52 lines
2.4 KiB
C++
52 lines
2.4 KiB
C++
// SPDX-License-Identifier: LGPL-3.0-or-later
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#pragma once
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#include <cstdint>
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#include <tuple>
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typedef uint8_t Transformation;
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const Transformation TRANSFORM_MIRROR_X = 1 << 0;
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const Transformation TRANSFORM_MIRROR_Y = 1 << 1;
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const Transformation TRANSFORM_ROTATE_CW = 1 << 2;
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const Transformation TRANSFORM_ROTATE_CCW = 1 << 3;
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// Applies the provided transformation to the point, mutating it in place.
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// Rotation is done before mirroring.
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void transform_mut(Transformation transformation, int &x, int &y);
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// Applies the provided transformation to the point,
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// returning the transformed point.
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// Rotation is done before mirroring.
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std::pair<int, int> transform(Transformation transformation, int x, int y);
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// Applies the inverse transformation to the point, mutating it in place.
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// Composition of this with the transformation is the identity function.
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void transform_inv_mut(Transformation transformation, int &x, int &y);
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// Applies the inverse transformation to the point,
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// returning the transformed point.
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// Composition of this with the transformation is the identity function.
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std::pair<int, int> transform_inv(Transformation transformation, int x, int y);
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// Returns the transformation required
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// to make the given endpoints of a line conform
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// to the standard case for rasterization.
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Transformation transformation_to_standard_case(int x0, int y0, int x1, int y1);
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// Returns the barycentric coordinates of the point given by (xp, yp)
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// in the triangle given by the three points (x0, y0), (x1, y1), (x2, y2).
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// May return non-real values when the points are on a straight line.
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std::tuple<float, float, float> barycentric_coordinates(int x0, int y0, int x1,
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int y1, int x2, int y2,
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int xp, int yp);
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// Checks if the point given by (xp, yp) is inside the triangle
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// given by the three points (x0, y0), (x1, y1), (x2, y2).
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bool point_in_triangle(int x0, int y0, int x1, int y1, int x2, int y2, int xp,
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int yp);
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// Sorts the points of a triangle to be in ascending order (y0 < y1 < y2).
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void sort_triangle_points(int &x0, int &y0, int &x1, int &y1, int &x2, int &y2);
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// This calculates the slope of a line from (x0, y0) to (x1, y1).
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// It handles special cases to ensure the return value will be real.
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float slope(int x0, int y0, int x1, int y1);
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