dolphin/Source/Core/VideoBackends/Software/NativeVertexFormat.h

// Copyright 2009 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#pragma once

#include "Common/ChunkFile.h"
#include "VideoBackends/Software/Vec3.h"

struct Vec4
{
  float x;
  float y;
  float z;
  float w;
};

struct InputVertexData
{
  u8 posMtx;
  u8 texMtx[8];

  Vec3 position;
  Vec3 normal[3];
  u8 color[2][4];
  float texCoords[8][2];
};

struct OutputVertexData
{
  // components in color channels
  enum
  {
    RED_C,
    GRN_C,
    BLU_C,
    ALP_C
  };

  Vec3 mvPosition = {};
  Vec4 projectedPosition = {};
  Vec3 screenPosition = {};
  Vec3 normal[3] = {};
  u8 color[2][4] = {};
  Vec3 texCoords[8] = {};

  void Lerp(float t, OutputVertexData* a, OutputVertexData* b)
  {
#define LINTERP(T, OUT, IN) (OUT) + ((IN - OUT) * T)

#define LINTERP_INT(T, OUT, IN) (OUT) + (((IN - OUT) * T) >> 8)

    mvPosition = LINTERP(t, a->mvPosition, b->mvPosition);

    projectedPosition.x = LINTERP(t, a->projectedPosition.x, b->projectedPosition.x);
    projectedPosition.y = LINTERP(t, a->projectedPosition.y, b->projectedPosition.y);
    projectedPosition.z = LINTERP(t, a->projectedPosition.z, b->projectedPosition.z);
    projectedPosition.w = LINTERP(t, a->projectedPosition.w, b->projectedPosition.w);

    for (int i = 0; i < 3; ++i)
    {
      normal[i] = LINTERP(t, a->normal[i], b->normal[i]);
    }

    u16 t_int = (u16)(t * 256);
    for (int i = 0; i < 4; ++i)
    {
      color[0][i] = LINTERP_INT(t_int, a->color[0][i], b->color[0][i]);
      color[1][i] = LINTERP_INT(t_int, a->color[1][i], b->color[1][i]);
    }

    for (int i = 0; i < 8; ++i)
    {
      texCoords[i] = LINTERP(t, a->texCoords[i], b->texCoords[i]);
    }

#undef LINTERP
#undef LINTERP_INT
  }
};