Fix trigo, use double point for position.
Fabien Freling
parent
8a17f7b8d8
commit
70a828b651
276
rotation.cpp
276
rotation.cpp
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@ -1,12 +1,14 @@
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#include <string>
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#include <fstream>
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#include <iostream>
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#include <sstream>
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#include <cmath>
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#include <cassert>
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#include <cstring>
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using namespace std;
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template <typename T>
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struct TPoint {
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T x;
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@ -99,6 +101,12 @@ struct Image {
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void set_pixel(unsigned int x, unsigned int y, uint8_t r, uint8_t g, uint8_t b)
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{
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if (x >= width || y >= height)
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{
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cerr << "Point (" << x << ", " << y << ") out of bounds" << endl;
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cerr << " Image dimensions: " << width << " x " << height << endl;
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assert(false);
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}
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int const index = y * width + x;
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r_chan[index] = r;
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g_chan[index] = g;
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@ -208,48 +216,22 @@ struct Image {
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};
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//
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//
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// Drawing
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//
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void draw_line(Image& img, unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2)
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{
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if (x1 > x2)
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{
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swap(x1, x2);
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swap(y1, y2);
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}
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double const slope = ((double) y2 - y1) / ((double) x2 - x1);
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cout << "draw slope = " << slope << endl;
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unsigned int previous_y = y1;
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for (unsigned int i = x1; i <= x2; ++i)
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{
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unsigned int y = slope * (i - x1) + y1;
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int inc = slope > 0 ? 1 : -1;
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for (unsigned int runner = previous_y; runner != y; runner+= inc)
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img.set_pixel(i, runner, 255, 0, 0); // set line to red
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previous_y = y;
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}
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}
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void draw_line(Image& img, Point const& p1, Point const& p2)
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{
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draw_line(img, p1.x, p1.y, p2.x, p2.y);
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}
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//
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//
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// Trigonometry
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//
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DPoint convert_grid_coord(Image const& img, Point const& p)
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{
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return DPoint(p.x - img.width / 2.0f + 0.5, p.y - img.height / 2.0f + 0.5);
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}
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double convert_radian(Image const& img, Point const& p, double const ratio)
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{
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double const centered_x = p.x - (img.width / 2.0f);
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double const centered_y = (- (int) p.y) + (img.height / 2.0f);
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double const cos_value = centered_x * ratio;
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double const sin_value = centered_y * ratio;
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DPoint centered = convert_grid_coord(img, p);
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double const cos_value = centered.x * ratio;
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double const sin_value = - (centered.y * ratio);
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double angle = acos(cos_value);
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if (sin_value < 0)
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angle = 2 * M_PI - angle;
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@ -257,14 +239,26 @@ double convert_radian(Image const& img, Point const& p, double const ratio)
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return angle;
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}
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APoint convert_abs_coord(double const angle, double const ratio)
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DPoint convert_abs_coord(double const angle, double const ratio)
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{
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return APoint((int) ceil(cos(angle) / ratio), (int) ceil(sin(angle) / ratio));
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return DPoint(cos(angle) / ratio, - (sin(angle) / ratio));
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}
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Point convert_img_coord(Image const& img, APoint const& p)
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Point convert_img_coord(Image const& img, DPoint const& p)
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{
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return Point(p.x + img.width / 2.0f, - p.y + img.height / 2.0f);
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int x = round(p.x + (img.width / 2.0f) - 0.5);
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int y = round(p.y + (img.height / 2.0f) - 0.5);
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Point p_mapped(x, y);
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// if (p_mapped.x >= img.width || p_mapped.y >= img.height)
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// {
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// cerr << "Point coord mapping" << endl;
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// cerr << " Input point:" << p << endl;
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// cerr << " Point " << p_mapped << " out of bounds" << endl;
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// cerr << " Image dimensions: " << img.width << " x " << img.height << endl;
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// assert(false);
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// }
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return p_mapped;
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}
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double compute_ratio(Image const& img)
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@ -272,7 +266,7 @@ double compute_ratio(Image const& img)
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unsigned int const nb_points = img.width * img.height;
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double const square_side = sqrt(nb_points) - 1;
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double const half_side = square_side / 2;
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unsigned int const trigo_length = (unsigned int) ceil(half_side * sqrt(2));
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double const trigo_length = ceil(half_side * sqrt(2));
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return 1.0f / trigo_length;
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}
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@ -285,15 +279,15 @@ bool fequal(float a, float b, float sigma)
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void compute_output_size(Image const& src, double const rotation, unsigned int& width, unsigned int& height)
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{
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double const ratio = compute_ratio(src);
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int min_w = 0;
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int max_w = 0;
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int min_h = 0;
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int max_h = 0;
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double min_w = 0;
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double max_w = 0;
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double min_h = 0;
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double max_h = 0;
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//cout << "Image dimensions: " << src.width << " x " << src.height << endl;
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Point p(0, 0);
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double angle = convert_radian(src, p, ratio);
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APoint tl = convert_abs_coord(angle + rotation, ratio);
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DPoint tl = convert_abs_coord(angle + rotation, ratio);
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min_w = min(min_w, tl.x);
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max_w = max(max_w, tl.x);
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min_h = min(min_h, tl.y);
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@ -302,7 +296,7 @@ void compute_output_size(Image const& src, double const rotation, unsigned int&
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p = Point(src.width - 1, 0);
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angle = convert_radian(src, p, ratio);
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APoint tr = convert_abs_coord(angle + rotation, ratio);
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DPoint tr = convert_abs_coord(angle + rotation, ratio);
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min_w = min(min_w, tr.x);
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max_w = max(max_w, tr.x);
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min_h = min(min_h, tr.y);
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@ -311,7 +305,7 @@ void compute_output_size(Image const& src, double const rotation, unsigned int&
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p = Point(0, src.height - 1);
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angle = convert_radian(src, p, ratio);
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APoint bl = convert_abs_coord(angle + rotation, ratio);
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DPoint bl = convert_abs_coord(angle + rotation, ratio);
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min_w = min(min_w, bl.x);
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max_w = max(max_w, bl.x);
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min_h = min(min_h, bl.y);
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@ -320,15 +314,15 @@ void compute_output_size(Image const& src, double const rotation, unsigned int&
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p = Point(src.width - 1, src.height - 1);
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angle = convert_radian(src, p, ratio);
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APoint br = convert_abs_coord(angle + rotation, ratio);
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DPoint br = convert_abs_coord(angle + rotation, ratio);
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min_w = min(min_w, br.x);
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max_w = max(max_w, br.x);
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min_h = min(min_h, br.y);
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max_h = max(max_h, br.y);
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//cout << "Rotated " << p << " (" << angle << ") = " << br << "(" << angle + rotation << ")" << endl << endl;
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width = max_w - min_w + 1;
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height = max_h - min_h + 1;
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width = (int) (max_w - min_w) + 1;
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height = (int) (max_h - min_h) + 1;
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}
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@ -340,7 +334,7 @@ void compute_output_size(Image const& src, double const rotation, unsigned int&
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Point rotate(Image const& src, Point const& p, double const ratio, double const rotation, Image const& rotated)
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{
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double angle = convert_radian(src, p, ratio);
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APoint a_point = convert_abs_coord(angle + rotation, ratio);
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DPoint a_point = convert_abs_coord(angle + rotation, ratio);
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return convert_img_coord(rotated, a_point);
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}
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@ -353,28 +347,102 @@ Image rotate(Image const& src, double angle)
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}
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//
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//
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// Drawing
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//
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void draw_line(Image& img, unsigned int x1, unsigned int y1, unsigned int x2, unsigned int y2)
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{
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if (x1 > x2)
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{
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swap(x1, x2);
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swap(y1, y2);
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}
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unsigned int const y_min = min(y1, y2);
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unsigned int const y_max = max(y1, y2);
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double const slope = ((double) y2 - y1) / ((double) x2 - x1);
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int y_inc = slope > 0 ? 1 : -1;
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unsigned int previous_y = y1;
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for (unsigned int i = x1; i <= x2; ++i)
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{
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unsigned int y = slope * (i - x1) + y1;
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y = min(y, y_max);
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y = max(y, y_min);
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for (unsigned int runner = previous_y; runner != y; runner+= y_inc)
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img.set_pixel(i, runner, 255, 0, 0); // set line to red
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previous_y = y;
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}
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}
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void draw_line(Image& img, Point const& p1, Point const& p2)
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{
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draw_line(img, p1.x, p1.y, p2.x, p2.y);
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}
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void draw_outline(Image const& input, unsigned int degrees, string const& name)
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{
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double const rotation = (degrees / 180.0f) * M_PI;
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unsigned int w = 0;
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unsigned int h = 0;
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compute_output_size(input, rotation, w, h);
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cout << "rotation(" << degrees << ") -> " << w << " x " << h << endl;
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Image rotated(w, h);
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double const ratio = compute_ratio(input);
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Point tl = rotate(input, Point(0, 0), ratio, rotation, rotated);
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Point tr = rotate(input, Point(input.width - 1, 0), ratio, rotation, rotated);
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Point bl = rotate(input, Point(0, input.height - 1), ratio, rotation, rotated);
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Point br = rotate(input, Point(input.width - 1, input.height - 1), ratio, rotation, rotated);
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cout << tl << " " << tr << " " << bl << " " << br << endl;
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draw_line(rotated, tl, tr);
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draw_line(rotated, tr, br);
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draw_line(rotated, br, bl);
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draw_line(rotated, bl, tl);
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stringstream ss;
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ss << "check_lines_" << name << "_" << degrees << ".ppm";
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rotated.save(ss.str());
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}
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//
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//
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// Check
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//
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bool check_points()
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{
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Image five(5, 5);
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Point origin(0, 0);
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DPoint d1 = convert_grid_coord(five, origin);
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assert(d1.x == -2);
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assert(d1.y == -2);
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return true;
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}
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bool check_trigo()
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{
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Image square(500, 500);
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double const ratio = compute_ratio(square);
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cout << "ratio: " << ratio << endl;
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// Check that the origin of a square image is at sqrt(2) / 2
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double const angle = convert_radian(square, Point(0, 0), ratio);
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double const sigma = 1.0e-2;
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if (abs(angle - (3 * M_PI / 4)) > sigma)
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if (!fequal(angle, 3 * M_PI / 4, sigma))
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{
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cout << "Invalid angle value: " << angle << " != " << 3 * M_PI / 4 << endl;
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cout << __LINE__ << " | Invalid angle value: " << angle << " != " << 3 * M_PI / 4 << endl;
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return false;
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}
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// Check that we can reverse the origin point.
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APoint const abs_reverse_point = convert_abs_coord(angle, ratio);
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DPoint const abs_reverse_point = convert_abs_coord(angle, ratio);
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cout << "reversed abs origin: " << abs_reverse_point << endl;
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Point const reverse_point = convert_img_coord(square, abs_reverse_point);
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cout << "reversed origin in square: " << reverse_point << endl;
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@ -398,10 +466,10 @@ bool check_trigo()
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compute_output_size(square, rotation, w, h);
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// failed check: is precision an issue?
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if (false)
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if (true)
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{
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if (!fequal(w, square.width * sqrt(2), sigma)
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|| !fequal(h, square.height * sqrt(2), sigma))
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if (!fequal(w, square.width * sqrt(2), sigma * square.width)
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|| !fequal(h, square.height * sqrt(2), sigma * square.height))
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{
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cerr << "Invalid rotated image dimensions " << w << " x " << h << endl;
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cerr << " expected " << (int) ceil(square.width * sqrt(2)) << " x " << (int) ceil(square.height * sqrt(2)) << endl;
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@ -411,20 +479,22 @@ bool check_trigo()
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Image rotated(w, h);
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APoint const a_p45 = convert_abs_coord(angle + rotation, ratio);
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DPoint const a_p45 = convert_abs_coord(angle + rotation, ratio);
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Point const p45 = convert_img_coord(rotated, a_p45);
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if (abs((float) (0) - p45.x) > sigma)
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if (!fequal(0, p45.x, sigma))
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{
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cerr << "Rotation origin by 45 degrees:" << endl;
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cerr << __LINE__ << " > Rotation origin by 45 degrees:" << endl;
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cerr << " invalid x value: " << p45.x << " != " << 0 << endl;
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cerr << " absolute point: " << a_p45 << endl;
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cerr << " relative point: " << p45 << endl;
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return false;
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}
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if (abs(0.0 - p45.y) > sigma)
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if (!fequal(p45.y, h / 2.0f - 1, sigma))
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{
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cerr << "Rotation origin by 45 degrees:" << endl;
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cerr << "Invalid y value: " << p45.y << " != " << 0 << endl;
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cerr << __LINE__ << " > Rotation origin by 45 degrees:" << endl;
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cerr << "Invalid y value: " << p45.y << " != " << h / 2.0f - 1 << endl;
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cerr << " absolute point: " << a_p45 << endl;
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cerr << " relative point: " << p45 << endl;
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return false;
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}
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}
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@ -435,80 +505,20 @@ bool check_trigo()
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void check_lines()
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{
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Image const square(500, 500);
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double const ratio = compute_ratio(square);
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unsigned int w = 0;
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unsigned int h = 0;
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{
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double const rotation = M_PI / 8; // 22 degrees
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compute_output_size(square, rotation, w, h);
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Image rotated(w, h);
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draw_outline(square, 22, "square");
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draw_outline(square, 33, "square");
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draw_outline(square, 45, "square");
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draw_outline(square, 90, "square");
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Point tl = rotate(square, Point(0, 0), ratio, rotation, rotated);
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Point tr = rotate(square, Point(square.width - 1, 0), ratio, rotation, rotated);
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Point bl = rotate(square, Point(0, square.height - 1), ratio, rotation, rotated);
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Point br = rotate(square, Point(square.width - 1, square.height - 1), ratio, rotation, rotated);
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draw_line(rotated, tl, tr);
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draw_line(rotated, tr, br);
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draw_line(rotated, br, bl);
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draw_line(rotated, bl, tl);
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rotated.save("check_lines_01.ppm");
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}
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{
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double const rotation = M_PI / 6; // 33 degrees
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compute_output_size(square, rotation, w, h);
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Image rotated(w, h);
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Point tl = rotate(square, Point(0, 0), ratio, rotation, rotated);
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Point tr = rotate(square, Point(square.width - 1, 0), ratio, rotation, rotated);
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Point bl = rotate(square, Point(0, square.height - 1), ratio, rotation, rotated);
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Point br = rotate(square, Point(square.width - 1, square.height - 1), ratio, rotation, rotated);
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draw_line(rotated, tl, tr);
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draw_line(rotated, tr, br);
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draw_line(rotated, br, bl);
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draw_line(rotated, bl, tl);
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rotated.save("check_lines_02.ppm");
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}
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{
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double const rotation = M_PI / 4; // 45 degrees
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compute_output_size(square, rotation, w, h);
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Image rotated(w, h);
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Point tl = rotate(square, Point(0, 0), ratio, rotation, rotated);
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Point tr = rotate(square, Point(square.width - 1, 0), ratio, rotation, rotated);
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Point bl = rotate(square, Point(0, square.height - 1), ratio, rotation, rotated);
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Point br = rotate(square, Point(square.width - 1, square.height - 1), ratio, rotation, rotated);
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draw_line(rotated, tl, tr);
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draw_line(rotated, tr, br);
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draw_line(rotated, br, bl);
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draw_line(rotated, bl, tl);
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rotated.save("check_lines_03.ppm");
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}
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{
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double const rotation = M_PI / 2; // 90 degrees
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compute_output_size(square, rotation, w, h);
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Image rotated(w, h);
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Point tl = rotate(square, Point(0, 0), ratio, rotation, rotated);
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Point tr = rotate(square, Point(square.width - 1, 0), ratio, rotation, rotated);
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Point bl = rotate(square, Point(0, square.height - 1), ratio, rotation, rotated);
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Point br = rotate(square, Point(square.width - 1, square.height - 1), ratio, rotation, rotated);
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draw_line(rotated, tl, tr);
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draw_line(rotated, tr, br);
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draw_line(rotated, br, bl);
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draw_line(rotated, bl, tl);
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rotated.save("check_lines_04.ppm");
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}
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Image const rect1(640, 480);
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||||
draw_outline(rect1, 22, "rect1");
|
||||
draw_outline(rect1, 33, "rect1");
|
||||
draw_outline(rect1, 45, "rect1");
|
||||
draw_outline(rect1, 90, "rect1");
|
||||
}
|
||||
|
||||
|
||||
|
||||
//
|
||||
//
|
||||
// Main
|
||||
|
|
@ -516,6 +526,8 @@ void check_lines()
|
|||
|
||||
int main()
|
||||
{
|
||||
check_points();
|
||||
|
||||
if (!check_trigo())
|
||||
return 1;
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue