Effect States

Effect states are used to initialize pipeline states in preparation for vertex and pixel processing.

effect state [ [index] ] = expression;

Where:

• effect state - Similar to the traditional fixed function pipeline states. A complete list of states is provided below.
• [ [index] ] - Optional integer index. The index identifies a particular state within an array of effect states. The outer brackets indicate that an index is optional. If an index is used, be sure to use the inner brackets.
• expression - State assignment expression. See Expressions.

Each state has a native data type. This is the data type that the state expects values to be in when the effect assigns them. The data types that each state expects are listed below.

Note that the effect interface will attempt to cast values to the appropriate type as early as possible. Literal values can be cast at compile time. Non-literals (i.e. regular variables) need to be cast when the appropriate Set methods are called. For example, the effect interface will cast values set using ID3DXBaseEffect::SetBool, ID3DXBaseEffect::SetValue, and other similar functions if necessary. For better performance ensure that the values passed to the effect interface are already the correct type and will not need casting. If the runtime is unable to cast a value, an error is returned.

Effect states can be broken up into the following categories:

• Light States
• Material States
• Render States
  • Pixel Pipe Render States
  • Vertex Pipe Render States
• Sampler States
• Sampler Stage States
• Shader States
• Shader Constant States
• Texture States
• Texture Stage States
• Transform States

Light States

To enable the best performance for applying an effect, all components of a light or a material should be specified in the effect file. States that you fail to declare are set to some default value because there is no way for Direct3D to set light states individually.

Example:

LightEnable[0] = TRUE;
LightType[0] = POINT;
LightPosition[0] = float3<10.0f, 1.0f, 23.0f>;
LightAmbient[0] = float4<0.7f, 0.0f, 0.0f, 1.0f>;

This will enable lighting, make point lighting the type, set the light postion to float3<10.0f, 1.0f, 23.0f>, and set the ambient color to float4<0.7f, 0.0f, 0.0f, 1.0f>.

Material States

States that you fail to declare are set to some default value because there is no way for Direct3D to set material states individually.

Example:

MaterialDiffuse = float4<0.7f, 0.0f, 0.0f, 1.0f>;
MaterialPower = 3.0f;

This will set the diffuse color to float4<0.7f, 0.0f, 0.0f, 1.0f> and make the power of the material 3.0f.

Render States

There are two types of render states:

• Pixel Pipe Render States
• Vertex Pipe Render States

Pixel Pipe Render States

Effect file render states have names similar to the fixed function pipeline states, often with the prefix removed.

Example:

AlphaBlendEnable = TRUE;
FillMode = WIREFRAME;

This will enable alpha blending and make all geometries render in wireframe.

Vertex Pipe Render States

Effect file render states have names similar to the fixed function pipeline states, often with the prefix removed.

Example:

Ambient = float4<0.7f, 0.0f, 0.0f, 1.0f>;
CullMode = CCW;
FogColor = 0xff0000;

This will make the ambient color float4<0.7f, 0.0f, 0.0f, 1.0f>, set the backface culling mode to counter-clockwise, and set the fog color to red.

Sampler States

A sampler state represents a sampler object.

Sampler Stage States

Sampler stage states are used to sample textures. Sampler state determines filtering types and texture addressing modes.

Example:

AddressU[0] = CLAMP;
AddressV[0] = CLAMP;
AddressW[0] = CLAMP;

This clamps UVW values to be in between 0 and 1.

Shader States

There are only two effect shader states: one associated with a vertex shader object and the other associated with a pixel shader object.

Example:

VertexShader = compile vs_1_1 VSTexture();
PixelShader  = NULL;

This will compile VSTexture, a vertex shader defined earlier in the .fx file, to the vertex shader version 1.1, and then set that compiled shader as the vertex shader. The pixel shader is assigned to null.

Shader Constant States

Shader constant states are used to access shader constant parameters.

Texture States

Texture states initialize textures used by the multitexture blender.

Texture Stage States

Texture stage states set up textures and the texture stages in the multitexture blender.

Transform States

Set transform states to initialize transformation matrices. Effects use transposed matrices for efficiency. You can provide transposed matrices to an effect, or an effect will automatically transpose the matrices before using them.