struct VertexData{
    float4 position:POSITION;
    float4 texcoord:TEXCOORD0;
    float4 normal:NORMAL;
    float4 tangent:TANGENT;
};

struct VSOut{
    float4 position:SV_POSITION;
    float4 normal:NORMAL;
    float4 texcoord:TEXCOORD0;
};

static const float PI=3.141592;
cbuffer globalConstants:register(b0){
    float4 misc;
};

Texture2D T_DiffuseTexture:register(t0);
SamplerState samplerState:register(s0);

struct MaterialData{
    float r;
};
StructuredBuffer<MaterialData> materialData:register(t0,space1);
cbuffer DefaultVertexCB:register(b1){
    float4x4 ProjectionMatrix;
    float4x4 ViewMatrix;
    float4x4 ModelMatrix;
    float4x4 IT_ModelMatrix;
    float4x4 ReservedMemory[1020];
};

VSOut MainVS(VertexData inVertexData){
    VSOut vo;
    vo.normal=mul(IT_ModelMatrix,inVertexData.normal);
    float4 positionWS=mul(ModelMatrix,inVertexData.position);
    float4 positionVS=mul(ViewMatrix,positionWS);
    vo.position=mul(ProjectionMatrix,positionVS);
    //vo.position=float4(positionWS.xyz+vo.normal.xyz*sin(misc.x)*0.2f,1.0f);
    vo.texcoord=inVertexData.texcoord;
    return vo;
}

[maxvertexcount(4)]
void MainGS(triangle VSOut inPoint[3],uint inPrimitiveID:SV_PrimitiveID,
    inout TriangleStream<VSOut> outTriangleStream){
    outTriangleStream.Append(inPoint[0]);
    outTriangleStream.Append(inPoint[1]);
    outTriangleStream.Append(inPoint[2]);
    /*VSOut vo;
    float3 positionWS=inPoint[0].position.xyz;
    float3 N=normalize(inPoint[0].normal.xyz);
    vo.normal=float4(N,0.0f);
    float3 helperVec=abs(N.y)>0.999?float3(0.0f,0.0f,1.0f):float3(0.0f,1.0f,0.0f);
    float3 tangent=normalize(cross(N,helperVec));//u
    float3 bitangent=normalize(cross(tangent,N));//v
    float scale=materialData[inPrimitiveID].r;

    
    float3 p0WS=positionWS-(bitangent*0.5f-tangent*0.5f)*scale;//left bottom
    float4 p0VS=mul(ViewMatrix,float4(p0WS,1.0f));
    vo.position=mul(ProjectionMatrix,p0VS);
    vo.texcoord=float4(0.0f,1.0f,0.0f,0.0f);
    outTriangleStream.Append(vo);
    
    float3 p1WS=positionWS-(bitangent*0.5f+tangent*0.5f)*scale;//right bottom
    float4 p1VS=mul(ViewMatrix,float4(p1WS,1.0f));
    vo.position=mul(ProjectionMatrix,p1VS);
    vo.texcoord=float4(1.0f,1.0f,0.0f,0.0f);
    outTriangleStream.Append(vo);

    float3 p2WS=positionWS+(bitangent*0.5f+tangent*0.5f)*scale;//left top
    float4 p2VS=mul(ViewMatrix,float4(p2WS,1.0f));
    vo.position=mul(ProjectionMatrix,p2VS);
    vo.texcoord=float4(0.0f,0.0f,0.0f,0.0f);
    outTriangleStream.Append(vo);

    float3 p3WS=positionWS+(bitangent*0.5f-tangent*0.5f)*scale;//right top
    float4 p3VS=mul(ViewMatrix,float4(p3WS,1.0f));
    vo.position=mul(ProjectionMatrix,p3VS);
    vo.texcoord=float4(1.0f,0.0f,0.0f,0.0f);
    outTriangleStream.Append(vo);*/

}

float4 MainPS(VSOut inPSInput):SV_TARGET{
    float3 N=normalize(inPSInput.normal.xyz);
    float3 bottomColor=float3(0.1f,0.4f,0.6f);
    float3 topColor=float3(0.7f,0.7f,0.7f);
    float theta=asin(N.y);//-PI/2 ~ PI/2
    theta/=PI;//-0.5~0.5
    theta+=0.5f;//0.0~1.0
    float ambientColorIntensity=1.0;
    float3 ambientColor=lerp(bottomColor,topColor,theta)*ambientColorIntensity;
    float4 diffuseColor=T_DiffuseTexture.Sample(samplerState,inPSInput.texcoord.xy);
    float3 surfaceColor=diffuseColor.rgb;
    return float4(surfaceColor,1.0f);
}