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//-----------------------------------------------------------------------------
// Name: enginemath.cpp
// Developer: Wolfire Games LLC
// Author: David Rosen
// Description: This contains most 3d math functions and classes
// License: Read below
//-----------------------------------------------------------------------------
//
// Copyright 2022 Wolfire Games LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
//-----------------------------------------------------------------------------
#include "enginemath.h"
#include <Math/vec3math.h>
#define _USE_MATH_DEFINES
#include <cmath>
#include <cstdlib>
#include <cstdio>
#include <algorithm>
void PlaneSpace(const vec3 &n, vec3 &p, vec3 &q) {
if (std::fabs(n[2]) > 0.7071067f) {
// choose p in y-z plane
float a = n[1] * n[1] + n[2] * n[2];
float k = 1.0f / sqrtf(a);
p[0] = 0;
p[1] = -n[2] * k;
p[2] = n[1] * k;
// set q = n x p
q[0] = a * k;
q[1] = -n[0] * p[2];
q[2] = n[0] * p[1];
} else {
// choose p in x-y plane
float a = n[0] * n[0] + n[1] * n[1];
float k = 1.0f / sqrtf(a);
p[0] = -n[1] * k;
p[1] = n[0] * k;
p[2] = 0;
// set q = n x p
q[0] = -n[2] * p[1];
q[1] = n[2] * p[0];
q[2] = a * k;
}
}
float RangedRandomFloat(float min, float max) {
if (min == max) {
return min;
}
return (((float)abs(rand())) / RAND_MAX * ((float)(max) - (float)(min)) + (float)(min));
}
int RangedRandomInt(int min, int max) { // Inclusive
return abs(rand()) % (max - min + 1) + min;
}
float Range(float val, float min_val, float max_val) {
float temp_val = val;
temp_val -= min_val;
temp_val /= (max_val - min_val);
return min(1.0f, max(0.0f, temp_val));
}
float YAxisRotationFromVector(const vec3 &theVector) {
vec3 vector(theVector.x(), 0, theVector.z());
vector = normalize(vector);
float new_rotation = std::acos(vector.z()) / 3.1415f * 180.0f;
if (vector.x() < 0) new_rotation *= -1;
new_rotation += 180;
return new_rotation;
}
vec3 AngleAxisRotation(const vec3 &thePoint, const vec3 &theAxis, const float howmuch) {
return AngleAxisRotationRadian(thePoint, theAxis, howmuch * deg2radf);
}
vec3 AngleAxisRotationRadian(const vec3 &thePoint, const vec3 &theAxis, const float howmuch) {
float costheta = cosf(howmuch);
return thePoint * costheta + theAxis * (dot(thePoint, theAxis)) * (1 - costheta) + cross(thePoint, theAxis) * sinf(howmuch);
}
vec3 doRotation(const vec3 &thePoint, const float xang, const float yang, const float zang) {
return doRotationRadian(thePoint, xang * deg2radf, yang * deg2radf, zang * deg2radf);
}
vec3 doRotationRadian(const vec3 &thePoint, const float xang, const float yang, const float zang) {
vec3 newpoint;
vec3 oldpoint;
oldpoint = thePoint;
if (yang != 0) {
newpoint.z() = oldpoint.z() * cosf(yang) - oldpoint.x() * sinf(yang);
newpoint.x() = oldpoint.z() * sinf(yang) + oldpoint.x() * cosf(yang);
oldpoint.z() = newpoint.z();
oldpoint.x() = newpoint.x();
}
if (zang != 0) {
newpoint.x() = oldpoint.x() * cosf(zang) - oldpoint.y() * sinf(zang);
newpoint.y() = oldpoint.y() * cosf(zang) + oldpoint.x() * sinf(zang);
oldpoint.x() = newpoint.x();
oldpoint.y() = newpoint.y();
}
if (xang != 0) {
newpoint.y() = oldpoint.y() * cosf(xang) - oldpoint.z() * sinf(xang);
newpoint.z() = oldpoint.y() * sinf(xang) + oldpoint.z() * cosf(xang);
oldpoint.z() = newpoint.z();
oldpoint.y() = newpoint.y();
}
return oldpoint;
}
int log2(unsigned int x) {
int log = -1; // special case for log2(0)
while (x != 0) {
x >>= 1;
log++;
}
return log;
}
void GetRotationBetweenVectors(const vec3 &a, const vec3 &b, quaternion &rotate) {
vec3 rotate_axis = normalize(cross(a, b));
vec3 up = normalize(a);
vec3 right_vec = cross(up, rotate_axis);
vec3 ik_dir = normalize(b);
float rotate_angle = atan2f(-dot(ik_dir, right_vec), dot(ik_dir, up));
rotate = quaternion(vec4(rotate_axis, rotate_angle));
}
const uint64_t m1 = 0x5555555555555555; // binary: 0101...
const uint64_t m2 = 0x3333333333333333; // binary: 00110011..
const uint64_t m4 = 0x0f0f0f0f0f0f0f0f; // binary: 4 zeros, 4 ones ...
const uint64_t m8 = 0x00ff00ff00ff00ff; // binary: 8 zeros, 8 ones ...
const uint64_t m16 = 0x0000ffff0000ffff; // binary: 16 zeros, 16 ones ...
const uint64_t m32 = 0x00000000ffffffff; // binary: 32 zeros, 32 ones
const uint64_t hff = 0xffffffffffffffff; // binary: all ones
const uint64_t h01 = 0x0101010101010101; // the sum of 256 to the power of 0,1,2,3...
int popcount(uint64_t x) {
x -= (x >> 1) & m1; // put count of each 2 bits into those 2 bits
x = (x & m2) + ((x >> 2) & m2); // put count of each 4 bits into those 4 bits
x = (x + (x >> 4)) & m4; // put count of each 8 bits into those 8 bits
return (x * h01) >> 56; // returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24) + ...
}
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