mirror of
https://github.com/nishiowo/nishbox
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46 lines
885 B
C
46 lines
885 B
C
#include "nb_pre.h"
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/* External library */
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#include <ode/odemath.h>
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/* Interface */
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#include "nb_math.h"
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/* NishBox */
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/* Standard */
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#include <stdlib.h>
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#include <math.h>
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float nb_log2(float x) { return log(x) / log(2); }
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nb_vector_t nb_calculate_normal(nb_vector_t v0, nb_vector_t v1, nb_vector_t v2) {
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int i;
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dReal length;
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nb_vector_t vec = malloc(sizeof(*vec) * 3);
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dReal res[3];
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dReal tmp0[3];
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dReal tmp1[3];
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dReal a[3]; /* v1 - v0 */
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dReal b[3]; /* v2 - v0 */
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NB_VECTOR_COPY(tmp0, v1);
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NB_VECTOR_COPY(tmp1, v0);
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dSubtractVectors3(a, tmp0, tmp1); /* v1 - v0 */
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NB_VECTOR_COPY(tmp0, v2);
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NB_VECTOR_COPY(tmp1, v0);
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dSubtractVectors3(b, tmp0, tmp1); /* v2 - v0 */
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dCalcVectorCross3(res, a, b);
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length = dCalcVectorLength3(res);
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NB_VECTOR_COPY(res, vec);
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vec[0] /= length;
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vec[1] /= length;
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vec[2] /= length;
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return vec;
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}
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