/*
 *	Copyright (C) 2007-2009 Gabest
 *	http://www.gabest.org
 *
 *  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; either version 2, or (at your option)
 *  any later version.
 *
 *  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 for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with GNU Make; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *  http://www.gnu.org/copyleft/gpl.html
 *
 */

// TODO: JIT Draw* (flags: depth, texture, color (+iip), scissor)

#include "stdafx.h"
#include "GSRasterizer.h"

// Set this to 1 to remove a lot of non-const div/modulus ops from the rasterization process.
// Might likely be a measurable speedup but limits threading to 1, 2, 4, and 8 threads.
// note by rama: Speedup is around 5% on average.

// #define UseConstThreadCount

#ifdef UseConstThreadCount
	// ThreadsConst - const number of threads.  User-configured threads (in GSdx panel) must match
	// this value if UseConstThreadCount is enabled. [yeah, it's hacky for now]
	static const int ThreadsConst = 2;
	static const int ThreadMaskConst = ThreadsConst - 1;
#endif

#define THREAD_HEIGHT 5

GSRasterizer::GSRasterizer(IDrawScanline* ds)
	: m_ds(ds)
	, m_id(0)
	, m_threads(1)
{
	m_edge.buff = (GSVertexSW*)vmalloc(sizeof(GSVertexSW) * 2048, false);
	m_edge.count = 0;
}

GSRasterizer::~GSRasterizer()
{
	if(m_edge.buff != NULL) vmfree(m_edge.buff, sizeof(GSVertexSW) * 2048);

	delete m_ds;
}

bool GSRasterizer::IsOneOfMyScanlines(int scanline) const
{
	#ifdef UseConstThreadCount

	return ThreadMaskConst == 0 || (scanline & ThreadMaskConst) == m_id;

	#else

	return m_threads == 1 || ((scanline >> THREAD_HEIGHT) % m_threads) == m_id;

	#endif
}

void GSRasterizer::Draw(const GSRasterizerData* data)
{
	m_ds->BeginDraw(data->param);

	const GSVertexSW* vertices = data->vertices;
	const int count = data->count;

	m_scissor = data->scissor;
	m_fscissor = GSVector4(data->scissor);

	m_stats.Reset();

	int64 start = __rdtsc();

	switch(data->primclass)
	{
	case GS_POINT_CLASS:
		m_stats.prims = count;
		for(int i = 0; i < count; i++) DrawPoint(&vertices[i]);
		break;
	case GS_LINE_CLASS:
		ASSERT(!(count & 1));
		m_stats.prims = count / 2;
		for(int i = 0; i < count; i += 2) DrawLine(&vertices[i]);
		break;
	case GS_TRIANGLE_CLASS:
		ASSERT(!(count % 3));
		m_stats.prims = count / 3;
		for(int i = 0; i < count; i += 3) DrawTriangle(&vertices[i]);
		break;
	case GS_SPRITE_CLASS:
		ASSERT(!(count & 1));
		m_stats.prims = count / 2;
		for(int i = 0; i < count; i += 2) DrawSprite(&vertices[i]);
		break;
	default:
		__assume(0);
	}

	m_stats.ticks = __rdtsc() - start;

	m_ds->EndDraw(m_stats, data->frame);
}

void GSRasterizer::GetStats(GSRasterizerStats& stats)
{
	stats = m_stats;
}

void GSRasterizer::DrawPoint(const GSVertexSW* v)
{
	GSVector4i p(v->p);

	if(m_scissor.left <= p.x && p.x < m_scissor.right && m_scissor.top <= p.y && p.y < m_scissor.bottom)
	{
		if(IsOneOfMyScanlines(p.y))
		{
			m_stats.pixels++;

			m_ds->SetupPrim(v, *v);

			m_ds->DrawScanline(1, p.x, p.y, *v);
		}
	}
}

void GSRasterizer::DrawLine(const GSVertexSW* v)
{
	GSVertexSW dv = v[1] - v[0];

	GSVector4 dp = dv.p.abs();

	int i = (dp < dp.yxwz()).mask() & 1; // |dx| <= |dy|

	if(m_ds->IsEdge())
	{
		DrawEdge(v[0], v[1], dv, i, 0);
		DrawEdge(v[0], v[1], dv, i, 1);

		Flush(v, GSVertexSW::zero(), true);

		return;
	}

	GSVector4i dpi(dp);

	if(dpi.y == 0)
	{
		if(dpi.x > 0)
		{
			// shortcut for horizontal lines

			GSVector4 mask = (v[0].p > v[1].p).xxxx();

			GSVertexSW l, dl;

			l.p = v[0].p.blend32(v[1].p, mask);
			l.t = v[0].t.blend32(v[1].t, mask);
			l.c = v[0].c.blend32(v[1].c, mask);

			GSVector4 r;

			r = v[1].p.blend32(v[0].p, mask);

			GSVector4i p(l.p);

			if(m_scissor.top <= p.y && p.y < m_scissor.bottom)
			{
				GSVertexSW dscan = dv / dv.p.xxxx();

				l.p = l.p.upl(r).xyzw(l.p); // r.x => l.y

				DrawTriangleSection(p.y, p.y + 1, l, dl, dscan);

				Flush(v, dscan);
			}
		}

		return;
	}

	int steps = dpi.v[i];

	if(steps > 0)
	{
		GSVertexSW edge = v[0];
		GSVertexSW dedge = dv / GSVector4(dp.v[i]);

		GSVertexSW* RESTRICT e = m_edge.buff;

		while(1)
		{
			GSVector4i p(edge.p);

			if(m_scissor.left <= p.x && p.x < m_scissor.right && m_scissor.top <= p.y && p.y < m_scissor.bottom)
			{
				if(IsOneOfMyScanlines(p.y))
				{
					*e = edge;

					e->p.i16[0] = (int16)p.x;
					e->p.i16[1] = (int16)p.y;
					e->p.i16[2] = 1;

					e++;
				}
			}

			if(--steps == 0) break;

			edge += dedge;
		}

		m_edge.count = e - m_edge.buff;

		m_stats.pixels += m_edge.count;

		Flush(v, GSVertexSW::zero());
	}
}

static const int s_abc[8][4] =
{
	{0, 1, 2, 0}, // c >= b >= a
	{1, 0, 2, 0}, // c >= a > b
	{0, 0, 0, 0},
	{1, 2, 0, 0}, // a > c >= b
	{0, 2, 1, 0}, // b > c >= a
	{0, 0, 0, 0},
	{2, 0, 1, 0}, // b >= a > c
	{2, 1, 0, 0}, // a > b > c
};

void GSRasterizer::DrawTriangle(const GSVertexSW* vertices)
{
	// TODO: GSVertexSW::c/t could be merged into a GSVector8

	GSVertexSW v[4];
	GSVertexSW dv[3];
	GSVertexSW ddv[3];
	GSVertexSW longest;
	GSVertexSW dscan;

	GSVector4 aabb = vertices[0].p.yyyy(vertices[1].p);
	GSVector4 bccb = vertices[1].p.yyyy(vertices[2].p).xzzx();

	int abc = (aabb > bccb).mask() & 7;

	v[0] = vertices[s_abc[abc][0]];
	v[1] = vertices[s_abc[abc][1]];
	v[2] = vertices[s_abc[abc][2]];

	aabb = v[0].p.yyyy(v[1].p);
	bccb = v[1].p.yyyy(v[2].p).xzzx();

	int i = (aabb == bccb).mask() & 7;

	GSVector4 tbf = aabb.xzxz(bccb).ceil();
	GSVector4 tbmax = tbf.max(m_fscissor.ywyw());
	GSVector4 tbmin = tbf.min(m_fscissor.ywyw());
	GSVector4i tb = GSVector4i(tbmax.xzyw(tbmin));

	dv[0] = v[1] - v[0];
	dv[1] = v[2] - v[0];
	dv[2] = v[2] - v[1];

	switch(i)
	{
	case 0: // a < b < c
		ddv[0] = dv[0] / dv[0].p.yyyy();
		ddv[1] = dv[1] / dv[1].p.yyyy();
		ddv[2] = dv[2] / dv[2].p.yyyy();
		longest = ddv[1] * dv[0].p.yyyy() - dv[0];
		v[3] = v[1] + longest; // point between v[0] and v[2] where y == v[1].y
		break;
	case 1: // a == b < c
		ddv[1] = dv[1] / dv[1].p.yyyy();
		ddv[2] = dv[2] / dv[2].p.yyyy();
		longest = dv[0]; // should be negated to be equal to "ddv[1] * dv[0].p.yyyy() - dv[0]", but it's easier to change the index of v/ddv later
		break;
	case 4: // a < b == c
		ddv[0] = dv[0] / dv[0].p.yyyy();
		ddv[1] = dv[1] / dv[1].p.yyyy();
		longest = dv[2];
		break;
	case 7: // a == b == c
		return;
	default:
		__assume(0);
	}

	int j = longest.p.upl(longest.p == GSVector4::zero()).mask();

	if(j & 2) return;

	j &= 1;

	dscan = longest * longest.p.xxxx().rcp();
	
	if(m_ds->IsEdge())
	{
		GSVector4 dx = dv[0].p.upl(dv[1].p).xyxy(dv[2].p);
		GSVector4 dy = dv[0].p.upl(dv[1].p).zwyx(dv[2].p);

		GSVector4 a = dx.abs() < dy.abs(); // |dx| <= |dy|
		GSVector4 b = dx < GSVector4::zero(); // dx < 0
		GSVector4 c = longest.p.xxxx() < GSVector4::zero(); // longest.p.x < 0

		int i = a.mask();
		int j = ((a | b) ^ c).mask() ^ 2; // evil

		DrawEdge(v[0], v[1], dv[0], i & 1, j & 1);
		DrawEdge(v[0], v[2], dv[1], i & 2, j & 2);
		DrawEdge(v[1], v[2], dv[2], i & 4, j & 4);

		Flush(v, GSVertexSW::zero(), true);
	}

	switch(i)
	{
	case 0: // a < b < c
		
		if(tb.x < tb.z)
		{
			GSVertexSW l = v[0];
			GSVertexSW dl = ddv[j];

			GSVector4 dy = tbmax.xxxx() - l.p.yyyy();

			l.p = l.p.xxzw(); // r.x => l.y
			dl.p = dl.p.upl(ddv[1 - j].p).xyzw(dl.p); // dr.x => dl.y

			l += dl * dy;

			DrawTriangleSection(tb.x, tb.z, l, dl, dscan);
		}

		if(tb.y < tb.w)
		{
			// TODO: j == 1 (x2 < x3 < x0 < x1)
			// v[3] isn't accurate enough, it may leave gaps horizontally if it happens to be on the left side of the triangle
			// example: previous triangle's scanline ends on 48.9999, this one's starts from 49.0001, the pixel at 49 isn't drawn

			GSVertexSW l = v[1 + (1 << j)];
			GSVertexSW dl = ddv[2 - j];

			GSVector4 dy = tbmax.zzzz() - l.p.yyyy();

			l.p = l.p.upl(v[3 - (1 << j)].p).xyzw(l.p); // r.x => l.y
			dl.p = dl.p.upl(ddv[1 + j].p).xyzw(dl.p); // dr.x => dl.y

			l += dl * dy;

			DrawTriangleSection(tb.y, tb.w, l, dl, dscan);
		}

		break;

	case 1: // a == b < c

		if(tb.x < tb.w)
		{
			GSVertexSW l = v[j];
			GSVertexSW dl = ddv[1 + j];

			GSVector4 dy = tbmax.xxxx() - l.p.yyyy();

			l.p = l.p.upl(v[1 - j].p).xyzw(l.p); // r.x => l.y
			dl.p = dl.p.upl(ddv[2 - j].p).xyzw(dl.p); // dr.x => dl.y

			l += dl * dy;

			DrawTriangleSection(tb.x, tb.w, l, dl, dscan);
		}

		break;

	case 4: // a < b == c

		if(tb.x < tb.w)
		{
			GSVertexSW l = v[0];
			GSVertexSW dl = ddv[j];

			GSVector4 dy = tbmax.xxxx() - l.p.yyyy();

			l.p = l.p.xxzw(); // r.x => l.y
			dl.p = dl.p.upl(ddv[1 - j].p).xyzw(dl.p); // dr.x => dl.y

			l += dl * dy;

			DrawTriangleSection(tb.x, tb.w, l, dl, dscan);
		}

		break;

	default:
		__assume(0);
	}

	Flush(v, dscan);
}

void GSRasterizer::DrawTriangleSection(int top, int bottom, GSVertexSW& l, const GSVertexSW& dl, const GSVertexSW& dscan)
{
	ASSERT(top < bottom);

	GSVertexSW* RESTRICT e = &m_edge.buff[m_edge.count];

	while(1)
	{
		if(IsOneOfMyScanlines(top))
		{
			GSVector4 lrf = l.p.ceil();
			GSVector4 lrmax = lrf.max(m_fscissor.xzxz());
			GSVector4 lrmin = lrf.min(m_fscissor.xzxz());
			GSVector4i lr = GSVector4i(lrmax.xxyy(lrmin));

			int left = lr.extract32<0>();
			int right = lr.extract32<2>();

			int pixels = right - left;

			if(pixels > 0)
			{
				m_stats.pixels += pixels;

				*e = l + dscan * (lrmax - l.p).xxxx();

				e->p.i16[0] = (int16)left;
				e->p.i16[1] = (int16)top;
				e->p.i16[2] = (int16)pixels;

				e++;
			}
		}

		if(++top >= bottom) break;

		l += dl;
	}

	m_edge.count += e - &m_edge.buff[m_edge.count];
}

void GSRasterizer::DrawSprite(const GSVertexSW* vertices)
{
	GSVertexSW v[2];

	GSVector4 mask = (vertices[0].p < vertices[1].p).xyzw(GSVector4::zero());

	v[0].p = vertices[1].p.blend32(vertices[0].p, mask);
	v[0].t = vertices[1].t.blend32(vertices[0].t, mask);
	v[0].c = vertices[1].c;

	v[1].p = vertices[0].p.blend32(vertices[1].p, mask);
	v[1].t = vertices[0].t.blend32(vertices[1].t, mask);

	GSVector4i r(v[0].p.xyxy(v[1].p).ceil());

	r = r.rintersect(m_scissor);

	if(r.rempty()) return;

	GSVertexSW scan = v[0];

	if(m_ds->IsRect())
	{
		if(m_id == 0)
		{
			m_ds->DrawRect(r, scan);

			m_stats.pixels += r.width() * r.height();
		}

		return;
	}

	GSVertexSW dedge = GSVertexSW::zero();
	GSVertexSW dscan = GSVertexSW::zero();

	GSVertexSW dv = v[1] - v[0];

	GSVector4 zero = GSVector4::zero();

	dedge.t = (dv.t / dv.p.yyyy()).xyxy(zero).wyww();
	dscan.t = (dv.t / dv.p.xxxx()).xyxy(zero).xwww();

	if(scan.p.y < (float)r.top) scan.t += dedge.t * ((float)r.top - scan.p.y);
	if(scan.p.x < (float)r.left) scan.t += dscan.t * ((float)r.left - scan.p.x);

	m_ds->SetupPrim(v, dscan);

	while(1)
	{
		if(IsOneOfMyScanlines(r.top))
		{
			m_stats.pixels += r.width();

			m_ds->DrawScanline(r.width(), r.left, r.top, scan);
		}

		if(++r.top >= r.bottom) break;

		scan.t += dedge.t;
	}
}

void GSRasterizer::DrawEdge(const GSVertexSW& v0, const GSVertexSW& v1, const GSVertexSW& dv, int orientation, int side)
{
	// orientation:
	// - true: |dv.p.y| > |dv.p.x|
	// - false |dv.p.x| > |dv.p.y|
	// side:
	// - true: top/left edge
	// - false: bottom/right edge

	// TODO: bit slow and too much duplicated code
	// TODO: inner pre-step is still missing (hardly noticable)

	GSVertexSW* RESTRICT e = &m_edge.buff[m_edge.count];
			
	GSVector4 lrtb = v0.p.upl(v1.p).ceil();

	if(orientation)
	{
		GSVector4 tbmax = lrtb.max(m_fscissor.yyyy());
		GSVector4 tbmin = lrtb.min(m_fscissor.wwww());
		GSVector4i tb = GSVector4i(tbmax.zwzw(tbmin));

		int top, bottom;

		GSVertexSW edge, dedge;

		if((dv.p >= GSVector4::zero()).mask() & 2)
		{
			top = tb.extract32<0>();
			bottom = tb.extract32<3>();

			if(top >= bottom) return;

			edge = v0;
			dedge = dv / dv.p.yyyy();

			edge += dedge * (tbmax.zzzz() - edge.p.yyyy());
		}
		else
		{
			top = tb.extract32<1>();
			bottom = tb.extract32<2>();

			if(top >= bottom) return;

			edge = v1;
			dedge = dv / dv.p.yyyy();

			edge += dedge * (tbmax.wwww() - edge.p.yyyy());
		}

		GSVector4i p = GSVector4i(edge.p.upl(dedge.p) * 0x10000);

		int x = p.extract32<0>();
		int dx = p.extract32<1>();

		if(side)
		{
			while(1)
			{
				int xi = x >> 16;
				int xf = x & 0xffff;

				if(m_scissor.left <= xi && xi < m_scissor.right && IsOneOfMyScanlines(xi))
				{
					m_stats.pixels++;

					*e = edge;

					e->t.u32[3] = (0x10000 - xf) & 0xffff;

					e->p.i16[0] = (int16)xi;
					e->p.i16[1] = (int16)top;
					e->p.i16[2] = 1;

					e++;
				}

				if(++top >= bottom) break;

				edge += dedge;
				x += dx;
			}
		}
		else
		{
			while(1)
			{
				int xi = (x >> 16) + 1;
				int xf = x & 0xffff;

				if(m_scissor.left <= xi && xi < m_scissor.right && IsOneOfMyScanlines(xi))
				{
					m_stats.pixels++;

					*e = edge;

					e->t.u32[3] = xf;

					e->p.i16[0] = (int16)xi;
					e->p.i16[1] = (int16)top;
					e->p.i16[2] = 1;

					e++;
				}

				if(++top >= bottom) break;

				edge += dedge;
				x += dx;
			}
		}
	}
	else
	{
		GSVector4 lrmax = lrtb.max(m_fscissor.xxxx());
		GSVector4 lrmin = lrtb.min(m_fscissor.zzzz());
		GSVector4i lr = GSVector4i(lrmax.xyxy(lrmin));

		int left, right;

		GSVertexSW edge, dedge;

		if((dv.p >= GSVector4::zero()).mask() & 1)
		{
			left = lr.extract32<0>();
			right = lr.extract32<3>();

			if(left >= right) return;

			edge = v0;
			dedge = dv / dv.p.xxxx();

			edge += dedge * (lrmax.xxxx() - edge.p.xxxx());
		}
		else
		{
			left = lr.extract32<1>();
			right = lr.extract32<2>();

			if(left >= right) return;

			edge = v1;
			dedge = dv / dv.p.xxxx();

			edge += dedge * (lrmax.yyyy() - edge.p.xxxx());
		}

		GSVector4i p = GSVector4i(edge.p.upl(dedge.p) * 0x10000);

		int y = p.extract32<2>();
		int dy = p.extract32<3>();

		if(side)
		{
			while(1)
			{
				int yi = y >> 16;
				int yf = y & 0xffff;

				if(m_scissor.top <= yi && yi < m_scissor.bottom && IsOneOfMyScanlines(yi))
				{
					m_stats.pixels++;

					*e = edge;
					
					e->t.u32[3] = (0x10000 - yf) & 0xffff;

					e->p.i16[0] = (int16)left;
					e->p.i16[1] = (int16)yi;
					e->p.i16[2] = 1;

					e++;
				}

				if(++left >= right) break;

				edge += dedge;
				y += dy;
			}
		}
		else
		{
			while(1)
			{
				int yi = (y >> 16) + 1;
				int yf = y & 0xffff;

				if(m_scissor.top <= yi && yi < m_scissor.bottom && IsOneOfMyScanlines(yi))
				{
					m_stats.pixels++;

					*e = edge;
					
					e->t.u32[3] = yf;

					e->p.i16[0] = (int16)left;
					e->p.i16[1] = (int16)yi;
					e->p.i16[2] = 1;

					e++;
				}

				if(++left >= right) break;

				edge += dedge;
				y += dy;
			}
		}
	}

	m_edge.count += e - &m_edge.buff[m_edge.count];
}

void GSRasterizer::Flush(const GSVertexSW* vertices, const GSVertexSW& dscan, bool edge)
{
	// TODO: on win64 this could be the place where xmm6-15 are preserved (not by each DrawScanline)

	int count = m_edge.count;

	if(count > 0)
	{
		m_ds->SetupPrim(vertices, dscan);

		const GSVertexSW* RESTRICT e = m_edge.buff;

		int i = 0;

		if(!edge)
		{
			do {m_ds->DrawScanline(e[i].p.i16[2], e[i].p.i16[0], e[i].p.i16[1], e[i]);}
			while(++i < count);
		}
		else
		{
			do {m_ds->DrawEdge(e[i].p.i16[2], e[i].p.i16[0], e[i].p.i16[1], e[i]);}
			while(++i < count);
		}

		m_edge.count = 0;
	}
}

//

GSRasterizerMT::GSRasterizerMT(IDrawScanline* ds, volatile long& sync)
	: GSRasterizer(ds)
	, m_sync(sync)
	, m_data(NULL)
{
	CreateThread();
}

GSRasterizerMT::~GSRasterizerMT()
{
    Draw(NULL);

	CloseThread();
}

void GSRasterizerMT::Draw(const GSRasterizerData* data)
{
	m_data = data;

	m_draw.Set();
}

void GSRasterizerMT::ThreadProc()
{
	while(m_draw.Wait() && m_data != NULL)
	{
		GSRasterizer::Draw(m_data);

        _interlockedbittestandreset(&m_sync, m_id);
	}
}

//

GSRasterizerList::GSRasterizerList()
	: m_sync(0)
{
}

GSRasterizerList::~GSRasterizerList()
{
	for(size_t i = 0; i < size(); i++) delete (*this)[i];
}

void GSRasterizerList::Sync()
{
	while(m_sync) _mm_pause();

	m_stats.ticks = __rdtsc() - m_start;

	for(int i = 0; i < m_threads; i++)
	{
		GSRasterizerStats s;

		(*this)[i]->GetStats(s);

		m_stats.pixels += s.pixels;
		m_stats.prims = std::max<int>(m_stats.prims, s.prims);
	}
}

void GSRasterizerList::Draw(const GSRasterizerData* data, int width, int height)
{
	m_stats.Reset();

	m_start = __rdtsc();

	m_threads = std::min<int>(1 + (height >> THREAD_HEIGHT), size());

	m_sync = 0;

	for(int i = 1; i < m_threads; i++)
	{
		m_sync |= 1 << i;
	}

	for(int i = 1; i < m_threads; i++)
	{
		(*this)[i]->SetThreadId(i, m_threads);
		(*this)[i]->Draw(data);
	}

	(*this)[0]->SetThreadId(0, m_threads);
	(*this)[0]->Draw(data);
}

void GSRasterizerList::GetStats(GSRasterizerStats& stats)
{
	stats = m_stats;
}

void GSRasterizerList::PrintStats()
{
	if(!empty())
	{
		front()->PrintStats();
	}
}