Multiple Techniques

An effect file defines the techniques used. The basic layout of an effect file starts with one or more declarations and then defines each technique for that effect. This sample shows a basic effect file that contains two textures and two techniques. This effect file allows a device that doesn't support single-pass rendering for two textures to use multiple passes to render the textures.

// Declare two textures.
texture tex0;        // First texture
texture tex1;        // Second texture

// Technique 't0' will render the scene in one pass.  The color 
// for each pixel is calculated to be tex0 + tex1.  Because it uses 
// two textures at once, it will work only on cards that support 
// multitexture.

technique t0
{
    pass p0
    {
        Texture[0] = <tex0>;
        ColorOp[0] = SelectArg1;
        ColorArg1[0] = Texture;
 
        Texture[1] = <tex1>;
        ColorOp[1] = Add;
        ColorArg1[1] = Texture;
        ColorArg2[1] = Current;
		        
        ColorOp[2] = Disable;
    }
}

// Technique 't1' renders the scene in two passes.  The first pass sets 
// each pixel to the color of tex0.  The second pass adds in the color 
// of tex1.  The result should look identical to the first 
// technique.  However, this technique can be used on cards that do not 
// support multitexture.
 
technique t1
{
    pass p0
    {
        AlphaBlendEnable = False;
 
        Texture[0] = <tex0>;
        
        ColorOp[0] = SelectArg1;
        ColorArg1[0] = Texture;
        ColorOp[1] = Disable;
    }
 
    pass p1
    {
        AlphaBlendEnable = True;
        SrcBlend = One;
        DestBlend = One;
 
        Texture[0] = <tex1>;
 
        ColorOp[0] = SelectArg1;
		
        ColorArg[0] = Texture;
        ColorOp[1] = Disable;
    }
}

This example shows the basic syntax and layout of a typical effect file.

//
// Sample Effect
// This effect adds two textures, using single pass or multipass technique.
//

texture tex0;
texture tex1;


// Single pass

technique t0
{
    pass p0
    {
        Texture[0] = <tex0>;
        Texture[1] = <tex1>;
        
        ColorOp[0] = SelectArg1;
        ColorArg1[0] = Texture;
        
        ColorOp[1] = Add;
        ColorArg1[1] = Texture;
        ColorArg2[1] = Current;
        
        ColorOp[2] = Disable;
    }
}

// Multipass

technique t1
{
    pass p0
    {
        Texture[0] = <tex0>;
        
        ColorOp[0] = SelectArg1;
        ColorArg1[0] = Texture;
        ColorOp[1] = Disable;  
    }
    
    pass p1
    {
        AlphaBlendEnable = True;        
        SrcBlend = One;
        DestBlend = One;
 
        Texture[0] = <tex1>;
               
        ColorOp[0] = SelectArg1;
        ColorArg1[0] = Texture;
        ColorOp[1] = Disable;  
    }
}