1/*-------------------------------------------------------------------------
2 * drawElements Quality Program Reference Renderer
3 * -----------------------------------------------
4 *
5 * Copyright 2014 The Android Open Source Project
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 *      http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 *
19 *//*!
20 * \file
21 * \brief Reference rasterizer
22 *//*--------------------------------------------------------------------*/
23
24#include "rrRasterizer.hpp"
25#include "deMath.h"
26#include "tcuVectorUtil.hpp"
27
28namespace rr
29{
30
31inline deInt64 toSubpixelCoord (float v)
32{
33	return (deInt64)(v * (1<<RASTERIZER_SUBPIXEL_BITS) + (v < 0.f ? -0.5f : 0.5f));
34}
35
36inline deInt64 toSubpixelCoord (deInt32 v)
37{
38	return v << RASTERIZER_SUBPIXEL_BITS;
39}
40
41inline deInt32 ceilSubpixelToPixelCoord (deInt64 coord, bool fillEdge)
42{
43	if (coord >= 0)
44		return (deInt32)((coord + ((1ll<<RASTERIZER_SUBPIXEL_BITS) - (fillEdge ? 0 : 1))) >> RASTERIZER_SUBPIXEL_BITS);
45	else
46		return (deInt32)((coord + (fillEdge ? 1 : 0)) >> RASTERIZER_SUBPIXEL_BITS);
47}
48
49inline deInt32 floorSubpixelToPixelCoord (deInt64 coord, bool fillEdge)
50{
51	if (coord >= 0)
52		return (deInt32)((coord - (fillEdge ? 1 : 0)) >> RASTERIZER_SUBPIXEL_BITS);
53	else
54		return (deInt32)((coord - ((1ll<<RASTERIZER_SUBPIXEL_BITS) - (fillEdge ? 0 : 1))) >> RASTERIZER_SUBPIXEL_BITS);
55}
56
57static inline void initEdgeCCW (EdgeFunction& edge, const HorizontalFill horizontalFill, const VerticalFill verticalFill, const deInt64 x0, const deInt64 y0, const deInt64 x1, const deInt64 y1)
58{
59	// \note See EdgeFunction documentation for details.
60
61	const deInt64	xd			= x1-x0;
62	const deInt64	yd			= y1-y0;
63	bool			inclusive	= false;	//!< Inclusive in CCW orientation.
64
65	if (yd == 0)
66		inclusive = verticalFill == FILL_BOTTOM ? xd >= 0 : xd <= 0;
67	else
68		inclusive = horizontalFill == FILL_LEFT ? yd <= 0 : yd >= 0;
69
70	edge.a			= (y0 - y1);
71	edge.b			= (x1 - x0);
72	edge.c			= x0*y1 - y0*x1;
73	edge.inclusive	= inclusive; //!< \todo [pyry] Swap for CW triangles
74}
75
76static inline void reverseEdge (EdgeFunction& edge)
77{
78	edge.a			= -edge.a;
79	edge.b			= -edge.b;
80	edge.c			= -edge.c;
81	edge.inclusive	= !edge.inclusive;
82}
83
84static inline deInt64 evaluateEdge (const EdgeFunction& edge, const deInt64 x, const deInt64 y)
85{
86	return edge.a*x + edge.b*y + edge.c;
87}
88
89static inline bool isInsideCCW (const EdgeFunction& edge, const deInt64 edgeVal)
90{
91	return edge.inclusive ? (edgeVal >= 0) : (edgeVal > 0);
92}
93
94namespace LineRasterUtil
95{
96
97struct SubpixelLineSegment
98{
99	const tcu::Vector<deInt64,2>	m_v0;
100	const tcu::Vector<deInt64,2>	m_v1;
101
102	SubpixelLineSegment (const tcu::Vector<deInt64,2>& v0, const tcu::Vector<deInt64,2>& v1)
103		: m_v0(v0)
104		, m_v1(v1)
105	{
106	}
107
108	tcu::Vector<deInt64,2> direction (void) const
109	{
110		return m_v1 - m_v0;
111	}
112};
113
114enum LINE_SIDE
115{
116	LINE_SIDE_INTERSECT = 0,
117	LINE_SIDE_LEFT,
118	LINE_SIDE_RIGHT
119};
120
121static tcu::Vector<deInt64,2> toSubpixelVector (const tcu::Vec2& v)
122{
123	return tcu::Vector<deInt64,2>(toSubpixelCoord(v.x()), toSubpixelCoord(v.y()));
124}
125
126static tcu::Vector<deInt64,2> toSubpixelVector (const tcu::IVec2& v)
127{
128	return tcu::Vector<deInt64,2>(toSubpixelCoord(v.x()), toSubpixelCoord(v.y()));
129}
130
131#if defined(DE_DEBUG)
132static bool isTheCenterOfTheFragment (const tcu::Vector<deInt64,2>& a)
133{
134	const deUint64 pixelSize = 1ll << (RASTERIZER_SUBPIXEL_BITS);
135	const deUint64 halfPixel = 1ll << (RASTERIZER_SUBPIXEL_BITS-1);
136	return	((a.x() & (pixelSize-1)) == halfPixel &&
137				(a.y() & (pixelSize-1)) == halfPixel);
138}
139
140static bool inViewport (const tcu::IVec2& p, const tcu::IVec4& viewport)
141{
142	return	p.x() >= viewport.x() &&
143			p.y() >= viewport.y() &&
144			p.x() <  viewport.x() + viewport.z() &&
145			p.y() <  viewport.y() + viewport.w();
146}
147#endif // DE_DEBUG
148
149// returns true if vertex is on the left side of the line
150static bool vertexOnLeftSideOfLine (const tcu::Vector<deInt64,2>& p, const SubpixelLineSegment& l)
151{
152	const tcu::Vector<deInt64,2> u = l.direction();
153	const tcu::Vector<deInt64,2> v = ( p - l.m_v0);
154	const deInt64 crossProduct = (u.x() * v.y() - u.y() * v.x());
155	return crossProduct < 0;
156}
157
158// returns true if vertex is on the right side of the line
159static bool vertexOnRightSideOfLine (const tcu::Vector<deInt64,2>& p, const SubpixelLineSegment& l)
160{
161	const tcu::Vector<deInt64,2> u = l.direction();
162	const tcu::Vector<deInt64,2> v = ( p - l.m_v0);
163	const deInt64 crossProduct = (u.x() * v.y() - u.y() * v.x());
164	return crossProduct > 0;
165}
166
167// returns true if vertex is on the line
168static bool vertexOnLine (const tcu::Vector<deInt64,2>& p, const SubpixelLineSegment& l)
169{
170	const tcu::Vector<deInt64,2> u = l.direction();
171	const tcu::Vector<deInt64,2> v = ( p - l.m_v0);
172	const deInt64 crossProduct = (u.x() * v.y() - u.y() * v.x());
173	return crossProduct == 0; // cross product == 0
174}
175
176// returns true if vertex is on the line segment
177static bool vertexOnLineSegment (const tcu::Vector<deInt64,2>& p, const SubpixelLineSegment& l)
178{
179	if (!vertexOnLine(p, l))
180		return false;
181
182	const tcu::Vector<deInt64,2> v	= l.direction();
183	const tcu::Vector<deInt64,2> u1	= ( p - l.m_v0);
184	const tcu::Vector<deInt64,2> u2	= ( p - l.m_v1);
185
186	if (v.x() == 0 && v.y() == 0)
187		return false;
188
189	return	tcu::dot( v, u1) >= 0 &&
190			tcu::dot(-v, u2) >= 0; // dot (A->B, A->V) >= 0 and dot (B->A, B->V) >= 0
191}
192
193static LINE_SIDE getVertexSide (const tcu::Vector<deInt64,2>& v, const SubpixelLineSegment& l)
194{
195	if (vertexOnLeftSideOfLine(v, l))
196		return LINE_SIDE_LEFT;
197	else if (vertexOnRightSideOfLine(v, l))
198		return LINE_SIDE_RIGHT;
199	else if (vertexOnLine(v, l))
200		return LINE_SIDE_INTERSECT;
201	else
202	{
203		DE_ASSERT(false);
204		return LINE_SIDE_INTERSECT;
205	}
206}
207
208// returns true if angle between line and given cornerExitNormal is in range (-45, 45)
209bool lineInCornerAngleRange (const SubpixelLineSegment& line, const tcu::Vector<deInt64,2>& cornerExitNormal)
210{
211	// v0 -> v1 has angle difference to cornerExitNormal in range (-45, 45)
212	const tcu::Vector<deInt64,2> v = line.direction();
213	const deInt64 dotProduct = dot(v, cornerExitNormal);
214
215	// dotProduct > |v1-v0|*|cornerExitNormal|/sqrt(2)
216	if (dotProduct < 0)
217		return false;
218	return 2 * dotProduct * dotProduct > tcu::lengthSquared(v)*tcu::lengthSquared(cornerExitNormal);
219}
220
221// returns true if angle between line and given cornerExitNormal is in range (-135, 135)
222bool lineInCornerOutsideAngleRange (const SubpixelLineSegment& line, const tcu::Vector<deInt64,2>& cornerExitNormal)
223{
224	// v0 -> v1 has angle difference to cornerExitNormal in range (-135, 135)
225	const tcu::Vector<deInt64,2> v = line.direction();
226	const deInt64 dotProduct = dot(v, cornerExitNormal);
227
228	// dotProduct > -|v1-v0|*|cornerExitNormal|/sqrt(2)
229	if (dotProduct >= 0)
230		return true;
231	return 2 * (-dotProduct) * (-dotProduct) < tcu::lengthSquared(v)*tcu::lengthSquared(cornerExitNormal);
232}
233
234bool doesLineSegmentExitDiamond (const SubpixelLineSegment& line, const tcu::Vector<deInt64,2>& diamondCenter)
235{
236	DE_ASSERT(isTheCenterOfTheFragment(diamondCenter));
237
238	// Diamond Center is at diamondCenter in subpixel coords
239
240	const deInt64 halfPixel = 1ll << (RASTERIZER_SUBPIXEL_BITS-1);
241
242	const struct DiamondBound
243	{
244		tcu::Vector<deInt64,2>	p0;
245		tcu::Vector<deInt64,2>	p1;
246		bool					edgeInclusive; // would a point on the bound be inside of the region
247	} bounds[] =
248	{
249		{ diamondCenter + tcu::Vector<deInt64,2>(0,				-halfPixel),	diamondCenter + tcu::Vector<deInt64,2>(-halfPixel,	0),				 false	},
250		{ diamondCenter + tcu::Vector<deInt64,2>(-halfPixel,	0),				diamondCenter + tcu::Vector<deInt64,2>(0,			halfPixel),		 false	},
251		{ diamondCenter + tcu::Vector<deInt64,2>(0,				halfPixel),		diamondCenter + tcu::Vector<deInt64,2>(halfPixel,	0),				 true	},
252		{ diamondCenter + tcu::Vector<deInt64,2>(halfPixel,		0),				diamondCenter + tcu::Vector<deInt64,2>(0,			-halfPixel),	 true	},
253	};
254
255	const struct DiamondCorners
256	{
257		enum CORNER_EDGE_CASE_BEHAVIOR
258		{
259			CORNER_EDGE_CASE_NONE,							// if the line intersects just a corner, no entering or exiting
260			CORNER_EDGE_CASE_HIT,							// if the line intersects just a corner, entering and exit
261			CORNER_EDGE_CASE_HIT_FIRST_QUARTER,				// if the line intersects just a corner and the line has either endpoint in (+X,-Y) direction (preturbing moves the line inside)
262			CORNER_EDGE_CASE_HIT_SECOND_QUARTER				// if the line intersects just a corner and the line has either endpoint in (+X,+Y) direction (preturbing moves the line inside)
263		};
264		enum CORNER_START_CASE_BEHAVIOR
265		{
266			CORNER_START_CASE_NONE,							// the line starting point is outside, no exiting
267			CORNER_START_CASE_OUTSIDE,						// exit, if line does not intersect the region (preturbing moves the start point inside)
268			CORNER_START_CASE_POSITIVE_Y_45,				// exit, if line the angle of line vector and X-axis is in range (0, 45] in positive Y side.
269			CORNER_START_CASE_NEGATIVE_Y_45					// exit, if line the angle of line vector and X-axis is in range [0, 45] in negative Y side.
270		};
271		enum CORNER_END_CASE_BEHAVIOR
272		{
273			CORNER_END_CASE_NONE,							// end is inside, no exiting (preturbing moves the line end inside)
274			CORNER_END_CASE_DIRECTION,						// exit, if line intersected the region (preturbing moves the line end outside)
275			CORNER_END_CASE_DIRECTION_AND_FIRST_QUARTER,	// exit, if line intersected the region, or line originates from (+X,-Y) direction (preturbing moves the line end outside)
276			CORNER_END_CASE_DIRECTION_AND_SECOND_QUARTER	// exit, if line intersected the region, or line originates from (+X,+Y) direction (preturbing moves the line end outside)
277		};
278
279		tcu::Vector<deInt64,2>		dp;
280		bool						pointInclusive;			// would a point in this corner intersect with the region
281		CORNER_EDGE_CASE_BEHAVIOR	lineBehavior;			// would a line segment going through this corner intersect with the region
282		CORNER_START_CASE_BEHAVIOR	startBehavior;			// how the corner behaves if the start point at the corner
283		CORNER_END_CASE_BEHAVIOR	endBehavior;			// how the corner behaves if the end point at the corner
284
285	} corners[] =
286	{
287		{ tcu::Vector<deInt64,2>(0,				-halfPixel),	false,	DiamondCorners::CORNER_EDGE_CASE_HIT_SECOND_QUARTER,	DiamondCorners::CORNER_START_CASE_POSITIVE_Y_45,	DiamondCorners::CORNER_END_CASE_DIRECTION_AND_SECOND_QUARTER},
288		{ tcu::Vector<deInt64,2>(-halfPixel,	0),				false,	DiamondCorners::CORNER_EDGE_CASE_NONE,					DiamondCorners::CORNER_START_CASE_NONE,				DiamondCorners::CORNER_END_CASE_DIRECTION					},
289		{ tcu::Vector<deInt64,2>(0,				halfPixel),		false,	DiamondCorners::CORNER_EDGE_CASE_HIT_FIRST_QUARTER,		DiamondCorners::CORNER_START_CASE_NEGATIVE_Y_45,	DiamondCorners::CORNER_END_CASE_DIRECTION_AND_FIRST_QUARTER	},
290		{ tcu::Vector<deInt64,2>(halfPixel,		0),				true,	DiamondCorners::CORNER_EDGE_CASE_HIT,					DiamondCorners::CORNER_START_CASE_OUTSIDE,			DiamondCorners::CORNER_END_CASE_NONE						},
291	};
292
293	// Corner cases at the corners
294	for (int ndx = 0; ndx < DE_LENGTH_OF_ARRAY(corners); ++ndx)
295	{
296		const tcu::Vector<deInt64,2> p	= diamondCenter + corners[ndx].dp;
297		const bool intersectsAtCorner	= LineRasterUtil::vertexOnLineSegment(p, line);
298
299		if (!intersectsAtCorner)
300			continue;
301
302		// line segment body intersects with the corner
303		if (p != line.m_v0 && p != line.m_v1)
304		{
305			if (corners[ndx].lineBehavior == DiamondCorners::CORNER_EDGE_CASE_HIT)
306				return true;
307
308			// endpoint in (+X, -Y) (X or Y may be 0) direction <==> x*y <= 0
309			if (corners[ndx].lineBehavior == DiamondCorners::CORNER_EDGE_CASE_HIT_FIRST_QUARTER &&
310				(line.direction().x() * line.direction().y()) <= 0)
311				return true;
312
313			// endpoint in (+X, +Y) (Y > 0) direction <==> x*y > 0
314			if (corners[ndx].lineBehavior == DiamondCorners::CORNER_EDGE_CASE_HIT_SECOND_QUARTER &&
315				(line.direction().x() * line.direction().y()) > 0)
316				return true;
317		}
318
319		// line exits the area at the corner
320		if (lineInCornerAngleRange(line, corners[ndx].dp))
321		{
322			const bool startIsInside = corners[ndx].pointInclusive || p != line.m_v0;
323			const bool endIsOutside = !corners[ndx].pointInclusive || p != line.m_v1;
324
325			// starting point is inside the region and end endpoint is outside
326			if (startIsInside && endIsOutside)
327				return true;
328		}
329
330		// line end is at the corner
331		if (p == line.m_v1)
332		{
333			if (corners[ndx].endBehavior == DiamondCorners::CORNER_END_CASE_DIRECTION ||
334				corners[ndx].endBehavior == DiamondCorners::CORNER_END_CASE_DIRECTION_AND_FIRST_QUARTER ||
335				corners[ndx].endBehavior == DiamondCorners::CORNER_END_CASE_DIRECTION_AND_SECOND_QUARTER)
336			{
337				// did the line intersect the region
338				if (lineInCornerAngleRange(line, corners[ndx].dp))
339					return true;
340			}
341
342			// due to the perturbed endpoint, lines at this the angle will cause and enter-exit pair
343			if (corners[ndx].endBehavior == DiamondCorners::CORNER_END_CASE_DIRECTION_AND_FIRST_QUARTER &&
344				line.direction().x() < 0 &&
345				line.direction().y() > 0)
346				return true;
347			if (corners[ndx].endBehavior == DiamondCorners::CORNER_END_CASE_DIRECTION_AND_SECOND_QUARTER &&
348				line.direction().x() > 0 &&
349				line.direction().y() > 0)
350				return true;
351		}
352
353		// line start is at the corner
354		if (p == line.m_v0)
355		{
356			if (corners[ndx].startBehavior == DiamondCorners::CORNER_START_CASE_OUTSIDE)
357			{
358				// if the line is not going inside, it will exit
359				if (lineInCornerOutsideAngleRange(line, corners[ndx].dp))
360					return true;
361			}
362
363			// exit, if line the angle between line vector and X-axis is in range (0, 45] in positive Y side.
364			if (corners[ndx].startBehavior == DiamondCorners::CORNER_START_CASE_POSITIVE_Y_45 &&
365				line.direction().x() > 0 &&
366				line.direction().y() > 0 &&
367				line.direction().y() <= line.direction().x())
368				return true;
369
370			// exit, if line the angle between line vector and X-axis is in range [0, 45] in negative Y side.
371			if (corners[ndx].startBehavior == DiamondCorners::CORNER_START_CASE_NEGATIVE_Y_45 &&
372				 line.direction().x() > 0 &&
373				 line.direction().y() <= 0 &&
374				-line.direction().y() <= line.direction().x())
375				return true;
376		}
377	}
378
379	// Does the line intersect boundary at the left == exits the diamond
380	for (int ndx = 0; ndx < DE_LENGTH_OF_ARRAY(bounds); ++ndx)
381	{
382		const bool startVertexInside =	LineRasterUtil::vertexOnLeftSideOfLine						(line.m_v0, LineRasterUtil::SubpixelLineSegment(bounds[ndx].p0, bounds[ndx].p1)) ||
383										(bounds[ndx].edgeInclusive && LineRasterUtil::vertexOnLine	(line.m_v0, LineRasterUtil::SubpixelLineSegment(bounds[ndx].p0, bounds[ndx].p1)));
384		const bool endVertexInside =	LineRasterUtil::vertexOnLeftSideOfLine						(line.m_v1, LineRasterUtil::SubpixelLineSegment(bounds[ndx].p0, bounds[ndx].p1)) ||
385										(bounds[ndx].edgeInclusive && LineRasterUtil::vertexOnLine	(line.m_v1, LineRasterUtil::SubpixelLineSegment(bounds[ndx].p0, bounds[ndx].p1)));
386
387		// start must be on inside this half space (left or at the inclusive boundary)
388		if (!startVertexInside)
389			continue;
390
391		// end must be outside of this half-space (right or at non-inclusive boundary)
392		if (endVertexInside)
393			continue;
394
395		// Does the line via v0 and v1 intersect the line segment p0-p1
396		// <==> p0 and p1 are the different sides (LEFT, RIGHT) of the v0-v1 line.
397		// Corners are not allowed, they are checked already
398		LineRasterUtil::LINE_SIDE sideP0 = LineRasterUtil::getVertexSide(bounds[ndx].p0, line);
399		LineRasterUtil::LINE_SIDE sideP1 = LineRasterUtil::getVertexSide(bounds[ndx].p1, line);
400
401		if (sideP0 != LineRasterUtil::LINE_SIDE_INTERSECT &&
402			sideP1 != LineRasterUtil::LINE_SIDE_INTERSECT &&
403			sideP0 != sideP1)
404			return true;
405	}
406
407	return false;
408}
409
410} // LineRasterUtil
411
412TriangleRasterizer::TriangleRasterizer (const tcu::IVec4& viewport, const int numSamples, const RasterizationState& state)
413	: m_viewport		(viewport)
414	, m_numSamples		(numSamples)
415	, m_winding			(state.winding)
416	, m_horizontalFill	(state.horizontalFill)
417	, m_verticalFill	(state.verticalFill)
418	, m_face			(FACETYPE_LAST)
419{
420}
421
422/*--------------------------------------------------------------------*//*!
423 * \brief Initialize triangle rasterization
424 * \param v0 Screen-space coordinates (x, y, z) and 1/w for vertex 0.
425 * \param v1 Screen-space coordinates (x, y, z) and 1/w for vertex 1.
426 * \param v2 Screen-space coordinates (x, y, z) and 1/w for vertex 2.
427 *//*--------------------------------------------------------------------*/
428void TriangleRasterizer::init (const tcu::Vec4& v0, const tcu::Vec4& v1, const tcu::Vec4& v2)
429{
430	m_v0 = v0;
431	m_v1 = v1;
432	m_v2 = v2;
433
434	// Positions in fixed-point coordinates.
435	const deInt64	x0		= toSubpixelCoord(v0.x());
436	const deInt64	y0		= toSubpixelCoord(v0.y());
437	const deInt64	x1		= toSubpixelCoord(v1.x());
438	const deInt64	y1		= toSubpixelCoord(v1.y());
439	const deInt64	x2		= toSubpixelCoord(v2.x());
440	const deInt64	y2		= toSubpixelCoord(v2.y());
441
442	// Initialize edge functions.
443	if (m_winding == WINDING_CCW)
444	{
445		initEdgeCCW(m_edge01, m_horizontalFill, m_verticalFill, x0, y0, x1, y1);
446		initEdgeCCW(m_edge12, m_horizontalFill, m_verticalFill, x1, y1, x2, y2);
447		initEdgeCCW(m_edge20, m_horizontalFill, m_verticalFill, x2, y2, x0, y0);
448	}
449	else
450	{
451		// Reverse edges
452		initEdgeCCW(m_edge01, m_horizontalFill, m_verticalFill, x1, y1, x0, y0);
453		initEdgeCCW(m_edge12, m_horizontalFill, m_verticalFill, x2, y2, x1, y1);
454		initEdgeCCW(m_edge20, m_horizontalFill, m_verticalFill, x0, y0, x2, y2);
455	}
456
457	// Determine face.
458	const deInt64	s				= evaluateEdge(m_edge01, x2, y2);
459	const bool		positiveArea	= (m_winding == WINDING_CCW) ? (s > 0) : (s < 0);
460	m_face = positiveArea ? FACETYPE_FRONT : FACETYPE_BACK;
461
462	if (!positiveArea)
463	{
464		// Reverse edges so that we can use CCW area tests & interpolation
465		reverseEdge(m_edge01);
466		reverseEdge(m_edge12);
467		reverseEdge(m_edge20);
468	}
469
470	// Bounding box
471	const deInt64	xMin	= de::min(de::min(x0, x1), x2);
472	const deInt64	xMax	= de::max(de::max(x0, x1), x2);
473	const deInt64	yMin	= de::min(de::min(y0, y1), y2);
474	const deInt64	yMax	= de::max(de::max(y0, y1), y2);
475
476	m_bboxMin.x() = floorSubpixelToPixelCoord	(xMin, m_horizontalFill	== FILL_LEFT);
477	m_bboxMin.y() = floorSubpixelToPixelCoord	(yMin, m_verticalFill	== FILL_BOTTOM);
478	m_bboxMax.x() = ceilSubpixelToPixelCoord	(xMax, m_horizontalFill	== FILL_RIGHT);
479	m_bboxMax.y() = ceilSubpixelToPixelCoord	(yMax, m_verticalFill	== FILL_TOP);
480
481	// Clamp to viewport
482	const int		wX0		= m_viewport.x();
483	const int		wY0		= m_viewport.y();
484	const int		wX1		= wX0 + m_viewport.z() - 1;
485	const int		wY1		= wY0 + m_viewport.w() -1;
486
487	m_bboxMin.x() = de::clamp(m_bboxMin.x(), wX0, wX1);
488	m_bboxMin.y() = de::clamp(m_bboxMin.y(), wY0, wY1);
489	m_bboxMax.x() = de::clamp(m_bboxMax.x(), wX0, wX1);
490	m_bboxMax.y() = de::clamp(m_bboxMax.y(), wY0, wY1);
491
492	m_curPos = m_bboxMin;
493}
494
495void TriangleRasterizer::rasterizeSingleSample (FragmentPacket* const fragmentPackets, float* const depthValues, const int maxFragmentPackets, int& numPacketsRasterized)
496{
497	DE_ASSERT(maxFragmentPackets > 0);
498
499	const deUint64	halfPixel	= 1ll << (RASTERIZER_SUBPIXEL_BITS-1);
500	int				packetNdx	= 0;
501
502	while (m_curPos.y() <= m_bboxMax.y() && packetNdx < maxFragmentPackets)
503	{
504		const int		x0		= m_curPos.x();
505		const int		y0		= m_curPos.y();
506
507		// Subpixel coords
508		const deInt64	sx0		= toSubpixelCoord(x0)	+ halfPixel;
509		const deInt64	sx1		= toSubpixelCoord(x0+1)	+ halfPixel;
510		const deInt64	sy0		= toSubpixelCoord(y0)	+ halfPixel;
511		const deInt64	sy1		= toSubpixelCoord(y0+1)	+ halfPixel;
512
513		const deInt64	sx[4]	= { sx0, sx1, sx0, sx1 };
514		const deInt64	sy[4]	= { sy0, sy0, sy1, sy1 };
515
516		// Viewport test
517		const bool		outX1	= x0+1 == m_viewport.x()+m_viewport.z();
518		const bool		outY1	= y0+1 == m_viewport.y()+m_viewport.w();
519
520		DE_ASSERT(x0 < m_viewport.x()+m_viewport.z());
521		DE_ASSERT(y0 < m_viewport.y()+m_viewport.w());
522
523		// Edge values
524		tcu::Vector<deInt64, 4>	e01;
525		tcu::Vector<deInt64, 4>	e12;
526		tcu::Vector<deInt64, 4>	e20;
527
528		// Coverage
529		deUint64		coverage	= 0;
530
531		// Evaluate edge values
532		for (int i = 0; i < 4; i++)
533		{
534			e01[i] = evaluateEdge(m_edge01, sx[i], sy[i]);
535			e12[i] = evaluateEdge(m_edge12, sx[i], sy[i]);
536			e20[i] = evaluateEdge(m_edge20, sx[i], sy[i]);
537		}
538
539		// Compute coverage mask
540		coverage = setCoverageValue(coverage, 1, 0, 0, 0,						isInsideCCW(m_edge01, e01[0]) && isInsideCCW(m_edge12, e12[0]) && isInsideCCW(m_edge20, e20[0]));
541		coverage = setCoverageValue(coverage, 1, 1, 0, 0, !outX1 &&				isInsideCCW(m_edge01, e01[1]) && isInsideCCW(m_edge12, e12[1]) && isInsideCCW(m_edge20, e20[1]));
542		coverage = setCoverageValue(coverage, 1, 0, 1, 0, !outY1 &&				isInsideCCW(m_edge01, e01[2]) && isInsideCCW(m_edge12, e12[2]) && isInsideCCW(m_edge20, e20[2]));
543		coverage = setCoverageValue(coverage, 1, 1, 1, 0, !outX1 && !outY1 &&	isInsideCCW(m_edge01, e01[3]) && isInsideCCW(m_edge12, e12[3]) && isInsideCCW(m_edge20, e20[3]));
544
545		// Advance to next location
546		m_curPos.x() += 2;
547		if (m_curPos.x() > m_bboxMax.x())
548		{
549			m_curPos.y() += 2;
550			m_curPos.x()  = m_bboxMin.x();
551		}
552
553		if (coverage == 0)
554			continue; // Discard.
555
556		// Floating-point edge values for barycentrics etc.
557		const tcu::Vec4		e01f	= e01.asFloat();
558		const tcu::Vec4		e12f	= e12.asFloat();
559		const tcu::Vec4		e20f	= e20.asFloat();
560
561		// Compute depth values.
562		if (depthValues)
563		{
564			const tcu::Vec4		ooSum	= 1.0f / (e01f + e12f + e20f);
565			const tcu::Vec4		z0		= e12f * ooSum;
566			const tcu::Vec4		z1		= e20f * ooSum;
567			const tcu::Vec4		z2		= e01f * ooSum;
568
569			depthValues[packetNdx*4+0] = z0[0]*m_v0.z() + z1[0]*m_v1.z() + z2[0]*m_v2.z();
570			depthValues[packetNdx*4+1] = z0[1]*m_v0.z() + z1[1]*m_v1.z() + z2[1]*m_v2.z();
571			depthValues[packetNdx*4+2] = z0[2]*m_v0.z() + z1[2]*m_v1.z() + z2[2]*m_v2.z();
572			depthValues[packetNdx*4+3] = z0[3]*m_v0.z() + z1[3]*m_v1.z() + z2[3]*m_v2.z();
573		}
574
575		// Compute barycentrics and write out fragment packet
576		{
577			FragmentPacket& packet = fragmentPackets[packetNdx];
578
579			const tcu::Vec4		b0		= e12f * m_v0.w();
580			const tcu::Vec4		b1		= e20f * m_v1.w();
581			const tcu::Vec4		b2		= e01f * m_v2.w();
582			const tcu::Vec4		ooSum	= 1.0f / (b0 + b1 + b2);
583
584			packet.position			= tcu::IVec2(x0, y0);
585			packet.coverage			= coverage;
586			packet.barycentric[0]	= b0 * ooSum;
587			packet.barycentric[1]	= b1 * ooSum;
588			packet.barycentric[2]	= 1.0f - packet.barycentric[0] - packet.barycentric[1];
589
590			packetNdx += 1;
591		}
592	}
593
594	DE_ASSERT(packetNdx <= maxFragmentPackets);
595	numPacketsRasterized = packetNdx;
596}
597
598// Sample positions - ordered as (x, y) list.
599
600// \note Macros are used to eliminate function calls even in debug builds.
601#define SAMPLE_POS_TO_SUBPIXEL_COORD(POS)	\
602	(deInt64)((POS) * (1<<RASTERIZER_SUBPIXEL_BITS) + 0.5f)
603
604#define SAMPLE_POS(X, Y)	\
605	SAMPLE_POS_TO_SUBPIXEL_COORD(X), SAMPLE_POS_TO_SUBPIXEL_COORD(Y)
606
607static const deInt64 s_samplePos2[] =
608{
609	SAMPLE_POS(0.3f, 0.3f),
610	SAMPLE_POS(0.7f, 0.7f)
611};
612
613static const deInt64 s_samplePos4[] =
614{
615	SAMPLE_POS(0.25f, 0.25f),
616	SAMPLE_POS(0.75f, 0.25f),
617	SAMPLE_POS(0.25f, 0.75f),
618	SAMPLE_POS(0.75f, 0.75f)
619};
620DE_STATIC_ASSERT(DE_LENGTH_OF_ARRAY(s_samplePos4) == 4*2);
621
622static const deInt64 s_samplePos8[] =
623{
624	SAMPLE_POS( 7.f/16.f,  9.f/16.f),
625	SAMPLE_POS( 9.f/16.f, 13.f/16.f),
626	SAMPLE_POS(11.f/16.f,  3.f/16.f),
627	SAMPLE_POS(13.f/16.f, 11.f/16.f),
628	SAMPLE_POS( 1.f/16.f,  7.f/16.f),
629	SAMPLE_POS( 5.f/16.f,  1.f/16.f),
630	SAMPLE_POS(15.f/16.f,  5.f/16.f),
631	SAMPLE_POS( 3.f/16.f, 15.f/16.f)
632};
633DE_STATIC_ASSERT(DE_LENGTH_OF_ARRAY(s_samplePos8) == 8*2);
634
635static const deInt64 s_samplePos16[] =
636{
637	SAMPLE_POS(1.f/8.f, 1.f/8.f),
638	SAMPLE_POS(3.f/8.f, 1.f/8.f),
639	SAMPLE_POS(5.f/8.f, 1.f/8.f),
640	SAMPLE_POS(7.f/8.f, 1.f/8.f),
641	SAMPLE_POS(1.f/8.f, 3.f/8.f),
642	SAMPLE_POS(3.f/8.f, 3.f/8.f),
643	SAMPLE_POS(5.f/8.f, 3.f/8.f),
644	SAMPLE_POS(7.f/8.f, 3.f/8.f),
645	SAMPLE_POS(1.f/8.f, 5.f/8.f),
646	SAMPLE_POS(3.f/8.f, 5.f/8.f),
647	SAMPLE_POS(5.f/8.f, 5.f/8.f),
648	SAMPLE_POS(7.f/8.f, 5.f/8.f),
649	SAMPLE_POS(1.f/8.f, 7.f/8.f),
650	SAMPLE_POS(3.f/8.f, 7.f/8.f),
651	SAMPLE_POS(5.f/8.f, 7.f/8.f),
652	SAMPLE_POS(7.f/8.f, 7.f/8.f)
653};
654DE_STATIC_ASSERT(DE_LENGTH_OF_ARRAY(s_samplePos16) == 16*2);
655
656#undef SAMPLE_POS
657#undef SAMPLE_POS_TO_SUBPIXEL_COORD
658
659template<int NumSamples>
660void TriangleRasterizer::rasterizeMultiSample (FragmentPacket* const fragmentPackets, float* const depthValues, const int maxFragmentPackets, int& numPacketsRasterized)
661{
662	DE_ASSERT(maxFragmentPackets > 0);
663
664	const deInt64*	samplePos	= DE_NULL;
665	const deUint64	halfPixel	= 1ll << (RASTERIZER_SUBPIXEL_BITS-1);
666	int				packetNdx	= 0;
667
668	switch (NumSamples)
669	{
670		case 2:		samplePos = s_samplePos2;	break;
671		case 4:		samplePos = s_samplePos4;	break;
672		case 8:		samplePos = s_samplePos8;	break;
673		case 16:	samplePos = s_samplePos16;	break;
674		default:
675			DE_ASSERT(false);
676	}
677
678	while (m_curPos.y() <= m_bboxMax.y() && packetNdx < maxFragmentPackets)
679	{
680		const int		x0		= m_curPos.x();
681		const int		y0		= m_curPos.y();
682
683		// Base subpixel coords
684		const deInt64	sx0		= toSubpixelCoord(x0);
685		const deInt64	sx1		= toSubpixelCoord(x0+1);
686		const deInt64	sy0		= toSubpixelCoord(y0);
687		const deInt64	sy1		= toSubpixelCoord(y0+1);
688
689		const deInt64	sx[4]	= { sx0, sx1, sx0, sx1 };
690		const deInt64	sy[4]	= { sy0, sy0, sy1, sy1 };
691
692		// Viewport test
693		const bool		outX1	= x0+1 == m_viewport.x()+m_viewport.z();
694		const bool		outY1	= y0+1 == m_viewport.y()+m_viewport.w();
695
696		DE_ASSERT(x0 < m_viewport.x()+m_viewport.z());
697		DE_ASSERT(y0 < m_viewport.y()+m_viewport.w());
698
699		// Edge values
700		tcu::Vector<deInt64, 4>	e01[NumSamples];
701		tcu::Vector<deInt64, 4>	e12[NumSamples];
702		tcu::Vector<deInt64, 4>	e20[NumSamples];
703
704		// Coverage
705		deUint64		coverage	= 0;
706
707		// Evaluate edge values at sample positions
708		for (int sampleNdx = 0; sampleNdx < NumSamples; sampleNdx++)
709		{
710			const deInt64 ox = samplePos[sampleNdx*2 + 0];
711			const deInt64 oy = samplePos[sampleNdx*2 + 1];
712
713			for (int fragNdx = 0; fragNdx < 4; fragNdx++)
714			{
715				e01[sampleNdx][fragNdx] = evaluateEdge(m_edge01, sx[fragNdx] + ox, sy[fragNdx] + oy);
716				e12[sampleNdx][fragNdx] = evaluateEdge(m_edge12, sx[fragNdx] + ox, sy[fragNdx] + oy);
717				e20[sampleNdx][fragNdx] = evaluateEdge(m_edge20, sx[fragNdx] + ox, sy[fragNdx] + oy);
718			}
719		}
720
721		// Compute coverage mask
722		for (int sampleNdx = 0; sampleNdx < NumSamples; sampleNdx++)
723		{
724			coverage = setCoverageValue(coverage, NumSamples, 0, 0, sampleNdx,						isInsideCCW(m_edge01, e01[sampleNdx][0]) && isInsideCCW(m_edge12, e12[sampleNdx][0]) && isInsideCCW(m_edge20, e20[sampleNdx][0]));
725			coverage = setCoverageValue(coverage, NumSamples, 1, 0, sampleNdx, !outX1 &&			isInsideCCW(m_edge01, e01[sampleNdx][1]) && isInsideCCW(m_edge12, e12[sampleNdx][1]) && isInsideCCW(m_edge20, e20[sampleNdx][1]));
726			coverage = setCoverageValue(coverage, NumSamples, 0, 1, sampleNdx, !outY1 &&			isInsideCCW(m_edge01, e01[sampleNdx][2]) && isInsideCCW(m_edge12, e12[sampleNdx][2]) && isInsideCCW(m_edge20, e20[sampleNdx][2]));
727			coverage = setCoverageValue(coverage, NumSamples, 1, 1, sampleNdx, !outX1 && !outY1 &&	isInsideCCW(m_edge01, e01[sampleNdx][3]) && isInsideCCW(m_edge12, e12[sampleNdx][3]) && isInsideCCW(m_edge20, e20[sampleNdx][3]));
728		}
729
730		// Advance to next location
731		m_curPos.x() += 2;
732		if (m_curPos.x() > m_bboxMax.x())
733		{
734			m_curPos.y() += 2;
735			m_curPos.x()  = m_bboxMin.x();
736		}
737
738		if (coverage == 0)
739			continue; // Discard.
740
741		// Compute depth values.
742		if (depthValues)
743		{
744			for (int sampleNdx = 0; sampleNdx < NumSamples; sampleNdx++)
745			{
746				// Floating-point edge values at sample coordinates.
747				const tcu::Vec4&	e01f	= e01[sampleNdx].asFloat();
748				const tcu::Vec4&	e12f	= e12[sampleNdx].asFloat();
749				const tcu::Vec4&	e20f	= e20[sampleNdx].asFloat();
750
751				const tcu::Vec4		ooSum	= 1.0f / (e01f + e12f + e20f);
752				const tcu::Vec4		z0		= e12f * ooSum;
753				const tcu::Vec4		z1		= e20f * ooSum;
754				const tcu::Vec4		z2		= e01f * ooSum;
755
756				depthValues[(packetNdx*4+0)*NumSamples + sampleNdx] = z0[0]*m_v0.z() + z1[0]*m_v1.z() + z2[0]*m_v2.z();
757				depthValues[(packetNdx*4+1)*NumSamples + sampleNdx] = z0[1]*m_v0.z() + z1[1]*m_v1.z() + z2[1]*m_v2.z();
758				depthValues[(packetNdx*4+2)*NumSamples + sampleNdx] = z0[2]*m_v0.z() + z1[2]*m_v1.z() + z2[2]*m_v2.z();
759				depthValues[(packetNdx*4+3)*NumSamples + sampleNdx] = z0[3]*m_v0.z() + z1[3]*m_v1.z() + z2[3]*m_v2.z();
760			}
761		}
762
763		// Compute barycentrics and write out fragment packet
764		{
765			FragmentPacket& packet = fragmentPackets[packetNdx];
766
767			// Floating-point edge values at pixel center.
768			tcu::Vec4			e01f;
769			tcu::Vec4			e12f;
770			tcu::Vec4			e20f;
771
772			for (int i = 0; i < 4; i++)
773			{
774				e01f[i] = float(evaluateEdge(m_edge01, sx[i] + halfPixel, sy[i] + halfPixel));
775				e12f[i] = float(evaluateEdge(m_edge12, sx[i] + halfPixel, sy[i] + halfPixel));
776				e20f[i] = float(evaluateEdge(m_edge20, sx[i] + halfPixel, sy[i] + halfPixel));
777			}
778
779			// Barycentrics & scale.
780			const tcu::Vec4		b0		= e12f * m_v0.w();
781			const tcu::Vec4		b1		= e20f * m_v1.w();
782			const tcu::Vec4		b2		= e01f * m_v2.w();
783			const tcu::Vec4		ooSum	= 1.0f / (b0 + b1 + b2);
784
785			packet.position			= tcu::IVec2(x0, y0);
786			packet.coverage			= coverage;
787			packet.barycentric[0]	= b0 * ooSum;
788			packet.barycentric[1]	= b1 * ooSum;
789			packet.barycentric[2]	= 1.0f - packet.barycentric[0] - packet.barycentric[1];
790
791			packetNdx += 1;
792		}
793	}
794
795	DE_ASSERT(packetNdx <= maxFragmentPackets);
796	numPacketsRasterized = packetNdx;
797}
798
799void TriangleRasterizer::rasterize (FragmentPacket* const fragmentPackets, float* const depthValues, const int maxFragmentPackets, int& numPacketsRasterized)
800{
801	DE_ASSERT(maxFragmentPackets > 0);
802
803	switch (m_numSamples)
804	{
805		case 1:		rasterizeSingleSample		(fragmentPackets, depthValues, maxFragmentPackets, numPacketsRasterized);	break;
806		case 2:		rasterizeMultiSample<2>		(fragmentPackets, depthValues, maxFragmentPackets, numPacketsRasterized);	break;
807		case 4:		rasterizeMultiSample<4>		(fragmentPackets, depthValues, maxFragmentPackets, numPacketsRasterized);	break;
808		case 8:		rasterizeMultiSample<8>		(fragmentPackets, depthValues, maxFragmentPackets, numPacketsRasterized);	break;
809		case 16:	rasterizeMultiSample<16>	(fragmentPackets, depthValues, maxFragmentPackets, numPacketsRasterized);	break;
810		default:
811			DE_ASSERT(DE_FALSE);
812	}
813}
814
815SingleSampleLineRasterizer::SingleSampleLineRasterizer (const tcu::IVec4& viewport)
816	: m_viewport		(viewport)
817	, m_curRowFragment	(0)
818	, m_lineWidth		(0.0f)
819{
820}
821
822SingleSampleLineRasterizer::~SingleSampleLineRasterizer	()
823{
824}
825
826void SingleSampleLineRasterizer::init (const tcu::Vec4& v0, const tcu::Vec4& v1, float lineWidth)
827{
828	const bool						isXMajor		= de::abs((v1 - v0).x()) >= de::abs((v1 - v0).y());
829
830	// Bounding box \note: with wide lines, the line is actually moved as in the spec
831	const deInt32					lineWidthPixels	= (lineWidth > 1.0f) ? (deInt32)floor(lineWidth + 0.5f) : 1;
832
833	const tcu::IVec2				minorDirection	= (isXMajor ? tcu::IVec2(0, 1) : tcu::IVec2(1, 0));
834	const tcu::Vector<deInt64,2>	widthOffset		= (isXMajor ? tcu::Vector<deInt64,2>(0, -1) : tcu::Vector<deInt64,2>(-1, 0)) * (toSubpixelCoord(lineWidthPixels - 1) / 2);
835
836	const deInt64					x0				= toSubpixelCoord(v0.x()) + widthOffset.x();
837	const deInt64					y0				= toSubpixelCoord(v0.y()) + widthOffset.y();
838	const deInt64					x1				= toSubpixelCoord(v1.x()) + widthOffset.x();
839	const deInt64					y1				= toSubpixelCoord(v1.y()) + widthOffset.y();
840
841	// line endpoints might be perturbed, add some margin
842	const deInt64					xMin			= de::min(x0, x1) - toSubpixelCoord(1);
843	const deInt64					xMax			= de::max(x0, x1) + toSubpixelCoord(1);
844	const deInt64					yMin			= de::min(y0, y1) - toSubpixelCoord(1);
845	const deInt64					yMax			= de::max(y0, y1) + toSubpixelCoord(1);
846
847	// Remove invisible area
848
849	if (isXMajor)
850	{
851		// clamp to viewport in major direction
852		m_bboxMin.x() = de::clamp(floorSubpixelToPixelCoord(xMin, true), m_viewport.x(), m_viewport.x() + m_viewport.z() - 1);
853		m_bboxMax.x() = de::clamp(ceilSubpixelToPixelCoord (xMax, true), m_viewport.x(), m_viewport.x() + m_viewport.z() - 1);
854
855		// clamp to padded viewport in minor direction (wide lines might bleed over viewport in minor direction)
856		m_bboxMin.y() = de::clamp(floorSubpixelToPixelCoord(yMin, true), m_viewport.y() - lineWidthPixels, m_viewport.y() + m_viewport.w() - 1);
857		m_bboxMax.y() = de::clamp(ceilSubpixelToPixelCoord (yMax, true), m_viewport.y() - lineWidthPixels, m_viewport.y() + m_viewport.w() - 1);
858	}
859	else
860	{
861		// clamp to viewport in major direction
862		m_bboxMin.y() = de::clamp(floorSubpixelToPixelCoord(yMin, true), m_viewport.y(), m_viewport.y() + m_viewport.w() - 1);
863		m_bboxMax.y() = de::clamp(ceilSubpixelToPixelCoord (yMax, true), m_viewport.y(), m_viewport.y() + m_viewport.w() - 1);
864
865		// clamp to padded viewport in minor direction (wide lines might bleed over viewport in minor direction)
866		m_bboxMin.x() = de::clamp(floorSubpixelToPixelCoord(xMin, true), m_viewport.x() - lineWidthPixels, m_viewport.x() + m_viewport.z() - 1);
867		m_bboxMax.x() = de::clamp(ceilSubpixelToPixelCoord (xMax, true), m_viewport.x() - lineWidthPixels, m_viewport.x() + m_viewport.z() - 1);
868	}
869
870	m_lineWidth = lineWidth;
871
872	m_v0 = v0;
873	m_v1 = v1;
874
875	m_curPos = m_bboxMin;
876	m_curRowFragment = 0;
877}
878
879void SingleSampleLineRasterizer::rasterize (FragmentPacket* const fragmentPackets, float* const depthValues, const int maxFragmentPackets, int& numPacketsRasterized)
880{
881	DE_ASSERT(maxFragmentPackets > 0);
882
883	const deInt64								halfPixel		= 1ll << (RASTERIZER_SUBPIXEL_BITS-1);
884	const deInt32								lineWidth		= (m_lineWidth > 1.0f) ? (deInt32)floor(m_lineWidth + 0.5f) : 1;
885	const bool									isXMajor		= de::abs((m_v1 - m_v0).x()) >= de::abs((m_v1 - m_v0).y());
886	const tcu::IVec2							minorDirection	= (isXMajor ? tcu::IVec2(0, 1) : tcu::IVec2(1, 0));
887	const tcu::Vector<deInt64,2>				widthOffset		= (isXMajor ? tcu::Vector<deInt64,2>(0, -1) : tcu::Vector<deInt64,2>(-1, 0)) * (toSubpixelCoord(lineWidth - 1) / 2);
888	const tcu::Vector<deInt64,2>				pa				= LineRasterUtil::toSubpixelVector(m_v0.xy()) + widthOffset;
889	const tcu::Vector<deInt64,2>				pb				= LineRasterUtil::toSubpixelVector(m_v1.xy()) + widthOffset;
890	const LineRasterUtil::SubpixelLineSegment	line			= LineRasterUtil::SubpixelLineSegment(pa, pb);
891
892	int											packetNdx 		= 0;
893
894	while (m_curPos.y() <= m_bboxMax.y() && packetNdx < maxFragmentPackets)
895	{
896		const tcu::Vector<deInt64,2> diamondPosition = LineRasterUtil::toSubpixelVector(m_curPos) + tcu::Vector<deInt64,2>(halfPixel,halfPixel);
897
898		// Should current fragment be drawn? == does the segment exit this diamond?
899		if (LineRasterUtil::doesLineSegmentExitDiamond(line, diamondPosition))
900		{
901			const tcu::Vector<deInt64,2> 	pr					= diamondPosition;
902			const float 					t					= tcu::dot((pr - pa).asFloat(), (pb - pa).asFloat()) / tcu::lengthSquared(pb.asFloat() - pa.asFloat());
903
904			// Rasterize on only fragments that are would end up in the viewport (i.e. visible)
905			const int						minViewportLimit	= (isXMajor) ? (m_viewport.y())                  : (m_viewport.x());
906			const int						maxViewportLimit	= (isXMajor) ? (m_viewport.y() + m_viewport.w()) : (m_viewport.x() + m_viewport.z());
907			const int						fragmentLocation	= (isXMajor) ? (m_curPos.y())                    : (m_curPos.x());
908
909			const int						rowFragBegin		= de::max(0, minViewportLimit - fragmentLocation);
910			const int						rowFragEnd			= de::min(maxViewportLimit - fragmentLocation, lineWidth);
911
912			// Wide lines require multiple fragments.
913			for (; rowFragBegin + m_curRowFragment < rowFragEnd; m_curRowFragment++)
914			{
915				const tcu::IVec2 fragmentPos = m_curPos + minorDirection * (rowFragBegin + m_curRowFragment);
916
917				// We only rasterize visible area
918				DE_ASSERT(LineRasterUtil::inViewport(fragmentPos, m_viewport));
919
920				// Compute depth values.
921				if (depthValues)
922				{
923					const float za = m_v0.z();
924					const float zb = m_v1.z();
925
926					depthValues[packetNdx*4+0] = (1 - t) * za + t * zb;
927					depthValues[packetNdx*4+1] = 0;
928					depthValues[packetNdx*4+2] = 0;
929					depthValues[packetNdx*4+3] = 0;
930				}
931
932				{
933					// output this fragment
934					// \note In order to make consistent output with multisampled line rasterization, output "barycentric" coordinates
935					FragmentPacket& packet = fragmentPackets[packetNdx];
936
937					const tcu::Vec4		b0		= tcu::Vec4(1 - t);
938					const tcu::Vec4		b1		= tcu::Vec4(t);
939					const tcu::Vec4		ooSum	= 1.0f / (b0 + b1);
940
941					packet.position			= fragmentPos;
942					packet.coverage			= getCoverageBit(1, 0, 0, 0);
943					packet.barycentric[0]	= b0 * ooSum;
944					packet.barycentric[1]	= b1 * ooSum;
945					packet.barycentric[2]	= tcu::Vec4(0.0f);
946
947					packetNdx += 1;
948				}
949
950				if (packetNdx == maxFragmentPackets)
951				{
952					m_curRowFragment++; // don't redraw this fragment again next time
953					numPacketsRasterized = packetNdx;
954					return;
955				}
956			}
957
958			m_curRowFragment = 0;
959		}
960
961		++m_curPos.x();
962		if (m_curPos.x() > m_bboxMax.x())
963		{
964			++m_curPos.y();
965			m_curPos.x() = m_bboxMin.x();
966		}
967	}
968
969	DE_ASSERT(packetNdx <= maxFragmentPackets);
970	numPacketsRasterized = packetNdx;
971}
972
973MultiSampleLineRasterizer::MultiSampleLineRasterizer (const int numSamples, const tcu::IVec4& viewport)
974	: m_numSamples			(numSamples)
975	, m_triangleRasterizer0 (viewport, m_numSamples, RasterizationState())
976	, m_triangleRasterizer1 (viewport, m_numSamples, RasterizationState())
977{
978}
979
980MultiSampleLineRasterizer::~MultiSampleLineRasterizer ()
981{
982}
983
984void MultiSampleLineRasterizer::init (const tcu::Vec4& v0, const tcu::Vec4& v1, float lineWidth)
985{
986	// allow creation of single sampled rasterizer objects but do not allow using them
987	DE_ASSERT(m_numSamples > 1);
988
989	const tcu::Vec2 lineVec		= tcu::Vec2(tcu::Vec4(v1).xy()) - tcu::Vec2(tcu::Vec4(v0).xy());
990	const tcu::Vec2 normal2		= tcu::normalize(tcu::Vec2(-lineVec[1], lineVec[0]));
991	const tcu::Vec4 normal4		= tcu::Vec4(normal2.x(), normal2.y(), 0, 0);
992	const float offset			= lineWidth / 2.0f;
993
994	const tcu::Vec4 p0 = v0 + normal4 * offset;
995	const tcu::Vec4 p1 = v0 - normal4 * offset;
996	const tcu::Vec4 p2 = v1 - normal4 * offset;
997	const tcu::Vec4 p3 = v1 + normal4 * offset;
998
999	// Edge 0 -> 1 is always along the line and edge 1 -> 2 is in 90 degree angle to the line
1000	m_triangleRasterizer0.init(p0, p3, p2);
1001	m_triangleRasterizer1.init(p2, p1, p0);
1002}
1003
1004void MultiSampleLineRasterizer::rasterize (FragmentPacket* const fragmentPackets, float* const depthValues, const int maxFragmentPackets, int& numPacketsRasterized)
1005{
1006	DE_ASSERT(maxFragmentPackets > 0);
1007
1008	m_triangleRasterizer0.rasterize(fragmentPackets, depthValues, maxFragmentPackets, numPacketsRasterized);
1009
1010	// Remove 3rd barycentric value and rebalance. Lines do not have non-zero barycentric at index 2
1011	for (int packNdx = 0; packNdx < numPacketsRasterized; ++packNdx)
1012	for (int fragNdx = 0; fragNdx < 4; fragNdx++)
1013	{
1014		float removedValue = fragmentPackets[packNdx].barycentric[2][fragNdx];
1015		fragmentPackets[packNdx].barycentric[2][fragNdx] = 0.0f;
1016		fragmentPackets[packNdx].barycentric[1][fragNdx] += removedValue;
1017	}
1018
1019	// rasterizer 0 filled the whole buffer?
1020	if (numPacketsRasterized == maxFragmentPackets)
1021		return;
1022
1023	{
1024		FragmentPacket* const nextFragmentPackets	= fragmentPackets + numPacketsRasterized;
1025		float* nextDepthValues						= (depthValues) ? (depthValues+4*numPacketsRasterized*m_numSamples) : (DE_NULL);
1026		int numPacketsRasterized2					= 0;
1027
1028		m_triangleRasterizer1.rasterize(nextFragmentPackets, nextDepthValues, maxFragmentPackets - numPacketsRasterized, numPacketsRasterized2);
1029
1030		numPacketsRasterized += numPacketsRasterized2;
1031
1032		// Fix swapped barycentrics in the second triangle
1033		for (int packNdx = 0; packNdx < numPacketsRasterized2; ++packNdx)
1034		for (int fragNdx = 0; fragNdx < 4; fragNdx++)
1035		{
1036			float removedValue = nextFragmentPackets[packNdx].barycentric[2][fragNdx];
1037			nextFragmentPackets[packNdx].barycentric[2][fragNdx] = 0.0f;
1038			nextFragmentPackets[packNdx].barycentric[1][fragNdx] += removedValue;
1039
1040			// edge has reversed direction
1041			std::swap(nextFragmentPackets[packNdx].barycentric[0][fragNdx], nextFragmentPackets[packNdx].barycentric[1][fragNdx]);
1042		}
1043	}
1044}
1045
1046} // rr
1047