From cee9de027d21ee15dea6e49d34614ed4ec0bbb1e Mon Sep 17 00:00:00 2001 From: Christophe Riccio Date: Wed, 22 Aug 2018 23:10:59 +0200 Subject: [PATCH] Progress on the manual update for GLM 0.9.9.1 --- manual.md | 100 +++++++++++++++++++++++++++++------------------------- 1 file changed, 54 insertions(+), 46 deletions(-) diff --git a/manual.md b/manual.md index 281b6858..c317bd4a 100644 --- a/manual.md +++ b/manual.md @@ -15,19 +15,22 @@ + [2. Preprocessor configurations](#section2) + [2.1. GLM\_FORCE\_MESSAGES: Platform auto detection and default configuration](#section2_1) + [2.2. GLM\_FORCE\_PLATFORM\_UNKNOWN: Force GLM to no detect the build platform](#section2_2) -+ [2.3. GLM\_FORCE\_CXX**: C++ language detection](#section2_3) -+ [2.4. GLM\_FORCE\_EXPLICIT\_CTOR: Requiring explicit conversions](#section2_4) -+ [2.5. GLM\_FORCE\_INLINE: Force inline](#section2_5) -+ [2.6. GLM\_FORCE\_DEFAULT\_ALIGNED_GENTYPES: Force GLM to use aligned types by default](#section2_6) -+ [2.7. GLM\_FORCE\_SIMD\_**: Using SIMD optimizations](#section2_7) -+ [2.8. GLM\_PRECISION\_**: Default precision](#section2_8) -+ [2.9. GLM\_FORCE\_SINGLE\_ONLY: Removed explicit 64-bits floating point types](#section2_9) -+ [2.10. GLM\_FORCE\_SWIZZLE: Enable swizzle operators](#section2_10) -+ [2.11. GLM\_FORCE\_XYZW\_ONLY: Only exposes x, y, z and w components](#section2_11) -+ [2.12. GLM\_FORCE\_LEFT\_HANDED: Force left handed coordinate system](#section2_12) -+ [2.13. GLM\_FORCE\_DEPTH\_ZERO\_TO\_ONE: Force the use of a clip space between 0 to 1](#section2_13) -+ [2.14. GLM\_FORCE\_SIZE\_T\_LENGTH: Vector and matrix static size type](#section2_14) -+ [2.15. GLM\_FORCE\_UNRESTRICTED\_GENTYPE: Removing genType restriction](#section2_15) ++ [2.3. GLM\_FORCE\_COMPILER\_UNKNOWN: Force GLM to no detect the C++ compiler ++ [2.4. GLM\_FORCE\_ARCH\_UNKNOWN: Force GLM to no detect the build architecture ++ [2.5. GLM\_FORCE\_CXX\_UNKNOWN: Force GLM to no detect the C++ standard ++ [2.6. GLM\_FORCE\_CXX**: C++ language detection](#section2_3) ++ [2.7. GLM\_FORCE\_EXPLICIT\_CTOR: Requiring explicit conversions](#section2_4) ++ [2.8. GLM\_FORCE\_INLINE: Force inline](#section2_5) ++ [2.9. GLM\_FORCE\_DEFAULT\_ALIGNED_GENTYPES: Force GLM to use aligned types by default](#section2_6) ++ [2.10. GLM\_FORCE\_SIMD\_**: Using SIMD optimizations](#section2_7) ++ [2.11. GLM\_PRECISION\_**: Default precision](#section2_8) ++ [2.12. GLM\_FORCE\_SINGLE\_ONLY: Removed explicit 64-bits floating point types](#section2_9) ++ [2.13. GLM\_FORCE\_SWIZZLE: Enable swizzle operators](#section2_10) ++ [2.14. GLM\_FORCE\_XYZW\_ONLY: Only exposes x, y, z and w components](#section2_11) ++ [2.15. GLM\_FORCE\_LEFT\_HANDED: Force left handed coordinate system](#section2_12) ++ [2.16. GLM\_FORCE\_DEPTH\_ZERO\_TO\_ONE: Force the use of a clip space between 0 to 1](#section2_13) ++ [2.17. GLM\_FORCE\_SIZE\_T\_LENGTH: Vector and matrix static size type](#section2_14) ++ [2.18. GLM\_FORCE\_UNRESTRICTED\_GENTYPE: Removing genType restriction](#section2_15) + [3. Stable extensions](#section3) + [3.1. Scalar types](#section3_1) + [3.2. Scalar functions](#section3_2) @@ -291,21 +294,21 @@ The following subsections describe each configurations and defines. ### 2.2. GLM\_FORCE\_PLATFORM\_UNKNOWN: Force GLM to no detect the build platform -TODO +`GLM_FORCE_PLATFORM_UNKNOWN` prevents GLM from detecting the build platform. -### 2.3. GLM\_FORCE\_COMPILER\_UNKNOWN: Force GLM to no detect the build compiler +### 2.3. GLM\_FORCE\_COMPILER\_UNKNOWN: Force GLM to no detect the C++ compiler -TODO +`GLM_FORCE_COMPILER_UNKNOWN` prevents GLM from detecting the C++ compiler. ### 2.4. GLM\_FORCE\_ARCH\_UNKNOWN: Force GLM to no detect the build architecture -TODO +`GLM_FORCE_ARCH_UNKNOWN` prevents GLM from detecting the build target architechture. ### 2.5. GLM\_FORCE\_CXX\_UNKNOWN: Force GLM to no detect the C++ standard -TODO +`GLM_FORCE_CSS_UNKNOWN` prevents GLM from detecting the C++ compiler standard support. -### 2.3. GLM\_FORCE\_CXX**: C++ language detection +### 2.6. GLM\_FORCE\_CXX**: C++ language detection GLM will automatically take advantage of compilers’ language extensions when enabled. To increase cross platform compatibility and to avoid compiler extensions, a programmer can define GLM\_FORCE\_CXX98 before any inclusion of <glm/glm.hpp> to restrict the language feature set C++98: @@ -328,7 +331,7 @@ GLM\_FORCE\_CXX11, GLM\_FORCE\_CXX14. GLM\_FORCE\_CXX14 overrides GLM\_FORCE\_CXX11 and GLM\_FORCE\_CXX11 overrides GLM\_FORCE\_CXX98 defines. -### 2.4. GLM\_FORCE\_EXPLICIT\_CTOR: Requiring explicit conversions +### 2.7. GLM\_FORCE\_EXPLICIT\_CTOR: Requiring explicit conversions GLSL supports implicit conversions of vector and matrix types. For example, an ivec4 can be implicitly converted into vec4. @@ -364,7 +367,7 @@ void foo() } ``` -### 2.5. GLM\_FORCE\_INLINE: Force inline +### 2.8. GLM\_FORCE\_INLINE: Force inline To push further the software performance, a programmer can define GLM\_FORCE\_INLINE before any inclusion of <glm/glm.hpp> to force the compiler to inline GLM code. @@ -373,11 +376,11 @@ To push further the software performance, a programmer can define GLM\_FORCE\_IN #include ``` -### 2.6. GLM\_FORCE\_DEFAULT\_ALIGNED_GENTYPES: Force GLM to use aligned types by default +### 2.9. GLM\_FORCE\_DEFAULT\_ALIGNED_GENTYPES: Force GLM to use aligned types by default TODO -### 2.7. GLM\_FORCE\_SIMD\_**: Using SIMD optimizations +### 2.10. GLM\_FORCE\_SIMD\_**: Using SIMD optimizations GLM provides some SIMD optimizations based on [compiler intrinsics](https://msdn.microsoft.com/en-us/library/26td21ds.aspx). These optimizations will be automatically thanks to compiler arguments. @@ -404,7 +407,7 @@ The use of intrinsic functions by GLM implementation can be avoided using the de Additionally, GLM provides a low level SIMD API in glm/simd directory for users who are really interested in writing fast algorithms. -### 2.8. GLM\_PRECISION\_**: Default precision +### 2.11. GLM\_PRECISION\_**: Default precision C++ does not provide a way to implement GLSL default precision selection (as defined in GLSL 4.10 specification section 4.5.3) with GLSL-like syntax. @@ -445,11 +448,11 @@ Available defines for unsigned integer types (glm::uvec\*): * GLM\_PRECISION\_MEDIUMP\_UINT: Medium precision * GLM\_PRECISION\_HIGHP\_UINT: High precision (default) -### 2.9. GLM\_FORCE\_SINGLE\_ONLY: Removed explicit 64-bits floating point types +### 2.12. GLM\_FORCE\_SINGLE\_ONLY: Removed explicit 64-bits floating point types Some platforms (Dreamcast) doesn't support double precision floating point values. To compile on such platforms, GCC has the --m4-single-only build argument. When defining GLM\_FORCE\_SINGLE\_ONLY before including GLM headers, GLM releases the requirement of double precision floating point values support. Effectivement, all the float64 types are no longer defined and double behaves like float. -### 2.10. GLM\_FORCE\_SWIZZLE: Enable swizzle operators +### 2.13. GLM\_FORCE\_SWIZZLE: Enable swizzle operators Shader languages like GLSL often feature so-called swizzle expressions, which may be used to freely select and arrange a vector's components. For example, `variable.x`, `variable.xzy` and `variable.zxyy` respectively form a scalar, a 3D vector and a 4D vector. The result of a swizzle expression in GLSL can be either an R-value or an L-value. Swizzle expressions can be written with characters from exactly one of `xyzw` (usually for positions), `rgba` (usually for colors), and `stpq` (usually for texture coordinates). @@ -469,7 +472,7 @@ GLM supports some of this functionality. Swizzling can be enabled by defining `G GLM has two levels of swizzling support described in the following subsections. -#### 2.10.1. Swizzle functions for standard C++ 98 +#### 2.13.1. Swizzle functions for standard C++ 98 When compiling GLM as C++98, R-value swizzle expressions are simulated through member functions of each vector type. @@ -479,14 +482,14 @@ When compiling GLM as C++98, R-value swizzle expressions are simulated through m void foo() { - glm::vec4 ColorRGBA = glm::vec4(1.0f, 0.5f, 0.0f, 1.0f); - glm::vec3 ColorBGR = ColorRGBA.bgr(); + glm::vec4 const ColorRGBA = glm::vec4(1.0f, 0.5f, 0.0f, 1.0f); + glm::vec3 const ColorBGR = ColorRGBA.bgr(); - glm::vec3 PositionA = glm::vec3(1.0f, 0.5f, 0.0f); - glm::vec3 PositionB = PositionXYZ.xyz() * 2.0f; + glm::vec3 const PositionA = glm::vec3(1.0f, 0.5f, 0.0f); + glm::vec3 const PositionB = PositionXYZ.xyz() * 2.0f; - glm::vec2 TexcoordST = glm::vec2(1.0f, 0.5f); - glm::vec4 TexcoordSTPQ = TexcoordST.stst(); + glm::vec2 const TexcoordST = glm::vec2(1.0f, 0.5f); + glm::vec4 const TexcoordSTPQ = TexcoordST.stst(); } ``` @@ -498,7 +501,7 @@ Swizzle operators return a **copy** of the component values, and thus *can't* be void foo() { - glm::vec3 A = glm::vec3(1.0f, 0.5f, 0.0f); + glm::vec3 const A = glm::vec3(1.0f, 0.5f, 0.0f); // No compiler error, but A is not modified. // An anonymous copy is being modified (and then discarded). @@ -506,7 +509,7 @@ void foo() } ``` -#### 2.10.2. Swizzle operations for C++ 98 with language extensions +#### 2.13.2. Swizzle operations for C++ 98 with language extensions Visual C++, GCC and Clang support, as a _non-standard language extension_, anonymous `struct`s as `union` members. This permits a powerful swizzling implementation that both allows L-value swizzle expressions and GLSL-like syntax. To use this feature, the language extension must be enabled by a supporting compiler and `GLM_FORCE_SWIZZLE` must be `#define`d. @@ -556,19 +559,24 @@ void foo() *Note: The implementation has a caveat: Swizzle operator types must be different on both size of the equal operator or the operation will fail. There is no known fix for this issue to date* -### 2.11. GLM\_FORCE\_XYZW\_ONLY: Only exposes x, y, z and w components +### 2.14. GLM\_FORCE\_XYZW\_ONLY: Only exposes x, y, z and w components + +Following GLSL specifications, GLM supports three sets of components to access vector types member: x, y, z, w; r, g, b, a; and s, t, p, q. +Also, this is making vector component very expressive in the code, it may make debugging vector types a little cubersom as the debuggers will typically display three time the values for each compoenents due to the existance of the three sets. + +To simplify vector types, GLM allows exposing only x, y, z and w components thanks to `GLM_FORCE_XYZW_ONLY` define. + +### 2.15. GLM\_FORCE\_LEFT\_HANDED: Force left handed coordinate system + +OpenGL is using by default a right handed coordinate system. However, others APIs such as Direct3D have done different choice and relies on the left handed coordinate system. + +GLM allows switching the coordinate system to left handed by defining `GLM_FORCE_LEFT_HANDED`. + +### 2.16. GLM\_FORCE\_DEPTH\_ZERO\_TO\_ONE: Force the use of a clip space between 0 to 1 TODO -### 2.12. GLM\_FORCE\_LEFT\_HANDED: Force left handed coordinate system - -TODO - -### 2.13. GLM\_FORCE\_DEPTH\_ZERO\_TO\_ONE: Force the use of a clip space between 0 to 1 - -TODO - -### 2.14. GLM\_FORCE\_SIZE\_T\_LENGTH: Vector and matrix static size +### 2.17. GLM\_FORCE\_SIZE\_T\_LENGTH: Vector and matrix static size GLSL supports the member function .length() for all vector and matrix types. @@ -597,7 +605,7 @@ void foo(vec4 const& v) } ``` -### 2.15. GLM\_FORCE\_UNRESTRICTED\_GENTYPE: Removing genType restriction +### 2.18. GLM\_FORCE\_UNRESTRICTED\_GENTYPE: Removing genType restriction By default GLM only supports basic types as genType for vector, matrix and quaternion types: