/*
Shader description:
TRANSFORM = 0
OUTPUTWORLDPOS = 0
OUTPUTWORLDNBT = 0
OUTPUTWORLDVIEW = 0
OUTPUTTANGENTVIEW = 0
NORMAL = 0
SPECULAR = 0
FOGTYPE = 0
ENVMAPTYPE = 0
PROJLIGHTMAPCOUNT = 0
PROJLIGHTMAPTYPES = 0
PROJSHADOWMAPCOUNT = 0
PROJSHADOWMAPTYPES = 0
OUTPUTUVCOUNT = 1
UVSET00 = 0
UVSET00TEXOUTPUT = 0
UVSET01 = 0
UVSET01TEXOUTPUT = 0
UVSET02 = 0
UVSET02TEXOUTPUT = 0
UVSET03 = 0
UVSET03TEXOUTPUT = 0
UVSET04 = 0
UVSET04TEXOUTPUT = 0
UVSET05 = 0
UVSET05TEXOUTPUT = 0
UVSET06 = 0
UVSET06TEXOUTPUT = 0
UVSET07 = 0
UVSET07TEXOUTPUT = 0
UVSET08 = 0
UVSET08TEXOUTPUT = 0
UVSET09 = 0
UVSET09TEXOUTPUT = 0
UVSET10 = 0
UVSET10TEXOUTPUT = 0
UVSET11 = 0
UVSET11TEXOUTPUT = 0
POINTLIGHTCOUNT = 0
SPOTLIGHTCOUNT = 0
DIRLIGHTCOUNT = 0
VERTEXCOLORS = 0
VERTEXLIGHTSONLY = 1
AMBDIFFEMISSIVE = 0
LIGHTINGMODE = 1
APPLYMODE = 0
*/

//----------------------------------------------------------
// 常量寄存中中的变量(这里需要在引擎里每帧设置进去)
//----------------------------------------------------------

float4x4 g_World;
float4x4 g_ViewProj;

//----------------------------------------------------------
// 入参:我们定义一个结构叫Input来确定入参结构
//----------------------------------------------------------

struct Input
{
    float3 Position : POSITION0;
    float2 UVSet0 : TEXCOORD0;
};

//---------------------------------------------------------------------------
// Output:
//----------------------------------------------------------

struct Output
{
    float4 PosProjected : POSITION0;
    float2 UVSet0 : TEXCOORD0;
};

//----------------------------------------------------------
// 函数:这里是用到的一些函数，简单的主要写了上次提到的几个函数。都是关于坐标系转换
// 的，关于坐标系转换的更高级内容，请参阅我写的：番外篇
//----------------------------------------------------------

/*

    This fragment is responsible for applying the view projection transform
    to the input position. Additionally, this fragment applies the world
    transform to the input position.
    
*/

void TransformPosition(float3 Position,
    float4x4 World,
    out float4 WorldPos)
{

    // 用于灯光啊，projected space的转换，转换到世界坐标系下。
    WorldPos = mul( float4(Position, 1.0f), World );

}
//----------------------------------------------------------
/*

    This fragment is responsible for applying the view projection transform
    to the input world position.
    
*/

void ProjectPositionWorldToProj(float4 WorldPosition,
    float4x4 ViewProjection,
    out float4 ProjPos)
{

    ProjPos = mul(WorldPosition, ViewProjection);
    
}
//----------------------------------------------------------
//----------------------------------------------------------
// Main():这是VS的主函数，从这里入参被处理好了以后交给像素处理管线去处理
//----------------------------------------------------------

Output Main(Input In)
{
    Output Out;
// Function call #0  把局部坐标转化为世界坐标
    float4 WorldPos_CallOut0;
    TransformPosition(In.Position, g_World, WorldPos_CallOut0);

// Function call #1  把世界坐标转换为视坐标
    ProjectPositionWorldToProj(WorldPos_CallOut0, g_ViewProj, Out.PosProjected);

    // 这里是UV信息，不做任何处理，用于像素着色器
    Out.UVSet0 = In.UVSet0;
    return Out;
}
///////////////////////////////////////////////////////////////////////////////////////////