mirror of
https://github.com/SerenityOS/serenity
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83 lines
3 KiB
C++
83 lines
3 KiB
C++
/*
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* Copyright (c) 2022, Jelle Raaijmakers <jelle@gmta.nl>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Array.h>
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#include <Demos/Tubes/Shapes.h>
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#include <LibGL/GL/gl.h>
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#include <LibGfx/Vector3.h>
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#include <math.h>
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constexpr u8 sphere_number_of_segments = 4;
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constexpr u8 tube_number_of_segments = 12;
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void draw_sphere()
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{
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// Draw a sphere by drawing a cube with many segments with normalized coordinates
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glBegin(GL_QUADS);
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auto draw_segment = [](Array<DoubleVector3, 4> corners, Optional<int> flip_a, Optional<int> flip_b, Optional<int> swap_a, Optional<int> swap_b) {
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for (DoubleVector3& corner : corners) {
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if (flip_a.has_value())
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corner[flip_a.value()] *= -1;
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if (flip_b.has_value())
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corner[flip_b.value()] *= -1;
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if (swap_a.has_value() && swap_b.has_value())
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swap(corner[swap_a.value()], corner[swap_b.value()]);
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glNormal3d(corner.x(), corner.y(), corner.z());
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glVertex3d(corner.x(), corner.y(), corner.z());
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}
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};
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double const segment_size = 2. / sphere_number_of_segments;
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for (int y = 0; y < sphere_number_of_segments; y++) {
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for (int x = 0; x < sphere_number_of_segments; x++) {
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DoubleVector3 bottomleft = { -1. + x * segment_size, -1. + y * segment_size, 1. };
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DoubleVector3 bottomright = { -1. + (x + 1) * segment_size, -1. + y * segment_size, 1. };
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DoubleVector3 topright = { -1. + (x + 1) * segment_size, -1. + (y + 1) * segment_size, 1. };
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DoubleVector3 topleft = { -1. + x * segment_size, -1. + (y + 1) * segment_size, 1. };
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Array<DoubleVector3, 4> normalized_corners = {
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bottomleft.normalized(),
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bottomright.normalized(),
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topright.normalized(),
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topleft.normalized(),
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};
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draw_segment(normalized_corners, {}, {}, {}, {}); // front face
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draw_segment(normalized_corners, 0, 2, {}, {}); // back face
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draw_segment(normalized_corners, 2, {}, 0, 2); // left face
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draw_segment(normalized_corners, 0, {}, 0, 2); // right face
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draw_segment(normalized_corners, 1, {}, 1, 2); // top face
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draw_segment(normalized_corners, 2, {}, 1, 2); // bottom face
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}
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}
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glEnd();
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}
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void draw_tube()
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{
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glBegin(GL_QUADS);
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double const segment_angle = 2 * M_PI / tube_number_of_segments;
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double last_x = 0.;
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double last_y = 1.;
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for (int i = 1; i <= tube_number_of_segments; ++i) {
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double angle = i * segment_angle;
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double segment_x = sin(angle);
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double segment_y = cos(angle);
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glNormal3d(last_x, last_y, 0.);
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glVertex3d(last_x, last_y, 0.);
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glNormal3d(segment_x, segment_y, 0.);
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glVertex3d(segment_x, segment_y, 0.);
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glVertex3d(segment_x, segment_y, -2.);
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glNormal3d(last_x, last_y, 0.);
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glVertex3d(last_x, last_y, -2.);
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last_x = segment_x;
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last_y = segment_y;
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}
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glEnd();
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}
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