// Copyright (c) 2012- PPSSPP Project.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0 or later versions.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official git repository and contact information can be found at
// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.

#pragma once

#include "../GPUState.h"
#include "../Globals.h"
#include "base/basictypes.h"

// DecVtxFormat - vertex formats for PC
// Kind of like a D3D VertexDeclaration.
// Can write code to easily bind these using OpenGL, or read these manually.
// No morph support, that is taken care of by the VertexDecoder.

enum {
	DEC_NONE,
	DEC_FLOAT_1,
	DEC_FLOAT_2,
	DEC_FLOAT_3,
	DEC_FLOAT_4,
	DEC_S8_3,
	DEC_S16_3,
	DEC_U8_4,
};

int DecFmtSize(u8 fmt);

struct DecVtxFormat {
	u8 w0fmt; u8 w0off;  // first 4 weights
	u8 w1fmt; u8 w1off;  // second 4 weights
	u8 uvfmt; u8 uvoff;
	u8 c0fmt; u8 c0off;  // First color
	u8 c1fmt; u8 c1off;
	u8 nrmfmt; u8 nrmoff;
	u8 posfmt; u8 posoff;
	short stride;
};

// This struct too.
struct TransformedVertex
{
	float x, y, z;     // in case of morph, preblend during decode
	float uv[2];      // scaled by uscale, vscale, if there
	float color0[4];   // prelit
	float color1[3];   // prelit
};

DecVtxFormat GetTransformedVtxFormat(const DecVtxFormat &fmt);

class VertexDecoder;

typedef void (VertexDecoder::*StepFunction)() const;


// Right now
//   - only contains computed information
//   - does decoding in nasty branchfilled loops
// Future TODO
//   - should be cached, not recreated every time
//   - will compile into list of called functions
//   - will compile into lighting fast specialized x86 and ARM
//   - will not bother translating components that can be read directly
//     by OpenGL ES. Will still have to translate 565 colors and things
//     like that. DecodedVertex will not be a fixed struct. Will have to
//     do morphing here.
class VertexDecoder
{
public:
	VertexDecoder() : coloff(0), nrmoff(0), posoff(0) {}
	~VertexDecoder() {}

	void SetVertexType(u32 vtype);

	const DecVtxFormat &GetDecVtxFmt() { return decFmt; }

	void DecodeVerts(u8 *decoded, const void *verts, const void *inds, int prim, int count, int *indexLowerBound, int *indexUpperBound) const;
	bool hasColor() const { return col != 0; }
	int VertexSize() const { return size; }

	void Step_WeightsU8() const;
	void Step_WeightsU16() const;
	void Step_WeightsFloat() const;

	void Step_TcU8() const;
	void Step_TcU16() const;
	void Step_TcFloat() const;
	void Step_TcU16Through() const;
	void Step_TcFloatThrough() const;

	// TODO: tcmorph

	void Step_Color4444() const;
	void Step_Color565() const;
	void Step_Color5551() const;
	void Step_Color8888() const;

	void Step_Color4444Morph() const;
	void Step_Color565Morph() const;
	void Step_Color5551Morph() const;
	void Step_Color8888Morph() const;

	void Step_NormalS8() const;
	void Step_NormalS16() const;
	void Step_NormalFloat() const;

	void Step_NormalS8Morph() const;
	void Step_NormalS16Morph() const;
	void Step_NormalFloatMorph() const;

	void Step_PosS8() const;
	void Step_PosS16() const;
	void Step_PosFloat() const;

	void Step_PosS8Morph() const;
	void Step_PosS16Morph() const;
	void Step_PosFloatMorph() const;

	void Step_PosS8Through() const;
	void Step_PosS16Through() const;
	void Step_PosFloatThrough() const;


	// Mutable decoder state
	mutable u8 *decoded_;
	mutable const u8 *ptr_;

	// "Immutable" state, set at startup

	// The decoding steps
	StepFunction steps_[5];
	int numSteps_;

	u32 fmt_;
	DecVtxFormat decFmt;

	bool throughmode;
	int biggest;
	int size;
	int onesize_;

	int weightoff;
	int tcoff;
	int coloff;
	int nrmoff;
	int posoff;

	int tc;
	int col;
	int nrm;
	int pos;
	int weighttype;
	int idx;
	int morphcount;
	int nweights;
};

// Reads decoded vertex formats in a convenient way. For software transform and debugging.
class VertexReader
{
public:
	VertexReader(u8 *base, const DecVtxFormat &decFmt) : base_(base), data_(base), decFmt_(decFmt) {}

	void ReadPos(float pos[3]) {
		switch (decFmt_.posfmt) {
		case DEC_FLOAT_3:
			memcpy(pos, data_ + decFmt_.posoff, 12);
			break;
		case DEC_S16_3:
			{
				s16 *p = (s16 *)(data_ + decFmt_.posoff);
				for (int i = 0; i < 3; i++)
					pos[i] = p[i] / 32767.0f;
			}
			break;
		case DEC_S8_3:
			{
				s8 *p = (s8 *)(data_ + decFmt_.posoff);
				for (int i = 0; i < 3; i++)
					pos[i] = p[i] / 127.0f;
			}
			break;
		default:
			ERROR_LOG(G3D, "Reader: Unsupported Pos Format");
			break;
		}
	}

	void ReadNrm(float nrm[3]) {
		switch (decFmt_.nrmfmt) {
		case DEC_FLOAT_3:
			memcpy(nrm, data_ + decFmt_.nrmoff, 12);
			break;
		case DEC_S16_3:
			{
				s16 *p = (s16 *)(data_ + decFmt_.nrmoff);
				for (int i = 0; i < 3; i++)
					nrm[i] = p[i] / 32767.0f;
			}
			break;
		case DEC_S8_3:
			{
				s8 *p = (s8 *)(data_ + decFmt_.nrmoff);
				for (int i = 0; i < 3; i++)
					nrm[i] = p[i] / 127.0f;
			}
			break;
		default:
			ERROR_LOG(G3D, "Reader: Unsupported Nrm Format");
			break;
		}
	}

	void ReadUV(float uv[2]) {
		switch (decFmt_.uvfmt) {
		case DEC_FLOAT_2:
			memcpy(uv, data_ + decFmt_.uvoff, 8); break;
		default:
			ERROR_LOG(G3D, "Reader: Unsupported UV Format");
			break;
		}
	}

	void ReadColor0(float color[4]) {
		switch (decFmt_.c0fmt) {
		case DEC_U8_4:
			{
				u8 *p = (u8 *)(data_ + decFmt_.c0off);
				for (int i = 0; i < 4; i++)
					color[i] = p[i] / 255.0f;
			}
			break;
		case DEC_FLOAT_4:
			memcpy(color, data_ + decFmt_.c0off, 16); break;
		default:
			ERROR_LOG(G3D, "Reader: Unsupported C0 Format");
			break;
		}
	}

	void ReadColor1(float color[3]) {
		switch (decFmt_.c1fmt) {
		case DEC_U8_4:
			{
				u8 *p = (u8 *)(data_ + decFmt_.c1off);
				for (int i = 0; i < 3; i++)
					color[i] = p[i] / 255.0f;
			}
			break;
		case DEC_FLOAT_4:
			memcpy(color, data_ + decFmt_.c1off, 16); break;
		default:
			ERROR_LOG(G3D, "Reader: Unsupported C1 Format");
			break;
		}
	}

	void ReadWeights(float weights[8]) {
		switch (decFmt_.w0fmt) {
		case DEC_FLOAT_1: memcpy(weights, data_ + decFmt_.w0off, 4); break;
		case DEC_FLOAT_2: memcpy(weights, data_ + decFmt_.w0off, 8); break;
		case DEC_FLOAT_3: memcpy(weights, data_ + decFmt_.w0off, 12); break;
		case DEC_FLOAT_4: memcpy(weights, data_ + decFmt_.w0off, 16); break;
		default:
			ERROR_LOG(G3D, "Reader: Unsupported W0 Format");
			break;
		}
		switch (decFmt_.w1fmt) {
		case 0:
			// It's fine for there to be w0 weights but not w1.
			break;
		case DEC_FLOAT_1: memcpy(weights + 4, data_ + decFmt_.w1off, 4); break;
		case DEC_FLOAT_2: memcpy(weights + 4, data_ + decFmt_.w1off, 8); break;
		case DEC_FLOAT_3: memcpy(weights + 4, data_ + decFmt_.w1off, 12); break;
		case DEC_FLOAT_4: memcpy(weights + 4, data_ + decFmt_.w1off, 16); break;
		default:
			ERROR_LOG(G3D, "Reader: Unsupported W1 Format");
			break;
		}
	}

	bool hasColor0() const { return decFmt_.c0fmt != 0; }
	bool hasNormal() const { return decFmt_.nrmfmt != 0; }
	bool hasUV() const { return decFmt_.uvfmt != 0; }

	void Goto(int index) {
		data_ = base_ + index * decFmt_.stride;
	}

private:
	u8 *base_;
	u8 *data_;
	DecVtxFormat decFmt_;
	int vtype_;
};

// Debugging utilities
void PrintDecodedVertex(VertexReader &vtx);