21 lines
699 B
C
21 lines
699 B
C
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#include "edge_equation.h"
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void EdgeEquationInit(EdgeEquation* edge, const float* v0, const float* v1) {
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edge->a = v0[1] - v1[1];
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edge->b = v1[0] - v0[0];
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edge->c = -(edge->a * (v0[0] + v1[0]) + edge->b * (v0[1] + v1[1])) / 2;
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edge->tie = edge->a != 0 ? edge->a > 0 : edge->b > 0;
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}
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float EdgeEquationEvaluate(const EdgeEquation* edge, float x, float y) {
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return edge->a * x + edge->b * y + edge->c;
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}
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bool EdgeEquationTestValue(const EdgeEquation* edge, float value) {
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return (value >= 0 || (value == 0 && edge->tie));
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}
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bool EdgeEquationTestPoint(const EdgeEquation* edge, float x, float y) {
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return EdgeEquationTestValue(edge, EdgeEquationEvaluate(edge, x, y));
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}
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