9.3. The Shader Object

A Shader object is a container of shading techniques.

9.3.1. Constructor

A Shader object can be constructed with the GraphicsDevice.createShader function.

9.3.2. Methods

9.3.2.1. getTechnique

Summary

Returns the requested shader technique.

Syntax

var techniqueByName = shader.getTechnique('blinn');
var techniqueByIndex = shader.getTechnique(1);

Returns a Technique object. Techniques can be requested by name or by index from zero to shader.numTechniques minus one. Returns a Technique object if the requested name or index exists, null otherwise. It is recommended to request techniques once at loading time and to store them somewhere else rather than to request them continuously.

9.3.2.2. getParameter

Summary

Returns the requested shader parameter information.

Syntax

var parameterInfoByName = shader.getParameter('lightColor');
var parameterInfoByIndex = shader.getParameter(1);

var parameterName = parameterInfoByIndex.name;
var parameterType = parameterInfoByIndex.type;
var parameterNumRows = parameterInfoByIndex.rows;
var parameterNumColumns = parameterInfoByIndex.columns;

Parameters can be requested by name or by index from zero to shader.numParameters minus one.

Returns a shader parameter information object if the requested name or index exists, null otherwise.

9.3.3. Properties

9.3.3.1. name

Summary

The name of the shader object, usually the path to the CgFX file that originated the shader definition used to create the shader.

Syntax

var shaderName = shader.name;

Note

Read Only

9.3.3.2. numTechniques

Summary

The number of shading techniques contained on the Shader object.

Syntax

var numTechniquesShader = shader.numTechniques;

Note

Read Only

9.3.3.3. numParameters

Summary

The number of shading parameters used by the techniques on the Shader object.

Syntax

var numParametersShader = shader.numParameters;

Note

Read Only

9.4. The Technique Object

A shading technique. This object is required to perform any geometry rendering.

9.4.1. Common Properties

9.4.1.1. name

Summary

The name of the shading technique.

Syntax

var techniqueName = technique.name;

Note

Read Only

9.4.2. Shading Properties

Shading techniques require shading parameters to be set before any effective rendering can be done, for example the vertex program could require the world transformation matrix and the view-projection one, whilst the fragment program may require a material color or a light position.

This shading properties can be modified by grouping them on a TechniqueParameters object to be set all at once by graphicsDevice.setTechniqueParameters, or one by one directly on the Technique object. The later method is recommended only when a handful of properties need to be changed between draw calls, for example:

graphicsDevice.setTechnique(sharedTechnique);

graphicsDevice.setTechniqueParameters(sharedTechniqueParameters);

var renderable, n;
for (n = 0; n < numRenderables; n += 1)
{
    renderable = renderables[n];

    sharedTechnique.world = renderable.worldMatrix;

    graphicsDevice.setStream(renderable.vertexBuffer, renderable.semantics);

    graphicsDevice.setIndexBuffer(renderable.indexBuffer);

    graphicsDevice.drawIndexed(renderable.primitive, renderable.numIndices);
}

The name of the shading property will be the name of the uniform variable used on the shading programs.

Valid types for shading properties are:

• Numbers

• Arrays of numbers

  • It is highly recommended to use those created by the MathDevice object.

• TechniqueParameterBuffer objects

• Texture objects

• Booleans

Setting a property directly onto a Technique object will cause the plugin to crash if the parameter is unsupported by the Technique. Be careful of this when debugging shaders as the compiler will remove any unused parameters from Techniques.