source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/shaders/treeanimation.cg @ 3046

/***********************************************/
/*     Vertex shaders for tree animation       */
/***********************************************/


struct vtxin
{
        float4 position: POSITION;
        float4 normal: NORMAL;
        
        float4 color: COLOR;
        //float4 color1: COLOR1;

        float4 texCoord: TEXCOORD0;
};

// vtx output
struct vtxout
{
        float4 position: POSITION;
        float4 texCoord: TEXCOORD0;    

        float4 color: COLOR0;  
        //float4 color1: COLOR1;  
        float4 eyePos: TEXCOORD1; // eye position
        float4 normal: TEXCOORD2;
};


/** Vertex shader which conducts an simple tree animation
        that bends the tree depending quadratically on the height
*/
vtxout animateVtx(vtxin IN,
                                  uniform float3 windDir,
                                  uniform float windStrength,
                                  uniform float frequency,
                                  uniform float2 minMaxPos,
                                  uniform float timer,
                                  uniform float3 lightDir)
{
        vtxout OUT;
        OUT.texCoord = IN.texCoord;
                
        const float pos = (minMaxPos.x - IN.position.z) / (minMaxPos.x - minMaxPos.y);
        float factor = pos * pos * windStrength * sin(timer * frequency);

        // transform the vertex position into post projection space
        OUT.position = mul(glstate.matrix.mvp, IN.position);
        // displace the input position
        OUT.position += float4(factor * windDir, 0);

        OUT.normal = normalize(mul(glstate.matrix.invtrans.modelview[0], IN.normal));
        //const float3 l = normalize(mul(glstate.matrix.modelview[0], float4(lightDir, 0))).xyz;
        const float3 l = normalize(lightDir);

        const float dif = max(.0f, dot(OUT.normal.xyz, l));

        //OUT.color.xyz = IN.color.xyz * max(0, dot(OUT.normal.xyz, normalize(lightDir)));
        OUT.color = glstate.material.ambient + glstate.material.front.diffuse * dif;
        OUT.color.w = IN.color.w;
        return OUT;
}

/** vertex shader which provides an simple tree animation
        that bends the tree depending quadratically on the height using vertex displacement.
        This version of the shader is used for deferred shading and thus only 
        displaces the vertices and outputs the color, put does not do any shading.
*/
vtxout animateVtxMrt(vtxin IN,
                                         uniform float3 windDir,
                                         uniform float windStrength,
                                         uniform float frequency,
                                         uniform float2 minMaxPos,
                                         uniform float timer)
{
        vtxout OUT;

        OUT.color = IN.color;
        OUT.texCoord = IN.texCoord;
                
        const float pos = (minMaxPos.x - IN.position.z) / (minMaxPos.x - minMaxPos.y);
        float factor = pos * pos * windStrength * sin(timer * frequency);

        // transform the vertex position into post projection space
        OUT.position = mul(glstate.matrix.mvp, IN.position);
        // displace the input position
        OUT.position += float4(factor * windDir, 0);

        // transform the vertex position into eye space
        OUT.eyePos = mul(glstate.matrix.modelview[0], IN.position);
        OUT.eyePos += float4(factor * windDir, 0);

        OUT.normal = mul(glstate.matrix.invtrans.modelview[0], IN.normal);
        
        return OUT;
}