src/glRenderer.cc

/*
 *  LDForge: LDraw parts authoring CAD
 *  Copyright (C) 2013, 2014 Santeri Piippo
 *
 *  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 3 of the License, 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#define GL_GLEXT_PROTOTYPES
#include <GL/glu.h>
#include <GL/glext.h>
#include <QGLWidget>
#include <QWheelEvent>
#include <QMouseEvent>
#include <QContextMenuEvent>
#include <QInputDialog>
#include <QToolTip>
#include <qtextdocument.h>
#include <QTimer>
#include <GL/glu.h>

#include "main.h"
#include "configuration.h"
#include "ldDocument.h"
#include "glRenderer.h"
#include "colors.h"
#include "mainWindow.h"
#include "miscallenous.h"
#include "editHistory.h"
#include "dialogs.h"
#include "addObjectDialog.h"
#include "messageLog.h"
#include "primitives.h"
#include "misc/ringFinder.h"
#include "glCompiler.h"

static const LDFixedCameraInfo g_FixedCameras[6] =
{
	{{  1,  0, 0 }, X, Z, false, false },
	{{  0,  0, 0 }, X, Y, false,  true },
	{{  0,  1, 0 }, Z, Y,  true,  true },
	{{ -1,  0, 0 }, X, Z, false,  true },
	{{  0,  0, 0 }, X, Y,  true,  true },
	{{  0, -1, 0 }, Z, Y, false,  true },
};

// Matrix templates for circle drawing. 2 is substituted with
// the scale value, 1 is inverted to -1 if needed.
static const Matrix g_circleDrawMatrixTemplates[3] =
{
	{ 2, 0, 0, 0, 1, 0, 0, 0, 2 },
	{ 2, 0, 0, 0, 0, 2, 0, 1, 0 },
	{ 0, 1, 0, 2, 0, 0, 0, 0, 2 },
};

cfg (String,	gl_bgcolor,				"#FFFFFF")
cfg (String,	gl_maincolor,			"#A0A0A0")
cfg (Float,		gl_maincolor_alpha,		1.0)
cfg (Int,		gl_linethickness,		2)
cfg (Bool,		gl_colorbfc,			false)
cfg (Int,		gl_camera,				GLRenderer::EFreeCamera)
cfg (Bool,		gl_blackedges,			false)
cfg (Bool,		gl_axes,				false)
cfg (Bool,		gl_wireframe,			false)
cfg (Bool,		gl_logostuds,			false)
cfg (Bool,		gl_aa,					true)
cfg (Bool,		gl_linelengths,			true)
cfg (Bool,		gl_drawangles,			false)

// argh
const char* g_CameraNames[7] =
{
	QT_TRANSLATE_NOOP ("GLRenderer",  "Top"),
	QT_TRANSLATE_NOOP ("GLRenderer",  "Front"),
	QT_TRANSLATE_NOOP ("GLRenderer",  "Left"),
	QT_TRANSLATE_NOOP ("GLRenderer",  "Bottom"),
	QT_TRANSLATE_NOOP ("GLRenderer",  "Back"),
	QT_TRANSLATE_NOOP ("GLRenderer",  "Right"),
	QT_TRANSLATE_NOOP ("GLRenderer",  "Free")
};

const GL::EFixedCamera g_Cameras[7] =
{
	GL::ETopCamera,
	GL::EFrontCamera,
	GL::ELeftCamera,
	GL::EBottomCamera,
	GL::EBackCamera,
	GL::ERightCamera,
	GL::EFreeCamera
};

struct LDGLAxis
{
	const QColor col;
	const Vertex vert;
};

// Definitions for visual axes, drawn on the screen
static const LDGLAxis g_GLAxes[3] =
{
	{ QColor (255,   0,   0), Vertex (10000, 0, 0) }, // X
	{ QColor (80,  192,   0), Vertex (0, 10000, 0) }, // Y
	{ QColor (0,   160, 192), Vertex (0, 0, 10000) }, // Z
};

static GLuint g_GLAxes_VBO;
static GLuint g_GLAxes_ColorVBO;

// =============================================================================
//
GLRenderer::GLRenderer (QWidget* parent) : QGLWidget (parent)
{
	m_isPicking = m_rangepick = false;
	m_camera = (EFixedCamera) gl_camera;
	m_drawToolTip = false;
	m_editMode = ESelectMode;
	m_rectdraw = false;
	m_panning = false;
	m_compiler = new GLCompiler;
	setDocument (null);
	setDrawOnly (false);
	setMessageLog (null);
	m_width = m_height = -1;
	m_hoverpos = g_origin;
	m_compiler = new GLCompiler;
	m_toolTipTimer = new QTimer (this);
	m_toolTipTimer->setSingleShot (true);
	connect (m_toolTipTimer, SIGNAL (timeout()), this, SLOT (slot_toolTipTimer()));

	m_thickBorderPen = QPen (QColor (0, 0, 0, 208), 2, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin);
	m_thinBorderPen = m_thickBorderPen;
	m_thinBorderPen.setWidth (1);

	// Init camera icons
	for (const GL::EFixedCamera cam : g_Cameras)
	{
		QString iconname = format ("camera-%1", tr (g_CameraNames[cam]).toLower());

		CameraIcon* info = &m_cameraIcons[cam];
		info->img = new QPixmap (getIcon (iconname));
		info->cam = cam;
	}

	calcCameraIcons();
}

// =============================================================================
//
GLRenderer::~GLRenderer()
{
	for (int i = 0; i < 6; ++i)
		delete currentDocumentData().overlays[i].img;

	for (CameraIcon& info : m_cameraIcons)
		delete info.img;

	delete m_compiler;
}

// =============================================================================
// Calculates the "hitboxes" of the camera icons so that we can tell when the
// cursor is pointing at the camera icon.
//
void GLRenderer::calcCameraIcons()
{
	int i = 0;

	for (CameraIcon& info : m_cameraIcons)
	{
		// MATH
		const long x1 = (m_width - (info.cam != EFreeCamera ? 48 : 16)) + ((i % 3) * 16) - 1,
			y1 = ((i / 3) * 16) + 1;

		info.srcRect = QRect (0, 0, 16, 16);
		info.destRect = QRect (x1, y1, 16, 16);
		info.selRect = QRect (
			info.destRect.x(),
			info.destRect.y(),
			info.destRect.width() + 1,
			info.destRect.height() + 1
		);

		++i;
	}
}

// =============================================================================
//
void GLRenderer::initGLData()
{
	glEnable (GL_BLEND);
	glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glEnable (GL_POLYGON_OFFSET_FILL);
	glPolygonOffset (1.0f, 1.0f);

	glEnable (GL_DEPTH_TEST);
	glShadeModel (GL_SMOOTH);
	glEnable (GL_MULTISAMPLE);

	if (gl_aa)
	{
		glEnable (GL_LINE_SMOOTH);
		glEnable (GL_POLYGON_SMOOTH);
		glHint (GL_LINE_SMOOTH_HINT, GL_NICEST);
		glHint (GL_POLYGON_SMOOTH_HINT, GL_NICEST);
	} else
	{
		glDisable (GL_LINE_SMOOTH);
		glDisable (GL_POLYGON_SMOOTH);
	}
}

// =============================================================================
//
void GLRenderer::resetAngles()
{
	rot (X) = 30.0f;
	rot (Y) = 325.f;
	pan (X) = pan (Y) = rot (Z) = 0.0f;
	zoomToFit();
}

// =============================================================================
//
void GLRenderer::resetAllAngles()
{
	EFixedCamera oldcam = camera();

	for (int i = 0; i < 7; ++i)
	{
		setCamera ((EFixedCamera) i);
		resetAngles();
	}

	setCamera (oldcam);
}

// =============================================================================
//
void GLRenderer::initializeGL()
{
	setBackground();
	glLineWidth (gl_linethickness);
	glLineStipple (1, 0x6666);
	setAutoFillBackground (false);
	setMouseTracking (true);
	setFocusPolicy (Qt::WheelFocus);
	compiler()->initialize();
	initializeAxes();
}

// =============================================================================
//
void GLRenderer::initializeAxes()
{
	float axesdata[18];
	float colordata[18];
	memset (axesdata, 0, sizeof axesdata);

	for (int i = 0; i < 3; ++i)
	{
		for (int j = 0; j < 3; ++j)
		{
			axesdata[(i * 6) + j] = g_GLAxes[i].vert.getCoordinate (j);
			axesdata[(i * 6) + 3 + j] = -g_GLAxes[i].vert.getCoordinate (j);
		}

		for (int j = 0; j < 2; ++j)
		{
			colordata[(i * 6) + (j * 3) + 0] = g_GLAxes[i].col.red();
			colordata[(i * 6) + (j * 3) + 1] = g_GLAxes[i].col.green();
			colordata[(i * 6) + (j * 3) + 2] = g_GLAxes[i].col.blue();
		}
	}

	glGenBuffers (1, &g_GLAxes_VBO);
	glBindBuffer (GL_ARRAY_BUFFER, g_GLAxes_VBO);
	glBufferData (GL_ARRAY_BUFFER, sizeof axesdata, axesdata, GL_STATIC_DRAW);
	glGenBuffers (1, &g_GLAxes_ColorVBO);
	glBindBuffer (GL_ARRAY_BUFFER, g_GLAxes_ColorVBO);
	glBufferData (GL_ARRAY_BUFFER, sizeof colordata, colordata, GL_STATIC_DRAW);
	glBindBuffer (GL_ARRAY_BUFFER, 0);
}

// =============================================================================
//
QColor GLRenderer::getMainColor()
{
	QColor col (gl_maincolor);

	if (!col.isValid())
		return QColor (0, 0, 0);

	col.setAlpha (gl_maincolor_alpha * 255.f);
	return col;
}

// =============================================================================
//
void GLRenderer::setBackground()
{
	QColor col (gl_bgcolor);

	if (!col.isValid())
		return;

	col.setAlpha (255);

	m_darkbg = luma (col) < 80;
	m_bgcolor = col;
	qglClearColor (col);
}

// =============================================================================
//
void GLRenderer::refresh()
{
	update();
	swapBuffers();
}

// =============================================================================
//
void GLRenderer::hardRefresh()
{
	compiler()->compileDocument (getCurrentDocument());
	refresh();
	glLineWidth (gl_linethickness); // TODO: ...?
}

// =============================================================================
//
void GLRenderer::resizeGL (int w, int h)
{
	m_width = w;
	m_height = h;

	calcCameraIcons();

	glViewport (0, 0, w, h);
	glMatrixMode (GL_PROJECTION);
	glLoadIdentity();
	gluPerspective (45.0f, (double) w / (double) h, 1.0f, 10000.0f);
	glMatrixMode (GL_MODELVIEW);
}

// =============================================================================
//
void GLRenderer::drawGLScene()
{
	if (document() == null)
		return;

	if (gl_wireframe && !isPicking())
		glPolygonMode (GL_FRONT_AND_BACK, GL_LINE);

	glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glEnable (GL_DEPTH_TEST);

	if (camera() != EFreeCamera)
	{
		glMatrixMode (GL_PROJECTION);
		glPushMatrix();

		glLoadIdentity();
		glOrtho (-m_virtWidth, m_virtWidth, -m_virtHeight, m_virtHeight, -100.0f, 100.0f);
		glTranslatef (pan (X), pan (Y), 0.0f);

		if (camera() != EFrontCamera && camera() != EBackCamera)
		{
			glRotatef (90.0f, g_FixedCameras[camera()].glrotate[0],
				g_FixedCameras[camera()].glrotate[1],
				g_FixedCameras[camera()].glrotate[2]);
		}

		// Back camera needs to be handled differently
		if (camera() == EBackCamera)
		{
			glRotatef (180.0f, 1.0f, 0.0f, 0.0f);
			glRotatef (180.0f, 0.0f, 0.0f, 1.0f);
		}
	}
	else
	{
		glMatrixMode (GL_MODELVIEW);
		glPushMatrix();
		glLoadIdentity();

		glTranslatef (0.0f, 0.0f, -2.0f);
		glTranslatef (pan (X), pan (Y), -zoom());
		glRotatef (rot (X), 1.0f, 0.0f, 0.0f);
		glRotatef (rot (Y), 0.0f, 1.0f, 0.0f);
		glRotatef (rot (Z), 0.0f, 0.0f, 1.0f);
	}

	glEnableClientState (GL_VERTEX_ARRAY);
	glEnableClientState (GL_COLOR_ARRAY);

	if (isPicking())
	{
		drawVBOs (VBOSF_Triangles, VBOCM_PickColors, GL_TRIANGLES);
		drawVBOs (VBOSF_Quads, VBOCM_PickColors, GL_QUADS);
		drawVBOs (VBOSF_Lines, VBOCM_PickColors, GL_LINES);
		drawVBOs (VBOSF_CondLines, VBOCM_PickColors, GL_LINES);
	}
	else
	{
		if (gl_colorbfc)
		{
			glEnable (GL_CULL_FACE);
			glCullFace (GL_BACK);
			drawVBOs (VBOSF_Triangles, VBOCM_BFCFrontColors, GL_TRIANGLES);
			drawVBOs (VBOSF_Quads, VBOCM_BFCFrontColors, GL_QUADS);
			glCullFace (GL_FRONT);
			drawVBOs (VBOSF_Triangles, VBOCM_BFCBackColors, GL_TRIANGLES);
			drawVBOs (VBOSF_Quads, VBOCM_BFCBackColors, GL_QUADS);
			glDisable (GL_CULL_FACE);
		}
		else
		{
			drawVBOs (VBOSF_Triangles, VBOCM_NormalColors, GL_TRIANGLES);
			drawVBOs (VBOSF_Quads, VBOCM_NormalColors, GL_QUADS);
		}

		drawVBOs (VBOSF_Lines, VBOCM_NormalColors, GL_LINES);
		drawVBOs (VBOSF_CondLines, VBOCM_NormalColors, GL_LINES);

		if (gl_axes)
		{
			glBindBuffer (GL_ARRAY_BUFFER, g_GLAxes_VBO);
			glVertexPointer (3, GL_FLOAT, 0, NULL);
			glBindBuffer (GL_ARRAY_BUFFER, g_GLAxes_VBO);
			glColorPointer (3, GL_FLOAT, 0, NULL);
			glDrawArrays (GL_LINES, 0, 6);
			checkGLError();
		}
	}

	glPopMatrix();
	glBindBuffer (GL_ARRAY_BUFFER, 0);
	glDisableClientState (GL_VERTEX_ARRAY);
	glDisableClientState (GL_COLOR_ARRAY);
	checkGLError();
	glDisable (GL_CULL_FACE);
	glMatrixMode (GL_MODELVIEW);
	glPolygonMode (GL_FRONT_AND_BACK, GL_FILL);
}

// =============================================================================
//
void GLRenderer::drawVBOs (EVBOSurface surface, EVBOComplement colors, GLenum type)
{
	int surfacenum = m_compiler->vboNumber (surface, VBOCM_Surfaces);
	int colornum = m_compiler->vboNumber (surface, colors);

	m_compiler->prepareVBO (surfacenum);
	m_compiler->prepareVBO (colornum);
	GLuint surfacevbo = m_compiler->vbo (surfacenum);
	GLuint colorvbo = m_compiler->vbo (colornum);
	GLsizei count = m_compiler->vboCount (surfacevbo);

	if (count > 0)
	{
		glBindBuffer (GL_ARRAY_BUFFER, surfacevbo);
		glVertexPointer (3, GL_FLOAT, 0, null);
		checkGLError();
		glBindBuffer (GL_ARRAY_BUFFER, colorvbo);
		glColorPointer (4, GL_FLOAT, 0, null);
		checkGLError();
		glDrawArrays (type, 0, count);
		checkGLError();
	}
}

// =============================================================================
// This converts a 2D point on the screen to a 3D point in the model. If 'snap'
// is true, the 3D point will snap to the current grid.
//
Vertex GLRenderer::coordconv2_3 (const QPoint& pos2d, bool snap) const
{
	assert (camera() != EFreeCamera);

	Vertex pos3d;
	const LDFixedCameraInfo* cam = &g_FixedCameras[camera()];
	const Axis axisX = cam->axisX;
	const Axis axisY = cam->axisY;
	const int negXFac = cam->negX ? -1 : 1,
				negYFac = cam->negY ? -1 : 1;

	// Calculate cx and cy - these are the LDraw unit coords the cursor is at.
	double cx = (-m_virtWidth + ((2 * pos2d.x() * m_virtWidth) / m_width) - pan (X));
	double cy = (m_virtHeight - ((2 * pos2d.y() * m_virtHeight) / m_height) - pan (Y));

	if (snap)
	{
		cx = Grid::snap (cx, (Grid::Config) axisX);
		cy = Grid::snap (cy, (Grid::Config) axisY);
	}

	cx *= negXFac;
	cy *= negYFac;

	roundToDecimals (cx, 4);
	roundToDecimals (cy, 4);

	// Create the vertex from the coordinates
	pos3d[axisX] = cx;
	pos3d[axisY] = cy;
	pos3d[3 - axisX - axisY] = getDepthValue();
	return pos3d;
}

// =============================================================================
//
// Inverse operation for the above - convert a 3D position to a 2D screen
// position. Don't ask me how this code manages to work, I don't even know.
//
QPoint GLRenderer::coordconv3_2 (const Vertex& pos3d) const
{
	GLfloat m[16];
	const LDFixedCameraInfo* cam = &g_FixedCameras[camera()];
	const Axis axisX = cam->axisX;
	const Axis axisY = cam->axisY;
	const int negXFac = cam->negX ? -1 : 1,
				negYFac = cam->negY ? -1 : 1;

	glGetFloatv (GL_MODELVIEW_MATRIX, m);

	const double x = pos3d.x();
	const double y = pos3d.y();
	const double z = pos3d.z();

	Vertex transformed;
	transformed[X] = (m[0] * x) + (m[1] * y) + (m[2] * z) + m[3];
	transformed[Y] = (m[4] * x) + (m[5] * y) + (m[6] * z) + m[7];
	transformed[Z] = (m[8] * x) + (m[9] * y) + (m[10] * z) + m[11];

	double rx = (((transformed[axisX] * negXFac) + m_virtWidth + pan (X)) * m_width) / (2 * m_virtWidth);
	double ry = (((transformed[axisY] * negYFac) - m_virtHeight + pan (Y)) * m_height) / (2 * m_virtHeight);

	return QPoint (rx, -ry);
}

// =============================================================================
//
void GLRenderer::paintEvent (QPaintEvent* ev)
{
	Q_UNUSED (ev)

	makeCurrent();
	m_virtWidth = zoom();
	m_virtHeight = (m_height * m_virtWidth) / m_width;

	initGLData();
	drawGLScene();

	const QPen textpen (m_darkbg ? Qt::white : Qt::black);
	const QBrush polybrush (QColor (64, 192, 0, 128));
	QPainter paint (this);
	QFontMetrics metrics = QFontMetrics (QFont());
	paint.setRenderHint (QPainter::HighQualityAntialiasing);

	// If we wish to only draw the brick, stop here
	if (isDrawOnly())
		return;

#ifndef RELEASE
	if (isPicking() == false)
	{
		QString text = format ("Rotation: (%1, %2, %3)\nPanning: (%4, %5), Zoom: %6",
			rot(X), rot(Y), rot(Z), pan(X), pan(Y), zoom());
		QRect textSize = metrics.boundingRect (0, 0, m_width, m_height, Qt::AlignCenter, text);

		paint.drawText ((width() - textSize.width()) / 2, height() - textSize.height(), textSize.width(),
			textSize.height(), Qt::AlignCenter, text);
	}
#endif

	if (camera() != EFreeCamera && !isPicking())
	{
		// Paint the overlay image if we have one
		const LDGLOverlay& overlay = currentDocumentData().overlays[camera()];

		if (overlay.img != null)
		{
			QPoint v0 = coordconv3_2 (currentDocumentData().overlays[camera()].v0),
					   v1 = coordconv3_2 (currentDocumentData().overlays[camera()].v1);

			QRect targRect (v0.x(), v0.y(), abs (v1.x() - v0.x()), abs (v1.y() - v0.y())),
				  srcRect (0, 0, overlay.img->width(), overlay.img->height());
			paint.drawImage (targRect, *overlay.img, srcRect);
		}

		// Paint the coordinates onto the screen.
		QString text = format (tr ("X: %1, Y: %2, Z: %3"), m_hoverpos[X], m_hoverpos[Y], m_hoverpos[Z]);
		QFontMetrics metrics = QFontMetrics (font());
		QRect textSize = metrics.boundingRect (0, 0, m_width, m_height, Qt::AlignCenter, text);
		paint.setPen (textpen);
		paint.drawText (m_width - textSize.width(), m_height - 16, textSize.width(),
			textSize.height(), Qt::AlignCenter, text);

		QPen linepen = m_thinBorderPen;
		linepen.setWidth (2);
		linepen.setColor (luma (m_bgcolor) < 40 ? Qt::white : Qt::black);

		// Mode-specific rendering
		if (editMode() == EDrawMode)
		{
			QPoint poly[4];
			Vertex poly3d[4];
			int numverts = 4;

			// Calculate polygon data
			if (!m_rectdraw)
			{
				numverts = m_drawedVerts.size() + 1;
				int i = 0;

				for (Vertex& vert : m_drawedVerts)
					poly3d[i++] = vert;

				// Draw the cursor vertex as the last one in the list.
				if (numverts <= 4)
					poly3d[i] = m_hoverpos;
				else
					numverts = 4;
			}
			else
			{
				// Get vertex information from m_rectverts
				if (m_drawedVerts.size() > 0)
					for (int i = 0; i < numverts; ++i)
						poly3d[i] = m_rectverts[i];
				else
					poly3d[0] = m_hoverpos;
			}

			// Convert to 2D
			for (int i = 0; i < numverts; ++i)
				poly[i] = coordconv3_2 (poly3d[i]);

			if (numverts > 0)
			{
				// Draw the polygon-to-be
				paint.setBrush (polybrush);
				paint.drawPolygon (poly, numverts);

				// Draw vertex blips
				for (int i = 0; i < numverts; ++i)
				{
					QPoint& blip = poly[i];
					paint.setPen (linepen);
					drawBlip (paint, blip);

					// Draw their coordinates
					paint.setPen (textpen);
					paint.drawText (blip.x(), blip.y() - 8, poly3d[i].toString (true));
				}

				// Draw line lenghts and angle info if appropriate
				if (numverts >= 2)
				{
					int numlines = (m_drawedVerts.size() == 1) ? 1 : m_drawedVerts.size() + 1;
					paint.setPen (textpen);

					for (int i = 0; i < numlines; ++i)
					{
						const int j = (i + 1 < numverts) ? i + 1 : 0;
						const int h = (i - 1 >= 0) ? i - 1 : numverts - 1;

						if (gl_linelengths)
						{
							const QString label = QString::number (poly3d[i].distanceTo (poly3d[j]));
							QPoint origin = QLineF (poly[i], poly[j]).pointAt (0.5).toPoint();
							paint.drawText (origin, label);
						}

						if (gl_drawangles)
						{
							QLineF l0 (poly[h], poly[i]),
								l1 (poly[i], poly[j]);

							double angle = 180 - l0.angleTo (l1);

							if (angle < 0)
								angle = 180 - l1.angleTo (l0);

							QString label = QString::number (angle) + QString::fromUtf8 (QByteArray ("\302\260"));
							QPoint pos = poly[i];
							pos.setY (pos.y() + metrics.height());

							paint.drawText (pos, label);
						}
					}
				}
			}
		}
		elif (editMode() == ECircleMode)
		{
			// If we have not specified the center point of the circle yet, preview it on the screen.
			if (m_drawedVerts.isEmpty())
				drawBlip (paint, coordconv3_2 (m_hoverpos));
			else
			{
				QVector<Vertex> verts, verts2;
				const double dist0 = getCircleDrawDist (0),
					dist1 = (m_drawedVerts.size() >= 2) ? getCircleDrawDist (1) : -1;
				const int segs = g_lores;
				const double angleUnit = (2 * pi) / segs;
				Axis relX, relY;
				QVector<QPoint> ringpoints, circlepoints, circle2points;

				getRelativeAxes (relX, relY);

				// Calculate the preview positions of vertices
				for (int i = 0; i < segs; ++i)
				{
					Vertex v = g_origin;
					v[relX] = m_drawedVerts[0][relX] + (cos (i * angleUnit) * dist0);
					v[relY] = m_drawedVerts[0][relY] + (sin (i * angleUnit) * dist0);
					verts << v;

					if (dist1 != -1)
					{
						v[relX] = m_drawedVerts[0][relX] + (cos (i * angleUnit) * dist1);
						v[relY] = m_drawedVerts[0][relY] + (sin (i * angleUnit) * dist1);
						verts2 << v;
					}
				}

				int i = 0;
				for (const Vertex& v : verts + verts2)
				{
					// Calculate the 2D point of the vertex
					QPoint point = coordconv3_2 (v);

					// Draw a green blip at where it is
					drawBlip (paint, point);

					// Add it to the list of points for the green ring fill.
					ringpoints << point;

					// Also add the circle points to separate lists
					if (i < verts.size())
						circlepoints << point;
					else
						circle2points << point;

					++i;
				}

				// Insert the first point as the seventeenth one so that
				// the ring polygon is closed properly.
				if (ringpoints.size() >= 16)
					ringpoints.insert (16, ringpoints[0]);

				// Same for the outer ring. Note that the indices are offset by 1
				// because of the insertion done above bumps the values.
				if (ringpoints.size() >= 33)
					ringpoints.insert (33, ringpoints[17]);

				// Draw the ring
				paint.setBrush ((m_drawedVerts.size() >= 2) ? polybrush : Qt::NoBrush);
				paint.setPen (Qt::NoPen);
				paint.drawPolygon (QPolygon (ringpoints));

				// Draw the circles
				paint.setBrush (Qt::NoBrush);
				paint.setPen (linepen);
				paint.drawPolygon (QPolygon (circlepoints));
				paint.drawPolygon (QPolygon (circle2points));

				{ // Draw the current radius in the middle of the circle.
					QPoint origin = coordconv3_2 (m_drawedVerts[0]);
					QString label = QString::number (dist0);
					paint.setPen (textpen);
					paint.drawText (origin.x() - (metrics.width (label) / 2), origin.y(), label);

					if (m_drawedVerts.size() >= 2)
					{
						label = QString::number (dist1);
						paint.drawText (origin.x() - (metrics.width (label) / 2), origin.y() + metrics.height(), label);
					}
				}
			}
		}
	}

	// Camera icons
	if (!isPicking())
	{
		// Draw a background for the selected camera
		paint.setPen (m_thinBorderPen);
		paint.setBrush (QBrush (QColor (0, 128, 160, 128)));
		paint.drawRect (m_cameraIcons[camera()].selRect);

		// Draw the actual icons
		for (CameraIcon& info : m_cameraIcons)
		{
			// Don't draw the free camera icon when in draw mode
			if (&info == &m_cameraIcons[GL::EFreeCamera] && editMode() != ESelectMode)
				continue;

			paint.drawPixmap (info.destRect, *info.img, info.srcRect);
		}

		QString formatstr = tr ("%1 Camera");

		// Draw a label for the current camera in the bottom left corner
		{
			const int margin = 4;

			QString label;
			label = format (formatstr, tr (g_CameraNames[camera()]));
			paint.setPen (textpen);
			paint.drawText (QPoint (margin, height() - (margin + metrics.descent())), label);
		}

		// Tool tips
		if (m_drawToolTip)
		{
			if (m_cameraIcons[m_toolTipCamera].destRect.contains (m_pos) == false)
				m_drawToolTip = false;
			else
			{
				QString label = format (formatstr, tr (g_CameraNames[m_toolTipCamera]));
				QToolTip::showText (m_globalpos, label);
			}
		}
	}

	// Message log
	if (messageLog())
	{
		int y = 0;
		const int margin = 2;
		QColor penColor = textpen.color();

		for (const MessageManager::Line& line : messageLog()->getLines())
		{
			penColor.setAlphaF (line.alpha);
			paint.setPen (penColor);
			paint.drawText (QPoint (margin, y + margin + metrics.ascent()), line.text);
			y += metrics.height();
		}
	}

	// If we're range-picking, draw a rectangle encompassing the selection area.
	if (m_rangepick && !isPicking() && m_totalmove >= 10)
	{
		int x0 = m_rangeStart.x(),
			y0 = m_rangeStart.y(),
			x1 = m_pos.x(),
			y1 = m_pos.y();

		QRect rect (x0, y0, x1 - x0, y1 - y0);
		QColor fillColor = (m_addpick ? "#40FF00" : "#00CCFF");
		fillColor.setAlphaF (0.2f);

		paint.setPen (m_thickBorderPen);
		paint.setBrush (QBrush (fillColor));
		paint.drawRect (rect);
	}
}

// =============================================================================
//
void GLRenderer::drawBlip (QPainter& paint, QPoint pos) const
{
	QPen pen = m_thinBorderPen;
	const int blipsize = 8;
	pen.setWidth (1);
	paint.setPen (pen);
	paint.setBrush (QColor (64, 192, 0));
	paint.drawEllipse (pos.x() - blipsize / 2, pos.y() - blipsize / 2, blipsize, blipsize);
}

// =============================================================================
//
void GLRenderer::clampAngle (double& angle) const
{
	while (angle < 0)
		angle += 360.0;

	while (angle > 360.0)
		angle -= 360.0;
}

// =============================================================================
//
void GLRenderer::addDrawnVertex (Vertex pos)
{
	// If we picked an already-existing vertex, stop drawing
	if (editMode() == EDrawMode)
	{
		for (Vertex& vert : m_drawedVerts)
		{
			if (vert == pos)
			{
				endDraw (true);
				return;
			}
		}
	}

	m_drawedVerts << pos;
}

// =============================================================================
//
void GLRenderer::mouseReleaseEvent (QMouseEvent* ev)
{
	const bool wasLeft = (m_lastButtons & Qt::LeftButton) && ! (ev->buttons() & Qt::LeftButton),
				   wasRight = (m_lastButtons & Qt::RightButton) && ! (ev->buttons() & Qt::RightButton),
				   wasMid = (m_lastButtons & Qt::MidButton) && ! (ev->buttons() & Qt::MidButton);

	if (m_panning)
		m_panning = false;

	if (wasLeft)
	{
		// Check if we selected a camera icon
		if (!m_rangepick)
		{
			for (CameraIcon & info : m_cameraIcons)
			{
				if (info.destRect.contains (ev->pos()))
				{
					setCamera (info.cam);
					goto end;
				}
			}
		}

		switch (editMode())
		{
			case EDrawMode:
			{
				if (m_rectdraw)
				{
					if (m_drawedVerts.size() == 2)
					{
						endDraw (true);
						return;
					}
				} else
				{
					// If we have 4 verts, stop drawing.
					if (m_drawedVerts.size() >= 4)
					{
						endDraw (true);
						return;
					}

					if (m_drawedVerts.isEmpty() && ev->modifiers() & Qt::ShiftModifier)
					{
						m_rectdraw = true;
						updateRectVerts();
					}
				}

				addDrawnVertex (m_hoverpos);
			} break;

			case ECircleMode:
			{
				if (m_drawedVerts.size() == 3)
				{
					endDraw (true);
					return;
				}

				addDrawnVertex (m_hoverpos);
			} break;

			case ESelectMode:
			{
				if (!isDrawOnly())
				{
					if (m_totalmove < 10)
						m_rangepick = false;

					if (!m_rangepick)
						m_addpick = (m_keymods & Qt::ControlModifier);

					if (m_totalmove < 10 || m_rangepick)
						pick (ev->x(), ev->y());
				}
			} break;
		}

		m_rangepick = false;
	}

	if (wasMid && editMode() != ESelectMode && m_drawedVerts.size() < 4 && m_totalmove < 10)
	{
		// Find the closest vertex to our cursor
		double mindist = 1024.0f;
		Vertex closest;
		bool valid = false;

		QPoint curspos = coordconv3_2 (m_hoverpos);

		for (const Vertex& pos3d: m_knownVerts)
		{
			QPoint pos2d = coordconv3_2 (pos3d);

			// Measure squared distance
			const double dx = abs (pos2d.x() - curspos.x()),
						 dy = abs (pos2d.y() - curspos.y()),
						 distsq = (dx * dx) + (dy * dy);

			if (distsq >= 1024.0f) // 32.0f ** 2
				continue; // too far away

			if (distsq < mindist)
			{
				mindist = distsq;
				closest = pos3d;
				valid = true;

				// If it's only 4 pixels away, I think we found our vertex now.
				if (distsq <= 16.0f) // 4.0f ** 2
					break;
			}
		}

		if (valid)
			addDrawnVertex (closest);
	}

	if (wasRight && !m_drawedVerts.isEmpty())
	{
		// Remove the last vertex
		m_drawedVerts.removeLast();

		if (m_drawedVerts.isEmpty())
			m_rectdraw = false;
	}

end:
	update();
	m_totalmove = 0;
}

// =============================================================================
//
void GLRenderer::mousePressEvent (QMouseEvent* ev)
{
	m_totalmove = 0;

	if (ev->modifiers() & Qt::ControlModifier)
	{
		m_rangepick = true;
		m_rangeStart.setX (ev->x());
		m_rangeStart.setY (ev->y());
		m_addpick = (m_keymods & Qt::AltModifier);
		ev->accept();
	}

	m_lastButtons = ev->buttons();
}

// =============================================================================
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
// =============================================================================
void GLRenderer::mouseMoveEvent (QMouseEvent* ev)
{
	int dx = ev->x() - m_pos.x();
	int dy = ev->y() - m_pos.y();
	m_totalmove += abs (dx) + abs (dy);

	const bool left = ev->buttons() & Qt::LeftButton,
			   mid = ev->buttons() & Qt::MidButton,
			   shift = ev->modifiers() & Qt::ShiftModifier;

	if (mid || (left && shift))
	{
		pan (X) += 0.03f * dx * (zoom() / 7.5f);
		pan (Y) -= 0.03f * dy * (zoom() / 7.5f);
		m_panning = true;
	} elif (left && !m_rangepick && camera() == EFreeCamera)
	{
		rot (X) = rot (X) + dy;
		rot (Y) = rot (Y) + dx;

		clampAngle (rot (X));
		clampAngle (rot (Y));
	}

	// Start the tool tip timer
	if (!m_drawToolTip)
		m_toolTipTimer->start (500);

	// Update 2d position
	m_pos = ev->pos();
	m_globalpos = ev->globalPos();

	// Calculate 3d position of the cursor
	m_hoverpos = (camera() != EFreeCamera) ? coordconv2_3 (m_pos, true) : g_origin;

	// Update rect vertices since m_hoverpos may have changed
	updateRectVerts();

	update();
}

// =============================================================================
//
void GLRenderer::keyPressEvent (QKeyEvent* ev)
{
	m_keymods = ev->modifiers();
}

// =============================================================================
//
void GLRenderer::keyReleaseEvent (QKeyEvent* ev)
{
	m_keymods = ev->modifiers();
}

// =============================================================================
//
void GLRenderer::wheelEvent (QWheelEvent* ev)
{
	makeCurrent();

	zoomNotch (ev->delta() > 0);
	zoom() = clamp (zoom(), 0.01, 10000.0);

	update();
	ev->accept();
}

// =============================================================================
//
void GLRenderer::leaveEvent (QEvent* ev)
{
	(void) ev;
	m_drawToolTip = false;
	m_toolTipTimer->stop();
	update();
}

// =============================================================================
//
void GLRenderer::contextMenuEvent (QContextMenuEvent* ev)
{
	g_win->spawnContextMenu (ev->globalPos());
}

// =============================================================================
//
void GLRenderer::setCamera (const GLRenderer::EFixedCamera cam)
{
	m_camera = cam;
	gl_camera = (int) cam;
	g_win->updateEditModeActions();
}

// =============================================================================
//
void GLRenderer::pick (int mouseX, int mouseY)
{
	makeCurrent();

	// Use particularly thick lines while picking ease up selecting lines.
	glLineWidth (max<double> (gl_linethickness, 6.5f));

	// Clear the selection if we do not wish to add to it.
	if (!m_addpick)
	{
		LDObjectList oldsel = selection();
		getCurrentDocument()->clearSelection();

		for (LDObject* obj : oldsel)
			compileObject (obj);
	}

	setPicking (true);

	// Paint the picking scene
	glDisable (GL_DITHER);
	glClearColor (1.0f, 1.0f, 1.0f, 1.0f);
	drawGLScene();

	int x0 = mouseX,
		  y0 = mouseY;
	int x1, y1;

	// Determine how big an area to read - with range picking, we pick by
	// the area given, with single pixel picking, we use an 1 x 1 area.
	if (m_rangepick)
	{
		x1 = m_rangeStart.x();
		y1 = m_rangeStart.y();
	}
	else
	{
		x1 = x0 + 1;
		y1 = y0 + 1;
	}

	// x0 and y0 must be less than x1 and y1, respectively.
	if (x0 > x1)
		qSwap (x0, x1);

	if (y0 > y1)
		qSwap (y0, y1);

	// Clamp the values to ensure they're within bounds
	x0 = max (0, x0);
	y0 = max (0, y0);
	x1 = min (x1, m_width);
	y1 = min (y1, m_height);
	const int areawidth = (x1 - x0);
	const int areaheight = (y1 - y0);
	const qint32 numpixels = areawidth * areaheight;

	// Allocate space for the pixel data.
	uchar* const pixeldata = new uchar[4 * numpixels];
	uchar* pixelptr = &pixeldata[0];

	// Read pixels from the color buffer.
	glReadPixels (x0, m_height - y1, areawidth, areaheight, GL_RGBA, GL_UNSIGNED_BYTE, pixeldata);

	LDObject* removedObj = null;

	// Go through each pixel read and add them to the selection.
	for (qint32 i = 0; i < numpixels; ++i)
	{
		qint32 idx =
			(*(pixelptr + 0) * 0x10000) +
			(*(pixelptr + 1) * 0x100) +
			*(pixelptr + 2);
		pixelptr += 4;

		if (idx == 0xFFFFFF)
			continue; // White is background; skip

		dprint ("id: %1\n", idx);
		LDObject* obj = LDObject::fromID (idx);
		assert (obj != null);

		// If this is an additive single pick and the object is currently selected,
		// we remove it from selection instead.
		if (!m_rangepick && m_addpick)
		{
			if (obj->isSelected())
			{
				obj->unselect();
				removedObj = obj;
				break;
			}
		}

		obj->select();
	}

	delete[] pixeldata;

	// Update everything now.
	g_win->updateSelection();

	// Recompile the objects now to update their color
	for (LDObject* obj : selection())
		compileObject (obj);

	if (removedObj)
		compileObject (removedObj);

	// Restore line thickness
	glLineWidth (gl_linethickness);

	setPicking (false);
	m_rangepick = false;
	glEnable (GL_DITHER);

	setBackground();
	repaint();
}

// =============================================================================
//
void GLRenderer::setEditMode (EditMode const& a)
{
	m_editMode = a;

	switch (a)
	{
		case ESelectMode:
		{
			unsetCursor();
			setContextMenuPolicy (Qt::DefaultContextMenu);
		} break;

		case EDrawMode:
		case ECircleMode:
		{
			// Cannot draw into the free camera - use top instead.
			if (camera() == EFreeCamera)
				setCamera (ETopCamera);

			// Disable the context menu - we need the right mouse button
			// for removing vertices.
			setContextMenuPolicy (Qt::NoContextMenu);

			// Use the crosshair cursor when drawing.
			setCursor (Qt::CrossCursor);

			// Clear the selection when beginning to draw.
			LDObjectList priorsel = selection();
			getCurrentDocument()->clearSelection();

			for (LDObject* obj : priorsel)
				compileObject (obj);

			g_win->updateSelection();
			m_drawedVerts.clear();
		} break;
	}

	g_win->updateEditModeActions();
	update();
}

// =============================================================================
//
void GLRenderer::setDocument (LDDocument* const& a)
{
	m_document = a;

	if (a != null)
	{
		initOverlaysFromObjects();

		if (currentDocumentData().init == false)
		{
			resetAllAngles();
			currentDocumentData().init = true;
		}
	}
}

// =============================================================================
//
Matrix GLRenderer::getCircleDrawMatrix (double scale)
{
	Matrix transform = g_circleDrawMatrixTemplates[camera() % 3];

	for (int i = 0; i < 9; ++i)
	{
		if (transform[i] == 2)
			transform[i] = scale;
		elif (transform[i] == 1 && camera() >= 3)
			transform[i] = -1;
	}

	return transform;
}

// =============================================================================
//
void GLRenderer::endDraw (bool accept)
{
	(void) accept;

	// Clean the selection and create the object
	QList<Vertex>& verts = m_drawedVerts;
	LDObjectList objs;

	switch (editMode())
	{
		case EDrawMode:
		{
			if (m_rectdraw)
			{
				LDQuad* quad = new LDQuad;

				// Copy the vertices from m_rectverts
				updateRectVerts();

				for (int i = 0; i < quad->vertices(); ++i)
					quad->setVertex (i, m_rectverts[i]);

				quad->setColor (maincolor);
				objs << quad;
			}
			else
			{
				switch (verts.size())
				{
					case 1:
					{
						// 1 vertex - add a vertex object
						LDVertex* obj = new LDVertex;
						obj->pos = verts[0];
						obj->setColor (maincolor);
						objs << obj;
					} break;

					case 2:
					{
						// 2 verts - make a line
						LDLine* obj = new LDLine (verts[0], verts[1]);
						obj->setColor (edgecolor);
						objs << obj;
					} break;

					case 3:
					case 4:
					{
						LDObject* obj = (verts.size() == 3) ?
							  static_cast<LDObject*> (new LDTriangle) :
							  static_cast<LDObject*> (new LDQuad);

						obj->setColor (maincolor);

						for (int i = 0; i < obj->vertices(); ++i)
							obj->setVertex (i, verts[i]);

						objs << obj;
					} break;
				}
			}
		} break;

		case ECircleMode:
		{
			const int segs = g_lores, divs = g_lores; // TODO: make customizable
			double dist0 = getCircleDrawDist (0),
				dist1 = getCircleDrawDist (1);
			LDDocument* refFile = null;
			Matrix transform;
			bool circleOrDisc = false;

			if (dist1 < dist0)
				std::swap<double> (dist0, dist1);

			if (dist0 == dist1)
			{
				// If the radii are the same, there's no ring space to fill. Use a circle.
				refFile = ::getDocument ("4-4edge.dat");
				transform = getCircleDrawMatrix (dist0);
				circleOrDisc = true;
			}
			elif (dist0 == 0 || dist1 == 0)
			{
				// If either radii is 0, use a disc.
				refFile = ::getDocument ("4-4disc.dat");
				transform = getCircleDrawMatrix ((dist0 != 0) ? dist0 : dist1);
				circleOrDisc = true;
			}
			elif (g_RingFinder.findRings (dist0, dist1))
			{
				// The ring finder found a solution, use that. Add the component rings to the file.
				for (const RingFinder::Component& cmp : g_RingFinder.bestSolution()->getComponents())
				{
					// Get a ref file for this primitive. If we cannot find it in the
					// LDraw library, generate it.
					if ((refFile = ::getDocument (radialFileName (::Ring, g_lores, g_lores, cmp.num))) == null)
					{
						refFile = generatePrimitive (::Ring, g_lores, g_lores, cmp.num);
						refFile->setImplicit (false);
					}

					LDSubfile* ref = new LDSubfile;
					ref->setFileInfo (refFile);
					ref->setTransform (getCircleDrawMatrix (cmp.scale));
					ref->setPosition (m_drawedVerts[0]);
					ref->setColor (maincolor);
					objs << ref;
				}
			}
			else
			{
				// Ring finder failed, last resort: draw the ring with quads
				QList<QLineF> c0, c1;
				Axis relX, relY, relZ;
				getRelativeAxes (relX, relY);
				relZ = (Axis) (3 - relX - relY);
				double x0 = m_drawedVerts[0][relX],
					y0 = m_drawedVerts[0][relY];

				Vertex templ;
				templ[relX] = x0;
				templ[relY] = y0;
				templ[relZ] = getDepthValue();

				// Calculate circle coords
				makeCircle (segs, divs, dist0, c0);
				makeCircle (segs, divs, dist1, c1);

				for (int i = 0; i < segs; ++i)
				{
					Vertex v0, v1, v2, v3;
					v0 = v1 = v2 = v3 = templ;
					v0[relX] += c0[i].x1();
					v0[relY] += c0[i].y1();
					v1[relX] += c0[i].x2();
					v1[relY] += c0[i].y2();
					v2[relX] += c1[i].x2();
					v2[relY] += c1[i].y2();
					v3[relX] += c1[i].x1();
					v3[relY] += c1[i].y1();

					LDQuad* q = new LDQuad (v0, v1, v2, v3);
					q->setColor (maincolor);

					// Ensure the quads always are BFC-front towards the camera
					if (camera() % 3 <= 0)
						q->invert();

					objs << q;
				}
			}

			if (circleOrDisc)
			{
				LDSubfile* ref = new LDSubfile;
				ref->setFileInfo (refFile);
				ref->setTransform (transform);
				ref->setPosition (m_drawedVerts[0]);
				ref->setColor (maincolor);
				objs << ref;
			}
		} break;

		case ESelectMode:
		{
			// this shouldn't happen
			assert (false);
			return;
		} break;
	}

	if (objs.size() > 0)
	{
		for (LDObject* obj : objs)
		{
			document()->addObject (obj);
			compileObject (obj);
		}

		g_win->refresh();
		g_win->endAction();
	}

	m_drawedVerts.clear();
	m_rectdraw = false;
}

// =============================================================================
//
double GLRenderer::getCircleDrawDist (int pos) const
{
	assert (m_drawedVerts.size() >= pos + 1);
	const Vertex& v1 = (m_drawedVerts.size() >= pos + 2) ? m_drawedVerts[pos + 1] : m_hoverpos;
	Axis relX, relY;
	getRelativeAxes (relX, relY);

	const double dx = m_drawedVerts[0][relX] - v1[relX];
	const double dy = m_drawedVerts[0][relY] - v1[relY];
	return sqrt ((dx * dx) + (dy * dy));
}

// =============================================================================
//
void GLRenderer::getRelativeAxes (Axis& relX, Axis& relY) const
{
	const LDFixedCameraInfo* cam = &g_FixedCameras[camera()];
	relX = cam->axisX;
	relY = cam->axisY;
}

// =============================================================================
//
static QList<Vertex> getVertices (LDObject* obj)
{
	QList<Vertex> verts;

	if (obj->vertices() >= 2)
	{
		for (int i = 0; i < obj->vertices(); ++i)
			verts << obj->vertex (i);
	}
	elif (obj->type() == LDObject::ESubfile)
	{
		LDSubfile* ref = static_cast<LDSubfile*> (obj);
		LDObjectList objs = ref->inlineContents (true, false);

		for (LDObject* obj : objs)
		{
			verts << getVertices (obj);
			obj->destroy();
		}
	}

	return verts;
}

// =============================================================================
//
void GLRenderer::compileObject (LDObject* obj)
{
	compiler()->stageForCompilation (obj);

	// Mark in known vertices of this object
	/*
	QList<Vertex> verts = getVertices (obj);
	m_knownVerts << verts;
	removeDuplicates (m_knownVerts);
	*/

	obj->setGLInit (true);
}

// =============================================================================
//
void GLRenderer::forgetObject (LDObject* obj)
{
	compiler()->dropObject (obj);
}

// =============================================================================
//
uchar* GLRenderer::getScreencap (int& w, int& h)
{
	w = m_width;
	h = m_height;
	uchar* cap = new uchar[4 * w * h];

	m_screencap = true;
	update();
	m_screencap = false;

	// Capture the pixels
	glReadPixels (0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, cap);

	return cap;
}

// =============================================================================
//
void GLRenderer::slot_toolTipTimer()
{
	// We come here if the cursor has stayed in one place for longer than a
	// a second. Check if we're holding it over a camera icon - if so, draw
	// a tooltip.
	for (CameraIcon & icon : m_cameraIcons)
	{
		if (icon.destRect.contains (m_pos))
		{
			m_toolTipCamera = icon.cam;
			m_drawToolTip = true;
			update();
			break;
		}
	}
}

// =============================================================================
//
Axis GLRenderer::getCameraAxis (bool y, GLRenderer::EFixedCamera camid)
{
	if (camid == (GL::EFixedCamera) - 1)
		camid = camera();

	const LDFixedCameraInfo* cam = &g_FixedCameras[camid];
	return (y) ? cam->axisY : cam->axisX;
}

// =============================================================================
//
bool GLRenderer::setupOverlay (EFixedCamera cam, QString file, int x, int y, int w, int h)
{
	QImage* img = new QImage (QImage (file).convertToFormat (QImage::Format_ARGB32));
	LDGLOverlay& info = getOverlay (cam);

	if (img->isNull())
	{
		critical (tr ("Failed to load overlay image!"));
		currentDocumentData().overlays[cam].invalid = true;
		delete img;
		return false;
	}

	delete info.img; // delete the old image

	info.fname = file;
	info.lw = w;
	info.lh = h;
	info.ox = x;
	info.oy = y;
	info.img = img;
	info.invalid = false;

	if (info.lw == 0)
		info.lw = (info.lh * img->width()) / img->height();
	elif (info.lh == 0)
		info.lh = (info.lw * img->height()) / img->width();

	const Axis x2d = getCameraAxis (false, cam),
		y2d = getCameraAxis (true, cam);
	const double negXFac = g_FixedCameras[cam].negX ? -1 : 1,
		negYFac = g_FixedCameras[cam].negY ? -1 : 1;

	info.v0 = info.v1 = g_origin;
	info.v0[x2d] = - (info.ox * info.lw * negXFac) / img->width();
	info.v0[y2d] = (info.oy * info.lh * negYFac) / img->height();
	info.v1[x2d] = info.v0[x2d] + info.lw;
	info.v1[y2d] = info.v0[y2d] + info.lh;

	// Set alpha of all pixels to 0.5
	for (long i = 0; i < img->width(); ++i)
	for (long j = 0; j < img->height(); ++j)
	{
		uint32 pixel = img->pixel (i, j);
		img->setPixel (i, j, 0x80000000 | (pixel & 0x00FFFFFF));
	}

	updateOverlayObjects();
	return true;
}

// =============================================================================
//
void GLRenderer::clearOverlay()
{
	if (camera() == EFreeCamera)
		return;

	LDGLOverlay& info = currentDocumentData().overlays[camera()];
	delete info.img;
	info.img = null;

	updateOverlayObjects();
}

// =============================================================================
//
void GLRenderer::setDepthValue (double depth)
{
	assert (camera() < EFreeCamera);
	currentDocumentData().depthValues[camera()] = depth;
}

// =============================================================================
//
double GLRenderer::getDepthValue() const
{
	assert (camera() < EFreeCamera);
	return currentDocumentData().depthValues[camera()];
}

// =============================================================================
//
const char* GLRenderer::getCameraName() const
{
	return g_CameraNames[camera()];
}

// =============================================================================
//
LDGLOverlay& GLRenderer::getOverlay (int newcam)
{
	return currentDocumentData().overlays[newcam];
}

// =============================================================================
//
void GLRenderer::zoomNotch (bool inward)
{
	if (zoom() > 15)
		zoom() *= inward ? 0.833f : 1.2f;
	else
		zoom() += inward ? -1.2f : 1.2f;
}

// =============================================================================
//
void GLRenderer::zoomToFit()
{
	print ("zooming %1 to fit..\n", camera());
	zoom() = 30.0f;

	if (document() == null || m_width == -1 || m_height == -1)
	{
		print ("document is invalid!\n");
		return;
	}

	bool lastfilled = false;
	bool firstrun = true;
	const uint32 white = 0xFFFFFFFF;
	bool inward = true;
	const int w = m_width, h = m_height;
	int runaway = 50;

	glClearColor (1.0, 1.0, 1.0, 1.0);
	glDisable (GL_DITHER);

	// Use the pick list while drawing the scene, this way we can tell whether borders
	// are background or not.
	setPicking (true);

	while (--runaway)
	{
		if (zoom() > 10000.0 || zoom() < 0.0)
		{
			// Obviously, there's nothing to draw if we get here.
			// Default to 30.0f and break out.
			zoom() = 30.0;
			break;
		}

		zoomNotch (inward);

		uchar* cap = new uchar[4 * w * h];
		drawGLScene();
		glReadPixels (0, 0, w, h, GL_RGBA, GL_UNSIGNED_BYTE, cap);
		uint32* imgdata = reinterpret_cast<uint32*> (cap);
		bool filled = false;

		// Check the top and bottom rows
		for (int i = 0; i < w; ++i)
		{
			if (imgdata[i] != white || imgdata[((h - 1) * w) + i] != white)
			{
				filled = true;
				break;
			}
		}

		// Left and right edges
		if (filled == false)
		{
			for (int i = 0; i < h; ++i)
			{
				if (imgdata[i * w] != white || imgdata[(i * w) + w - 1] != white)
				{
					filled = true;
					break;
				}
			}
		}

		delete[] cap;

		if (firstrun)
		{
			// If this is the first run, we don't know enough to determine
			// whether the zoom was to fit, so we mark in our knowledge so
			// far and start over.
			inward = !filled;
			firstrun = false;
		}
		else
		{
			// If this run filled the screen and the last one did not, the
			// last run had ideal zoom - zoom a bit back and we should reach it.
			if (filled && !lastfilled)
			{
				zoomNotch (false);
				break;
			}

			// If this run did not fill the screen and the last one did, we've
			// now reached ideal zoom so we're done here.
			if (!filled && lastfilled)
				break;

			inward = !filled;
		}

		lastfilled = filled;
	}

	setBackground();
	setPicking (false);
	print ("zoom to fit done.\n");
}

// =============================================================================
//
void GLRenderer::zoomAllToFit()
{
	EFixedCamera oldcam = camera();

	for (int i = 0; i < 7; ++i)
	{
		setCamera ((EFixedCamera) i);
		zoomToFit();
	}

	setCamera (oldcam);
}

// =============================================================================
//
void GLRenderer::updateRectVerts()
{
	if (!m_rectdraw)
		return;

	if (m_drawedVerts.isEmpty())
	{
		for (int i = 0; i < 4; ++i)
			m_rectverts[i] = m_hoverpos;

		return;
	}

	Vertex v0 = m_drawedVerts[0],
		   v1 = (m_drawedVerts.size() >= 2) ? m_drawedVerts[1] : m_hoverpos;

	const Axis ax = getCameraAxis (false),
			   ay = getCameraAxis (true),
			   az = (Axis) (3 - ax - ay);

	for (int i = 0; i < 4; ++i)
		m_rectverts[i][az] = getDepthValue();

	m_rectverts[0][ax] = v0[ax];
	m_rectverts[0][ay] = v0[ay];
	m_rectverts[1][ax] = v1[ax];
	m_rectverts[1][ay] = v0[ay];
	m_rectverts[2][ax] = v1[ax];
	m_rectverts[2][ay] = v1[ay];
	m_rectverts[3][ax] = v0[ax];
	m_rectverts[3][ay] = v1[ay];
}

// =============================================================================
//
void GLRenderer::mouseDoubleClickEvent (QMouseEvent* ev)
{
	if (!(ev->buttons() & Qt::LeftButton) || editMode() != ESelectMode)
		return;

	pick (ev->x(), ev->y());

	if (selection().isEmpty())
		return;

	LDObject* obj = selection().first();
	AddObjectDialog::staticDialog (obj->type(), obj);
	g_win->endAction();
	ev->accept();
}

// =============================================================================
//
LDOverlay* GLRenderer::findOverlayObject (EFixedCamera cam)
{
	LDOverlay* ovlobj = null;

	for (LDObject* obj : document()->objects())
	{
		if (obj->type() == LDObject::EOverlay && static_cast<LDOverlay*> (obj)->camera() == cam)
		{
			ovlobj = static_cast<LDOverlay*> (obj);
			break;
		}
	}

	return ovlobj;
}

// =============================================================================
//
// Read in overlays from the current file and update overlay info accordingly.
//
void GLRenderer::initOverlaysFromObjects()
{
	for (EFixedCamera cam : g_Cameras)
	{
		if (cam == EFreeCamera)
			continue;

		LDGLOverlay& meta = currentDocumentData().overlays[cam];
		LDOverlay* ovlobj = findOverlayObject (cam);

		if (!ovlobj && meta.img)
		{
			delete meta.img;
			meta.img = null;
		}
		elif (ovlobj && (meta.img == null || meta.fname != ovlobj->fileName()) && meta.invalid == false)
			setupOverlay (cam, ovlobj->fileName(), ovlobj->x(),
				ovlobj->y(), ovlobj->width(), ovlobj->height());
	}
}

// =============================================================================
//
void GLRenderer::updateOverlayObjects()
{
	for (EFixedCamera cam : g_Cameras)
	{
		if (cam == EFreeCamera)
			continue;

		LDGLOverlay& meta = currentDocumentData().overlays[cam];
		LDOverlay* ovlobj = findOverlayObject (cam);

		if (meta.img == null && ovlobj != null)
		{
			// If this is the last overlay image, we need to remove the empty space after it as well.
			LDObject* nextobj = ovlobj->next();

			if (nextobj && nextobj->type() == LDObject::EEmpty)
				nextobj->destroy();

			// If the overlay object was there and the overlay itself is
			// not, remove the object.
			ovlobj->destroy();
		}
		elif (meta.img != null && ovlobj == null)
		{
			// Inverse case: image is there but the overlay object is
			// not, thus create the object.
			ovlobj = new LDOverlay;

			// Find a suitable position to place this object. We want to place
			// this into the header, which is everything up to the first scemantic
			// object. If we find another overlay object, place this object after
			// the last one found. Otherwise, place it before the first schemantic
			// object and put an empty object after it (though don't do this if
			// there was no schemantic elements at all)
			int i, lastOverlay = -1;
			bool found = false;

			for (i = 0; i < document()->getObjectCount(); ++i)
			{
				LDObject* obj = document()->getObject (i);

				if (obj->isScemantic())
				{
					found = true;
					break;
				}

				if (obj->type() == LDObject::EOverlay)
					lastOverlay = i;
			}

			if (lastOverlay != -1)
				document()->insertObj (lastOverlay + 1, ovlobj);
			else
			{
				document()->insertObj (i, ovlobj);

				if (found)
					document()->insertObj (i + 1, new LDEmpty);
			}
		}

		if (meta.img && ovlobj)
		{
			ovlobj->setCamera (cam);
			ovlobj->setFileName (meta.fname);
			ovlobj->setX (meta.ox);
			ovlobj->setY (meta.oy);
			ovlobj->setWidth (meta.lw);
			ovlobj->setHeight (meta.lh);
		}
	}

	if (g_win->R() == this)
		g_win->refresh();
}