////////////////////////////////////////////////////////////
//~ Gpu math types

#define Pi              ((f32)3.14159265358979323846)
#define Tau             ((f32)6.28318530717958647693)
#define GoldenRatio     ((f32)1.61803398874989484820)

typedef float2 Vec2;
typedef float3 Vec3;
typedef float4 Vec4;
typedef int2 Vec2I32;
typedef int3 Vec3I32;
typedef int4 Vec4I32;
typedef uint2 Vec2U32;
typedef uint3 Vec3U32;
typedef uint4 Vec4U32;
typedef float2x3 Xform;
typedef float4 Rect;
typedef float4 ClipRect;
typedef float4 Aabb;
typedef float4 Quad;
typedef float4x4 Mat4x4;

////////////////////////////////////////////////////////////
//~ Root constants

Struct(RootConstants_f32)                       { f32                       c[MaxShaderConstants]; };
Struct(RootConstants_u32)                       { u32                       c[MaxShaderConstants]; };
Struct(RootConstants_StructuredBufferHandle)    { StructuredBufferHandle    c[MaxShaderConstants]; };
Struct(RootConstants_RWStructuredBufferHandle)  { RWStructuredBufferHandle  c[MaxShaderConstants]; };
Struct(RootConstants_Texture1DHandle)           { Texture1DHandle           c[MaxShaderConstants]; };
Struct(RootConstants_RWTexture1DHandle)         { RWTexture1DHandle         c[MaxShaderConstants]; };
Struct(RootConstants_Texture2DHandle)           { Texture2DHandle           c[MaxShaderConstants]; };
Struct(RootConstants_RWTexture2DHandle)         { RWTexture2DHandle         c[MaxShaderConstants]; };
Struct(RootConstants_Texture3DHandle)           { Texture3DHandle           c[MaxShaderConstants]; };
Struct(RootConstants_RWTexture3DHandle)         { RWTexture3DHandle         c[MaxShaderConstants]; };
Struct(RootConstants_SamplerHandle)             { SamplerHandle             c[MaxShaderConstants]; };

ConstantBuffer<RootConstants_f32>                      g_root_constants_f32                      : register(b0);
ConstantBuffer<RootConstants_u32>                      g_root_constants_u32                      : register(b0);
ConstantBuffer<RootConstants_StructuredBufferHandle>   g_root_constants_StructuredBufferHandle   : register(b0);
ConstantBuffer<RootConstants_RWStructuredBufferHandle> g_root_constants_RWStructuredBufferHandle : register(b0);
ConstantBuffer<RootConstants_Texture1DHandle>          g_root_constants_Texture1DHandle          : register(b0);
ConstantBuffer<RootConstants_RWTexture1DHandle>        g_root_constants_RWTexture1DHandle        : register(b0);
ConstantBuffer<RootConstants_Texture2DHandle>          g_root_constants_Texture2DHandle          : register(b0);
ConstantBuffer<RootConstants_RWTexture2DHandle>        g_root_constants_RWTexture2DHandle        : register(b0);
ConstantBuffer<RootConstants_Texture3DHandle>          g_root_constants_Texture3DHandle          : register(b0);
ConstantBuffer<RootConstants_RWTexture3DHandle>        g_root_constants_RWTexture3DHandle        : register(b0);
ConstantBuffer<RootConstants_SamplerHandle>            g_root_constants_SamplerHandle            : register(b0);

#define GetConstant(type, name) (g_root_constants_##type.c[ShaderConstant(type, name)])

////////////////////////////////////////////////////////////
//~ Handle dereference

#define ResourceFromUniformHandle(h)            ResourceDescriptorHeap[(h)]
#define ResourceFromNonUniformHandle(h)         ResourceDescriptorHeap[NonUniformResourceIndex(h)]
#define ResourceFromConstantHandle(type, name)  ResourceFromUniformHandle(GetConstant(type, name))

#define SamplerFromUniformHandle(h)             SamplerDescriptorHeap[(h)]
#define SamplerFromNonUniformHandle(h)          SamplerDescriptorHeap[NonUniformResourceIndex(h)]
#define SamplerFromConstantHandle(type, name)   SamplerFromUniformHandle(GetConstant(type, name))

////////////////////////////////////////////////////////////
//~ Texture dimension helpers

u32 Count1D(Texture1D tex)
{
    u32 result;
    tex.GetDimensions(result.x);
    return result;
}

template<typename T>
u32 Count1D(RWTexture1D<T> tex)
{
    u32 result;
    tex.GetDimensions(result.x);
    return result;
}

Vec2U32 Count2D(Texture2D tex)
{
    Vec2U32 result;
    tex.GetDimensions(result.x, result.y);
    return result;
}

template<typename T>
Vec2U32 Count2D(RWTexture2D<T> tex)
{
    Vec2U32 result;
    tex.GetDimensions(result.x, result.y);
    return result;
}

Vec3U32 Count3D(Texture3D tex)
{
    Vec3U32 result;
    tex.GetDimensions(result.x, result.y, result.z);
    return result;
}

template<typename T>
Vec3U32 Count3D(RWTexture3D<T> tex)
{
    Vec3U32 result;
    tex.GetDimensions(result.x, result.y, result.z);
    return result;
}

////////////////////////////////////////////////////////////
//~ Vertex ID helpers

Vec2 RectUvFromVertexId(u32 id)
{
    static const Vec2 uvs[4] = {
        Vec2(0, 0),
        Vec2(1, 0),
        Vec2(1, 1),
        Vec2(0, 1)
    };
    return uvs[id];
}

////////////////////////////////////////////////////////////
//~ Ndc helpers

Vec2 NdcFromPos(Vec2 pos, Vec2 size)
{
    Vec2 result;
    result = pos / size;
    result *= Vec2(2, -2);
    result += Vec2(-1, 1);
    return result;
}