forked from mia/Aegisub
119 lines
3.5 KiB
C++
119 lines
3.5 KiB
C++
// Copyright (c) 2007, Rodrigo Braz Monteiro
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of the Aegisub Group nor the names of its contributors
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// may be used to endorse or promote products derived from this software
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// without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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//
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// -----------------------------------------------------------------------------
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//
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// AEGISUB
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//
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// Website: http://aegisub.cellosoft.com
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// Contact: mailto:zeratul@cellosoft.com
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//
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///////////
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// Headers
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#include "spline_curve.h"
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#include "utils.h"
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/////////////////////
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// Curve constructor
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SplineCurve::SplineCurve() {
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type = CURVE_INVALID;
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}
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/////////////////////////////////////////////////////////
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// Split a curve in two using the de Casteljau algorithm
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void SplineCurve::Split(SplineCurve &c1,SplineCurve &c2,float t) {
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// Split a line
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if (type == CURVE_LINE) {
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c1.type = CURVE_LINE;
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c2.type = CURVE_LINE;
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c1.p1 = p1;
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c1.p2 = p1*t+p2*(1-t);
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c2.p1 = c1.p2;
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c2.p2 = p2;
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}
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// Split a bicubic
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else if (type == CURVE_BICUBIC) {
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c1.type = CURVE_BICUBIC;
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c2.type = CURVE_BICUBIC;
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// Sub-divisions
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float u = 1-t;
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Vector2D p12 = p1*t+p2*u;
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Vector2D p23 = p2*t+p3*u;
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Vector2D p34 = p3*t+p4*u;
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Vector2D p123 = p12*t+p23*u;
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Vector2D p234 = p23*t+p34*u;
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Vector2D p1234 = p123*t+p234*u;
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// Set points
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c1.p1 = p1;
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c1.p2 = p12;
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c1.p3 = p123;
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c1.p4 = p1234;
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c2.p1 = p1234;
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c2.p2 = p234;
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c2.p3 = p34;
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c2.p4 = p4;
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}
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}
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//////////////////////
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// Smoothes the curve
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// Based on http://antigrain.com/research/bezier_interpolation/index.html
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void SplineCurve::Smooth(Vector2D P0,Vector2D P3,float smooth) {
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// Validate
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if (type != CURVE_LINE) return;
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smooth = MID(0.0f,smooth,1.0f);
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// Get points
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Vector2D P1 = p1;
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Vector2D P2 = p2;
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// Calculate intermediate points
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Vector2D c1 = (P0+P1)/2.0f;
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Vector2D c2 = (P1+P2)/2.0f;
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Vector2D c3 = (P2+P3)/2.0f;
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float len1 = (P1-P0).Len();
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float len2 = (P2-P1).Len();
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float len3 = (P3-P2).Len();
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float k1 = len1/(len1+len2);
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float k2 = len2/(len2+len3);
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Vector2D m1 = c1+(c2-c1)*k1;
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Vector2D m2 = c2+(c3-c2)*k2;
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// Set curve points
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p4 = p2;
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p2 = m1+(c2-m1)*smooth + P1 - m1;
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p3 = m2+(c2-m2)*smooth + P2 - m2;
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type = CURVE_BICUBIC;
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}
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