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
	}
};