////////////////////////////////////////////////////////////
//~ Gpu math constants

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

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

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;

////////////////////////////////////////////////////////////
//~ Integer -> float

Vec4 Vec4NormFromU32(u32 v)
{
    Vec4 result;
    result.r = ((v >> 0) & 0xFF) / 255.0;
    result.g = ((v >> 8) & 0xFF) / 255.0;
    result.b = ((v >> 16) & 0xFF) / 255.0;
    result.a = ((v >> 24) & 0xFF) / 255.0;
    return result;
}

////////////////////////////////////////////////////////////
//~ Srgb -> linear

/* Linear color from normalized sRGB */
Vec4 LinearFromSrgbVec4(Vec4 srgb)
{
    return Vec4(pow(abs(srgb.rgb), 2.2), srgb.a);
}

/* Linear color from R8G8B8A8 sRGB  */
Vec4 LinearFromSrgbU32(u32 srgb32)
{
    return LinearFromSrgbVec4(Vec4NormFromU32(srgb32));
}

////////////////////////////////////////////////////////////
//~ 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 NdcFromViewport(Vec2 viewport_size, Vec2 viewport_coords)
{
    Vec2 result;
    result = viewport_coords / viewport_size;
    result *= Vec2(2, -2);
    result += Vec2(-1, 1);
    return result;
}