power_play/src/base/base_shader.gh

////////////////////////////////////////////////////////////
//~ Base 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 Affine;
typedef float4 Rect;
typedef float4 ClipRect;
typedef float4 Aabb;
typedef float4 Quad;
typedef float4x4 Mat4x4;

////////////////////////////////////////////////////////////
//~ Range types

Struct(Rng)    { f32 min; f32 max; };
Struct(RngI32) { i32 min; i32 max; };
Struct(RngU32) { u32 min; u32 max; };

Struct(Rng2)    { Vec2 p0;    Vec2 p1; };
Struct(Rng2I32) { Vec2I32 p0; Vec2I32 p1; };
Struct(Rng2U32) { Vec2U32 p0; Vec2U32 p1; };

Struct(Rng3)    { Vec3 p0;    Vec3 p1; };
Struct(Rng3I32) { Vec3I32 p0; Vec3I32 p1; };
Struct(Rng3U32) { Vec3U32 p0; Vec3U32 p1; };

////////////////////////////////////////////////////////////
//~ Countof

template<typename T, u32 N>
u32 countof(T arr[N])
{
  return N;
}

////////////////////////////////////////////////////////////
//~ C -> HLSL interoperability stubs

//- Min
#define MinU8 min
#define MinI8 min
#define MinU32 min
#define MinI32 min
#define MinF32 min
#define MinU64 min
#define MinI64 min
#define MinF64 min

//- Max
#define MaxU8 max
#define MaxI8 max
#define MaxU32 max
#define MaxI32 max
#define MaxF32 max
#define MaxU64 max
#define MaxI64 max
#define MaxF64 max

//- Clamp
#define ClampU32 clamp
#define ClampI32 clamp
#define ClampF32 clamp
#define ClampU64 clamp
#define ClampI64 clamp
#define ClampF64 clamp

//- Round
#define RoundF32 round
#define RoundF64 round

//- Floor
#define FloorF32 floor
#define FloorF64 floor

//- Ceil
#define CeilF32 ceil
#define CeilF64 ceil

//- Trunc
#define TruncF32 trunc
#define TruncF64 trunc

//- Mod
#define ModF32 fmod
#define ModF64 fmod

//- Abs
#define AbsF32 abs
#define AbsF64 abs

//- Sign
#define SignF32 sign
#define SignF64 sign

//- Smoothstep
#define SmoothstepF32 smoothstep
#define SmoothstepF64 smoothstep

//- Matchfloor
#define MatchFloor(a, b) all(floor(a) == floor(b))

////////////////////////////////////////////////////////////
//~ Derivative helpers

#define fwidth_fine(v) (abs(ddx_fine((v))) + abs(ddy_fine((v))))

////////////////////////////////////////////////////////////
//~ Color helpers

Inline Vec4 Vec4FromU32(u32 v)
{
  Vec4 result = 0;
  result.x = ((v >> 0) & 0xFF) / 255.0;
  result.y = ((v >> 8) & 0xFF) / 255.0;
  result.z = ((v >> 16) & 0xFF) / 255.0;
  result.w = ((v >> 24) & 0xFF) / 255.0;
  return result;
}

Inline u32 U32FromVec4(Vec4 v)
{
  u32 result = 0;
  result |= (((u32)(v.x * 255.0)) & 0xFF) << 0;
  result |= (((u32)(v.y * 255.0)) & 0xFF) << 8;
  result |= (((u32)(v.z * 255.0)) & 0xFF) << 16;
  result |= (((u32)(v.w * 255.0)) & 0xFF) << 24;
  return result;
}

Inline f32 LinearFromSrgbF32(f32 srgb)
{
  f32 result;
  if (srgb <= 0.04045f)
  {
    result = srgb / 12.92f;
  }
  else
  {
    result = pow((srgb + 0.055f) / 1.055f, 2.4f);
  }
  return result;
}

Inline Vec4 LinearFromSrgb(Vec4 srgb)
{
  Vec4 result;
  result.x = LinearFromSrgbF32(srgb.x);
  result.y = LinearFromSrgbF32(srgb.y);
  result.z = LinearFromSrgbF32(srgb.z);
  result.w = srgb.w;
  return result;
}

Inline Vec4 Premul(Vec4 v)
{
  Vec4 result;
  result.rgb = v.rgb * v.a;
  result.a = v.a;
  return result;
}

Inline Vec4 Unpremul(Vec4 v)
{
  Vec4 result = 0;
  if (v.a > 0.0)
  {
    result.rgb = v.rgb / v.a;
  }
  result.a = v.a;
  return result;
}

Inline Vec4 BlendPremul(Vec4 src, Vec4 dst)
{
  Vec4 result;
  result.rgb = src.rgb + (dst.rgb * (1.0 - src.a));
  result.a = src.a + (dst.a * (1.0 - src.a));
  return result;
}

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

Inline Vec2 RectUvFromIdx(u32 idx)
{
  static const Vec2 uvs[4] = {
    Vec2(0, 0),
    Vec2(1, 0),
    Vec2(1, 1),
    Vec2(0, 1)
  };
  return uvs[idx];
}

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

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

Inline Vec2 NdcFromUv(Vec2 uv)
{
  Vec2 result;
  result = uv;
  result *= Vec2(2, -2);
  result += Vec2(-1, 1);
  return result;
}

////////////////////////////////////////////////////////////
//~ String helpers

// https://therealmjp.github.io/posts/hlsl-printf/
template<typename T>
u32 U32FromChar(in T c)
{
  if(c == ' ') return 32;
  if(c == '!') return 33;
  if(c == '\"' || c == '\"') return 34;
  if(c == '#') return 35;
  if(c == '$') return 36;
  if(c == '%') return 37;
  if(c == '&') return 38;
  if(c == '\'') return 39;
  if(c == '(') return 40;
  if(c == ')') return 41;
  if(c == '*') return 42;
  if(c == '+') return 43;
  if(c == ',') return 44;
  if(c == '-') return 45;
  if(c == '.') return 46;
  if(c == '/') return 47;
  if(c == '0') return 48;
  if(c == '1') return 49;
  if(c == '2') return 50;
  if(c == '3') return 51;
  if(c == '4') return 52;
  if(c == '5') return 53;
  if(c == '6') return 54;
  if(c == '7') return 55;
  if(c == '8') return 56;
  if(c == '9') return 57;
  if(c == ':') return 58;
  if(c == ';') return 59;
  if(c == '<') return 60;
  if(c == '=') return 61;
  if(c == '>') return 62;
  if(c == '?') return 63;
  if(c == '@') return 64;
  if(c == 'A') return 65;
  if(c == 'B') return 66;
  if(c == 'C') return 67;
  if(c == 'D') return 68;
  if(c == 'E') return 69;
  if(c == 'F') return 70;
  if(c == 'G') return 71;
  if(c == 'H') return 72;
  if(c == 'I') return 73;
  if(c == 'J') return 74;
  if(c == 'K') return 75;
  if(c == 'L') return 76;
  if(c == 'M') return 77;
  if(c == 'N') return 78;
  if(c == 'O') return 79;
  if(c == 'P') return 80;
  if(c == 'Q') return 81;
  if(c == 'R') return 82;
  if(c == 'S') return 83;
  if(c == 'T') return 84;
  if(c == 'U') return 85;
  if(c == 'V') return 86;
  if(c == 'W') return 87;
  if(c == 'X') return 88;
  if(c == 'Y') return 89;
  if(c == 'Z') return 90;
  if(c == '[') return 91;
  if(c == '\\') return 92;
  if(c == ']') return 93;
  if(c == '^') return 94;
  if(c == '_') return 95;
  if(c == '`') return 96;
  if(c == 'a') return 97;
  if(c == 'b') return 98;
  if(c == 'c') return 99;
  if(c == 'd') return 100;
  if(c == 'e') return 101;
  if(c == 'f') return 102;
  if(c == 'g') return 103;
  if(c == 'h') return 104;
  if(c == 'i') return 105;
  if(c == 'j') return 106;
  if(c == 'k') return 107;
  if(c == 'l') return 108;
  if(c == 'm') return 109;
  if(c == 'n') return 110;
  if(c == 'o') return 111;
  if(c == 'p') return 112;
  if(c == 'q') return 113;
  if(c == 'r') return 114;
  if(c == 's') return 115;
  if(c == 't') return 116;
  if(c == 'u') return 117;
  if(c == 'v') return 118;
  if(c == 'w') return 119;
  if(c == 'x') return 120;
  if(c == 'y') return 121;
  if(c == 'z') return 122;
  if(c == '{') return 123;
  if(c == '|') return 124;
  if(c == '}') return 125;
  if(c == '~') return 126;
  return 0;
}