// Copyright 2020 Google LLC

struct VSInput
{
[[vk::location(0)]] float3 Pos : POSITION0;
[[vk::location(1)]] float2 UV : TEXCOORD0;
[[vk::location(2)]] float3 Color : COLOR0;
[[vk::location(3)]] float3 Normal : NORMAL0;
};

struct UBO
{
	float4x4 projection;
	float4x4 view;
	float4x4 model;
	float4x4 lightSpace;
	float4 lightPos;
	float zNear;
	float zFar;
};

cbuffer ubo : register(b0) { UBO ubo; }

struct VSOutput
{
	float4 Pos : SV_POSITION;
[[vk::location(0)]] float3 Normal : NORMAL0;
[[vk::location(1)]] float3 Color : COLOR0;
[[vk::location(2)]] float3 ViewVec : TEXCOORD1;
[[vk::location(3)]] float3 LightVec : TEXCOORD2;
[[vk::location(4)]] float4 ShadowCoord : TEXCOORD3;
};

static const float4x4 biasMat = float4x4(
	0.5, 0.0, 0.0, 0.5,
	0.0, 0.5, 0.0, 0.5,
	0.0, 0.0, 1.0, 0.0,
	0.0, 0.0, 0.0, 1.0 );

VSOutput main(VSInput input)
{
	VSOutput output = (VSOutput)0;
	output.Color = input.Color;
	output.Normal = input.Normal;

	output.Pos = mul(ubo.projection, mul(ubo.view, mul(ubo.model, float4(input.Pos.xyz, 1.0))));

    float4 pos = mul(ubo.model, float4(input.Pos, 1.0));
    output.Normal = mul((float3x3)ubo.model, input.Normal);
    output.LightVec = normalize(ubo.lightPos.xyz - input.Pos);
    output.ViewVec = -pos.xyz;

	output.ShadowCoord = mul(biasMat, mul(ubo.lightSpace, mul(ubo.model, float4(input.Pos, 1.0))));
	return output;
}