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/* Copyright (c) 2013 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 <QtGui>
#include "glwidget.h"
#include <QWidget>
#include <cmath>
#include <algorithm>
GLWidget::GLWidget(QWidget *parent) : QWidget(parent)
{
front = QImage(QString(":/images/side1.png"));
back = QImage(QString(":/images/side6.png"));
rotateBy(0, 0, 0);
}
GLWidget::~GLWidget()
{
}
void GLWidget::paintEvent ( QPaintEvent * event ) {
QWidget::paintEvent(event);
QPainter p(this);
project_quad_texture();
p.drawImage(event->rect(), texture);
}
void GLWidget::rotateBy(double xAngle, double yAngle, double zAngle)
{
double ch = cos(xAngle / 57.295781);
double sh = sin(xAngle / 57.295781);
double ca = cos(yAngle / 57.295781);
double sa = sin(yAngle / 57.295781);
double cb = cos(zAngle / 57.295781);
double sb = sin(zAngle / 57.295781);
matrix[0 * 3 + 0] = ch * ca;
matrix[0 * 3 + 1]= sh*sb - ch*sa*cb;
matrix[0 * 3 + 2]= ch*sa*sb + sh*cb;
matrix[1 * 3 + 0]= sa;
matrix[1 * 3 + 1]= ca*cb;
matrix[1 * 3 + 2]= -ca*sb;
matrix[2 * 3 + 0]= -sh*ca;
matrix[2 * 3 + 1]= sh*sa*cb + ch*sb;
matrix[2 * 3 + 2]= -sh*sa*sb + ch*cb;
update();
}
class Triangle {
public:
Triangle(const Vec2f& p1,
const Vec2f& p2,
const Vec2f& p3)
{
origin = p1;
v0 = Vec2f(p3.x - p1.x, p3.y - p1.y);
v1 = Vec2f(p2.x - p1.x, p2.y - p1.y);
dot00 = dot(v0, v0);
dot01 = dot(v0, v1);
dot11 = dot(v1, v1);
invDenom = 1 / (dot00 * dot11 - dot01 * dot01);
}
bool barycentric_coords(const Vec2f& px, Vec2f& uv) const
{
Vec2f v2(px.x - origin.x, px.y - origin.y);
double dot12 = dot(v1, v2);
double dot02 = dot(v0, v2);
double u = (dot11 * dot02 - dot01 * dot12) * invDenom;
double v = (dot00 * dot12 - dot01 * dot02) * invDenom;
uv.x = u;
uv.y = v;
return (u >= 0) && (v >= 0) && (u + v <= 1);
}
private:
double dot00, dot01, dot11, invDenom;
Vec2f v0, v1, origin;
double dot(const Vec2f& p1, const Vec2f& p2) const {
return p1.x * p2.x + p1.y * p2.y;
}
};
static __inline Vec3f cross(const Vec3f& p1, const Vec3f& p2)
{
return Vec3f(p1.y * p2.z - p2.y * p1.z,
p2.x * p1.z - p1.x * p2.z,
p1.x * p2.y - p1.y * p2.x);
}
static __inline Vec3f normal(const Vec3f& p1, const Vec3f& p2, const Vec3f& p3)
{
Vec3f u(p2.x - p1.x, p2.y - p1.y, p2.z - p1.z);
Vec3f v(p3.x - p1.x, p3.y - p1.y, p3.z - p1.z);
Vec3f tmp = cross(u, v);
double i = 1./sqrt(tmp.x * tmp.x + tmp.y * tmp.y + tmp.z * tmp.z);
return Vec3f(i * tmp.x, i * tmp.y, i * tmp.z);
}
void GLWidget::project_quad_texture() {
const int sx = width(), sy = height();
Point pt[4];
static Vec3f corners[] = {
Vec3f(0, 0, 0),
Vec3f(sx-1, 0, 0),
Vec3f(0, sy-1, 0),
Vec3f(sx-1, sy-1, 0)
};
for (int i = 0; i < 4; i++) {
pt[i] = project(Vec3f(corners[i].x - sx/2, corners[i].y - sy/2, 0));
pt[i].x += sx/2;
pt[i].y += sy/2;
}
Vec3f normal1(0, 0, 1);
Vec3f normal2;
{
Vec3f foo[3];
for (int i = 0; i < 3; i++)
foo[i] = project2(corners[i]);
normal2 = normal(foo[0], foo[1], foo[2]);
}
double dir = normal1.x * normal2.x + normal1.y * normal2.y + normal1.z * normal2.z;
QImage& tex = dir < 0 ? back : front;
int ow = tex.width(), oh = tex.height();
Vec2f p2[4];
for (int i = 0; i < 4; i++)
p2[i] = Vec2f(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 Vec2f projected[2][3] = { { p2[0], p2[1], p2[2] }, { p2[3], p2[1], p2[2] } };
const Vec2f origs[2][3] = {
{ Vec2f(0, 0), Vec2f(ow-1, 0), Vec2f(0, oh-1) },
{ Vec2f(ow-1, oh-1), Vec2f(ow-1, 0), Vec2f(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])
};
int orig_pitch = tex.bytesPerLine();
int dest_pitch = texture.bytesPerLine();
const unsigned char* orig = tex.bits();
unsigned char* dest = texture.bits();
int orig_depth = tex.depth() / 8;
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++) {
Vec2f pos;
pos.x = x;
pos.y = y;
for (int i = 0; i < 2; i++) {
Vec2f coords;
if (triangles[i].barycentric_coords(pos, coords))
{
double qx = origs[i][0].x
+ coords.x * (origs[i][2].x - origs[i][0].x)
+ coords.y * (origs[i][1].x - origs[i][0].x);
double qy = origs[i][0].y
+ coords.x * (origs[i][2].y - origs[i][0].y)
+ coords.y * (origs[i][1].y - origs[i][0].y);
int qx1 = std::min<int>(ow - 1, std::max<int>(0, qx));
int qy1 = std::min<int>(oh - 1, std::max<int>(0, qy));
int qx2 = std::min<int>(ow - 1, std::max<int>(0, qx + 1.0));
int qy2 = std::min<int>(oh - 1, std::max<int>(0, qy + 1.0));
int r = (4 * orig[qy1 * orig_pitch + qx1 * orig_depth + 2]
+ 1 * orig[qy2 * orig_pitch + qx2 * orig_depth + 2]
+ 2 * orig[qy1 * orig_pitch + qx2 * orig_depth + 2]
+ 2 * orig[qy2 * orig_pitch + qx1 * orig_depth + 2]) / 9;
int g = (4 * orig[qy1 * orig_pitch + qx1 * orig_depth + 1]
+ 1 * orig[qy2 * orig_pitch + qx2 * orig_depth + 1]
+ 2 * orig[qy1 * orig_pitch + qx2 * orig_depth + 1]
+ 2 * orig[qy2 * orig_pitch + qx1 * orig_depth + 1]) / 9;
int b = (4 * orig[qy1 * orig_pitch + qx1 * orig_depth + 0]
+ 1 * orig[qy2 * orig_pitch + qx2 * orig_depth + 0]
+ 2 * orig[qy1 * orig_pitch + qx2 * orig_depth + 0]
+ 2 * orig[qy2 * orig_pitch + qx1 * orig_depth + 0]) / 9;
dest[y * dest_pitch + x * dest_depth + 0] = std::max<int>(0, std::min<int>(255, r));
dest[y * dest_pitch + x * dest_depth + 1] = std::max<int>(0, std::min<int>(255, g));
dest[y * dest_pitch + x * dest_depth + 2] = std::max<int>(0, std::min<int>(255, b));
break;
}
}
}
this->texture = texture;
}
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