// 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/.

#include "IndexGenerator.h"

#include "Common/Common.h"

// Points don't need indexing...
static const u8 indexedPrimitiveType[7] = {
	GE_PRIM_POINTS,
	GE_PRIM_LINES,
	GE_PRIM_LINES,
	GE_PRIM_TRIANGLES,
	GE_PRIM_TRIANGLES,
	GE_PRIM_TRIANGLES,
	GE_PRIM_RECTANGLES,
};

void IndexGenerator::Reset() {
	prim_ = -1;
	count_ = 0;
	index_ = 0;
	seenPrims_ = 0;
	pureCount_ = 0;
	this->inds_ = indsBase_;
}

bool IndexGenerator::PrimCompatible(int prim1, int prim2) {
	if (prim1 == -1)
		return true;
	return indexedPrimitiveType[prim1] == indexedPrimitiveType[prim2];
}

bool IndexGenerator::PrimCompatible(int prim) {
	if (prim_ == -1)
		return true;
	return indexedPrimitiveType[prim] == prim_;
}

void IndexGenerator::Setup(u16 *inds) {
	this->indsBase_ = inds;
	Reset();
}

void IndexGenerator::AddPrim(int prim, int vertexCount) {
	switch (prim) {
	case GE_PRIM_POINTS: AddPoints(vertexCount); break;
	case GE_PRIM_LINES: AddLineList(vertexCount); break;
	case GE_PRIM_LINE_STRIP: AddLineStrip(vertexCount); break;
	case GE_PRIM_TRIANGLES: AddList(vertexCount); break;
	case GE_PRIM_TRIANGLE_STRIP: AddStrip(vertexCount); break;
	case GE_PRIM_TRIANGLE_FAN: AddFan(vertexCount); break;
	case GE_PRIM_RECTANGLES: AddRectangles(vertexCount); break;  // Same
	}
}

void IndexGenerator::AddPoints(int numVerts) {
	for (int i = 0; i < numVerts; i++)
		*inds_++ = index_ + i;
	// ignore overflow verts
	index_ += numVerts;
	count_ += numVerts;
	prim_ = GE_PRIM_POINTS;
	seenPrims_ |= 1 << GE_PRIM_POINTS;
}

void IndexGenerator::AddList(int numVerts) {
	int numTris = numVerts / 3;
	for (int i = 0; i < numTris; i++) {
		*inds_++ = index_ + i*3;
		*inds_++ = index_ + i*3 + 1;
		*inds_++ = index_ + i*3 + 2;
	}

	// ignore overflow verts
	index_ += numVerts;
	count_ += numTris * 3;
	prim_ = GE_PRIM_TRIANGLES;
	seenPrims_ |= 1 << GE_PRIM_TRIANGLES;
}

void IndexGenerator::AddStrip(int numVerts) {
	bool wind = false;
	int numTris = numVerts - 2;
	for (int i = 0; i < numTris; i++) {
		*inds_++ = index_ + i;
		*inds_++ = index_ + i+(wind?2:1);
		*inds_++ = index_ + i+(wind?1:2);
		wind = !wind;
	}
	index_ += numVerts;
	count_ += numTris * 3;
	// This is so we can detect one single strip by just looking at seenPrims_.
	if (!seenPrims_) {
		seenPrims_ = 1 << GE_PRIM_TRIANGLE_STRIP;
		prim_ = GE_PRIM_TRIANGLE_STRIP;
		pureCount_ = numVerts;
	} else {
		seenPrims_ |= 1 << GE_PRIM_TRIANGLE_STRIP;
		seenPrims_ |= 1 << GE_PRIM_TRIANGLES;
		prim_ = GE_PRIM_TRIANGLES;
		pureCount_ = 0;
	}
}

void IndexGenerator::AddFan(int numVerts) {
	int numTris = numVerts - 2;
	for (int i = 0; i < numTris; i++) {
		*inds_++ = index_;
		*inds_++ = index_ + i + 1;
		*inds_++ = index_ + i + 2;
	}
	index_ += numVerts;
	count_ += numTris * 3;
	prim_ = GE_PRIM_TRIANGLES;
	seenPrims_ |= 1 << GE_PRIM_TRIANGLE_FAN;
}

//Lines
void IndexGenerator::AddLineList(int numVerts) {
	int numLines = numVerts / 2;
	for (int i = 0; i < numLines; i++) {
		*inds_++ = index_ + i*2;
		*inds_++ = index_ + i*2+1;
	}
	index_ += numVerts;
	count_ += numLines * 2;
	prim_ = GE_PRIM_LINES;
	seenPrims_ |= 1 << prim_;
}

void IndexGenerator::AddLineStrip(int numVerts) {
	int numLines = numVerts - 1;
	for (int i = 0; i < numLines; i++) {
		*inds_++ = index_ + i;
		*inds_++ = index_ + i + 1;
	}
	index_ += numVerts;
	count_ += numLines * 2;
	prim_ = GE_PRIM_LINES;
	seenPrims_ |= 1 << GE_PRIM_LINE_STRIP;
}

void IndexGenerator::AddRectangles(int numVerts) {
	int numRects = numVerts / 2;
	for (int i = 0; i < numRects; i++) {
		*inds_++ = index_ + i*2;
		*inds_++ = index_ + i*2+1;
	}
	index_ += numVerts;
	count_ += numRects * 2;
	prim_ = GE_PRIM_RECTANGLES;
	seenPrims_ |= 1 << GE_PRIM_RECTANGLES;
}

void IndexGenerator::TranslatePrim(int prim, int numInds, const u8 *inds, int indexOffset) {
	switch (prim) {
	case GE_PRIM_POINTS: TranslatePoints(numInds, inds, indexOffset); break;
	case GE_PRIM_LINES: TranslateLineList(numInds, inds, indexOffset); break;
	case GE_PRIM_LINE_STRIP: TranslateLineStrip(numInds, inds, indexOffset); break;
	case GE_PRIM_TRIANGLES: TranslateList(numInds, inds, indexOffset); break;
	case GE_PRIM_TRIANGLE_STRIP: TranslateStrip(numInds, inds, indexOffset); break;
	case GE_PRIM_TRIANGLE_FAN: TranslateFan(numInds, inds, indexOffset); break;
	case GE_PRIM_RECTANGLES: TranslateRectangles(numInds, inds, indexOffset); break;  // Same
	}
}

void IndexGenerator::TranslatePrim(int prim, int numInds, const u16 *inds, int indexOffset) {
	switch (prim) {
	case GE_PRIM_POINTS: TranslatePoints(numInds, inds, indexOffset); break;
	case GE_PRIM_LINES: TranslateLineList(numInds, inds, indexOffset); break;
	case GE_PRIM_LINE_STRIP: TranslateLineStrip(numInds, inds, indexOffset); break;
	case GE_PRIM_TRIANGLES: TranslateList(numInds, inds, indexOffset); break;
	case GE_PRIM_TRIANGLE_STRIP: TranslateStrip(numInds, inds, indexOffset); break;
	case GE_PRIM_TRIANGLE_FAN: TranslateFan(numInds, inds, indexOffset); break;
	case GE_PRIM_RECTANGLES: TranslateRectangles(numInds, inds, indexOffset); break;  // Same
	}
}

void IndexGenerator::TranslatePoints(int numInds, const u8 *inds, int indexOffset) {
	for (int i = 0; i < numInds; i++)
		*inds_++ = index_ - indexOffset + inds[i];
	count_ += numInds;
	prim_ = GE_PRIM_POINTS;
	seenPrims_ |= (1 << GE_PRIM_POINTS) | SEEN_INDEX8;
}

void IndexGenerator::TranslatePoints(int numInds, const u16 *_inds, int indexOffset) {
	const u16_le *inds = (u16_le*)_inds;
	for (int i = 0; i < numInds; i++)
		*inds_++ = index_ - indexOffset + inds[i];
	count_ += numInds;
	prim_ = GE_PRIM_POINTS;
	seenPrims_ |= (1 << GE_PRIM_POINTS) | SEEN_INDEX16;
}

void IndexGenerator::TranslateList(int numInds, const u8 *inds, int indexOffset) {
	int numTris = numInds / 3;
	for (int i = 0; i < numTris; i++) {
		*inds_++ = index_ - indexOffset + inds[i*3];
		*inds_++ = index_ - indexOffset + inds[i*3 + 1];
		*inds_++ = index_ - indexOffset + inds[i*3 + 2];
	}
	count_ += numTris * 3;
	prim_ = GE_PRIM_TRIANGLES;
	seenPrims_ |= (1 << GE_PRIM_TRIANGLES) | SEEN_INDEX8;
}

void IndexGenerator::TranslateStrip(int numInds, const u8 *inds, int indexOffset) {
	bool wind = false;
	int numTris = numInds - 2;
	for (int i = 0; i < numTris; i++) {
		*inds_++ = index_ - indexOffset + inds[i];
		*inds_++ = index_ - indexOffset + inds[i + (wind?2:1)];
		*inds_++ = index_ - indexOffset + inds[i + (wind?1:2)];
		wind = !wind;
	}
	count_ += numTris * 3;
	prim_ = GE_PRIM_TRIANGLES;
	seenPrims_ |= (1 << GE_PRIM_TRIANGLE_STRIP) | SEEN_INDEX8;
}

void IndexGenerator::TranslateFan(int numInds, const u8 *inds, int indexOffset) {
	if (numInds <= 0) return;
	int numTris = numInds - 2;
	for (int i = 0; i < numTris; i++) {
		*inds_++ = index_ - indexOffset + inds[0];
		*inds_++ = index_ - indexOffset + inds[i + 1];
		*inds_++ = index_ - indexOffset + inds[i + 2];
	}
	count_ += numTris * 3;
	prim_ = GE_PRIM_TRIANGLES;
	seenPrims_ |= (1 << GE_PRIM_TRIANGLE_FAN) | SEEN_INDEX8;
}

void IndexGenerator::TranslateList(int numInds, const u16 *_inds, int indexOffset) {
	const u16_le *inds = (u16_le*)_inds;
	int numTris = numInds / 3;
	for (int i = 0; i < numTris; i++) {
		*inds_++ = index_ - indexOffset + inds[i*3];
		*inds_++ = index_ - indexOffset + inds[i*3 + 1];
		*inds_++ = index_ - indexOffset + inds[i*3 + 2];
	}
	count_ += numTris * 3;
	prim_ = GE_PRIM_TRIANGLES;
	seenPrims_ |= (1 << GE_PRIM_TRIANGLES) | SEEN_INDEX16;
}

void IndexGenerator::TranslateStrip(int numInds, const u16 *_inds, int indexOffset) {
	const u16_le *inds = (u16_le*)_inds;
	bool wind = false;
	int numTris = numInds - 2;
	for (int i = 0; i < numTris; i++) {
		*inds_++ = index_ - indexOffset + inds[i];
		*inds_++ = index_ - indexOffset + inds[i + (wind?2:1)];
		*inds_++ = index_ - indexOffset + inds[i + (wind?1:2)];
		wind = !wind;
	}
	count_ += numTris * 3;
	prim_ = GE_PRIM_TRIANGLES;
	seenPrims_ |= (1 << GE_PRIM_TRIANGLE_STRIP) | SEEN_INDEX16;
}

void IndexGenerator::TranslateFan(int numInds, const u16 *_inds, int indexOffset) {
	const u16_le *inds = (u16_le*)_inds;
	if (numInds <= 0) return;
	int numTris = numInds - 2;
	for (int i = 0; i < numTris; i++) {
		*inds_++ = index_ - indexOffset + inds[0];
		*inds_++ = index_ - indexOffset + inds[i + 1];
		*inds_++ = index_ - indexOffset + inds[i + 2];
	}
	count_ += numTris * 3;
	prim_ = GE_PRIM_TRIANGLES;
	seenPrims_ |= (1 << GE_PRIM_TRIANGLE_FAN) | SEEN_INDEX16;
}

void IndexGenerator::TranslateLineList(int numInds, const u8 *inds, int indexOffset) {
	int numLines = numInds / 2;
	for (int i = 0; i < numLines; i++) {
		*inds_++ = index_ - indexOffset + inds[i*2];
		*inds_++ = index_ - indexOffset + inds[i*2+1];
	}
	count_ += numLines * 2;
	prim_ = GE_PRIM_LINES;
	seenPrims_ |= (1 << GE_PRIM_LINES) | SEEN_INDEX8;
}

void IndexGenerator::TranslateLineStrip(int numInds, const u8 *inds, int indexOffset) {
	int numLines = numInds - 1;
	for (int i = 0; i < numLines; i++) {
		*inds_++ = index_ - indexOffset + inds[i];
		*inds_++ = index_ - indexOffset + inds[i + 1];
	}
	count_ += numLines * 2;
	prim_ = GE_PRIM_LINES;
	seenPrims_ |= (1 << GE_PRIM_LINE_STRIP) | SEEN_INDEX8;
}

void IndexGenerator::TranslateLineList(int numInds, const u16 *_inds, int indexOffset) {
	const u16_le *inds = (u16_le*)_inds;
	int numLines = numInds / 2;
	for (int i = 0; i < numLines; i++) {
		*inds_++ = index_ - indexOffset + inds[i*2];
		*inds_++ = index_ - indexOffset + inds[i*2+1];
	}
	count_ += numLines * 2;
	prim_ = GE_PRIM_LINES;
	seenPrims_ |= (1 << GE_PRIM_LINES) | SEEN_INDEX16;
}

void IndexGenerator::TranslateLineStrip(int numInds, const u16 *_inds, int indexOffset) {	
	const u16_le *inds = (u16_le*)_inds;
	int numLines = numInds - 1;
	for (int i = 0; i < numLines; i++) {
		*inds_++ = index_ - indexOffset + inds[i];
		*inds_++ = index_ - indexOffset + inds[i + 1];
	}
	count_ += numLines * 2;
	prim_ = GE_PRIM_LINES;
	seenPrims_ |= (1 << GE_PRIM_LINE_STRIP) | SEEN_INDEX16;
}

void IndexGenerator::TranslateRectangles(int numInds, const u8 *inds, int indexOffset) {
	int numRects = numInds / 2;
	for (int i = 0; i < numRects; i++) {
		*inds_++ = index_ - indexOffset + inds[i*2];
		*inds_++ = index_ - indexOffset + inds[i*2+1];
	}
	count_ += numRects * 2;
	prim_ = GE_PRIM_RECTANGLES;
	seenPrims_ |= (1 << GE_PRIM_RECTANGLES) | SEEN_INDEX8;
}

void IndexGenerator::TranslateRectangles(int numInds, const u16 *_inds, int indexOffset) {	
	const u16_le *inds = (u16_le*)_inds;
	int numRects = numInds / 2;
	for (int i = 0; i < numRects; i++) {
		*inds_++ = index_ - indexOffset + inds[i*2];
		*inds_++ = index_ - indexOffset + inds[i*2+1];
	}
	count_ += numRects * 2;
	prim_ = GE_PRIM_RECTANGLES;
	seenPrims_ |= (1 << GE_PRIM_RECTANGLES) | SEEN_INDEX16;
}