From VFXPedia

Parent Class: None

The ViewShader object encapsulates a Cg shader program string, and a number of exposed, run-time parameters. It should be created by the ScriptViewShader:SetupShader() function, and is freed automatically when ScriptViewShader:FreeShader() is called. The created ViewShader is passed to ScriptViewShader:SetupParams() every redraw so that any run-time parameters can be set.

Details on programming Cg shaders can be found at nVidia's developer site.

Contents 1 Constructor: 2 Methods: 3 Members: 4 Example: 5 The Shader String 5.1 Methods: 5.2 Examples 5.3 See Also: 5.4 Tips for ViewShader (edit)

Constructor:

ViewShader

Constructs a new ViewShader object

Methods:

AddParam	Exposes a run-time parameter in the shader
SetParam	Sets the value of a run-time parameter

Members:

Name	The name of the ViewShader-derived struct
String	The Cg shader program string
Len	The length of the shader program string
ParamName	A table of run-time parameter names

Example:

Example of constructing a ViewShader object from a Cg program in "shaderstring":

local vs = ViewShader("GammaFuse", shaderstring)

The Shader String

The Cg shader string used to construct a ViewShader object consists of a definition of a struct derived from the ViewShader baseclass. This struct must contain a ViewShader member object called 'source', and must implement the ShadePixel() function. It can also contain other data members, which may be exposed with AddParam and set with SetParam.

Methods:

ShadePixel

Called to process each pixel

Examples

This is an example of a simple gamma shader program:

shaderstring = [[
 
struct GammaFuse : ViewShader
{
    ViewShader source;	                        // need this line
    float gamma;                                // run-time parameter
 
    void ShadePixel(inout FuPixel f)            // required ShadePixel() function
    {
        source.ShadePixel(f);                   // get source pixel
 
        f.Color.rgb = pow(f.Color.rgb, gamma);  // apply simple gamma
    }
};
 
]]

See Also:

• FuPixel
• ScriptViewShader:SetupShader()
• ScriptViewShader:SetupParams()

Tips for ViewShader (edit)

EyeonTips:Script/Reference/Applications/Fuse/Classes/ViewShader