = 2;

// GL2 Minimum Maximums// GL2 Minimum Maximums

const int gl_MaxVertexAttributesGL2 = 16;const int gl_MaxVertexAttributesGL2 = 16;

const int gl_MaxVertexUniformWordsGL2 = 512;const int gl_MaxVertexUniformWordsGL2 = 512;

const int gl_MaxVaryingFloatsGL2 = 32;const int gl_MaxVaryingFloatsGL2 = 32;

const int gl_MaxVertexTextureUnitsGL2 = 1;const int gl_MaxVertexTextureUnitsGL2 = 1;

const int gl_MaxFragmentTextureUnitsGL2 = 2;const int gl_MaxFragmentTextureUnitsGL2 = 2;

const int gl_MaxFragmentUniformWordsGL2 = 64;const int gl_MaxFragmentUniformWordsGL2 = 64;

GL2 Shading LanguageGL2 Shading LanguageBuilt-in uniformsBuilt-in uniforms


// Matrix state, p. 31, 32, 37, 39, 40// Matrix state, p. 31, 32, 37, 39, 40

uniform mat4 gl_ModelViewMatrix;uniform mat4 gl_ModelViewMatrix;

uniform mat4 gl_ProjectionMatrix;uniform mat4 gl_ProjectionMatrix;

uniform mat4 gl_ModelViewProjectionMatrix;uniform mat4 gl_ModelViewProjectionMatrix;

uniform mat3 gl_NormalMatrix;uniform mat3 gl_NormalMatrix;

uniform mat4 gl_TextureMatrix[uniform mat4 gl_TextureMatrix[nn];];

// Normal scaling, p. 33// Normal scaling, p. 33

uniform float gl_NormalScale;uniform float gl_NormalScale;

// Depth range in window coordinates, p. 33// Depth range in window coordinates, p. 33

struct gl_DepthRangeParameters {struct gl_DepthRangeParameters {

float near; float near; // n// n

float far; float far; // f// f

float diff; float diff; // f – n// f – n

};};

uniform gl_DepthRangeParameters gl_DepthRange;uniform gl_DepthRangeParameters gl_DepthRange;



// Clip planes, p. 32// Clip planes, p. 32

uniform vec4 gl_ClipPlanes[gl_MaxClipPlanes]uniform vec4 gl_ClipPlanes[gl_MaxClipPlanes]

// Point Size, p. 66, 67// Point Size, p. 66, 67

struct gl_PointParameters {struct gl_PointParameters {

float size;float size;

float sizeMin;float sizeMin;

float sizeMax;float sizeMax;

float fadeThreshold;float fadeThreshold;

float distanceConstantAttenuation;float distanceConstantAttenuation;

float distanceLinearAttenuation;float distanceLinearAttenuation;

float distanceQuadraticAttenuation;float distanceQuadraticAttenuation;

};};

uniform gl_PointParameters gl_Point;uniform gl_PointParameters gl_Point;



// Material State, p. 50, 55// Material State, p. 50, 55

struct gl_MaterialParameters {struct gl_MaterialParameters {

vec4 emission;vec4 emission;

vec4 ambient;vec4 ambient;

vec4 diffuse;vec4 diffuse;

vec4 specular;vec4 specular;

float shininess;float shininess;

};};

uniform gl_MaterialParameters gl_FrontMaterial;uniform gl_MaterialParameters gl_FrontMaterial;

uniform gl_MaterialParameters gl_BackMaterial;uniform gl_MaterialParameters gl_BackMaterial;



// Light State, p. 50, 53, 55// Light State, p. 50, 53, 55

struct gl_LightSourceParameters {struct gl_LightSourceParameters {

vec4 ambient; vec4 ambient; // Acli // Acli

vec4 diffuse; vec4 diffuse; // Dcli // Dcli

vec4 specular; vec4 specular; // Scli // Scli

vec4 position; vec4 position; // Ppli // Ppli

vec4 halfVector; vec4 halfVector; // Derived: Hi// Derived: Hi

vec3 spotDirection; vec3 spotDirection; // Sdli // Sdli

float spotExponent; float spotExponent; // Srli // Srli

float spotCutoff; float spotCutoff; // Crli ([0.0,90.0],180.0) // Crli ([0.0,90.0],180.0)

float spotCosCutoff; float spotCosCutoff; // Derived: cos(Crli) ([1.0, 0.0],-1.0)// Derived: cos(Crli) ([1.0, 0.0],-1.0)

float constantAttenuation float constantAttenuation // K0// K0

float linearAttenuation float linearAttenuation // K1// K1

float quadraticAttenuation float quadraticAttenuation // K2// K2

};};

uniform gl_LightSourceParameters gl_LightSource[gl_MaxLights];uniform gl_LightSourceParameters gl_LightSource[gl_MaxLights];



struct gl_LightModelParameters {struct gl_LightModelParameters {

vec4 ambient; vec4 ambient; // Acs// Acs

};};

uniform gl_LightModelParameters gl_LightModel;uniform gl_LightModelParameters gl_LightModel;

struct gl_LightModelProducts {struct gl_LightModelProducts {

vec4 sceneColor; vec4 sceneColor; // Ecm + Acm * Acs// Ecm + Acm * Acs

};};

uniform gl_LightModelProducts gl_FrontLightModelProduct;uniform gl_LightModelProducts gl_FrontLightModelProduct;

uniform gl_LightModelProducts gl_BackLightModelProduct;uniform gl_LightModelProducts gl_BackLightModelProduct;

struct gl_LightProducts {struct gl_LightProducts {

vec4 ambient;vec4 ambient; // Acm * Acl // Acm * Acl

vec4 diffuse;vec4 diffuse; // Dcm * Dcl // Dcm * Dcl

vec4 specular; vec4 specular; // Scm * Scl // Scm * Scl

};};

uniform gl_LightProducts gl_FrontLightProduct[gl_MaxLights];uniform gl_LightProducts gl_FrontLightProduct[gl_MaxLights];

uniform gl_LightProducts gl_BackLightProduct[gl_MaxLights];uniform gl_LightProducts gl_BackLightProduct[gl_MaxLights];



// Texture Environment and Generation, p. 152, p. 40-42// Texture Environment and Generation, p. 152, p. 40-42

uniform vec4 gl_TextureEnvColor[gl_MaxFragmentTextureUnitsGL2];uniform vec4 gl_TextureEnvColor[gl_MaxFragmentTextureUnitsGL2];

uniform vec4 gl_EyePlaneS[gl_MaxTextureCoordsARB]uniform vec4 gl_EyePlaneS[gl_MaxTextureCoordsARB]

,gl_EyePlaneT[gl_MaxTextureCoordsARB],gl_EyePlaneT[gl_MaxTextureCoordsARB]

,gl_EyePlaneR[gl_MaxTextureCoordsARB],gl_EyePlaneR[gl_MaxTextureCoordsARB]

,gl_EyePlaneQ[gl_MaxTextureCoordsARB];,gl_EyePlaneQ[gl_MaxTextureCoordsARB];

uniform vec4 gl_ObjectPlaneS[gl_MaxTextureCoordsARB]uniform vec4 gl_ObjectPlaneS[gl_MaxTextureCoordsARB]

,gl_ObjectPlaneT[gl_MaxTextureCoordsARB],gl_ObjectPlaneT[gl_MaxTextureCoordsARB]

,gl_ObjectPlaneR[gl_MaxTextureCoordsARB],gl_ObjectPlaneR[gl_MaxTextureCoordsARB]

,gl_ObjectPlaneQ[gl_MaxTextureCoordsARB];,gl_ObjectPlaneQ[gl_MaxTextureCoordsARB];



// Fog, p. 161// Fog, p. 161

struct gl_FogParameters {struct gl_FogParameters {

vec4 color;vec4 color;

float density;float density;

float start;float start;

float end;float end;

float scale; float scale; // 1.0/(end-start)// 1.0/(end-start)

};};

uniform gl_FogParameters gl_Fog; uniform gl_FogParameters gl_Fog;

GL2 Shading LanguageGL2 Shading LanguageUser-defined uniformsUser-defined uniformsGL2 Shading LanguageGL2 Shading LanguageUser-defined uniformsUser-defined uniforms

uniform mat4 myGlobalMatrix;uniform mat4 myGlobalMatrix;

uniform vec4 myAmbient;uniform vec4 myAmbient;

uniform vec4 myDiffuseMatLight;uniform vec4 myDiffuseMatLight;

uniform vec4 mySpecularMatLight;uniform vec4 mySpecularMatLight;

uniform float myGlow;uniform float myGlow;

uniform vec4 myWarm;uniform vec4 myWarm;

uniform vec4 myCool;uniform vec4 myCool;

uniform float myCurrentTime;uniform float myCurrentTime;

// etc...// etc...

GL2 Shading LanguageGL2 Shading LanguageUniformsUniforms

Program ObjectProgram Object

gl_ModelViewMatrixgl_ModelViewMatrix

gl_NormalMatrix; gl_NormalMatrix;

myWarm;myWarm;

myCurrentTime;myCurrentTime;

// etc...// etc...


FragmenFragmentt

ShaderShader

Uniform ValuesUniform Values

GL2 Shading LanguageGL2 Shading LanguageBuilt-in varyingBuilt-in varying

GL2 Shading LanguageGL2 Shading LanguageBuilt-in varyingBuilt-in varying

varying vec4 gl_FrontColorvarying vec4 gl_FrontColor // vertex// vertex

varying vec4 gl_BackColor;varying vec4 gl_BackColor; // vertex// vertex

varying vec4 gl_FrontSecColor;varying vec4 gl_FrontSecColor; //// vertexvertex

varying vec4 gl_BackSecColor;varying vec4 gl_BackSecColor; // vertex// vertex

varying vec4 gl_Color;varying vec4 gl_Color; // fragment // fragment

varying vec4 gl_SecondaryColor;varying vec4 gl_SecondaryColor; // fragment // fragment

varying vec4 gl_TexCoord[];varying vec4 gl_TexCoord[]; // both// both

varying float gl_FogFragCoord;varying float gl_FogFragCoord; // both// both

GL2 Shading LanguageGL2 Shading LanguageUser-defined varyingUser-defined varying

GL2 Shading LanguageGL2 Shading LanguageUser-defined varyingUser-defined varying

varying vec3 myNormalPrime;varying vec3 myNormalPrime;

varying vec3 myTangentPrime;varying vec3 myTangentPrime;

varying vec3 myBinormalPrime;varying vec3 myBinormalPrime;

varying float myPressurePrime;varying float myPressurePrime;

// etc...// etc...

GL2 Built-in FunctionsGL2 Built-in FunctionsAngles and TrigonometryAngles and Trigonometry

GL2 Built-in FunctionsGL2 Built-in FunctionsAngles and TrigonometryAngles and TrigonometrygenType radians( genType degrees)genType radians( genType degrees)

genType degrees( genType radians)genType degrees( genType radians)

genType sin( genType angle)genType sin( genType angle) // radians// radians

genType cos( genType angle)genType cos( genType angle)

genType tan( genType angle)genType tan( genType angle)

genType asin( genType angle)genType asin( genType angle)

genType acos( genType angle)genType acos( genType angle)

genType atan( genType y ,genType x)genType atan( genType y ,genType x)

genType atan( genType y_over_x)genType atan( genType y_over_x)

GL2 Built-in Functions GL2 Built-in Functions Exponentials, etc.Exponentials, etc.

GL2 Built-in Functions GL2 Built-in Functions Exponentials, etc.Exponentials, etc.

genType pow( genType x ,genType y)genType pow( genType x ,genType y)

genType exp2( genType x)genType exp2( genType x)

genType log2( genType x)genType log2( genType x)

genType sqrt( genType x)genType sqrt( genType x)

genType inversesqrt( genType x)genType inversesqrt( genType x)

GL2 Built-in Functions GL2 Built-in Functions CommonCommon


genType abs( genType x)genType abs( genType x)

genType sign( genType x)genType sign( genType x)

genType floor( genType x)genType floor( genType x)

genType ceil( genType x)genType ceil( genType x)

genType fract( genType x)genType fract( genType x)



genType mod( genType x ,float y)genType mod( genType x ,float y)

genType mod( genType x ,genType y)genType mod( genType x ,genType y)

genType min( genType x ,genType y)genType min( genType x ,genType y)

genType max( genType x ,genType y)genType max( genType x ,genType y)

genType clamp( genType xgenType clamp( genType x

,float v0, float v1),float v0, float v1)

genType clamp( genType xgenType clamp( genType x

,genType v0, genType v1),genType v0, genType v1)

GL2 Built-in Functions GL2 Built-in Functions InterpolationsInterpolations


// return x*( 1.0-a) + y*a// return x*( 1.0-a) + y*a

genType mix( genType x ,genType y ,float a)genType mix( genType x ,genType y ,float a)

genType mix( genType x ,genType y ,genType a)genType mix( genType x ,genType y ,genType a)

// x <= edge ? 0.0 : 1.0// x <= edge ? 0.0 : 1.0

genType step( float edge ,genType x)genType step( float edge ,genType x)

genType step( genType edge ,genType x)genType step( genType edge ,genType x)



// genType t;// genType t;

// t = (x-edge0)/(edge1-edge0);// t = (x-edge0)/(edge1-edge0);

// t = clamp( t, 0.0, 1.0);// t = clamp( t, 0.0, 1.0);

// return t*t*(3.0-2.0*t);// return t*t*(3.0-2.0*t);

genType smoothstep( float edge0genType smoothstep( float edge0

,float edge1,float edge1

,genType x),genType x)

genType smoothstep( genType edge0genType smoothstep( genType edge0

,genType edge1,genType edge1

,genType x),genType x)

GL2 Built-in Functions GL2 Built-in Functions GeometricGeometric

GL2 Built-in Functions GL2 Built-in Functions GeometricGeometric

float length( genType x)float length( genType x)

float distance( genType p0 ,genType p1)float distance( genType p0 ,genType p1)

float dot( genType x ,genType y)float dot( genType x ,genType y)

vec3 cross( vec3 x ,vec3 y)vec3 cross( vec3 x ,vec3 y)

genType normalize( genType x)genType normalize( genType x)

genType faceforward( genType NgenType faceforward( genType N

,genType I,genType I

,genType Nref),genType Nref)

genType reflect( genType IgenType reflect( genType I

,genType N),genType N)

GL2 Built-in FunctionsGL2 Built-in FunctionsMatrixMatrix

GL2 Built-in FunctionsGL2 Built-in FunctionsMatrixMatrix

mat matrixCompMult( mat x ,mat y)mat matrixCompMult( mat x ,mat y)

GL2 Built-in FunctionsGL2 Built-in FunctionsVector RelationalVector Relational

GL2 Built-in FunctionsGL2 Built-in FunctionsVector RelationalVector Relational

bGenType lessThan( genType x ,genType y)bGenType lessThan( genType x ,genType y)

bGenType lessThanEqual( genType xbGenType lessThanEqual( genType x

,genType y),genType y)

bGenType greaterThan( genType x ,genType y)bGenType greaterThan( genType x ,genType y)

bGenType greaterThanEqual( genType xbGenType greaterThanEqual( genType x

,genType y),genType y)

bGenType equal( genType x ,genType y)bGenType equal( genType x ,genType y)

bGenType notEqual( genType x , genType y)bGenType notEqual( genType x , genType y)

bGenType not( genType x)bGenType not( genType x)

bool any( bGenType x)bool any( bGenType x)

bool all( bGenType x)bool all( bGenType x)

GL2 Built-in FunctionsGL2 Built-in FunctionsTextureTexture

GL2 Built-in FunctionsGL2 Built-in FunctionsTextureTexture

vec4 texture1D( sampler1D samplervec4 texture1D( sampler1D sampler

,float coord ,float coord ,float bias,float bias))


,vec2 coord ,vec2 coord ,float bias,float bias))


,vec3 coord,vec3 coord ,float bias ,float bias))

vec4 textureCube( samplerCube samplervec4 textureCube( samplerCube sampler


GL2 Built-in Functions GL2 Built-in Functions TextureTexture


vec4 texture1DProj( sampler1D samplervec4 texture1DProj( sampler1D sampler





,vec4 coord,vec4 coord ,float bias ,float bias))

vec4 textureCubeProj( samplerCube samplervec4 textureCubeProj( samplerCube sampler


GL2 Built-in Functions GL2 Built-in Functions ShadowShadow

GL2 Built-in Functions GL2 Built-in Functions ShadowShadow

vec4 shadow1D( samplerShadow1D samplervec4 shadow1D( samplerShadow1D sampler


vec4 shadow2D( samplerShadow2D samplervec4 shadow2D( samplerShadow2D sampler


vec4 shadow1DProj( samplerShadow1D samplervec4 shadow1DProj( samplerShadow1D sampler


vec4 shadow2DProj( samplerShadow2D samplervec4 shadow2DProj( samplerShadow2D sampler


GL2 Built-in FunctionsGL2 Built-in FunctionsVertexVertex

GL2 Built-in FunctionsGL2 Built-in FunctionsVertexVertex

vec4 ftransform()vec4 ftransform()

// Example usage:// Example usage:

gl_Position = ftransform();gl_Position = ftransform();

GL2 Built-in Functions GL2 Built-in Functions FragmentFragment

GL2 Built-in Functions GL2 Built-in Functions FragmentFragment

genType dFdx( genType p)genType dFdx( genType p)

genType dFdy( genType p)genType dFdy( genType p)

genType fwidth( genType p)genType fwidth( genType p)

GL2 Built-in FunctionsGL2 Built-in FunctionsNoiseNoise

GL2 Built-in FunctionsGL2 Built-in FunctionsNoiseNoise

float noise1( genType coord)float noise1( genType coord)

vec2 noise2( genType coord)vec2 noise2( genType coord)



GL2 Trivial ExampleGL2 Trivial ExampleVertex ShaderVertex Shader

GL2 Trivial ExampleGL2 Trivial ExampleVertex ShaderVertex Shader

varying vec3 Normal;varying vec3 Normal; // output// output

#define MVP gl_ModelViewProjectionMatrix#define MVP gl_ModelViewProjectionMatrix

#define MV gl_ModelViewMatrix#define MV gl_ModelViewMatrix

#define MV_IT gl_NormalMatrix#define MV_IT gl_NormalMatrix

void main( void) void main( void) // Vertex Shader// Vertex Shader

{{

gl_Position = MVP * gl_Vertex;gl_Position = MVP * gl_Vertex;

//gl_ClipVertex = MV * gl_Vertex;//gl_ClipVertex = MV * gl_Vertex;

Normal = normalize( MV_IT * gl_Normal);Normal = normalize( MV_IT * gl_Normal);

}}

GL2 Trivial ExampleGL2 Trivial ExampleFragment ShaderFragment Shader

GL2 Trivial ExampleGL2 Trivial ExampleFragment ShaderFragment Shader

varying vec3 Normal;varying vec3 Normal; // input // input

uniform vec3 LightColor;uniform vec3 LightColor; // Light Color// Light Color

uniform vec3 LightPos;uniform vec3 LightPos; // Light Position// Light Position

void main( void) void main( void) // Fragment Shader// Fragment Shader

{{

vec3 color = LightColor;vec3 color = LightColor;

color *=color *=

max(0.0,dot(normalize(Normal),LightPos));max(0.0,dot(normalize(Normal),LightPos));

gl_FragColor = vec4( color,1.0);gl_FragColor = vec4( color,1.0);

}}

GL2 ToyBall ExampleGL2 ToyBall ExampleVertex ShaderVertex Shader

GL2 ToyBall ExampleGL2 ToyBall ExampleVertex ShaderVertex Shader

varying vec4 v_ObjPos;varying vec4 v_ObjPos;

varying vec4 v_EyePos;varying vec4 v_EyePos;

void main( void) void main( void) // Vertex Shader // Vertex Shader

{ {

vec4 ObjPos;vec4 ObjPos;

vec4 EyePosvec4 EyePos

ObjPos = gl_Vertex;ObjPos = gl_Vertex;

gl_Position = gl_ModelViewProjectionMatrix * ObjPos;gl_Position = gl_ModelViewProjectionMatrix * ObjPos;

v_ObjPos = ObjPos;v_ObjPos = ObjPos;

EyePos = gl_ModelViewMatrix * ObjPos;EyePos = gl_ModelViewMatrix * ObjPos;

v_EyePos = EyePos;v_EyePos = EyePos;

}}

GL2 ToyBall ExampleGL2 ToyBall ExampleFragment ShaderFragment Shader


varying vec4 v_EyePos;varying vec4 v_EyePos;

varying vec4 v_ObjPos;varying vec4 v_ObjPos;

uniform vec4 myLightDir; uniform vec4 myLightDir; // NOTA BENE: please normalize// NOTA BENE: please normalize

uniform vec4 myEyeDir; uniform vec4 myEyeDir; // (0.0, 0.0, 1.0, 0.0)// (0.0, 0.0, 1.0, 0.0)

uniform vec4 myHVector;uniform vec4 myHVector;

uniform vec4 myEyeCenter;uniform vec4 myEyeCenter;



uniform vec4 mySpecularColor;uniform vec4 mySpecularColor;

uniform vec4 myRed, myYellow, myBlue;uniform vec4 myRed, myYellow, myBlue;

uniform vec4 myHalfSpace0;uniform vec4 myHalfSpace0;





uniform vec4 toyBallConst; uniform vec4 toyBallConst; // (-3.0, 0.4, 0.0, 0.0)// (-3.0, 0.4, 0.0, 0.0)

uniform vec4 one;uniform vec4 one;

uniform float myFWidth;uniform float myFWidth;



void main( void) void main( void) // Fragment Shader // Fragment Shader

{{

vec4 NNormal;vec4 NNormal;

vec4 P; vec4 P; // The point in shader space// The point in shader space

vec4 SurfColor;vec4 SurfColor;

float Intensity;float Intensity;

vec4 PDistance;vec4 PDistance;

float InOrOut;float InOrOut;

P = v_ObjPos; P = v_ObjPos; // Analytically calculate P// Analytically calculate P

P.w = 0.0;P.w = 0.0;

P = normalize( P);P = normalize( P);

P.w = 1.0;P.w = 1.0;



InOrOut = toyBallConst.x;InOrOut = toyBallConst.x;

PDistance.x = dot( P, myHalfSpace0); PDistance.x = dot( P, myHalfSpace0); // Fig 1// Fig 1

PDistance.y = dot( P, myHalfSpace1); PDistance.y = dot( P, myHalfSpace1); // Fig 2// Fig 2

PDistance.z = dot( P, myHalfSpace2); PDistance.z = dot( P, myHalfSpace2); // Fig 3// Fig 3

PDistance.w = dot( P, myHalfSpace3); PDistance.w = dot( P, myHalfSpace3); // Fig 4// Fig 4

PDistance = smoothstep( -myFWidth, myFWidth, PDistance);PDistance = smoothstep( -myFWidth, myFWidth, PDistance);

InOrOut += dot( PDistance, one);InOrOut += dot( PDistance, one);

PDistance.x = dot( P, myHalfSpace4); PDistance.x = dot( P, myHalfSpace4); // Fig 5// Fig 5

PDistance.y = toyBallConst.y - abs( P.z);PDistance.y = toyBallConst.y - abs( P.z);

PDistance = smoothstep( -myFWidth, myFWidth, PDistance);PDistance = smoothstep( -myFWidth, myFWidth, PDistance);



InOrOut += PDistance.x; InOrOut += PDistance.x; // Fig 1// Fig 1

InOrOut = clamp( InOrOut, 0.0, 1.0); InOrOut = clamp( InOrOut, 0.0, 1.0); // Fig 2// Fig 2

SurfColor = mix( myYellow, myRed, InOrOut); SurfColor = mix( myYellow, myRed, InOrOut); // Fig 3// Fig 3

SurfColor = mix( SurfColor, myBlue, PDistance.y ); SurfColor = mix( SurfColor, myBlue, PDistance.y ); // Fig 4// Fig 4



////

// Analytically calculate the sphere NNormal in eye coordinates// Analytically calculate the sphere NNormal in eye coordinates

NNormal = v_EyePos – myEyeCenter;NNormal = v_EyePos – myEyeCenter;

NNormal = normalize( NNormal);NNormal = normalize( NNormal);

////

// Per fragment diffuse lighting// Per fragment diffuse lighting

Intensity = 0.2; // ambientIntensity = 0.2; // ambient

Intensity += clamp( dot( myLightDir, NNormal), 0.0, 1.0) * 0.8;Intensity += clamp( dot( myLightDir, NNormal), 0.0, 1.0) * 0.8;

SurfColor *= Intensity; SurfColor *= Intensity; // Fig 1// Fig 1



////

// Per fragment specular lighting// Per fragment specular lighting

Intensity = clamp( dot( myHVector, NNormal), 0.0, 1.0);Intensity = clamp( dot( myHVector, NNormal), 0.0, 1.0);

Intensity = pow ( Intensity, mySpecularColor.a);Intensity = pow ( Intensity, mySpecularColor.a);

SurfColor += mySpecularColor * Intensity; SurfColor += mySpecularColor * Intensity; // Fig 1// Fig 1

SurfColor.a = 1.0;SurfColor.a = 1.0;

gl_FragColor = SurfColor;gl_FragColor = SurfColor;

}}

GL2 ToyBall DemoGL2 ToyBall DemoGL2 ToyBall DemoGL2 ToyBall Demo

GL2 Shading LanguageGL2 Shading LanguageQuestions?Questions?

GL2 Shading LanguageGL2 Shading LanguageQuestions?Questions?

• How we replace Fixed FunctionHow we replace Fixed Function• Review Shading LanguageReview Shading Language• Trivial Shading Language exampleTrivial Shading Language example• Procedural Shader demoProcedural Shader demo

• [email protected]@ati.com

• How we replace Fixed FunctionHow we replace Fixed Function• Review Shading LanguageReview Shading Language• Trivial Shading Language exampleTrivial Shading Language example• Procedural Shader demoProcedural Shader demo

• [email protected]@ati.com

gl2 shading language

Documents

1994gl2 shading languageback

1968gl2 shading languageback

1993gl2 shading languageback

opengl graphics interface

graphics hardware

certain operations

arbitrary points

arbitrary algorithms