glm/readme.md

![glm](doc/logo.png)

[OpenGL Mathematics](http://glm.g-truc.net/) (*GLM*) is a header only C++ mathematics library for graphics software based on the [OpenGL Shading Language (GLSL) specifications](https://www.opengl.org/registry/doc/GLSLangSpec.4.50.diff.pdf).

*GLM* provides classes and functions designed and implemented with the same naming conventions and functionalities than *GLSL* so that anyone who knows *GLSL*, can use *GLM* as well in C++.

This project isn't limited to *GLSL* features. An extension system, based on the *GLSL* extension conventions, provides extended capabilities: matrix transformations, quaternions, data packing, random numbers, noise, etc...

This library works perfectly with *[OpenGL](https://www.opengl.org)* but it also ensures interoperability with other third party libraries and SDK. It is a good candidate for software rendering (raytracing / rasterisation), image processing, physic simulations and any development context that requires a simple and convenient mathematics library.

*GLM* is written in C++98 but can take advantage of C++11 when supported by the compiler. It is a platform independent library with no dependence and it officially supports the following compilers:
- [Apple Clang 4.0](https://developer.apple.com/library/mac/documentation/CompilerTools/Conceptual/LLVMCompilerOverview/index.html) and higher
- [GCC](http://gcc.gnu.org/) 4.2 and higher
- [Intel C++ Composer](https://software.intel.com/en-us/intel-compilers) XE 2013 and higher
- [LLVM](http://llvm.org/) 3.0 and higher
- [Visual C++](http://www.visualstudio.com/) 2010 and higher
- [CUDA](https://developer.nvidia.com/about-cuda) 4.0 and higher (experimental)
- Any conform C++98 or C++11 compiler

For more information about *GLM*, please have a look at the [manual](http://glm.g-truc.net/0.9.7/glm-0.9.7.pdf) and the [API reference documentation](http://glm.g-truc.net/0.9.7/api/index.html).
The source code and the documentation are licensed under the [Happy Bunny License (Modified MIT) or the MIT License](./copying.txt).

Thanks for contributing to the project by [submitting issues](https://github.com/g-truc/glm/issues) for bug reports and feature requests. Any feedback is welcome at [glm@g-truc.net](mailto://glm@g-truc.net).


```c++
#include <glm/vec3.hpp> // glm::vec3
#include <glm/vec4.hpp> // glm::vec4
#include <glm/mat4x4.hpp> // glm::mat4
#include <glm/gtc/matrix_transform.hpp> // glm::translate, glm::rotate, glm::scale, glm::perspective
#include <glm/gtc/constants.hpp> // glm::pi

glm::mat4 camera(float Translate, glm::vec2 const & Rotate)
{
	glm::mat4 Projection = glm::perspective(glm::pi<float>() * 0.25f, 4.0f / 3.0f, 0.1f, 100.f);
	glm::mat4 View = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, -Translate));
	View = glm::rotate(View, Rotate.y, glm::vec3(-1.0f, 0.0f, 0.0f));
	View = glm::rotate(View, Rotate.x, glm::vec3(0.0f, 1.0f, 0.0f));
	glm::mat4 Model = glm::scale(glm::mat4(1.0f), glm::vec3(0.5f));
	return Projection * View * Model;
}
```

## Project Health

| Service | System | Compiler | Status |
| ------- | ------ | -------- | ------ |
| [Drone](https://drone.io/github.com/g-truc/glm) | Linux 64 bits | GCC 4.6.3 | [![Build Status](https://drone.io/github.com/g-truc/glm/status.png)](https://drone.io/github.com/g-truc/glm/latest) |

## [Lastest release](https://github.com/g-truc/glm/releases/latest)

## Release notes

#### [GLM 0.9.7.2](https://github.com/g-truc/glm/tree/0.9.7) - 2015-XX-XX
##### Fixes:
- Fixed GTC_round floorMultiple/ceilMultiple #412
- Fixed GTC_packing unpackUnorm3x10_1x2 #414
- Fixed GTC_matrix_inverse affineInverse #192
- Fixed Cygwin build errors when using C++11 #405

#### [GLM 0.9.7.1](https://github.com/g-truc/glm/releases/tag/0.9.7.1) - 2015-09-07
##### Improvements:
- Improved constexpr for constant functions coverage #198
- Added to_string for quat and dual_quat in GTX_string_cast #375
- Improved overall execution time of unit tests #396

##### Fixes:
- Fixed strict alignment warnings #235 #370
- Fixed link errors on compilers not supported default function #377
- Fixed compilation warnings in vec4
- Fixed non-identity quaternions for equal vectors #234
- Fixed excessive GTX_fast_trigonometry execution time #396
- Fixed Visual Studio 2015 'hides class member' warnings #394
- Fixed builtin bitscan never being used #392
- Removed unused func_noise.* files #398

#### [GLM 0.9.7.0](https://github.com/g-truc/glm/releases/tag/0.9.7.0) - 2015-08-02
##### Features:
- Added GTC_color_space: convertLinearToSRGB and convertSRGBToLinear functions
- Added 'fmod' overload to GTX_common with tests #308
- Left handed perspective and lookAt functions #314
- Added functions eulerAngleXYZ and extractEulerAngleXYZ #311
- Added <glm/gtx/hash.hpp> to perform std::hash on GLM types #320 #367
- Added <glm/gtx/wrap.hpp> for texcoord wrapping
- Added static components and precision members to all vector and quat types #350
- Added .gitignore #349
- Added support of defaulted functions to GLM types, to use them in unions #366

##### Improvements:
- Changed usage of __has_include to support Intel compiler #307
- Specialized integer implementation of YCoCg-R #310
- Don't show status message in 'FindGLM' if 'QUIET' option is set. #317
- Added master branch continuous integration service on Linux 64 #332
- Clarified manual regarding angle unit in GLM, added FAQ 11 #326
- Updated list of compiler versions

##### Fixes:
- Fixed default precision for quat and dual_quat type #312
- Fixed (u)int64 MSB/LSB handling on BE archs #306
- Fixed multi-line comment warning in g++. #315
- Fixed specifier removal by 'std::make_pair<>' #333
- Fixed perspective fovy argument documentation #327
- Removed -m64 causing build issues on Linux 32 #331
- Fixed isfinite with C++98 compilers #343
- Fixed Intel compiler build error on Linux #354
- Fixed use of libstdc++ with Clang #351
- Fixed quaternion pow #346
- Fixed decompose warnings #373
- Fixed matrix conversions #371

##### Deprecation:
- Removed integer specification for 'mod' in GTC_integer #308
- Removed GTX_multiple, replaced by GTC_round

--------------------------------------------------------------------------------
#### [GLM 0.9.6.3](https://github.com/g-truc/glm/releases/tag/0.9.6.3) - 2015-02-15
- Fixed Android doesn't have C++ 11 STL #284

--------------------------------------------------------------------------------
#### [GLM 0.9.6.2](https://github.com/g-truc/glm/releases/tag/0.9.6.2) - 2015-02-15
##### Features:
- Added display of GLM version with other GLM_MESSAGES
- Added ARM instruction set detection

--------------------------------------------------------------------------------
##### Improvements:
- Removed assert for perspective with zFar < zNear #298
- Added Visual Studio natvis support for vec1, quat and dualqual types
- Cleaned up C++11 feature detections
- Clarify GLM licensing

##### Fixes:
- Fixed faceforward build #289
- Fixed conflict with Xlib #define True 1 #293
- Fixed decompose function VS2010 templating issues #294
- Fixed mat4x3 = mat2x3 * mat4x2 operator #297
- Fixed warnings in F2x11_1x10 packing function in GTC_packing #295
- Fixed Visual Studio natvis support for vec4 #288
- Fixed GTC_packing *pack*norm*x* build and added tests #292
- Disabled GTX_scalar_multiplication for GCC, failing to build tests #242
- Fixed Visual C++ 2015 constexpr errors: Disabled only partial support
- Fixed functions not inlined with Clang #302
- Fixed memory corruption (undefined behaviour) #303

--------------------------------------------------------------------------------
#### [GLM 0.9.6.1](https://github.com/g-truc/glm/releases/tag/0.9.6.1) - 2014-12-10
##### Features:
- Added GLM_LANG_CXX14_FLAG and GLM_LANG_CXX1Z_FLAG language feature flags
- Added C++14 detection

##### Improvements:
- Clean up GLM_MESSAGES compilation log to report only detected capabilities

##### Fixes:
- Fixed scalar uaddCarry build error with Cuda #276
- Fixed C++11 explicit conversion operators detection #282
- Fixed missing explicit convertion when using integer log2 with *vec1 types
- Fixed 64 bits integer GTX_string_cast to_string on VC 32 bit compiler
- Fixed Android build issue, STL C++11 is not supported by the NDK #284
- Fixed unsupported _BitScanForward64 and _BitScanReverse64 in VC10
- Fixed Visual C++ 32 bit build #283
- Fixed GLM_FORCE_SIZE_FUNC pragma message
- Fixed C++98 only build
- Fixed conflict between GTX_compatibility and GTC_quaternion #286
- Fixed C++ language restriction using GLM_FORCE_CXX**

--------------------------------------------------------------------------------
#### [GLM 0.9.6.0](https://github.com/g-truc/glm/releases/tag/0.9.6.0) - 2014-11-30
##### Features:
- Exposed template vector and matrix types in 'glm' namespace #239, #244
- Added GTX_scalar_multiplication for C++ 11 compiler only #242
- Added GTX_range for C++ 11 compiler only #240
- Added closestPointOnLine function for tvec2 to GTX_closest_point #238
- Added GTC_vec1 extension, *vec1 support to *vec* types
- Updated GTX_associated_min_max with vec1 support
- Added support of precision and integers to linearRand #230
- Added Integer types support to GTX_string_cast #249
- Added vec3 slerp #237
- Added GTX_common with isdenomal #223
- Added GLM_FORCE_SIZE_FUNC to replace .length() by .size() #245
- Added GLM_FORCE_NO_CTOR_INIT
- Added 'uninitialize' to explicitly not initialize a GLM type
- Added GTC_bitfield extension, promoted GTX_bit
- Added GTC_integer extension, promoted GTX_bit and GTX_integer
- Added GTC_round extension, promoted GTX_bit
- Added GLM_FORCE_EXPLICIT_CTOR to require explicit type conversions #269
- Added GTX_type_aligned for aligned vector, matrix and quaternion types

##### Improvements:
- Rely on C++11 to implement isinf and isnan
- Removed GLM_FORCE_CUDA, Cuda is implicitly detected
- Separated Apple Clang and LLVM compiler detection
- Used pragma once
- Undetected C++ compiler automatically compile with GLM_FORCE_CXX98 and 
  GLM_FORCE_PURE
- Added not function (from GLSL specification) on VC12
- Optimized bitfieldReverse and bitCount functions
- Optimized findLSB and findMSB functions.
- Optimized matrix-vector multiple performance with Cuda #257, #258
- Reduced integer type redifinitions #233
- Rewrited of GTX_fast_trigonometry #264 #265
- Made types trivially copyable #263
- Removed <iostream> in GLM tests
- Used std features within GLM without redeclaring
- Optimized cot function #272
- Optimized sign function #272
- Added explicit cast from quat to mat3 and mat4 #275

##### Fixes:
- Fixed std::nextafter not supported with C++11 on Android #217
- Fixed missing value_type for dual quaternion
- Fixed return type of dual quaternion length
- Fixed infinite loop in isfinite function with GCC #221
- Fixed Visual Studio 14 compiler warnings
- Fixed implicit conversion from another tvec2 type to another tvec2 #241
- Fixed lack of consistency of quat and dualquat constructors
- Fixed uaddCarray #253
- Fixed float comparison warnings #270

##### Deprecation:
- Removed degrees for function parameters
- Removed GLM_FORCE_RADIANS, active by default
- Removed VC 2005 / 8 and 2008 / 9 support
- Removed GCC 3.4 to 4.3 support
- Removed LLVM GCC support
- Removed LLVM 2.6 to 3.1 support
- Removed CUDA 3.0 to 3.2 support

--------------------------------------------------------------------------------
#### [GLM 0.9.5.4 - 2014-06-21](https://github.com/g-truc/glm/releases/tag/0.9.5.4)
- Fixed non-utf8 character #196
- Added FindGLM install for CMake #189
- Fixed GTX_color_space - saturation #195
- Fixed glm::isinf and glm::isnan for with Android NDK 9d #191
- Fixed builtin GLM_ARCH_SSE4 #204
- Optimized Quaternion vector rotation #205
- Fixed missing doxygen @endcond tag #211
- Fixed instruction set detection with Clang #158
- Fixed orientate3 function #207
- Fixed lerp when cosTheta is close to 1 in quaternion slerp #210
- Added GTX_io for io with <iostream> #144
- Fixed fastDistance ambiguity #215
- Fixed tweakedInfinitePerspective #208 and added user-defined epsilon to
  tweakedInfinitePerspective
- Fixed std::copy and std::vector with GLM types #214
- Fixed strict aliasing issues #212, #152
- Fixed std::nextafter not supported with C++11 on Android #213
- Fixed corner cases in exp and log functions for quaternions #199

--------------------------------------------------------------------------------
#### GLM 0.9.5.3 - 2014-04-02
- Added instruction set auto detection with Visual C++ using _M_IX86_FP - /arch
  compiler argument
- Fixed GTX_raw_data code dependency
- Fixed GCC instruction set detection
- Added GLM_GTX_matrix_transform_2d extension (#178, #176)
- Fixed CUDA issues (#169, #168, #183, #182)
- Added support for all extensions but GTX_string_cast to CUDA
- Fixed strict aliasing warnings in GCC 4.8.1 / Android NDK 9c (#152)
- Fixed missing bitfieldInterleave definisions
- Fixed usubBorrow (#171)
- Fixed eulerAngle*** not consistent for right-handed coordinate system (#173)
- Added full tests for eulerAngle*** functions (#173)
- Added workaround for a CUDA compiler bug (#186, #185)

--------------------------------------------------------------------------------
#### GLM 0.9.5.2 - 2014-02-08
- Fixed initializer list ambiguity (#159, #160)
- Fixed warnings with the Android NDK 9c
- Fixed non power of two matrix products
- Fixed mix function link error
- Fixed SSE code included in GLM tests on "pure" platforms
- Fixed undefined reference to fastInverseSqrt (#161)
- Fixed GLM_FORCE_RADIANS with <glm/ext.hpp> build error (#165)
- Fix dot product clamp range for vector angle functions. (#163)
- Tentative fix for strict aliasing warning in GCC 4.8.1 / Android NDK 9c (#152)
- Fixed GLM_GTC_constants description brief (#162)

--------------------------------------------------------------------------------
#### GLM 0.9.5.1 - 2014-01-11
- Fixed angle and orientedAngle that sometimes return NaN values (#145)
- Deprecated degrees for function parameters and display a message
- Added possible static_cast conversion of GLM types (#72)
- Fixed error 'inverse' is not a member of 'glm' from glm::unProject (#146)
- Fixed mismatch between some declarations and definitions
- Fixed inverse link error when using namespace glm; (#147)
- Optimized matrix inverse and division code (#149)
- Added intersectRayPlane function (#153)
- Fixed outerProduct return type (#155)

--------------------------------------------------------------------------------
#### GLM 0.9.5.0 - 2013-12-25
- Added forward declarations (glm/fwd.hpp) for faster compilations
- Added per feature headers
- Minimized GLM internal dependencies
- Improved Intel Compiler detection
- Added bitfieldInterleave and _mm_bit_interleave_si128 functions
- Added GTX_scalar_relational
- Added GTX_dual_quaternion
- Added rotation function to GTX_quaternion (#22)
- Added precision variation of each type
- Added quaternion comparison functions
- Fixed GTX_multiple for negative value
- Removed GTX_ocl_type extension
- Fixed post increment and decrement operators
- Fixed perspective with zNear == 0 (#71)
- Removed l-value swizzle operators
- Cleaned up compiler detection code for unsupported compilers
- Replaced C cast by C++ casts
- Fixed .length() that should return a int and not a size_t
- Added GLM_FORCE_SIZE_T_LENGTH and glm::length_t
- Removed unnecessary conversions
- Optimized packing and unpacking functions
- Removed the normalization of the up argument of lookAt function (#114)
- Added low precision specializations of inversesqrt
- Fixed ldexp and frexp implementations
- Increased assert coverage
- Increased static_assert coverage
- Replaced GLM traits by STL traits when possible
- Allowed including individual core feature
- Increased unit tests completness
- Added creating of a quaternion from two vectors
- Added C++11 initializer lists
- Fixed umulExtended and imulExtended implementations for vector types (#76)
- Fixed CUDA coverage for GTC extensions
- Added GTX_io extension
- Improved GLM messages enabled when defining GLM_MESSAGES
- Hidden matrix _inverse function implementation detail into private section

--------------------------------------------------------------------------------
#### [GLM 0.9.4.6](https://github.com/g-truc/glm/releases/tag/0.9.4.6) - 2013-09-20
- Fixed detection to select the last known compiler if newer version #106
- Fixed is_int and is_uint code duplication with GCC and C++11 #107 
- Fixed test suite build while using Clang in C++11 mode
- Added c++1y mode support in CMake test suite
- Removed ms extension mode to CMake when no using Visual C++
- Added pedantic mode to CMake test suite for Clang and GCC
- Added use of GCC frontend on Unix for ICC and Visual C++ fronted on Windows
  for ICC
- Added compilation errors for unsupported compiler versions
- Fixed glm::orientation with GLM_FORCE_RADIANS defined #112
- Fixed const ref issue on assignment operator taking a scalar parameter #116
- Fixed glm::eulerAngleY implementation #117

--------------------------------------------------------------------------------
#### GLM 0.9.4.5 - 2013-08-12
- Fixed CUDA support
- Fixed inclusion of intrinsics in "pure" mode #92
- Fixed language detection on GCC when the C++0x mode isn't enabled #95
- Fixed issue #97: register is deprecated in C++11
- Fixed issue #96: CUDA issues
- Added Windows CE detection #92
- Added missing value_ptr for quaternions #99

--------------------------------------------------------------------------------
#### GLM 0.9.4.4 - 2013-05-29
- Fixed slerp when costheta is close to 1 #65
- Fixed mat4x2 value_type constructor #70
- Fixed glm.natvis for Visual C++ 12 #82
- Added assert in inversesqrt to detect division by zero #61
- Fixed missing swizzle operators #86
- Fixed CUDA warnings #86
- Fixed GLM natvis for VC11 #82
- Fixed GLM_GTX_multiple with negative values #79
- Fixed glm::perspective when zNear is zero #71

--------------------------------------------------------------------------------
#### GLM 0.9.4.3 - 2013-03-20
- Detected qualifier for Clang
- Fixed C++11 mode for GCC, couldn't be enabled without MS extensions
- Fixed squad, intermediate and exp quaternion functions
- Fixed GTX_polar_coordinates euclidean function, takes a vec2 instead of a vec3
- Clarify the license applying on the manual
- Added a docx copy of the manual
- Fixed GLM_GTX_matrix_interpolation
- Fixed isnan and isinf on Android with Clang
- Autodetected C++ version using __cplusplus value
- Fixed mix for bool and bvec* third parameter

--------------------------------------------------------------------------------
#### GLM 0.9.4.2 - 2013-02-14
- Fixed compAdd from GTX_component_wise
- Fixed SIMD support for Intel compiler on Windows
- Fixed isnan and isinf for CUDA compiler
- Fixed GLM_FORCE_RADIANS on glm::perspective
- Fixed GCC warnings
- Fixed packDouble2x32 on XCode
- Fixed mix for vec4 SSE implementation
- Fixed 0x2013 dash character in comments that cause issue in Windows 
  Japanese mode
- Fixed documentation warnings
- Fixed CUDA warnings

--------------------------------------------------------------------------------
#### GLM 0.9.4.1 - 2012-12-22
- Improved half support: -0.0 case and implicit conversions
- Fixed Intel Composer Compiler support on Linux
- Fixed interaction between quaternion and euler angles
- Fixed GTC_constants build
- Fixed GTX_multiple
- Fixed quat slerp using mix function when cosTheta close to 1
- Improved fvec4SIMD and fmat4x4SIMD implementations
- Fixed assert messages
- Added slerp and lerp quaternion functions and tests

--------------------------------------------------------------------------------
#### GLM 0.9.4.0 - 2012-11-18
- Added Intel Composer Compiler support
- Promoted GTC_espilon extension
- Promoted GTC_ulp extension
- Removed GLM website from the source repository
- Added GLM_FORCE_RADIANS so that all functions takes radians for arguments
- Fixed detection of Clang and LLVM GCC on MacOS X
- Added debugger visualizers for Visual C++ 2012

--------------------------------------------------------------------------------
#### [GLM 0.9.3.4](https://github.com/g-truc/glm/releases/tag/0.9.3.4) - 2012-06-30
- Added SSE4 and AVX2 detection.
- Removed VIRTREV_xstream and the incompatibility generated with GCC
- Fixed C++11 compiler option for GCC
- Removed MS language extension option for GCC (not fonctionnal)
- Fixed bitfieldExtract for vector types
- Fixed warnings
- Fixed SSE includes

--------------------------------------------------------------------------------
#### GLM 0.9.3.3 - 2012-05-10
- Fixed isinf and isnan
- Improved compatibility with Intel compiler
- Added CMake test build options: SIMD, C++11, fast math and MS land ext
- Fixed SIMD mat4 test on GCC
- Fixed perspectiveFov implementation
- Fixed matrixCompMult for none-square matrices
- Fixed namespace issue on stream operators
- Fixed various warnings
- Added VC11 support

--------------------------------------------------------------------------------
#### GLM 0.9.3.2 - 2012-03-15
- Fixed doxygen documentation
- Fixed Clang version detection
- Fixed simd mat4 /= operator

--------------------------------------------------------------------------------
#### GLM 0.9.3.1 - 2012-01-25
- Fixed platform detection
- Fixed warnings
- Removed detail code from Doxygen doc

--------------------------------------------------------------------------------
#### GLM 0.9.3.0 - 2012-01-09
- Added CPP Check project
- Fixed conflict with Windows headers
- Fixed isinf implementation
- Fixed Boost conflict
- Fixed warnings

--------------------------------------------------------------------------------
#### GLM 0.9.3.B - 2011-12-12
- Added support for Chrone Native Client
- Added epsilon constant
- Removed value_size function from vector types
- Fixed roundEven on GCC
- Improved API documentation
- Fixed modf implementation
- Fixed step function accuracy
- Fixed outerProduct

--------------------------------------------------------------------------------
#### GLM 0.9.3.A - 2011-11-11
- Improved doxygen documentation
- Added new swizzle operators for C++11 compilers
- Added new swizzle operators declared as functions
- Added GLSL 4.20 length for vector and matrix types
- Promoted GLM_GTC_noise extension: simplex, perlin, periodic noise functions
- Promoted GLM_GTC_random extension: linear, gaussian and various random number 
generation distribution
- Added GLM_GTX_constants: provides usefull constants
- Added extension versioning
- Removed many unused namespaces
- Fixed half based type contructors
- Added GLSL core noise functions

--------------------------------------------------------------------------------
#### [GLM 0.9.2.7](https://github.com/g-truc/glm/releases/tag/0.9.2.7) - 2011-10-24
- Added more swizzling constructors
- Added missing none-squared matrix products

--------------------------------------------------------------------------------
#### [GLM 0.9.2.6](https://github.com/g-truc/glm/releases/tag/0.9.2.6) - 2011-10-01
- Fixed half based type build on old GCC
- Fixed /W4 warnings on Visual C++
- Fixed some missing l-value swizzle operators

--------------------------------------------------------------------------------
#### GLM 0.9.2.5 - 2011-09-20
- Fixed floatBitToXint functions
- Fixed pack and unpack functions
- Fixed round functions

--------------------------------------------------------------------------------
#### GLM 0.9.2.4 - 2011-09-03
- Fixed extensions bugs

--------------------------------------------------------------------------------
#### GLM 0.9.2.3 - 2011-06-08
- Fixed build issues

--------------------------------------------------------------------------------
#### GLM 0.9.2.2 - 2011-06-02
- Expend matrix constructors flexibility
- Improved quaternion implementation
- Fixed many warnings across platforms and compilers

--------------------------------------------------------------------------------
#### GLM 0.9.2.1 - 2011-05-24
- Automatically detect CUDA support
- Improved compiler detection
- Fixed errors and warnings in VC with C++ extensions disabled
- Fixed and tested GLM_GTX_vector_angle
- Fixed and tested GLM_GTX_rotate_vector

--------------------------------------------------------------------------------
#### GLM 0.9.2.0 - 2011-05-09
- Added CUDA support
- Added CTest test suite
- Added GLM_GTX_ulp extension
- Added GLM_GTX_noise extension
- Added GLM_GTX_matrix_interpolation extension
- Updated quaternion slerp interpolation

--------------------------------------------------------------------------------
#### [GLM 0.9.1.3](https://github.com/g-truc/glm/releases/tag/0.9.1.3) - 2011-05-07
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.9.1.2 - 2011-04-15
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.9.1.1 - 2011-03-17
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.9.1.0 - 2011-03-03
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.9.1.B - 2011-02-13
- Updated API documentation
- Improved SIMD implementation
- Fixed Linux build

--------------------------------------------------------------------------------
#### [GLM 0.9.0.8](https://github.com/g-truc/glm/releases/tag/0.9.0.8) - 2011-02-13
- Added quaternion product operator.
- Clarify that GLM is a header only library.

--------------------------------------------------------------------------------
#### GLM 0.9.1.A - 2011-01-31
- Added SIMD support
- Added new swizzle functions
- Improved static assert error message with C++0x static_assert
- New setup system
- Reduced branching
- Fixed trunc implementation

--------------------------------------------------------------------------------
#### [GLM 0.9.0.7](https://github.com/g-truc/glm/releases/tag/0.9.0.7) - 2011-01-30
- Added GLSL 4.10 packing functions
- Added == and != operators for every types.

--------------------------------------------------------------------------------
#### GLM 0.9.0.6 - 2010-12-21
- Many matrices bugs fixed

--------------------------------------------------------------------------------
#### GLM 0.9.0.5 - 2010-11-01
- Improved Clang support
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.9.0.4 - 2010-10-04
- Added autoexp for GLM
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.9.0.3 - 2010-08-26
- Fixed non-squared matrix operators

--------------------------------------------------------------------------------
#### GLM 0.9.0.2 - 2010-07-08
- Added GLM_GTX_int_10_10_10_2
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.9.0.1 - 2010-06-21
- Fixed extensions errors

--------------------------------------------------------------------------------
#### GLM 0.9.0.0 - 2010-05-25
- Objective-C support
- Fixed warnings
- Updated documentation

--------------------------------------------------------------------------------
#### GLM 0.9.B.2 - 2010-04-30
- Git transition
- Removed experimental code from releases
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.9.B.1 - 2010-04-03
- Based on GLSL 4.00 specification
- Added the new core functions
- Added some implicit conversion support

--------------------------------------------------------------------------------
#### GLM 0.9.A.2 - 2010-02-20
- Improved some possible errors messages
- Improved declarations and definitions match

--------------------------------------------------------------------------------
#### GLM 0.9.A.1 - 2010-02-09
- Removed deprecated features
- Internal redesign

--------------------------------------------------------------------------------
#### GLM 0.8.4.4 final - 2010-01-25
- Fixed warnings

--------------------------------------------------------------------------------
#### GLM 0.8.4.3 final - 2009-11-16
- Fixed Half float arithmetic
- Fixed setup defines

--------------------------------------------------------------------------------
#### GLM 0.8.4.2 final - 2009-10-19
- Fixed Half float adds

--------------------------------------------------------------------------------
#### GLM 0.8.4.1 final - 2009-10-05
- Updated documentation
- Fixed MacOS X build

--------------------------------------------------------------------------------
#### GLM 0.8.4.0 final - 2009-09-16
- Added GCC 4.4 and VC2010 support
- Added matrix optimizations

--------------------------------------------------------------------------------
#### GLM 0.8.3.5 final - 2009-08-11
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.8.3.4 final - 2009-08-10
- Updated GLM according GLSL 1.5 spec
- Fixed bugs

--------------------------------------------------------------------------------
#### GLM 0.8.3.3 final - 2009-06-25
- Fixed bugs

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#### GLM 0.8.3.2 final - 2009-06-04
- Added GLM_GTC_quaternion
- Added GLM_GTC_type_precision

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#### GLM 0.8.3.1 final - 2009-05-21
- Fixed old extension system.

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#### GLM 0.8.3.0 final - 2009-05-06
- Added stable extensions.
- Added new extension system.

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#### GLM 0.8.2.3 final - 2009-04-01
- Fixed bugs.

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#### GLM 0.8.2.2 final - 2009-02-24
- Fixed bugs.

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#### GLM 0.8.2.1 final - 2009-02-13
- Fixed bugs.

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#### GLM 0.8.2 final - 2009-01-21
- Fixed bugs.

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#### GLM 0.8.1 final - 2008-10-30
- Fixed bugs.

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#### GLM 0.8.0 final - 2008-10-23
- New method to use extension.

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#### GLM 0.8.0 beta3 - 2008-10-10
- Added CMake support for GLM tests.

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#### GLM 0.8.0 beta2 - 2008-10-04
- Improved half scalars and vectors support.

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#### GLM 0.8.0 beta1 - 2008-09-26
- Improved GLSL conformance
- Added GLSL 1.30 support
- Improved API documentation

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#### GLM 0.7.6 final - 2008-08-08
- Improved C++ standard comformance
- Added Static assert for types checking

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#### GLM 0.7.5 final - 2008-07-05
- Added build message system with Visual Studio
- Pedantic build with GCC

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#### GLM 0.7.4 final - 2008-06-01
- Added external dependencies system.

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#### GLM 0.7.3 final - 2008-05-24
- Fixed bugs
- Added new extension group

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#### GLM 0.7.2 final - 2008-04-27
- Updated documentation
- Added preprocessor options

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#### GLM 0.7.1 final - 2008-03-24
- Disabled half on GCC
- Fixed extensions

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#### GLM 0.7.0 final - 2008-03-22
- Changed to MIT license
- Added new documentation

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#### GLM 0.6.4 - 2007-12-10
- Fixed swizzle operators

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#### GLM 0.6.3 - 2007-11-05
- Fixed type data accesses
- Fixed 3DSMax sdk conflict

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#### GLM 0.6.2 - 2007-10-08
- Fixed extension

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#### GLM 0.6.1 - 2007-10-07
- Fixed a namespace error
- Added extensions

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#### GLM 0.6.0 : 2007-09-16
- Added new extension namespace mecanium
- Added Automatic compiler detection

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#### GLM 0.5.1 - 2007-02-19
- Fixed swizzle operators

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#### GLM 0.5.0 - 2007-01-06
- Upgrated to GLSL 1.2
- Added swizzle operators
- Added setup settings

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#### GLM 0.4.1 - 2006-05-22
- Added OpenGL examples

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#### GLM 0.4.0 - 2006-05-17
- Added missing operators to vec* and mat*
- Added first GLSL 1.2 features
- Fixed windows.h before glm.h when windows.h required

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#### GLM 0.3.2 - 2006-04-21
- Fixed texcoord components access.
- Fixed mat4 and imat4 division operators.

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#### GLM 0.3.1 - 2006-03-28
- Added GCC 4.0 support under MacOS X.
- Added GCC 4.0 and 4.1 support under Linux.
- Added code optimisations.

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#### GLM 0.3 - 2006-02-19
- Improved GLSL type conversion and construction compliance.
- Added experimental extensions.
- Added Doxygen Documentation.
- Added code optimisations.
- Fixed bugs.

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#### GLM 0.2 - 2005-05-05
- Improve adaptative from GLSL.
- Add experimental extensions based on OpenGL extension process.
- Fixe bugs.

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#### GLM 0.1 - 2005-02-21
- Add vec2, vec3, vec4 GLSL types
- Add ivec2, ivec3, ivec4 GLSL types
- Add bvec2, bvec3, bvec4 GLSL types
- Add mat2, mat3, mat4 GLSL types
- Add almost all functions