69 lines
2.1 KiB
C
69 lines
2.1 KiB
C
#ifndef XYVECTOR_H
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#define XYVECTOR_H
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#include <math.h>
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// A 2D vector:
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typedef struct xyVector
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{
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double xComponent;
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double yComponent;
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} xyVector;
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static inline double angleBetweenVectors(xyVector * vectorA, xyVector * vectorB)
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{
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double dotProduct = (vectorA->xComponent * vectorB->xComponent) + (vectorA->yComponent * vectorB->yComponent);
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double determinant = (vectorA->xComponent * vectorB->yComponent) - (vectorA->yComponent * vectorB->xComponent);
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return atan2(dotProduct, determinant) / 0.01745329;
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}
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// Calculate the vector from point A to point B:
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static inline void xyVectorBetweenPoints(long ax, long ay, long bx, long by, xyVector * vector)
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{
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vector->xComponent = bx - ax;
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vector->yComponent = by - ay;
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}
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// Normalize a vector, returning the magnitude:
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static inline double normalizeXYVector(xyVector * vector)
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{
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double magnitude = sqrt(pow(vector->xComponent, 2) + pow(vector->yComponent, 2));
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if(magnitude != 0)
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{
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vector->xComponent /= magnitude;
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vector->yComponent /= magnitude;
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}
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return magnitude;
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}
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// Rotate XY vector by a given number of degrees:
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static inline void rotateXYVector(xyVector * vector, double degrees)
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{
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double xComponent = vector->xComponent, yComponent = vector->yComponent;
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vector->xComponent = (cos(degrees * 0.01745329) * xComponent) - (sin(degrees * 0.01745329) * yComponent);
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vector->yComponent = (sin(degrees * 0.01745329) * xComponent) + (cos(degrees * 0.01745329) * yComponent);
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}
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// Add vector B to vector A:
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static inline void addXYVector(xyVector * vectorA, xyVector * vectorB)
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{
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vectorA->xComponent += vectorB->xComponent;
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vectorA->yComponent += vectorB->yComponent;
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}
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// Add vector B to vector A, scaled for units per frame:
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static inline void addXYVectorDeltaScaled(xyVector * vectorA, xyVector * vectorB, double deltaTime)
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{
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vectorA->xComponent += vectorB->xComponent * (0.001 * deltaTime) * 60;
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vectorA->yComponent += vectorB->yComponent * (0.001 * deltaTime) * 60;
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}
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// Multiply a vector by a scalar constant:
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static inline void multiplyXYVector(xyVector * vector, double scalar)
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{
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vector->xComponent *= scalar;
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vector->yComponent *= scalar;
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}
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#endif
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