A Guide to Torque X Shaders & Materials

I've decided to learn the shader effect framework for Torque X tonight. This is not an authorative guide to Torque X shaders, just a summary of my findings in case anyone else is interested in wandering down this path. For this summary, I've posted a sample shader that simply takes a sprite on screen and turns it into black&white.


Shader Effect Code (Required)
Recap: Shader effects are implemented as HLSL code that instruct the GPU to do interesting things. Shader
effects can be created manually or with design tools, such as ATI's Render Monkey. For Torque X, the resulting HLSL code should be saved to a .fx file somewhere within the game's data folder, such as:

/data/effects/myshader.fx

This one shader (.fx) file combines the pixel shader and vertex shader code together with variable declarations at the top. XNA will compile the shader file into a .xnb file - reminder for when you edit your .txscene file.

float4x4 worldViewProjection;
texture baseTexture;
 
sampler2D baseTextureSampler = sampler_state
{
	Texture = <baseTexture>;
};
 
struct vertexshader_Input
{
	float4 position : POSITION;
    float4 color : COLOR;
	float2 texCoord : TEXCOORD0;
};
 
struct vertexshader_Output
{
	float4 position : POSITION;
    float4 color : COLOR0;
	float2 texCoord : TEXCOORD0;
};
 		
vertexshader_Output vertexshader_main(vertexshader_Input input)
{
	vertexshader_Output output;

	//pass the texture info through to the pixelshader (test)
	output.position = mul(input.position, worldViewProjection);
	output.texCoord = input.texCoord;
	output.color = input.color;

	return output;
}
 
float4 pixelshader_main(vertexshader_Output input) : COLOR
{
	//get the color
    float4 color = tex2D(baseTextureSampler, input.texCoord);
    
    //set new color range
    float intensity = (0.299 * color.r) + (0.587 * color.g) + (0.184 * color.b);
    
	//apply the black&white color value
	color = float4(intensity.xxx,color.a);
		
    return color;
}
 
technique TexturedTechnique
{
    pass P0
    {
        VertexShader = compile vs_1_1 vertexshader_main();
        PixelShader  = compile ps_1_1 pixelshader_main();
    }
}

C# Source Code (Optional)
Different shaders take different inputs from TorqueX. For each custom shader you write, you might need to create your own BaseDXEffect derrived class. Your derrived class needs to implement _LoadEffect(), _ClearEffectParameters(), _SetupEffectValues(), and Init().

DefaultEffect - lighting, bump mapping, specular mapping, and refraction (used by all scene objects added with Torque X Builder)

GenericEffect - user defined name and semantic bind support

SimpleEffect - simple rendering such as solid color or texturin

In my test, I used the GenericEffect, so that I wont need to create my own BaseDXEffect-derrived class.

Scene XML (Required)
The levelData.txscene contains the definition for the shader effect.

<Materials>
    <DefaultEffect name="OLD_GGLogoMaterial">
        <BaseTex>data/images/GGLogo.png</BaseTex>
        <Translucent>true</Translucent>
        <SpecularPower>1.000</SpecularPower>
        <SpecularColor>
            <X>1</X>
            <Y>1</Y>
            <Z>1</Z>
            <W>1</W>
        </SpecularColor>
        <EnableLighting>false</EnableLighting>
        <Additive>false</Additive>
    </DefaultEffect>
	<GenericEffect name="GGLogoMaterial">
		<Filename>data/effects/myshader.xnb</Filename>
		<EffectTextureBinds>
			<GenericEffectTextureBind>
				<BindType>Name</BindType>
				<BindAddress>baseTexture</BindAddress>
				<Value>data/images/gglogo.png</Value>
			</GenericEffectTextureBind>
		</EffectTextureBinds>
	</GenericEffect>[/b]
</Materials>

That's it. Nothing fancy, but hopefully a starting point for others to work from and maybe kick-off some interesting discussions.

John K.