// Desc: Vertex blending vertex shader. Supports meshes with 2-4 bone
// influences per vertex. We can dynamically set NumVertInfluences
// so that the shader knows how many weights it is processing
// per vertex. In order to support dynamic loops, we must use
// at least vertex shader version 2.0.
//
////////////////////////////////////////////////////////////////////////////

extern float4x4 WorldViewProj;
extern float4x4 FinalTransforms[35];
extern texture Tex;
extern int NumVertInfluences = 2; // <--- Normally set dynamically.

sampler S0 = sampler_state
{
Texture = <Tex>;
MinFilter = LINEAR;
MagFilter = LINEAR;
MipFilter = LINEAR;
};

struct VS_OUTPUT
{
float4 pos : POSITION0;
float2 texCoord : TEXCOORD;
float4 diffuse : COLOR0;
};

VS_OUTPUT VertexBlend(float4 pos : POSITION0,
float2 texCoord : TEXCOORD0,
float4 weights : BLENDWEIGHT0,
int4 boneIndices : BLENDINDICES0)
{

VS_OUTPUT output = (VS_OUTPUT)0;

float4 p = float4(0.0f, 0.0f, 0.0f, 1.0f);
float lastWeight = 0.0f;
int n = NumVertInfluences-1;
for(int i = 0; i < n; ++i)
{
lastWeight += weights[i];
p += weights[i] * mul(pos, FinalTransforms[boneIndices[i]]);
}
lastWeight = 1.0f - lastWeight;

p += lastWeight * mul(pos, FinalTransforms[boneIndices[n]]);

p.w = 1.0f;

output.pos = mul(p, WorldViewProj);
output.texCoord = texCoord;
output.diffuse = float4(1.0f, 1.0f, 1.0f, 1.0f);

return output;
}

technique VertexBlendingTech
{
pass P0
{
vertexShader = compile vs_2_0 VertexBlend();
Sampler[0] = <S0>;

Lighting = true;
}
}