// I just reuse this one for the shadow mapping right?

uint getCharFromUintArray(uint color, uint index)
{
    return uint((color >> 8 * index) & 0xFF);
}

struct Input
{
    float3 Position : TEXCOORD0;
    float3 Normal : TEXCOORD1;
    float4 Color : TEXCOORD2;
    float2 UV : TEXCOORD3;
    uint Bones : TEXCOORD4;
    uint weights : TEXCOORD5;

    uint Instance : SV_InstanceID;
};

struct Output
{
    float2 TexCoord : TEXCOORD0;
    float3 WorldPos : TEXCOORD1;
    float3 Normal: TEXCOORD2;
    float4 DirectionalShadowFragPos: TEXCOORD3;
    uint Instance: TEXCOORD4;
    float3 ScreenNormal: TEXCOORD5;

    float4 Position : SV_Position;
};

struct Scene
{
    float4x4 Model;

    uint textureMode; // 0 = regular triple, 
                     // 0x10 = video yuv,

    int animation; // -1 means no animation, any non-zero value means an index into the animationBuffer
    uint flags; // 0 -> 0: always in front
                // 1 -> 1: useAltCamera
    uint pad2;
};

StructuredBuffer<Scene> scene: register(t0, space0);

struct BoneTransform
{
    float4x4 final;
};

StructuredBuffer<BoneTransform> animationBuffer: register(t1, space0);

cbuffer Uniforms : register(b0, space1)
{
    float4x4 ViewProjection;
    float4x4 NoTranslateView;
    float4x4 ShadowMapProjection;
    float time;
};

float4x4 ExtractRotation(float4x4 m)
{
    // Extract basis vectors
    float3 x = float3(m._11, m._12, m._13);
    float3 y = float3(m._21, m._22, m._23);
    float3 z = float3(m._31, m._32, m._33);

    // Remove scale by normalizing each axis
    x = normalize(x);
    y = normalize(y);
    z = normalize(z);

    // Reconstruct rotation matrix
    float3x3 m2 = float3x3(x, y, z);

    return float4x4(
        float4(m2[0][0], m2[0][1], m2[0][2], 0.0),
        float4(m2[1][0], m2[1][1], m2[1][2], 0.0),
        float4(m2[2][0], m2[2][1], m2[2][2], 0.0),
        float4(0.0,     0.0,     0.0,     1.0)
    );}

Output main(Input input)
{
    Output output;
    output.TexCoord = input.UV;

    int animation = scene[input.Instance].animation;

    float3 vertexPos = input.Position;

    if(animation != -1)
    {
        vertexPos = float3(0.0, 0.0, 0.0);
        for(int i = 0; i < 4; i += 1)
        {
            uint boneIndex = getCharFromUintArray(input.Bones, i);

            float weight = float(getCharFromUintArray(input.weights, i)) / 255;

            // this will depend on ozz's finals format
            BoneTransform boneTransform = animationBuffer[uint(animation) + boneIndex];
            vertexPos += weight * (  mul(boneTransform.final, float4(input.Position, 1.0)) ).xyz;
        }
    }

    // float4 pos = float4(input.Position, 1.0);
    float4 pos = float4(vertexPos, 1.0);

    // pos.x += 0.2 * sin(time * 0.5 ) * pos.y * 0.5;
    // pos.y += 0.2 * cos(time * 0.5 ) * pos.z * 0.5;
    
    // todo. maybe all world position values should be 
    // transformed into screen space
    float4 WorldPos = mul(scene[input.Instance].Model, pos);
    output.Position = mul(ViewProjection, mul(scene[input.Instance].Model, pos));
    output.WorldPos = WorldPos.xyz;
    
    float4x4 noTranslate = ExtractRotation(scene[input.Instance].Model);
    output.Normal = normalize(mul(noTranslate, float4(input.Normal, 1.0))).xyz;

    float4x4 noTranslateScreen = mul(NoTranslateView, noTranslate);
    output.ScreenNormal = mul(noTranslateScreen, float4(input.Normal, 1.0)).xyz;


    // output.ScreenNormal = mul(noTranslateScreen, float4(input.Normal, 1.0)).xyz;
    // output.ScreenNormal = input.Normal;
    // output.ScreenNormal = float4(input.Normal, 1.0).xyz;

    output.DirectionalShadowFragPos = mul(ShadowMapProjection, WorldPos);
    output.Instance = input.Instance;

    return output;
}