#include "viewerwidget.h"

#include "panels/panels.h"
#include "panels/viewer.h"
#include "panels/timeline.h"
#include "panels/project.h"
#include "project/sequence.h"
#include "project/clip.h"
#include "project/effect.h"
#include "project/transition.h"
#include "playback/playback.h"
#include "playback/audio.h"
#include "project/footage.h"
#include "ui_timeline.h"
#include "playback/cacher.h"
#include "io/config.h"
#include "debug.h"
#include "io/math.h"
#include "ui/collapsiblewidget.h"
#include "project/undo.h"
#include "project/media.h"
#include "ui/viewercontainer.h"
#include "io/avtogl.h"

#include <QPainter>
#include <QAudioOutput>
#include <QOpenGLShaderProgram>
#include <QtMath>
#include <QOpenGLFramebufferObject>
#include <QMouseEvent>
#include <QMimeData>
#include <QDrag>
#include <QMenu>
#include <QOffscreenSurface>
#include <QFileDialog>
#include <QPolygon>
#include <QDesktopWidget>

extern "C" {
	#include <libavformat/avformat.h>
}

#define GL_DEFAULT_BLEND glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE);

ViewerWidget::ViewerWidget(QWidget *parent) :
	QOpenGLWidget(parent),
	default_fbo(NULL),
	waveform(false),
    dragging(false),
    selected_gizmo(NULL),
    waveform_zoom(1.0),
    waveform_scroll(0)
{
    setMouseTracking(true);
	setFocusPolicy(Qt::ClickFocus);

	QSurfaceFormat format;
	format.setDepthBufferSize(24);
	setFormat(format);

    // error handler - retries after 50ms if we couldn't get the entire image
    retry_timer.setInterval(50);
	connect(&retry_timer, SIGNAL(timeout()), this, SLOT(retry()));

	setContextMenuPolicy(Qt::CustomContextMenu);
    connect(this, SIGNAL(customContextMenuRequested(const QPoint&)), this, SLOT(show_context_menu()));
}

void ViewerWidget::delete_function() {
    // destroy all textures as well
	if (viewer->seq != NULL) {
        makeCurrent();
        closeActiveClips(viewer->seq, true);
        doneCurrent();
    }
}

void ViewerWidget::set_waveform_scroll(int s) {
    if (waveform) {
        waveform_scroll = s;
        update();
    }
}

void ViewerWidget::show_context_menu() {
	QMenu menu(this);

	QAction* save_frame_as_image = menu.addAction("Save Frame as Image...");
	connect(save_frame_as_image, SIGNAL(triggered(bool)), this, SLOT(save_frame()));

    QAction* show_fullscreen_action = menu.addAction("Show Fullscreen");
    connect(show_fullscreen_action, SIGNAL(triggered()), this, SLOT(show_fullscreen()));

	menu.exec(QCursor::pos());
}

void ViewerWidget::save_frame() {
    QFileDialog fd(this);
    fd.setAcceptMode(QFileDialog::AcceptSave);
    fd.setFileMode(QFileDialog::AnyFile);
    fd.setWindowTitle("Save Frame");
    fd.setNameFilter("Portable Network Graphic (*.png);;JPEG (*.jpg);;Windows Bitmap (*.bmp);;Portable Pixmap (*.ppm);;X11 Bitmap (*.xbm);;X11 Pixmap (*.xpm)");

    if (fd.exec()) {
        QString fn = fd.selectedFiles().at(0);
        QString selected_ext = fd.selectedNameFilter().mid(fd.selectedNameFilter().indexOf(QRegExp("\\*.[a-z][a-z][a-z]")) + 1, 4);
        if (!fn.endsWith(selected_ext,  Qt::CaseInsensitive)) {
            fn += selected_ext;
        }
		QOpenGLFramebufferObject fbo(viewer->seq->width, viewer->seq->height, QOpenGLFramebufferObject::CombinedDepthStencil, GL_TEXTURE_RECTANGLE);

		rendering = true;
		fbo.bind();

        default_fbo = &fbo;

		paintGL();

		QImage img(viewer->seq->width, viewer->seq->height, QImage::Format_RGBA8888);
		glReadPixels(0, 0, img.width(), img.height(), GL_RGBA, GL_UNSIGNED_BYTE, img.bits());
		img.save(fn);

		fbo.release();
        default_fbo = NULL;
		rendering = false;
    }
}

void ViewerWidget::show_fullscreen() {
    showFullScreen();
}

void ViewerWidget::retry() {
	update();
}

void ViewerWidget::initializeGL() {
    initializeOpenGLFunctions();

    connect(context(), SIGNAL(aboutToBeDestroyed()), this, SLOT(delete_function()), Qt::DirectConnection);

    retry_timer.start();
}

//void ViewerWidget::resizeGL(int w, int h)
//{
//}

void ViewerWidget::paintEvent(QPaintEvent *e) {
	if (!rendering) {
		makeCurrent();
		QOpenGLWidget::paintEvent(e);
	}
}

void ViewerWidget::seek_from_click(int x) {
    viewer->seek(getFrameFromScreenPoint(waveform_zoom, x+waveform_scroll));
}

EffectGizmo* ViewerWidget::get_gizmo_from_mouse(int x, int y) {
    if (gizmos != NULL) {        
        double multiplier = (double) viewer->seq->width / (double) width();
        QPoint mouse_pos(qRound(x*multiplier), qRound(y*multiplier));
        int dot_size = 2 * qRound(GIZMO_DOT_SIZE * multiplier);
        int target_size = 2 * qRound(GIZMO_TARGET_SIZE * multiplier);
        for (int i=0;i<gizmos->gizmo_count();i++) {
            EffectGizmo* g = gizmos->gizmo(i);

            switch (g->get_type()) {
            case GIZMO_TYPE_DOT:
                if (mouse_pos.x() > g->screen_pos[0].x() - dot_size
                        && mouse_pos.y() > g->screen_pos[0].y() - dot_size
                        && mouse_pos.x() < g->screen_pos[0].x() + dot_size
                        && mouse_pos.y() < g->screen_pos[0].y() + dot_size) {
                    return g;
                }
                break;
            case GIZMO_TYPE_POLY:
                if (QPolygon(g->screen_pos).containsPoint(mouse_pos, Qt::OddEvenFill)) {
                    return g;
                }
                break;
            case GIZMO_TYPE_TARGET:
                if (mouse_pos.x() > g->screen_pos[0].x() - target_size
                        && mouse_pos.y() > g->screen_pos[0].y() - target_size
                        && mouse_pos.x() < g->screen_pos[0].x() + target_size
                        && mouse_pos.y() < g->screen_pos[0].y() + target_size) {
                    return g;
                }
                break;
            }

        }
    }
    return NULL;
}

void ViewerWidget::move_gizmos(QMouseEvent *event, bool done) {
    if (selected_gizmo != NULL) {
        double multiplier = (double) viewer->seq->width / (double) width();

        int x_movement = (event->pos().x() - drag_start_x)*multiplier;
        int y_movement = (event->pos().y() - drag_start_y)*multiplier;

        gizmos->gizmo_move(selected_gizmo, x_movement, y_movement, get_timecode(gizmos->parent_clip, gizmos->parent_clip->sequence->playhead), done);

        gizmo_x_mvmt += x_movement;
        gizmo_y_mvmt += y_movement;

        drag_start_x = event->pos().x();
        drag_start_y = event->pos().y();

        gizmos->field_changed();
    }
}

void ViewerWidget::mousePressEvent(QMouseEvent* event) {
    if (waveform) {
        seek_from_click(event->x());
    } else if (event->buttons() & Qt::MiddleButton) {
        container->dragScrollPress(event->pos());
    } else {
        drag_start_x = event->pos().x();
        drag_start_y = event->pos().y();

        gizmo_x_mvmt = 0;
        gizmo_y_mvmt = 0;

        selected_gizmo = get_gizmo_from_mouse(event->pos().x(), event->pos().y());

        if (selected_gizmo != NULL) {
            selected_gizmo->set_previous_value();
        }
    }
    dragging = true;
}

void ViewerWidget::mouseMoveEvent(QMouseEvent* event) {
    if (dragging) {
		if (waveform) {
			seek_from_click(event->x());
        } else if (event->buttons() & Qt::MiddleButton) {
            container->dragScrollMove(event->pos());
        } else if (gizmos == NULL) {
			QDrag* drag = new QDrag(this);
			QMimeData* mimeData = new QMimeData;
            mimeData->setText("h"); // QMimeData will fail without some kind of data
			drag->setMimeData(mimeData);
			drag->exec();
            dragging = false;
        } else {
            move_gizmos(event, false);
        }
    } else {
        unsetCursor();
        EffectGizmo* g = get_gizmo_from_mouse(event->pos().x(), event->pos().y());
        if (g != NULL) {
            if (g->get_cursor() > -1) {
                setCursor(static_cast<enum Qt::CursorShape>(g->get_cursor()));
            }
        }
    }
}

void ViewerWidget::mouseReleaseEvent(QMouseEvent *event) {
    move_gizmos(event, true);
    dragging = false;
}

void ViewerWidget::drawTitleSafeArea() {
    double halfWidth = 0.5;
    double halfHeight = 0.5;
    double viewportAr = (double) width() / (double) height();
    double halfAr = viewportAr*0.5;

    if (config.use_custom_title_safe_ratio && config.custom_title_safe_ratio > 0) {
        if (config.custom_title_safe_ratio > viewportAr) {
            halfHeight = (config.custom_title_safe_ratio/viewportAr)*0.5;
        } else {
            halfWidth = (viewportAr/config.custom_title_safe_ratio)*0.5;
        }
    }

    glLoadIdentity();
    glOrtho(-halfWidth, halfWidth, halfHeight, -halfHeight, 0, 1);

	glColor4f(0.66f, 0.66f, 0.66f, 1.0f);
    glBegin(GL_LINES);

    // action safe rectangle
    glVertex2d(-0.45, -0.45);
    glVertex2d(0.45, -0.45);
    glVertex2d(0.45, -0.45);
    glVertex2d(0.45, 0.45);
    glVertex2d(0.45, 0.45);
    glVertex2d(-0.45, 0.45);
    glVertex2d(-0.45, 0.45);
    glVertex2d(-0.45, -0.45);

    // title safe rectangle
    glVertex2d(-0.4, -0.4);
    glVertex2d(0.4, -0.4);
    glVertex2d(0.4, -0.4);
    glVertex2d(0.4, 0.4);
    glVertex2d(0.4, 0.4);
    glVertex2d(-0.4, 0.4);
    glVertex2d(-0.4, 0.4);
    glVertex2d(-0.4, -0.4);

    // horizontal centers
    glVertex2d(-0.45, 0);
    glVertex2d(-0.375, 0);
    glVertex2d(0.45, 0);
    glVertex2d(0.375, 0);

    // vertical centers
    glVertex2d(0, -0.45);
    glVertex2d(0, -0.375);
    glVertex2d(0, 0.45);
    glVertex2d(0, 0.375);

    glEnd();

    // center cross
    glLoadIdentity();
    glOrtho(-halfAr, halfAr, 0.5, -0.5, -1, 1);

    glBegin(GL_LINES);

    glVertex2d(-0.05, 0);
    glVertex2d(0.05, 0);
    glVertex2d(0, -0.05);
    glVertex2d(0, 0.05);

    glEnd();
}

GLuint ViewerWidget::draw_clip(QOpenGLFramebufferObject* fbo, GLuint texture, bool clear) {
    glPushMatrix();
    glLoadIdentity();
    glOrtho(0, 1, 0, 1, -1, 1);

    fbo->bind();

    if (clear) glClear(GL_COLOR_BUFFER_BIT);

    // get current blend mode
    GLint src_rgb, src_alpha, dst_rgb, dst_alpha;
    glGetIntegerv(GL_BLEND_SRC_RGB, &src_rgb);
    glGetIntegerv(GL_BLEND_SRC_ALPHA, &src_alpha);
    glGetIntegerv(GL_BLEND_DST_RGB, &dst_rgb);
    glGetIntegerv(GL_BLEND_DST_ALPHA, &dst_alpha);

    GL_DEFAULT_BLEND

    glBindTexture(GL_TEXTURE_2D, texture);
    glBegin(GL_QUADS);
	glTexCoord2f(0, 0); // top left
	glVertex2f(0, 0); // top left
	glTexCoord2f(1, 0); // top right
	glVertex2f(1, 0); // top right
	glTexCoord2f(1, 1); // bottom right
	glVertex2f(1, 1); // bottom right
	glTexCoord2f(0, 1); // bottom left
	glVertex2f(0, 1); // bottom left
	glEnd();
    glBindTexture(GL_TEXTURE_2D, 0);

	fbo->release();

    // restore previous blendFunc
    glBlendFuncSeparate(src_rgb, dst_rgb, src_alpha, dst_alpha);

    if (default_fbo != NULL) default_fbo->bind();

	glPopMatrix();
	return fbo->texture();
}

void ViewerWidget::process_effect(Clip* c, Effect* e, double timecode, GLTextureCoords& coords, GLuint& composite_texture, bool& fbo_switcher, int data) {
	if (e->is_enabled()) {
		if (e->enable_coords) {
            e->process_coords(timecode, coords, data);
		}
		if (e->enable_shader || e->enable_superimpose) {
            e->startEffect();
            if (e->enable_shader) {
                e->process_shader(timecode, coords);
                composite_texture = draw_clip(c->fbo[fbo_switcher], composite_texture, true);
                fbo_switcher = !fbo_switcher;
            }
            if (e->enable_superimpose) {
                GLuint superimpose_texture = e->process_superimpose(timecode);
                if (superimpose_texture == 0) {
                    dout << "[WARNING] Superimpose texture was NULL, retrying...";
                    texture_failed = true;
                } else {
                    composite_texture = draw_clip(c->fbo[!fbo_switcher], superimpose_texture, false);
                }
            }
            e->endEffect();
		}
    }
}

int motion_blur_prog = 0;
int motion_blur_lim = 4;

GLuint ViewerWidget::compose_sequence(QVector<Clip*>& nests, bool render_audio) {
	Sequence* s = viewer->seq;
	long playhead = s->playhead;

	if (!nests.isEmpty()) {
		for (int i=0;i<nests.size();i++) {
            s = nests.at(i)->media->to_sequence();
            playhead += nests.at(i)->clip_in - nests.at(i)->get_timeline_in_with_transition();
			playhead = refactor_frame_number(playhead, nests.at(i)->sequence->frame_rate, s->frame_rate);
		}

		if (nests.last()->fbo != NULL) {
			nests.last()->fbo[0]->bind();
			glClear(GL_COLOR_BUFFER_BIT);
			nests.last()->fbo[0]->release();
		}
	}

	int audio_track_count = 0;

    QVector<Clip*> current_clips;

    for (int i=0;i<s->clips.size();i++) {
		Clip* c = s->clips.at(i);

        // if clip starts within one second and/or hasn't finished yet
		if (c != NULL) {
			if (!(!nests.isEmpty() && !same_sign(c->track, nests.last()->track))) {
				bool clip_is_active = false;

                if (c->media != NULL && c->media->get_type() == MEDIA_TYPE_FOOTAGE) {
                    Footage* m = c->media->to_footage();
                    if (!m->invalid && !(c->track >= 0 && !is_audio_device_set())) {
                        if (m->ready) {
                            FootageStream* ms = m->get_stream_from_file_index(c->track < 0, c->media_stream);
                            if (ms != NULL && is_clip_active(c, playhead)) {
                                // if thread is already working, we don't want to touch this,
                                // but we also don't want to hang the UI thread
                                if (!c->open) {
                                    open_clip(c, !rendering);
                                }
                                clip_is_active = true;
                                if (c->track >= 0) audio_track_count++;
                            } else if (c->open) {
                                close_clip(c);
                            }
                        } else {
                            //dout << "[WARNING] Media '" + m->name + "' was not ready, retrying...";
                            texture_failed = true;
                        }
                    }
                } else {
                    if (is_clip_active(c, playhead)) {
                        if (!c->open) open_clip(c, !rendering);
                        clip_is_active = true;
                    } else if (c->open) {
                        close_clip(c);
                    }
                }
				if (clip_is_active) {
					bool added = false;
					for (int j=0;j<current_clips.size();j++) {
						if (current_clips.at(j)->track < c->track) {
							current_clips.insert(j, c);
							added = true;
							break;
						}
					}
					if (!added) {
						current_clips.append(c);
					}
				}
			}
		}
	}

	int half_width = s->width/2;
	int half_height = s->height/2;
	if (rendering || !nests.isEmpty()) half_height = -half_height; // invert vertical

    glPushMatrix();
    glLoadIdentity();
    glOrtho(-half_width, half_width, half_height, -half_height, -1, 10);

    for (int i=0;i<current_clips.size();i++) {
        GL_DEFAULT_BLEND
        glColor4f(1.0, 1.0, 1.0, 1.0);

        Clip* c = current_clips.at(i);

        if (c->media != NULL && c->media->get_type() == MEDIA_TYPE_FOOTAGE && !c->finished_opening) {
			dout << "[WARNING] Tried to display clip" << i << "but it's closed";
            texture_failed = true;
        } else {
			if (c->track < 0) {
				GLuint textureID = 0;
				int video_width = c->getWidth();
				int video_height = c->getHeight();

                if (c->media != NULL) {
                    switch (c->media->get_type()) {
                    case MEDIA_TYPE_FOOTAGE:
                        // set up opengl texture
                        if (c->texture == NULL) {
                            c->texture = new QOpenGLTexture(QOpenGLTexture::Target2D);
                            c->texture->setSize(c->stream->codecpar->width, c->stream->codecpar->height);
							c->texture->setFormat(get_gl_tex_fmt_from_av(c->pix_fmt));
                            c->texture->setMipLevels(c->texture->maximumMipLevels());
                            c->texture->setMinMagFilters(QOpenGLTexture::Linear, QOpenGLTexture::Linear);
							c->texture->allocateStorage(get_gl_pix_fmt_from_av(c->pix_fmt), QOpenGLTexture::UInt8);
                        }
                        get_clip_frame(c, playhead);
                        textureID = c->texture->textureId();
                        break;
                    case MEDIA_TYPE_SEQUENCE:
                        textureID = -1;
                        break;
                    }
                }

                if (textureID == 0 && c->media != NULL) {
					dout << "[WARNING] Texture hasn't been created yet";
					texture_failed = true;
                } else if (playhead >= c->get_timeline_in_with_transition()) {
					glPushMatrix();

					// start preparing cache
					if (c->fbo == NULL) {
						c->fbo = new QOpenGLFramebufferObject* [2];
						c->fbo[0] = new QOpenGLFramebufferObject(video_width, video_height);
						c->fbo[1] = new QOpenGLFramebufferObject(video_width, video_height);
					}

					// clear fbos
					/*c->fbo[0]->bind();
					glClear(GL_COLOR_BUFFER_BIT);
					c->fbo[0]->release();
					c->fbo[1]->bind();
					glClear(GL_COLOR_BUFFER_BIT);
					c->fbo[1]->release();*/

					bool fbo_switcher = false;

					glViewport(0, 0, video_width, video_height);

                    GLuint composite_texture;

                    if (c->media == NULL) {
                        c->fbo[fbo_switcher]->bind();
                        glClear(GL_COLOR_BUFFER_BIT);
                        c->fbo[fbo_switcher]->release();
						composite_texture = c->fbo[fbo_switcher]->texture();
					} else {
                        // for nested sequences
                        if (c->media->get_type()== MEDIA_TYPE_SEQUENCE) {
                            nests.append(c);
                            textureID = compose_sequence(nests, render_audio);
                            nests.removeLast();
                            fbo_switcher = true;
                        }

                        composite_texture = draw_clip(c->fbo[fbo_switcher], textureID, true);
					}

                    fbo_switcher = !fbo_switcher;

                    // set up default coords
                    GLTextureCoords coords;
                    coords.grid_size = 1;
					coords.vertexTopLeftX = coords.vertexBottomLeftX = -video_width/2;
					coords.vertexTopLeftY = coords.vertexTopRightY = -video_height/2;
					coords.vertexTopRightX = coords.vertexBottomRightX = video_width/2;
                    coords.vertexBottomLeftY = coords.vertexBottomRightY = video_height/2;
                    coords.vertexBottomLeftZ = coords.vertexBottomRightZ = coords.vertexTopLeftZ = coords.vertexTopRightZ = 1;
                    coords.textureTopLeftY = coords.textureTopRightY = coords.textureTopLeftX = coords.textureBottomLeftX = 0.0;
					coords.textureBottomLeftY = coords.textureBottomRightY = coords.textureTopRightX = coords.textureBottomRightX = 1.0;
                    coords.textureTopLeftQ = coords.textureTopRightQ = coords.textureTopLeftQ = coords.textureBottomLeftQ = 1;

                    // set up autoscale
                    if (c->autoscale && (video_width != s->width && video_height != s->height)) {
                        float width_multiplier = (float) s->width / (float) video_width;
                        float height_multiplier = (float) s->height / (float) video_height;
                        float scale_multiplier = qMin(width_multiplier, height_multiplier);
						glScalef(scale_multiplier, scale_multiplier, 1);
					}

					// EFFECT CODE START
                    double timecode = get_timecode(c, playhead);

                    Effect* first_gizmo_effect = NULL;
                    Effect* selected_effect = NULL;

					for (int j=0;j<c->effects.size();j++) {
                        Effect* e = c->effects.at(j);
                        process_effect(c, e, timecode, coords, composite_texture, fbo_switcher, TA_NO_TRANSITION);

                        if (e->are_gizmos_enabled()) {
                            if (first_gizmo_effect == NULL) first_gizmo_effect = e;
                            if (e->container->selected) selected_effect = e;
                        }
					}

                    if (!rendering) {
                        if (selected_effect != NULL) {
                            gizmos = selected_effect;
                        } else if (panel_timeline->is_clip_selected(c, true)) {
                            gizmos = first_gizmo_effect;
                        }
                    }

                    if (c->get_opening_transition() != NULL) {
                        int transition_progress = playhead - c->get_timeline_in_with_transition();
                        if (transition_progress < c->get_opening_transition()->get_length()) {
                            process_effect(c, c->get_opening_transition(), (double)transition_progress/(double)c->get_opening_transition()->get_length(), coords, composite_texture, fbo_switcher, TA_OPENING_TRANSITION);
						}
                    }

                    if (c->get_closing_transition() != NULL) {
                        int transition_progress = playhead - (c->get_timeline_out_with_transition() - c->get_closing_transition()->get_length());
                        if (transition_progress >= 0 && transition_progress < c->get_closing_transition()->get_length()) {
                            process_effect(c, c->get_closing_transition(), (double)transition_progress/(double)c->get_closing_transition()->get_length(), coords, composite_texture, fbo_switcher, TA_CLOSING_TRANSITION);
						}
                    }
					// EFFECT CODE END

					if (!nests.isEmpty()) {
						nests.last()->fbo[0]->bind();
						glViewport(0, 0, s->width, s->height);
					} else if (rendering) {
						glViewport(0, 0, s->width, s->height);
					} else {
                        int widget_width = width();
                        int widget_height = height();

                        QString qt_scale_factor = QString(qgetenv("QT_SCALE_FACTOR"));
                        if (!qt_scale_factor.isEmpty()) {
                            double scale = qt_scale_factor.toDouble();
                            widget_width *= scale;
                            widget_height *= scale;
                        }

                        glViewport(0, 0, widget_width, widget_height);
					}

					glBindTexture(GL_TEXTURE_2D, composite_texture);

					glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
					glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

                    glBegin(GL_QUADS);

					if (coords.grid_size <= 1) {
                        float z = 0.0f;

                        glTexCoord2f(coords.textureTopLeftX, coords.textureTopLeftY); // top left
                        glVertex3f(coords.vertexTopLeftX, coords.vertexTopLeftY, z); // top left
                        glTexCoord2f(coords.textureTopRightX, coords.textureTopRightY); // top right
                        glVertex3f(coords.vertexTopRightX, coords.vertexTopRightY, z); // top right
                        glTexCoord2f(coords.textureBottomRightX, coords.textureBottomRightY); // bottom right
                        glVertex3f(coords.vertexBottomRightX, coords.vertexBottomRightY, z); // bottom right
                        glTexCoord2f(coords.textureBottomLeftX, coords.textureBottomLeftY); // bottom left
                        glVertex3f(coords.vertexBottomLeftX, coords.vertexBottomLeftY, z); // bottom left
					} else {
                        float rows = coords.grid_size;
                        float cols = coords.grid_size;

                        for (float k=0;k<rows;k++) {
                            float row_prog = k/rows;
                            float next_row_prog = (k+1)/rows;
                            for (float j=0;j<cols;j++) {
                                float col_prog = j/cols;
                                float next_col_prog = (j+1)/cols;

                                float vertexTLX = float_lerp(coords.vertexTopLeftX, coords.vertexBottomLeftX, row_prog);
                                float vertexTRX = float_lerp(coords.vertexTopRightX, coords.vertexBottomRightX, row_prog);
                                float vertexBLX = float_lerp(coords.vertexTopLeftX, coords.vertexBottomLeftX, next_row_prog);
                                float vertexBRX = float_lerp(coords.vertexTopRightX, coords.vertexBottomRightX, next_row_prog);

                                float vertexTLY = float_lerp(coords.vertexTopLeftY, coords.vertexTopRightY, col_prog);
                                float vertexTRY = float_lerp(coords.vertexTopLeftY, coords.vertexTopRightY, next_col_prog);
                                float vertexBLY = float_lerp(coords.vertexBottomLeftY, coords.vertexBottomRightY, col_prog);
                                float vertexBRY = float_lerp(coords.vertexBottomLeftY, coords.vertexBottomRightY, next_col_prog);

                                glTexCoord2f(float_lerp(coords.textureTopLeftX, coords.textureTopRightX, col_prog), float_lerp(coords.textureTopLeftY, coords.textureBottomLeftY, row_prog)); // top left
                                glVertex2f(float_lerp(vertexTLX, vertexTRX, col_prog), float_lerp(vertexTLY, vertexBLY, row_prog)); // top left
                                glTexCoord2f(float_lerp(coords.textureTopLeftX, coords.textureTopRightX, next_col_prog), float_lerp(coords.textureTopRightY, coords.textureBottomRightY, row_prog)); // top right
                                glVertex2f(float_lerp(vertexTLX, vertexTRX, next_col_prog), float_lerp(vertexTRY, vertexBRY, row_prog)); // top right
                                glTexCoord2f(float_lerp(coords.textureBottomLeftX, coords.textureBottomRightX, next_col_prog), float_lerp(coords.textureTopRightY, coords.textureBottomRightY, next_row_prog)); // bottom right
                                glVertex2f(float_lerp(vertexBLX, vertexBRX, next_col_prog), float_lerp(vertexTRY, vertexBRY, next_row_prog)); // bottom right
                                glTexCoord2f(float_lerp(coords.textureBottomLeftX, coords.textureBottomRightX, col_prog), float_lerp(coords.textureTopLeftY, coords.textureBottomLeftY, next_row_prog)); // bottom left
                                glVertex2f(float_lerp(vertexBLX, vertexBRX, col_prog), float_lerp(vertexTLY, vertexBLY, next_row_prog)); // bottom left
                            }
                        }
					}

					glEnd();

                    glBindTexture(GL_TEXTURE_2D, 0); // unbind texture

                    if (gizmos != NULL && !drawn_gizmos) {
                        gizmos->gizmo_draw(timecode, coords); // set correct gizmo coords
                        gizmos->gizmo_world_to_screen();

                        drawn_gizmos = true;
                    }

					if (!nests.isEmpty()) {
						nests.last()->fbo[0]->release();
						if (default_fbo != NULL) default_fbo->bind();
					}

					glPopMatrix();

                    /*GLfloat motion_blur_frac = (GLfloat) motion_blur_prog / (GLfloat) motion_blur_lim;
                    if (motion_blur_prog == 0) {
                        glAccum(GL_LOAD, motion_blur_frac);
                    } else {
                        glAccum(GL_ACCUM, motion_blur_frac);
                    }
                    motion_blur_prog++;*/
				}
            } else {
                if (render_audio || (config.enable_audio_scrubbing && audio_scrub)) {
                    if (c->media != NULL && c->media->get_type() == MEDIA_TYPE_SEQUENCE) {
                        nests.append(c);
                        compose_sequence(nests, render_audio);
                        nests.removeLast();
                    } else {
                        if (c->lock.tryLock()) {
                            // clip is not caching, start caching audio
                            cache_clip(c, playhead, c->audio_reset, !render_audio, nests);
                            c->lock.unlock();
                        }
                    }
				}

				// visually update all the keyframe values
				if (c->sequence == viewer->seq) { // only if you can currently see them
                    double ts = (playhead - c->get_timeline_in_with_transition() + c->get_clip_in_with_transition())/s->frame_rate;
					for (int i=0;i<c->effects.size();i++) {
						Effect* e = c->effects.at(i);
						for (int j=0;j<e->row_count();j++) {
							EffectRow* r = e->row(j);
							for (int k=0;k<r->fieldCount();k++) {
								r->field(k)->validate_keyframe_data(ts);
							}
						}
					}
				}
			}
        }
	}

	if (audio_track_count == 0) {
		viewer->play_wake();
	}

	glPopMatrix();

	if (!nests.isEmpty() && nests.last()->fbo != NULL) {
		// returns nested clip's texture
		return nests.last()->fbo[0]->texture();
	}

	return 0;
}

void ViewerWidget::paintGL() {
    drawn_gizmos = false;
    force_quit = false;
    if (viewer->seq != NULL) {
        gizmos = NULL;

        bool render_audio = (viewer->playing || rendering);
        bool loop = false;
        do {
            loop = false;

            glClearColor(0, 0, 0, 1);
            glMatrixMode(GL_MODELVIEW);
            glEnable(GL_TEXTURE_2D);
            glEnable(GL_BLEND);
            glEnable(GL_DEPTH);

            texture_failed = false;

            if (!rendering) retry_timer.stop();

            glClear(GL_COLOR_BUFFER_BIT);

            // compose video preview
            glClearColor(0, 0, 0, 0);

            QVector<Clip*> nests;

            compose_sequence(nests, render_audio);

            if (waveform) {
                QPainter p(this);
                if (viewer->seq->using_workarea) {
                    int in_x = getScreenPointFromFrame(waveform_zoom, viewer->seq->workarea_in) - waveform_scroll;
                    int out_x = getScreenPointFromFrame(waveform_zoom, viewer->seq->workarea_out) - waveform_scroll;

                    p.fillRect(QRect(in_x, 0, out_x - in_x, height()), QColor(255, 255, 255, 64));
                    p.setPen(Qt::white);
                    p.drawLine(in_x, 0, in_x, height());
                    p.drawLine(out_x, 0, out_x, height());
                }
                QRect wr = rect();
                wr.setX(wr.x() - waveform_scroll);

                p.setPen(Qt::green);
                draw_waveform(waveform_clip, waveform_ms, waveform_clip->timeline_out, &p, wr, waveform_scroll, width()+waveform_scroll, waveform_zoom);
                p.setPen(Qt::red);
                int playhead_x = getScreenPointFromFrame(waveform_zoom, viewer->seq->playhead) - waveform_scroll;
                p.drawLine(playhead_x, 0, playhead_x, height());
            }

            if (force_quit) break;
            if (texture_failed) {
                if (rendering) {
                    dout << "[INFO] Texture failed - looping";
                    loop = true;
                } else {
                    retry_timer.start();
                }
            }

            if (config.show_title_safe_area && !rendering) {
                drawTitleSafeArea();
            }

            if (gizmos != NULL && drawn_gizmos) {
                float color[4];
                glGetFloatv(GL_CURRENT_COLOR, color);

                float dot_size = GIZMO_DOT_SIZE / width() * viewer->seq->width;
                float target_size = GIZMO_TARGET_SIZE / width() * viewer->seq->width;

                glPushMatrix();
                glLoadIdentity();
                glOrtho(0, viewer->seq->width, viewer->seq->height, 0, -1, 10);
                float gizmo_z = 0.0f;
                for (int j=0;j<gizmos->gizmo_count();j++) {
                    EffectGizmo* g = gizmos->gizmo(j);
                    glColor4f(g->color.redF(), g->color.greenF(), g->color.blueF(), 1.0);
                    switch (g->get_type()) {
                    case GIZMO_TYPE_DOT: // draw dot
                        glBegin(GL_QUADS);
                        glVertex3f(g->screen_pos[0].x()-dot_size, g->screen_pos[0].y()-dot_size, gizmo_z);
                        glVertex3f(g->screen_pos[0].x()+dot_size, g->screen_pos[0].y()-dot_size, gizmo_z);
                        glVertex3f(g->screen_pos[0].x()+dot_size, g->screen_pos[0].y()+dot_size, gizmo_z);
                        glVertex3f(g->screen_pos[0].x()-dot_size, g->screen_pos[0].y()+dot_size, gizmo_z);
                        glEnd();
                        break;
                    case GIZMO_TYPE_POLY: // draw lines
                        glBegin(GL_LINES);
                        for (int k=1;k<g->get_point_count();k++) {
                            glVertex3f(g->screen_pos[k-1].x(), g->screen_pos[k-1].y(), gizmo_z);
                            glVertex3f(g->screen_pos[k].x(), g->screen_pos[k].y(), gizmo_z);
                        }
                        glVertex3f(g->screen_pos[g->get_point_count()-1].x(), g->screen_pos[g->get_point_count()-1].y(), gizmo_z);
                        glVertex3f(g->screen_pos[0].x(), g->screen_pos[0].y(), gizmo_z);
                        glEnd();
                        break;
                    case GIZMO_TYPE_TARGET: // draw target
                        glBegin(GL_LINES);
                        glVertex3f(g->screen_pos[0].x()-target_size, g->screen_pos[0].y()-target_size, gizmo_z);
                        glVertex3f(g->screen_pos[0].x()+target_size, g->screen_pos[0].y()-target_size, gizmo_z);

                        glVertex3f(g->screen_pos[0].x()+target_size, g->screen_pos[0].y()-target_size, gizmo_z);
                        glVertex3f(g->screen_pos[0].x()+target_size, g->screen_pos[0].y()+target_size, gizmo_z);

                        glVertex3f(g->screen_pos[0].x()+target_size, g->screen_pos[0].y()+target_size, gizmo_z);
                        glVertex3f(g->screen_pos[0].x()-target_size, g->screen_pos[0].y()+target_size, gizmo_z);

                        glVertex3f(g->screen_pos[0].x()-target_size, g->screen_pos[0].y()+target_size, gizmo_z);
                        glVertex3f(g->screen_pos[0].x()-target_size, g->screen_pos[0].y()-target_size, gizmo_z);

                        glVertex3f(g->screen_pos[0].x()-target_size, g->screen_pos[0].y(), gizmo_z);
                        glVertex3f(g->screen_pos[0].x()+target_size, g->screen_pos[0].y(), gizmo_z);

                        glVertex3f(g->screen_pos[0].x(), g->screen_pos[0].y()-target_size, gizmo_z);
                        glVertex3f(g->screen_pos[0].x(), g->screen_pos[0].y()+target_size, gizmo_z);
                        glEnd();
                        break;
                    }
                }
                glPopMatrix();

                glColor4f(color[0], color[1], color[2], color[3]);

                drawn_gizmos = true;
            }

            glDisable(GL_DEPTH);
            glDisable(GL_BLEND);
            glDisable(GL_TEXTURE_2D);
        } while (loop);
    }
}