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/* Copyright (c) 2013, 2015 Stanislaw Halik <sthalik@misaki.pl>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*/
#include "glwidget.h"
#include <cmath>
#include <algorithm>
#include <QPainter>
#include <QPaintEvent>
#ifdef __GNUC__
#pragma GCC diagnostic ignored "-Wnarrowing"
#endif
GLWidget::GLWidget(QWidget *parent) : QWidget(parent)
{
Q_INIT_RESOURCE(posewidget);
front = QImage(QString(":/images/side1.png"));
back = QImage(QString(":/images/side6.png"));
rotateBy(0, 0, 0, 0, 0, 0);
}
GLWidget::~GLWidget()
{
}
void GLWidget::paintEvent ( QPaintEvent * event ) {
QPainter p(this);
project_quad_texture();
p.drawImage(event->rect(), texture);
}
void GLWidget::rotateBy(float xAngle, float yAngle, float zAngle, float x, float y, float z)
{
float c1 = cos(yAngle / 57.295781);
float s1 = sin(yAngle / 57.295781);
float c2 = cos(xAngle / 57.295781);
float s2 = sin(xAngle / 57.295781);
float c3 = cos(zAngle / 57.295781);
float s3 = sin(zAngle / 57.295781);
rotation = rmat(c2*c3, -c2*s3, s2,
c1*s3+c3*s1*s2, c1*c3-s1*s2*s3, -c2*s1,
s1*s3-c1*c3*s2, c3*s1+c1*s2*s3, c1*c2);
translation = vec3(x, y, z);
update();
}
class Triangle {
using num = GLWidget::num;
using vec2 = GLWidget::vec2;
using vec3 = GLWidget::vec3;
public:
Triangle(const vec2& p1,
const vec2& p2,
const vec2& p3)
{
origin = p1;
v0 = vec2(p3.x() - p1.x(), p3.y() - p1.y());
v1 = vec2(p2.x() - p1.x(), p2.y() - p1.y());
dot00 = v0.dot(v0);
dot01 = v0.dot(v1);
dot11 = v1.dot(v1);
invDenom = 1 / (dot00 * dot11 - dot01 * dot01);
}
bool barycentric_coords(const vec2& px, vec2& uv) const
{
const vec2 v2 = px - origin;
const num dot12 = v1.dot(v2);
const num dot02 = v0.dot(v2);
const num u = (dot11 * dot02 - dot01 * dot12) * invDenom;
const num v = (dot00 * dot12 - dot01 * dot02) * invDenom;
uv = vec2(u, v);
return (u >= 0) && (v >= 0) && (u + v <= 1);
}
private:
num dot00, dot01, dot11, invDenom;
vec2 v0, v1, origin;
};
inline GLWidget::vec3 GLWidget::normal(const vec3& p1, const vec3& p2, const vec3& p3)
{
vec3 u = p2 - p1;
vec3 v = p3 - p1;
vec3 tmp = u.cross(v);
num i = 1./sqrt(tmp.dot(tmp));
return tmp * i;
}
void GLWidget::project_quad_texture() {
const int sx = width(), sy = height();
vec2 pt[4];
const vec3 corners[] = {
vec3(0., 0, 0),
vec3(sx-1, 0, 0),
vec3(0, sy-1, 0),
vec3(sx-1, sy-1, 0.)
};
for (int i = 0; i < 4; i++) {
pt[i] = project(vec3(corners[i].x() - sx/2, corners[i].y() - sy/2, 0));
pt[i].x() += sx/2.;
pt[i].y() += sy/2.;
}
vec3 normal1(0, 0, 1);
vec3 normal2;
{
vec3 foo[3];
for (int i = 0; i < 3; i++)
foo[i] = project2(corners[i]);
normal2 = normal(foo[0], foo[1], foo[2]);
}
num dir = normal1.dot(normal2);
QImage& tex = dir < 0 ? back : front;
int ow = tex.width(), oh = tex.height();
vec2 p2[4];
for (int i = 0; i < 4; i++)
p2[i] = vec2(pt[i].x(), pt[i].y());
QImage texture(QSize(sx, sy), QImage::Format_RGB888);
QColor bgColor = palette().color(QPalette::Current, QPalette::Window);
texture.fill(bgColor);
const vec2 projected[2][3] = { { p2[0], p2[1], p2[2] }, { p2[3], p2[1], p2[2] } };
const vec2 origs[2][3] = {
{ vec2(0, 0), vec2(ow-1, 0), vec2(0, oh-1) },
{ vec2(ow-1, oh-1), vec2(ow-1, 0), vec2(0, oh-1) }
};
const Triangle triangles[2] = {
Triangle(projected[0][0], projected[0][1], projected[0][2]),
Triangle(projected[1][0], projected[1][1], projected[1][2])
};
const int orig_pitch = tex.bytesPerLine();
const int dest_pitch = texture.bytesPerLine();
const unsigned char* orig = tex.bits();
unsigned char* dest = texture.bits();
const int orig_depth = tex.depth() / 8;
const int dest_depth = texture.depth() / 8;
/* image breakage? */
if (orig_depth < 3)
return;
for (int y = 0; y < sy; y++)
for (int x = 0; x < sx; x++) {
vec2 pos(x, y);
for (int i = 0; i < 2; i++) {
vec2 uv;
if (triangles[i].barycentric_coords(pos, uv))
{
const int px = origs[i][0].x()
+ uv.x() * (origs[i][2].x() - origs[i][0].x())
+ uv.y() * (origs[i][1].x() - origs[i][0].x());
const int py = origs[i][0].y()
+ uv.x() * (origs[i][2].y() - origs[i][0].y())
+ uv.y() * (origs[i][1].y() - origs[i][0].y());
int r = orig[py * orig_pitch + px * orig_depth + 2];
int g = orig[py * orig_pitch + px * orig_depth + 1];
int b = orig[py * orig_pitch + px * orig_depth + 0];
dest[y * dest_pitch + x * dest_depth + 0] = r;
dest[y * dest_pitch + x * dest_depth + 1] = g;
dest[y * dest_pitch + x * dest_depth + 2] = b;
break;
}
}
}
this->texture = texture;
}
GLWidget::vec2 GLWidget::project(const vec3 &point)
{
vec3 ret = rotation * point;
num z = std::max<num>(.75, 1. + translation.z()/-60);
int w = width(), h = height();
num x = w * translation.x() / 2 / -40;
if (std::abs(x) > w/2)
x = x > 0 ? w/2 : w/-2;
num y = h * translation.y() / 2 / -40;
if (std::abs(y) > h/2)
y = y > 0 ? h/2 : h/-2;
return vec2(z * (ret.x() + x), z * (ret.y() + y));
}
GLWidget::vec3 GLWidget::project2(const vec3 &point)
{
return rotation * point;
}
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