577 lines
17 KiB
C++
577 lines
17 KiB
C++
/*************************************************************************/
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/* line_builder.cpp */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* http://www.godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2017 Godot Engine contributors (cf. AUTHORS.md) */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#include "line_builder.h"
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//----------------------------------------------------------------------------
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// Util
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//----------------------------------------------------------------------------
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enum SegmentIntersectionResult {
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SEGMENT_PARALLEL = 0,
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SEGMENT_NO_INTERSECT = 1,
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SEGMENT_INTERSECT = 2
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};
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static SegmentIntersectionResult segment_intersection(
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Vector2 a, Vector2 b, Vector2 c, Vector2 d,
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Vector2 *out_intersection) {
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// http://paulbourke.net/geometry/pointlineplane/ <-- Good stuff
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Vector2 cd = d - c;
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Vector2 ab = b - a;
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float div = cd.y * ab.x - cd.x * ab.y;
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if (Math::abs(div) > 0.001f) {
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float ua = (cd.x * (a.y - c.y) - cd.y * (a.x - c.x)) / div;
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float ub = (ab.x * (a.y - c.y) - ab.y * (a.x - c.x)) / div;
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*out_intersection = a + ua * ab;
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if (ua >= 0.f && ua <= 1.f &&
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ub >= 0.f && ub <= 1.f)
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return SEGMENT_INTERSECT;
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return SEGMENT_NO_INTERSECT;
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}
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return SEGMENT_PARALLEL;
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}
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// TODO I'm pretty sure there is an even faster way to swap things
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template <typename T>
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static inline void swap(T &a, T &b) {
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T tmp = a;
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a = b;
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b = tmp;
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}
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static float calculate_total_distance(const Vector<Vector2> &points) {
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float d = 0.f;
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for (int i = 1; i < points.size(); ++i) {
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d += points[i].distance_to(points[i - 1]);
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}
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return d;
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}
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static inline Vector2 rotate90(const Vector2 &v) {
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// Note: the 2D referential is X-right, Y-down
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return Vector2(v.y, -v.x);
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}
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static inline Vector2 interpolate(const Rect2 &r, const Vector2 &v) {
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return Vector2(
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Math::lerp(r.position.x, r.position.x + r.get_size().x, v.x),
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Math::lerp(r.position.y, r.position.y + r.get_size().y, v.y));
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}
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//----------------------------------------------------------------------------
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// LineBuilder
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//----------------------------------------------------------------------------
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LineBuilder::LineBuilder() {
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joint_mode = LINE_JOINT_SHARP;
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width = 10;
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default_color = Color(0.4, 0.5, 1);
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gradient = NULL;
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sharp_limit = 2.f;
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round_precision = 8;
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begin_cap_mode = LINE_CAP_NONE;
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end_cap_mode = LINE_CAP_NONE;
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_interpolate_color = false;
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_last_index[0] = 0;
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_last_index[1] = 0;
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}
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void LineBuilder::clear_output() {
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vertices.clear();
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colors.clear();
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indices.clear();
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}
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void LineBuilder::build() {
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// Need at least 2 points to draw a line
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if (points.size() < 2) {
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clear_output();
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return;
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}
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const float hw = width / 2.f;
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const float hw_sq = hw * hw;
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const float sharp_limit_sq = sharp_limit * sharp_limit;
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const int len = points.size();
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// Initial values
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Vector2 pos0 = points[0];
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Vector2 pos1 = points[1];
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Vector2 f0 = (pos1 - pos0).normalized();
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Vector2 u0 = rotate90(f0);
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Vector2 pos_up0 = pos0 + u0 * hw;
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Vector2 pos_down0 = pos0 - u0 * hw;
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Color color0;
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Color color1;
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float current_distance0 = 0.f;
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float current_distance1 = 0.f;
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float total_distance;
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_interpolate_color = gradient != NULL;
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bool distance_required = _interpolate_color || texture_mode == LINE_TEXTURE_TILE;
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if (distance_required)
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total_distance = calculate_total_distance(points);
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if (_interpolate_color)
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color0 = gradient->get_color(0);
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else
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colors.push_back(default_color);
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float uvx0 = 0.f;
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float uvx1 = 0.f;
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// Begin cap
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if (begin_cap_mode == LINE_CAP_BOX) {
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// Push back first vertices a little bit
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pos_up0 -= f0 * hw;
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pos_down0 -= f0 * hw;
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// The line's outer length will be a little higher due to begin and end caps
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total_distance += width;
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current_distance0 += hw;
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current_distance1 = current_distance0;
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} else if (begin_cap_mode == LINE_CAP_ROUND) {
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if (texture_mode == LINE_TEXTURE_TILE) {
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uvx0 = 0.5f;
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}
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new_arc(pos0, pos_up0 - pos0, -Math_PI, color0, Rect2(0.f, 0.f, 1.f, 1.f));
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total_distance += width;
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current_distance0 += hw;
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current_distance1 = current_distance0;
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}
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strip_begin(pos_up0, pos_down0, color0, uvx0);
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// pos_up0 ------------- pos_up1 --------------------
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// | |
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// pos0 - - - - - - - - - pos1 - - - - - - - - - pos2
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// | |
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// pos_down0 ------------ pos_down1 ------------------
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//
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// i-1 i i+1
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// http://labs.hyperandroid.com/tag/opengl-lines
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// (not the same implementation but visuals help a lot)
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// For each additional segment
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for (int i = 1; i < len - 1; ++i) {
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pos1 = points[i];
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Vector2 pos2 = points[i + 1];
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Vector2 f1 = (pos2 - pos1).normalized();
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Vector2 u1 = rotate90(f1);
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// Determine joint orientation
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const float dp = u0.dot(f1);
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const Orientation orientation = (dp > 0.f ? UP : DOWN);
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Vector2 inner_normal0, inner_normal1;
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if (orientation == UP) {
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inner_normal0 = u0 * hw;
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inner_normal1 = u1 * hw;
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} else {
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inner_normal0 = -u0 * hw;
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inner_normal1 = -u1 * hw;
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}
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// ---------------------------
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// /
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// 0 / 1
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// / /
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// --------------------x------ /
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// / / (here shown with orientation == DOWN)
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// / /
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// / /
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// / /
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// 2 /
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// /
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// Find inner intersection at the joint
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Vector2 corner_pos_in, corner_pos_out;
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SegmentIntersectionResult intersection_result = segment_intersection(
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pos0 + inner_normal0, pos1 + inner_normal0,
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pos1 + inner_normal1, pos2 + inner_normal1,
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&corner_pos_in);
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if (intersection_result == SEGMENT_INTERSECT)
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// Inner parts of the segments intersect
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corner_pos_out = 2.f * pos1 - corner_pos_in;
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else {
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// No intersection, segments are either parallel or too sharp
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corner_pos_in = pos1 + inner_normal0;
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corner_pos_out = pos1 - inner_normal0;
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}
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Vector2 corner_pos_up, corner_pos_down;
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if (orientation == UP) {
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corner_pos_up = corner_pos_in;
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corner_pos_down = corner_pos_out;
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} else {
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corner_pos_up = corner_pos_out;
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corner_pos_down = corner_pos_in;
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}
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LineJointMode current_joint_mode = joint_mode;
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Vector2 pos_up1, pos_down1;
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if (intersection_result == SEGMENT_INTERSECT) {
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// Fallback on bevel if sharp angle is too high (because it would produce very long miters)
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if (current_joint_mode == LINE_JOINT_SHARP && corner_pos_out.distance_squared_to(pos1) / hw_sq > sharp_limit_sq) {
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current_joint_mode = LINE_JOINT_BEVEL;
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}
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if (current_joint_mode == LINE_JOINT_SHARP) {
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// In this case, we won't create joint geometry,
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// The previous and next line quads will directly share an edge.
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pos_up1 = corner_pos_up;
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pos_down1 = corner_pos_down;
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} else {
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// Bevel or round
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if (orientation == UP) {
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pos_up1 = corner_pos_up;
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pos_down1 = pos1 - u0 * hw;
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} else {
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pos_up1 = pos1 + u0 * hw;
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pos_down1 = corner_pos_down;
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}
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}
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} else {
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// No intersection: fallback
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pos_up1 = corner_pos_up;
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pos_down1 = corner_pos_down;
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}
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// Add current line body quad
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// Triangles are clockwise
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if (distance_required) {
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current_distance1 += pos0.distance_to(pos1);
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}
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if (_interpolate_color) {
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color1 = gradient->get_color_at_offset(current_distance1 / total_distance);
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}
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if (texture_mode == LINE_TEXTURE_TILE) {
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uvx0 = current_distance0 / width;
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uvx1 = current_distance1 / width;
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}
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strip_add_quad(pos_up1, pos_down1, color1, uvx1);
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// Swap vars for use in the next line
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color0 = color1;
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u0 = u1;
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f0 = f1;
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pos0 = pos1;
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current_distance0 = current_distance1;
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if (intersection_result == SEGMENT_INTERSECT) {
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if (current_joint_mode == LINE_JOINT_SHARP) {
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pos_up0 = pos_up1;
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pos_down0 = pos_down1;
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} else {
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if (orientation == UP) {
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pos_up0 = corner_pos_up;
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pos_down0 = pos1 - u1 * hw;
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} else {
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pos_up0 = pos1 + u1 * hw;
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pos_down0 = corner_pos_down;
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}
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}
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} else {
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pos_up0 = pos1 + u1 * hw;
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pos_down0 = pos1 - u1 * hw;
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}
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// From this point, bu0 and bd0 concern the next segment
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// Add joint geometry
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if (current_joint_mode != LINE_JOINT_SHARP) {
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// ________________ cbegin
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// / \
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// / \
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// ____________/_ _ _\ cend
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// | |
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// | |
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// | |
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Vector2 cbegin, cend;
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if (orientation == UP) {
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cbegin = pos_down1;
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cend = pos_down0;
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} else {
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cbegin = pos_up1;
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cend = pos_up0;
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}
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if (current_joint_mode == LINE_JOINT_BEVEL) {
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strip_add_tri(cend, orientation);
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} else if (current_joint_mode == LINE_JOINT_ROUND) {
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Vector2 vbegin = cbegin - pos1;
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Vector2 vend = cend - pos1;
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strip_add_arc(pos1, vend.angle_to(vbegin), orientation);
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}
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if (intersection_result != SEGMENT_INTERSECT)
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// In this case the joint is too fucked up to be re-used,
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// start again the strip with fallback points
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strip_begin(pos_up0, pos_down0, color1, uvx1);
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}
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}
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// Last (or only) segment
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pos1 = points[points.size() - 1];
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Vector2 pos_up1 = pos1 + u0 * hw;
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Vector2 pos_down1 = pos1 - u0 * hw;
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// End cap (box)
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if (end_cap_mode == LINE_CAP_BOX) {
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pos_up1 += f0 * hw;
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pos_down1 += f0 * hw;
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}
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if (distance_required) {
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current_distance1 += pos0.distance_to(pos1);
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}
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if (_interpolate_color) {
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color1 = gradient->get_color(gradient->get_points_count() - 1);
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}
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if (texture_mode == LINE_TEXTURE_TILE) {
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uvx1 = current_distance1 / width;
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}
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strip_add_quad(pos_up1, pos_down1, color1, uvx1);
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// End cap (round)
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if (end_cap_mode == LINE_CAP_ROUND) {
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// Note: color is not used in case we don't interpolate...
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Color color = _interpolate_color ? gradient->get_color(gradient->get_points_count() - 1) : Color(0, 0, 0);
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new_arc(pos1, pos_up1 - pos1, Math_PI, color, Rect2(uvx1 - 0.5f, 0.f, 1.f, 1.f));
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}
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}
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void LineBuilder::strip_begin(Vector2 up, Vector2 down, Color color, float uvx) {
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int vi = vertices.size();
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vertices.push_back(up);
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vertices.push_back(down);
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if (_interpolate_color) {
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colors.push_back(color);
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colors.push_back(color);
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}
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if (texture_mode != LINE_TEXTURE_NONE) {
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uvs.push_back(Vector2(uvx, 0.f));
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uvs.push_back(Vector2(uvx, 1.f));
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}
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_last_index[UP] = vi;
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_last_index[DOWN] = vi + 1;
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}
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void LineBuilder::strip_new_quad(Vector2 up, Vector2 down, Color color, float uvx) {
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int vi = vertices.size();
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vertices.push_back(vertices[_last_index[UP]]);
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vertices.push_back(vertices[_last_index[DOWN]]);
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vertices.push_back(up);
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vertices.push_back(down);
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if (_interpolate_color) {
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colors.push_back(color);
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colors.push_back(color);
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colors.push_back(color);
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colors.push_back(color);
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}
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if (texture_mode != LINE_TEXTURE_NONE) {
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uvs.push_back(uvs[_last_index[UP]]);
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uvs.push_back(uvs[_last_index[DOWN]]);
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uvs.push_back(Vector2(uvx, UP));
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uvs.push_back(Vector2(uvx, DOWN));
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}
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indices.push_back(vi);
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indices.push_back(vi + 3);
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indices.push_back(vi + 1);
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indices.push_back(vi);
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indices.push_back(vi + 2);
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indices.push_back(vi + 3);
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_last_index[UP] = vi + 2;
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_last_index[DOWN] = vi + 3;
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}
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void LineBuilder::strip_add_quad(Vector2 up, Vector2 down, Color color, float uvx) {
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int vi = vertices.size();
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vertices.push_back(up);
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vertices.push_back(down);
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if (_interpolate_color) {
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colors.push_back(color);
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colors.push_back(color);
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}
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if (texture_mode != LINE_TEXTURE_NONE) {
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uvs.push_back(Vector2(uvx, 0.f));
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uvs.push_back(Vector2(uvx, 1.f));
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}
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indices.push_back(_last_index[UP]);
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indices.push_back(vi + 1);
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indices.push_back(_last_index[DOWN]);
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indices.push_back(_last_index[UP]);
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indices.push_back(vi);
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indices.push_back(vi + 1);
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_last_index[UP] = vi;
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_last_index[DOWN] = vi + 1;
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}
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void LineBuilder::strip_add_tri(Vector2 up, Orientation orientation) {
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int vi = vertices.size();
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vertices.push_back(up);
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if (_interpolate_color) {
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colors.push_back(colors[colors.size() - 1]);
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}
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Orientation opposite_orientation = orientation == UP ? DOWN : UP;
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if (texture_mode != LINE_TEXTURE_NONE) {
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// UVs are just one slice of the texture all along
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// (otherwise we can't share the bottom vertice)
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uvs.push_back(uvs[_last_index[opposite_orientation]]);
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}
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indices.push_back(_last_index[opposite_orientation]);
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indices.push_back(vi);
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indices.push_back(_last_index[orientation]);
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_last_index[opposite_orientation] = vi;
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}
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void LineBuilder::strip_add_arc(Vector2 center, float angle_delta, Orientation orientation) {
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// Take the two last vertices and extrude an arc made of triangles
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// that all share one of the initial vertices
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Orientation opposite_orientation = orientation == UP ? DOWN : UP;
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Vector2 vbegin = vertices[_last_index[opposite_orientation]] - center;
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float radius = vbegin.length();
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float angle_step = Math_PI / static_cast<float>(round_precision);
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float steps = Math::abs(angle_delta) / angle_step;
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if (angle_delta < 0.f)
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angle_step = -angle_step;
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float t = vbegin.angle_to(Vector2(1, 0));
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float end_angle = t + angle_delta;
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Vector2 rpos(0, 0);
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// Arc vertices
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for (int ti = 0; ti < steps; ++ti, t += angle_step) {
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rpos = center + Vector2(Math::cos(t), Math::sin(t)) * radius;
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|
strip_add_tri(rpos, orientation);
|
|
}
|
|
|
|
// Last arc vertice
|
|
rpos = center + Vector2(Math::cos(end_angle), Math::sin(end_angle)) * radius;
|
|
strip_add_tri(rpos, orientation);
|
|
}
|
|
|
|
void LineBuilder::new_arc(Vector2 center, Vector2 vbegin, float angle_delta, Color color, Rect2 uv_rect) {
|
|
|
|
// Make a standalone arc that doesn't use existing vertices,
|
|
// with undistorted UVs from within a square section
|
|
|
|
float radius = vbegin.length();
|
|
float angle_step = Math_PI / static_cast<float>(round_precision);
|
|
float steps = Math::abs(angle_delta) / angle_step;
|
|
|
|
if (angle_delta < 0.f)
|
|
angle_step = -angle_step;
|
|
|
|
float t = vbegin.angle_to(Vector2(1, 0));
|
|
float end_angle = t + angle_delta;
|
|
Vector2 rpos(0, 0);
|
|
float tt_begin = -Math_PI / 2.f;
|
|
float tt = tt_begin;
|
|
|
|
// Center vertice
|
|
int vi = vertices.size();
|
|
vertices.push_back(center);
|
|
if (_interpolate_color)
|
|
colors.push_back(color);
|
|
if (texture_mode != LINE_TEXTURE_NONE)
|
|
uvs.push_back(interpolate(uv_rect, Vector2(0.5f, 0.5f)));
|
|
|
|
// Arc vertices
|
|
for (int ti = 0; ti < steps; ++ti, t += angle_step) {
|
|
Vector2 sc = Vector2(Math::cos(t), Math::sin(t));
|
|
rpos = center + sc * radius;
|
|
|
|
vertices.push_back(rpos);
|
|
if (_interpolate_color)
|
|
colors.push_back(color);
|
|
if (texture_mode != LINE_TEXTURE_NONE) {
|
|
Vector2 tsc = Vector2(Math::cos(tt), Math::sin(tt));
|
|
uvs.push_back(interpolate(uv_rect, 0.5f * (tsc + Vector2(1.f, 1.f))));
|
|
tt += angle_step;
|
|
}
|
|
}
|
|
|
|
// Last arc vertice
|
|
Vector2 sc = Vector2(Math::cos(end_angle), Math::sin(end_angle));
|
|
rpos = center + sc * radius;
|
|
vertices.push_back(rpos);
|
|
if (_interpolate_color)
|
|
colors.push_back(color);
|
|
if (texture_mode != LINE_TEXTURE_NONE) {
|
|
tt = tt_begin + angle_delta;
|
|
Vector2 tsc = Vector2(Math::cos(tt), Math::sin(tt));
|
|
uvs.push_back(interpolate(uv_rect, 0.5f * (tsc + Vector2(1.f, 1.f))));
|
|
}
|
|
|
|
// Make up triangles
|
|
int vi0 = vi;
|
|
for (int ti = 0; ti < steps; ++ti) {
|
|
indices.push_back(vi0);
|
|
indices.push_back(++vi);
|
|
indices.push_back(vi + 1);
|
|
}
|
|
}
|