学步园

最近开始学CG，在OGRE官网中的shader有一些教程。看完Getting Started With Ogre CG Materials后能简单的写一些CG程序。

首先设置材质

// CG Vertex shader definition
vertex_program PlainTexture_VS cg            
{
        // Look in this source file for shader code
    source GameObjStandard.cg
        // Use this function for the vertex shader            
    entry_point main_plain_texture_vp    
        // Compile the shader to vs_1_1 format    
    profiles vs_1_1                    
 
    // This block saves us from manually setting parameters in code
        default_params                    
    {
                // Ogre will put the worldviewproj into our 'worldViewProj' parameter for us.
        param_named_auto worldViewProj worldviewproj_matrix        
                // Note that 'worldViewProj' is a parameter in the cg code.
    }
}
 
// CG Pixel shader definition
fragment_program PlainTexture_PS cg            
{
        // Look in this source file for shader code
    source GameObjStandard.cg        
        // Use this function for the pixel shader    
    entry_point main_plain_texture_fp    
        // Compile to ps_1_1 format    
    profiles ps_1_1                    
}
 
material PlainTexture
{
        // Material has one technique
    technique                    
    {
                // This technique has one pass
        pass                    
        {
                        // Make this pass use the vertex shader defined above
            vertex_program_ref PlainTexture_VS    
            {
            }
                        // Make this pass use the pixel shader defined above
            fragment_program_ref PlainTexture_PS    
            {
            }
            texture_unit
            {
                                // This pass will use this 2D texture as its input
                texture Ten.png 2d        
            }
        }
    }
}

上面材质设完之后开始CG程序

void main_plain_texture_vp(
        // Vertex Inputs
        float4 position        : POSITION,    // Vertex position in model space
        float2 texCoord0    : TEXCOORD0,    // Texture UV set 0
 
        // Outputs
        out float4 oPosition    : POSITION,    // Transformed vertex position
        out float2 uv0        : TEXCOORD0,    // UV0
 
        // Model Level Inputs
        uniform float4x4 worldViewProj)
{
    // Calculate output position
    oPosition = mul(worldViewProj, position);
 
    // Simply copy the input vertex UV to the output
    uv0 = texCoord0;
}
 
void main_plain_texture_fp(
        // Pixel Inputs
        float2 uv0        : TEXCOORD0,    // UV interpolated for current pixel
 
        // Outputs
        out float4 color    : COLOR,    // Output color we want to write
 
        // Model Level Inputs
        uniform sampler2D texture)        // Texture we're going to use
{
    // Just sample texture using supplied UV
    color = tex2D(texture, uv0);
}
 
 
 
The keyword uniform identifies the parameters you will have to supply in the material file. 


Some parameters can be supplied by the Ogre Engine (param_named_auto), like a light position. 
Some parameters can be supplied by your material file (param_named) like a texture map. 
Some parameters can be supplied by your application (custom). 

CG中 关键字 uniform  需要在材质中提供 或者在材质中设置param_named_auto colorModulate custom 1索引
然后在 ogre 中设置参数setCustomParameter(1, value)  
编译CG程序
 设置cgc的工作路径
cd "C:\Path\to\my\cg\file" 
然后
cgc -entry yourMainFP -profile ps_2_0 yourFile.cg

or 
cgc -entry yourMainVP -profile vs_1_1 yourFile.cg