overte/libraries/shared/src/GLMHelpers.cpp
Anthony J. Thibault bcd31e3d99 Adjust size and offset of grab balls to better align with hand controllers.
(cherry picked from commit d97a8c2e7eace2494d3142e8187022a33aedc060)
2016-10-19 15:59:26 -07:00

576 lines
23 KiB
C++

//
// GLMHelpers.cpp
// libraries/shared/src
//
// Created by Stephen Birarda on 2014-08-07.
// Copyright 2014 High Fidelity, Inc.
//
// Distributed under the Apache License, Version 2.0.
// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//
#include "GLMHelpers.h"
#include <glm/gtc/matrix_transform.hpp>
#include "NumericalConstants.h"
const vec3 Vectors::UNIT_X{ 1.0f, 0.0f, 0.0f };
const vec3 Vectors::UNIT_Y{ 0.0f, 1.0f, 0.0f };
const vec3 Vectors::UNIT_Z{ 0.0f, 0.0f, 1.0f };
const vec3 Vectors::UNIT_NEG_X{ -1.0f, 0.0f, 0.0f };
const vec3 Vectors::UNIT_NEG_Y{ 0.0f, -1.0f, 0.0f };
const vec3 Vectors::UNIT_NEG_Z{ 0.0f, 0.0f, -1.0f };
const vec3 Vectors::UNIT_XY{ glm::normalize(UNIT_X + UNIT_Y) };
const vec3 Vectors::UNIT_XZ{ glm::normalize(UNIT_X + UNIT_Z) };
const vec3 Vectors::UNIT_YZ{ glm::normalize(UNIT_Y + UNIT_Z) };
const vec3 Vectors::UNIT_XYZ{ glm::normalize(UNIT_X + UNIT_Y + UNIT_Z) };
const vec3 Vectors::MAX{ FLT_MAX };
const vec3 Vectors::MIN{ -FLT_MAX };
const vec3 Vectors::ZERO{ 0.0f };
const vec3 Vectors::ONE{ 1.0f };
const vec3 Vectors::TWO{ 2.0f };
const vec3 Vectors::HALF{ 0.5f };
const vec3& Vectors::RIGHT = Vectors::UNIT_X;
const vec3& Vectors::UP = Vectors::UNIT_Y;
const vec3& Vectors::FRONT = Vectors::UNIT_NEG_Z;
const quat Quaternions::IDENTITY{ 1.0f, 0.0f, 0.0f, 0.0f };
const quat Quaternions::X_180{ 0.0f, 1.0f, 0.0f, 0.0f };
const quat Quaternions::Y_180{ 0.0f, 0.0f, 1.0f, 0.0f };
const quat Quaternions::Z_180{ 0.0f, 0.0f, 0.0f, 1.0f };
// Safe version of glm::mix; based on the code in Nick Bobick's article,
// http://www.gamasutra.com/features/19980703/quaternions_01.htm (via Clyde,
// https://github.com/threerings/clyde/blob/master/src/main/java/com/threerings/math/Quaternion.java)
glm::quat safeMix(const glm::quat& q1, const glm::quat& q2, float proportion) {
float cosa = q1.x * q2.x + q1.y * q2.y + q1.z * q2.z + q1.w * q2.w;
float ox = q2.x, oy = q2.y, oz = q2.z, ow = q2.w, s0, s1;
// adjust signs if necessary
if (cosa < 0.0f) {
cosa = -cosa;
ox = -ox;
oy = -oy;
oz = -oz;
ow = -ow;
}
// calculate coefficients; if the angle is too close to zero, we must fall back
// to linear interpolation
if ((1.0f - cosa) > EPSILON) {
float angle = acosf(cosa), sina = sinf(angle);
s0 = sinf((1.0f - proportion) * angle) / sina;
s1 = sinf(proportion * angle) / sina;
} else {
s0 = 1.0f - proportion;
s1 = proportion;
}
return glm::normalize(glm::quat(s0 * q1.w + s1 * ow, s0 * q1.x + s1 * ox, s0 * q1.y + s1 * oy, s0 * q1.z + s1 * oz));
}
// Allows sending of fixed-point numbers: radix 1 makes 15.1 number, radix 8 makes 8.8 number, etc
int packFloatScalarToSignedTwoByteFixed(unsigned char* buffer, float scalar, int radix) {
int16_t outVal = (int16_t)(scalar * (float)(1 << radix));
memcpy(buffer, &outVal, sizeof(uint16_t));
return sizeof(uint16_t);
}
int unpackFloatScalarFromSignedTwoByteFixed(const int16_t* byteFixedPointer, float* destinationPointer, int radix) {
*destinationPointer = *byteFixedPointer / (float)(1 << radix);
return sizeof(int16_t);
}
int packFloatVec3ToSignedTwoByteFixed(unsigned char* destBuffer, const glm::vec3& srcVector, int radix) {
const unsigned char* startPosition = destBuffer;
destBuffer += packFloatScalarToSignedTwoByteFixed(destBuffer, srcVector.x, radix);
destBuffer += packFloatScalarToSignedTwoByteFixed(destBuffer, srcVector.y, radix);
destBuffer += packFloatScalarToSignedTwoByteFixed(destBuffer, srcVector.z, radix);
return destBuffer - startPosition;
}
int unpackFloatVec3FromSignedTwoByteFixed(const unsigned char* sourceBuffer, glm::vec3& destination, int radix) {
const unsigned char* startPosition = sourceBuffer;
sourceBuffer += unpackFloatScalarFromSignedTwoByteFixed((int16_t*) sourceBuffer, &(destination.x), radix);
sourceBuffer += unpackFloatScalarFromSignedTwoByteFixed((int16_t*) sourceBuffer, &(destination.y), radix);
sourceBuffer += unpackFloatScalarFromSignedTwoByteFixed((int16_t*) sourceBuffer, &(destination.z), radix);
return sourceBuffer - startPosition;
}
int packFloatAngleToTwoByte(unsigned char* buffer, float degrees) {
const float ANGLE_CONVERSION_RATIO = (std::numeric_limits<uint16_t>::max() / 360.0f);
uint16_t angleHolder = floorf((degrees + 180.0f) * ANGLE_CONVERSION_RATIO);
memcpy(buffer, &angleHolder, sizeof(uint16_t));
return sizeof(uint16_t);
}
int unpackFloatAngleFromTwoByte(const uint16_t* byteAnglePointer, float* destinationPointer) {
*destinationPointer = (*byteAnglePointer / (float) std::numeric_limits<uint16_t>::max()) * 360.0f - 180.0f;
return sizeof(uint16_t);
}
int packOrientationQuatToBytes(unsigned char* buffer, const glm::quat& quatInput) {
glm::quat quatNormalized = glm::normalize(quatInput);
const float QUAT_PART_CONVERSION_RATIO = (std::numeric_limits<uint16_t>::max() / 2.0f);
uint16_t quatParts[4];
quatParts[0] = floorf((quatNormalized.x + 1.0f) * QUAT_PART_CONVERSION_RATIO);
quatParts[1] = floorf((quatNormalized.y + 1.0f) * QUAT_PART_CONVERSION_RATIO);
quatParts[2] = floorf((quatNormalized.z + 1.0f) * QUAT_PART_CONVERSION_RATIO);
quatParts[3] = floorf((quatNormalized.w + 1.0f) * QUAT_PART_CONVERSION_RATIO);
memcpy(buffer, &quatParts, sizeof(quatParts));
return sizeof(quatParts);
}
int unpackOrientationQuatFromBytes(const unsigned char* buffer, glm::quat& quatOutput) {
uint16_t quatParts[4];
memcpy(&quatParts, buffer, sizeof(quatParts));
quatOutput.x = ((quatParts[0] / (float) std::numeric_limits<uint16_t>::max()) * 2.0f) - 1.0f;
quatOutput.y = ((quatParts[1] / (float) std::numeric_limits<uint16_t>::max()) * 2.0f) - 1.0f;
quatOutput.z = ((quatParts[2] / (float) std::numeric_limits<uint16_t>::max()) * 2.0f) - 1.0f;
quatOutput.w = ((quatParts[3] / (float) std::numeric_limits<uint16_t>::max()) * 2.0f) - 1.0f;
return sizeof(quatParts);
}
#define HI_BYTE(x) (uint8_t)(x >> 8)
#define LO_BYTE(x) (uint8_t)(0xff & x)
int packOrientationQuatToSixBytes(unsigned char* buffer, const glm::quat& quatInput) {
// find largest component
uint8_t largestComponent = 0;
for (int i = 1; i < 4; i++) {
if (fabs(quatInput[i]) > fabs(quatInput[largestComponent])) {
largestComponent = i;
}
}
// ensure that the sign of the dropped component is always negative.
glm::quat q = quatInput[largestComponent] > 0 ? -quatInput : quatInput;
const float MAGNITUDE = 1.0f / sqrtf(2.0f);
const uint32_t NUM_BITS_PER_COMPONENT = 15;
const uint32_t RANGE = (1 << NUM_BITS_PER_COMPONENT) - 1;
// quantize the smallest three components into integers
uint16_t components[3];
for (int i = 0, j = 0; i < 4; i++) {
if (i != largestComponent) {
// transform component into 0..1 range.
float value = (q[i] + MAGNITUDE) / (2.0f * MAGNITUDE);
// quantize 0..1 into 0..range
components[j] = (uint16_t)(value * RANGE);
j++;
}
}
// encode the largestComponent into the high bits of the first two components
components[0] = (0x7fff & components[0]) | ((0x01 & largestComponent) << 15);
components[1] = (0x7fff & components[1]) | ((0x02 & largestComponent) << 14);
buffer[0] = HI_BYTE(components[0]);
buffer[1] = LO_BYTE(components[0]);
buffer[2] = HI_BYTE(components[1]);
buffer[3] = LO_BYTE(components[1]);
buffer[4] = HI_BYTE(components[2]);
buffer[5] = LO_BYTE(components[2]);
return 6;
}
int unpackOrientationQuatFromSixBytes(const unsigned char* buffer, glm::quat& quatOutput) {
uint16_t components[3];
components[0] = ((uint16_t)(0x7f & buffer[0]) << 8) | buffer[1];
components[1] = ((uint16_t)(0x7f & buffer[2]) << 8) | buffer[3];
components[2] = ((uint16_t)(0x7f & buffer[4]) << 8) | buffer[5];
// largestComponent is encoded into the highest bits of the first 2 components
uint8_t largestComponent = ((0x80 & buffer[2]) >> 6) | ((0x80 & buffer[0]) >> 7);
const uint32_t NUM_BITS_PER_COMPONENT = 15;
const float RANGE = (float)((1 << NUM_BITS_PER_COMPONENT) - 1);
const float MAGNITUDE = 1.0f / sqrtf(2.0f);
float floatComponents[3];
for (int i = 0; i < 3; i++) {
floatComponents[i] = ((float)components[i] / RANGE) * (2.0f * MAGNITUDE) - MAGNITUDE;
}
// missingComponent is always negative.
float missingComponent = -sqrtf(1.0f - floatComponents[0] * floatComponents[0] - floatComponents[1] * floatComponents[1] - floatComponents[2] * floatComponents[2]);
for (int i = 0, j = 0; i < 4; i++) {
if (i != largestComponent) {
quatOutput[i] = floatComponents[j];
j++;
} else {
quatOutput[i] = missingComponent;
}
}
return 6;
}
// Safe version of glm::eulerAngles; uses the factorization method described in David Eberly's
// http://www.geometrictools.com/Documentation/EulerAngles.pdf (via Clyde,
// https://github.com/threerings/clyde/blob/master/src/main/java/com/threerings/math/Quaternion.java)
glm::vec3 safeEulerAngles(const glm::quat& q) {
float sy = 2.0f * (q.y * q.w - q.x * q.z);
glm::vec3 eulers;
if (sy < 1.0f - EPSILON) {
if (sy > -1.0f + EPSILON) {
eulers = glm::vec3(
atan2f(q.y * q.z + q.x * q.w, 0.5f - (q.x * q.x + q.y * q.y)),
asinf(sy),
atan2f(q.x * q.y + q.z * q.w, 0.5f - (q.y * q.y + q.z * q.z)));
} else {
// not a unique solution; x + z = atan2(-m21, m11)
eulers = glm::vec3(
0.0f,
- PI_OVER_TWO,
atan2f(q.x * q.w - q.y * q.z, 0.5f - (q.x * q.x + q.z * q.z)));
}
} else {
// not a unique solution; x - z = atan2(-m21, m11)
eulers = glm::vec3(
0.0f,
PI_OVER_TWO,
-atan2f(q.x * q.w - q.y * q.z, 0.5f - (q.x * q.x + q.z * q.z)));
}
// adjust so that z, rather than y, is in [-pi/2, pi/2]
if (eulers.z < -PI_OVER_TWO) {
if (eulers.x < 0.0f) {
eulers.x += PI;
} else {
eulers.x -= PI;
}
eulers.y = -eulers.y;
if (eulers.y < 0.0f) {
eulers.y += PI;
} else {
eulers.y -= PI;
}
eulers.z += PI;
} else if (eulers.z > PI_OVER_TWO) {
if (eulers.x < 0.0f) {
eulers.x += PI;
} else {
eulers.x -= PI;
}
eulers.y = -eulers.y;
if (eulers.y < 0.0f) {
eulers.y += PI;
} else {
eulers.y -= PI;
}
eulers.z -= PI;
}
return eulers;
}
// Helper function returns the positive angle (in radians) between two 3D vectors
float angleBetween(const glm::vec3& v1, const glm::vec3& v2) {
return acosf((glm::dot(v1, v2)) / (glm::length(v1) * glm::length(v2)));
}
// Helper function return the rotation from the first vector onto the second
glm::quat rotationBetween(const glm::vec3& v1, const glm::vec3& v2) {
return glm::rotation(glm::normalize(v1), glm::normalize(v2));
}
bool isPointBehindTrianglesPlane(glm::vec3 point, glm::vec3 p0, glm::vec3 p1, glm::vec3 p2) {
glm::vec3 v1 = p0 - p1, v2 = p2 - p1; // Non-collinear vectors contained in the plane
glm::vec3 n = glm::cross(v1, v2); // Plane's normal vector, pointing out of the triangle
float d = -glm::dot(n, p0); // Compute plane's equation constant
return (glm::dot(n, point) + d) >= 0;
}
glm::vec3 extractTranslation(const glm::mat4& matrix) {
return glm::vec3(matrix[3][0], matrix[3][1], matrix[3][2]);
}
void setTranslation(glm::mat4& matrix, const glm::vec3& translation) {
matrix[3][0] = translation.x;
matrix[3][1] = translation.y;
matrix[3][2] = translation.z;
}
glm::quat extractRotation(const glm::mat4& matrix, bool assumeOrthogonal) {
// uses the iterative polar decomposition algorithm described by Ken Shoemake at
// http://www.cs.wisc.edu/graphics/Courses/838-s2002/Papers/polar-decomp.pdf
// code adapted from Clyde, https://github.com/threerings/clyde/blob/master/core/src/main/java/com/threerings/math/Matrix4f.java
// start with the contents of the upper 3x3 portion of the matrix
glm::mat3 upper = glm::mat3(matrix);
if (!assumeOrthogonal) {
for (int i = 0; i < 10; i++) {
// store the results of the previous iteration
glm::mat3 previous = upper;
// compute average of the matrix with its inverse transpose
float sd00 = previous[1][1] * previous[2][2] - previous[2][1] * previous[1][2];
float sd10 = previous[0][1] * previous[2][2] - previous[2][1] * previous[0][2];
float sd20 = previous[0][1] * previous[1][2] - previous[1][1] * previous[0][2];
float det = previous[0][0] * sd00 + previous[2][0] * sd20 - previous[1][0] * sd10;
if (fabsf(det) == 0.0f) {
// determinant is zero; matrix is not invertible
break;
}
float hrdet = 0.5f / det;
upper[0][0] = +sd00 * hrdet + previous[0][0] * 0.5f;
upper[1][0] = -sd10 * hrdet + previous[1][0] * 0.5f;
upper[2][0] = +sd20 * hrdet + previous[2][0] * 0.5f;
upper[0][1] = -(previous[1][0] * previous[2][2] - previous[2][0] * previous[1][2]) * hrdet + previous[0][1] * 0.5f;
upper[1][1] = +(previous[0][0] * previous[2][2] - previous[2][0] * previous[0][2]) * hrdet + previous[1][1] * 0.5f;
upper[2][1] = -(previous[0][0] * previous[1][2] - previous[1][0] * previous[0][2]) * hrdet + previous[2][1] * 0.5f;
upper[0][2] = +(previous[1][0] * previous[2][1] - previous[2][0] * previous[1][1]) * hrdet + previous[0][2] * 0.5f;
upper[1][2] = -(previous[0][0] * previous[2][1] - previous[2][0] * previous[0][1]) * hrdet + previous[1][2] * 0.5f;
upper[2][2] = +(previous[0][0] * previous[1][1] - previous[1][0] * previous[0][1]) * hrdet + previous[2][2] * 0.5f;
// compute the difference; if it's small enough, we're done
glm::mat3 diff = upper - previous;
if (diff[0][0] * diff[0][0] + diff[1][0] * diff[1][0] + diff[2][0] * diff[2][0] + diff[0][1] * diff[0][1] +
diff[1][1] * diff[1][1] + diff[2][1] * diff[2][1] + diff[0][2] * diff[0][2] + diff[1][2] * diff[1][2] +
diff[2][2] * diff[2][2] < EPSILON) {
break;
}
}
}
// now that we have a nice orthogonal matrix, we can extract the rotation quaternion
// using the method described in http://en.wikipedia.org/wiki/Rotation_matrix#Conversions
float x2 = fabs(1.0f + upper[0][0] - upper[1][1] - upper[2][2]);
float y2 = fabs(1.0f - upper[0][0] + upper[1][1] - upper[2][2]);
float z2 = fabs(1.0f - upper[0][0] - upper[1][1] + upper[2][2]);
float w2 = fabs(1.0f + upper[0][0] + upper[1][1] + upper[2][2]);
return glm::normalize(glm::quat(0.5f * sqrtf(w2),
0.5f * sqrtf(x2) * (upper[1][2] >= upper[2][1] ? 1.0f : -1.0f),
0.5f * sqrtf(y2) * (upper[2][0] >= upper[0][2] ? 1.0f : -1.0f),
0.5f * sqrtf(z2) * (upper[0][1] >= upper[1][0] ? 1.0f : -1.0f)));
}
glm::quat glmExtractRotation(const glm::mat4& matrix) {
glm::vec3 scale = extractScale(matrix);
// quat_cast doesn't work so well with scaled matrices, so cancel it out.
glm::mat4 tmp = glm::scale(matrix, 1.0f / scale);
return glm::normalize(glm::quat_cast(tmp));
}
glm::vec3 extractScale(const glm::mat4& matrix) {
glm::mat3 m(matrix);
float det = glm::determinant(m);
if (det < 0) {
// left handed matrix, flip sign to compensate.
return glm::vec3(-glm::length(m[0]), glm::length(m[1]), glm::length(m[2]));
} else {
return glm::vec3(glm::length(m[0]), glm::length(m[1]), glm::length(m[2]));
}
}
float extractUniformScale(const glm::mat4& matrix) {
return extractUniformScale(extractScale(matrix));
}
float extractUniformScale(const glm::vec3& scale) {
return (scale.x + scale.y + scale.z) / 3.0f;
}
QByteArray createByteArray(const glm::vec3& vector) {
return QByteArray::number(vector.x) + ',' + QByteArray::number(vector.y) + ',' + QByteArray::number(vector.z);
}
QByteArray createByteArray(const glm::quat& quat) {
return QByteArray::number(quat.x) + ',' + QByteArray::number(quat.y) + "," + QByteArray::number(quat.z) + ","
+ QByteArray::number(quat.w);
}
bool isSimilarOrientation(const glm::quat& orientionA, const glm::quat& orientionB, float similarEnough) {
// Compute the angular distance between the two orientations
float angleOrientation = orientionA == orientionB ? 0.0f : glm::degrees(glm::angle(orientionA * glm::inverse(orientionB)));
if (isNaN(angleOrientation)) {
angleOrientation = 0.0f;
}
return (angleOrientation <= similarEnough);
}
bool isSimilarPosition(const glm::vec3& positionA, const glm::vec3& positionB, float similarEnough) {
// Compute the distance between the two points
float positionDistance = glm::distance(positionA, positionB);
return (positionDistance <= similarEnough);
}
glm::uvec2 toGlm(const QSize& size) {
return glm::uvec2(size.width(), size.height());
}
glm::ivec2 toGlm(const QPoint& pt) {
return glm::ivec2(pt.x(), pt.y());
}
glm::vec2 toGlm(const QPointF& pt) {
return glm::vec2(pt.x(), pt.y());
}
glm::vec3 toGlm(const xColor& color) {
static const float MAX_COLOR = 255.0f;
return glm::vec3(color.red, color.green, color.blue) / MAX_COLOR;
}
glm::vec4 toGlm(const QColor& color) {
return glm::vec4(color.redF(), color.greenF(), color.blueF(), color.alphaF());
}
ivec4 toGlm(const QRect& rect) {
return ivec4(rect.x(), rect.y(), rect.width(), rect.height());
}
QMatrix4x4 fromGlm(const glm::mat4 & m) {
return QMatrix4x4(&m[0][0]).transposed();
}
QSize fromGlm(const glm::ivec2 & v) {
return QSize(v.x, v.y);
}
vec4 toGlm(const xColor& color, float alpha) {
return vec4((float)color.red / 255.0f, (float)color.green / 255.0f, (float)color.blue / 255.0f, alpha);
}
QRectF glmToRect(const glm::vec2 & pos, const glm::vec2 & size) {
QRectF result(pos.x, pos.y, size.x, size.y);
return result;
}
// create matrix from orientation and position
glm::mat4 createMatFromQuatAndPos(const glm::quat& q, const glm::vec3& p) {
glm::mat4 m = glm::mat4_cast(q);
m[3] = glm::vec4(p, 1.0f);
return m;
}
// create matrix from a non-uniform scale, orientation and position
glm::mat4 createMatFromScaleQuatAndPos(const glm::vec3& scale, const glm::quat& rot, const glm::vec3& trans) {
glm::vec3 xAxis = rot * glm::vec3(scale.x, 0.0f, 0.0f);
glm::vec3 yAxis = rot * glm::vec3(0.0f, scale.y, 0.0f);
glm::vec3 zAxis = rot * glm::vec3(0.0f, 0.0f, scale.z);
return glm::mat4(glm::vec4(xAxis, 0.0f), glm::vec4(yAxis, 0.0f),
glm::vec4(zAxis, 0.0f), glm::vec4(trans, 1.0f));
}
// cancel out roll
glm::quat cancelOutRoll(const glm::quat& q) {
glm::vec3 forward = q * Vectors::FRONT;
return glm::quat_cast(glm::inverse(glm::lookAt(Vectors::ZERO, forward, Vectors::UP)));
}
// cancel out roll and pitch
glm::quat cancelOutRollAndPitch(const glm::quat& q) {
glm::vec3 zAxis = q * glm::vec3(0.0f, 0.0f, 1.0f);
// cancel out the roll and pitch
glm::vec3 newZ = (zAxis.x == 0 && zAxis.z == 0.0f) ? vec3(1.0f, 0.0f, 0.0f) : glm::normalize(vec3(zAxis.x, 0.0f, zAxis.z));
glm::vec3 newX = glm::cross(vec3(0.0f, 1.0f, 0.0f), newZ);
glm::vec3 newY = glm::cross(newZ, newX);
glm::mat4 temp(glm::vec4(newX, 0.0f), glm::vec4(newY, 0.0f), glm::vec4(newZ, 0.0f), glm::vec4(0.0f, 0.0f, 0.0f, 1.0f));
return glm::quat_cast(temp);
}
// cancel out roll and pitch
glm::mat4 cancelOutRollAndPitch(const glm::mat4& m) {
glm::vec3 zAxis = glm::vec3(m[2]);
// cancel out the roll and pitch
glm::vec3 newZ = (zAxis.x == 0.0f && zAxis.z == 0.0f) ? vec3(1.0f, 0.0f, 0.0f) : glm::normalize(vec3(zAxis.x, 0.0f, zAxis.z));
glm::vec3 newX = glm::cross(vec3(0.0f, 1.0f, 0.0f), newZ);
glm::vec3 newY = glm::cross(newZ, newX);
glm::mat4 temp(glm::vec4(newX, 0.0f), glm::vec4(newY, 0.0f), glm::vec4(newZ, 0.0f), m[3]);
return temp;
}
glm::vec3 transformPoint(const glm::mat4& m, const glm::vec3& p) {
glm::vec4 temp = m * glm::vec4(p, 1.0f);
return glm::vec3(temp.x / temp.w, temp.y / temp.w, temp.z / temp.w);
}
// does not handle non-uniform scale correctly, but it's faster then transformVectorFull
glm::vec3 transformVectorFast(const glm::mat4& m, const glm::vec3& v) {
glm::mat3 rot(m);
return rot * v;
}
// handles non-uniform scale.
glm::vec3 transformVectorFull(const glm::mat4& m, const glm::vec3& v) {
glm::mat3 rot(m);
return glm::inverse(glm::transpose(rot)) * v;
}
void generateBasisVectors(const glm::vec3& primaryAxis, const glm::vec3& secondaryAxis,
glm::vec3& uAxisOut, glm::vec3& vAxisOut, glm::vec3& wAxisOut) {
// primaryAxis & secondaryAxis must not be zero.
#ifndef NDEBUG
const float MIN_LENGTH_SQUARED = 1.0e-6f;
#endif
assert(glm::length2(primaryAxis) > MIN_LENGTH_SQUARED);
assert(glm::length2(secondaryAxis) > MIN_LENGTH_SQUARED);
uAxisOut = glm::normalize(primaryAxis);
glm::vec3 normSecondary = glm::normalize(secondaryAxis);
// if secondaryAxis is parallel with the primaryAxis, pick another axis.
const float EPSILON = 1.0e-4f;
if (fabsf(fabsf(glm::dot(uAxisOut, secondaryAxis)) - 1.0f) > EPSILON) {
// pick a better secondaryAxis.
normSecondary = glm::vec3(1.0f, 0.0f, 0.0f);
if (fabsf(fabsf(glm::dot(uAxisOut, secondaryAxis)) - 1.0f) > EPSILON) {
normSecondary = glm::vec3(0.0f, 1.0f, 0.0f);
}
}
wAxisOut = glm::normalize(glm::cross(uAxisOut, secondaryAxis));
vAxisOut = glm::cross(wAxisOut, uAxisOut);
}
glm::vec2 getFacingDir2D(const glm::quat& rot) {
glm::vec3 facing3D = rot * Vectors::UNIT_NEG_Z;
glm::vec2 facing2D(facing3D.x, facing3D.z);
const float ALMOST_ZERO = 0.0001f;
if (glm::length(facing2D) < ALMOST_ZERO) {
return glm::vec2(1.0f, 0.0f);
} else {
return glm::normalize(facing2D);
}
}
glm::vec2 getFacingDir2D(const glm::mat4& m) {
glm::vec3 facing3D = transformVectorFast(m, Vectors::UNIT_NEG_Z);
glm::vec2 facing2D(facing3D.x, facing3D.z);
const float ALMOST_ZERO = 0.0001f;
if (glm::length(facing2D) < ALMOST_ZERO) {
return glm::vec2(1.0f, 0.0f);
} else {
return glm::normalize(facing2D);
}
}
glm::mat4 orthoInverse(const glm::mat4& m) {
glm::mat4 r = m;
r[3] = glm::vec4(0.0f, 0.0f, 0.0f, 1.0f);
r = glm::transpose(r);
r[3] = -(r * m[3]);
r[3][3] = 1.0f;
return r;
}