Updated manual
This commit is contained in:
Christophe Riccio
parent
3ca24a12a1
commit
c583fe0257
185
manual.md
185
manual.md
@ -155,38 +155,26 @@ To further help compilation time, GLM 0.9.5 introduced
|
||||
|
||||
```cpp
|
||||
// Include GLM core features
|
||||
\#include <glm/vec3.hpp>
|
||||
\#include <glm/vec4.hpp>
|
||||
\#include <glm/mat4x4.hpp>
|
||||
\#include <glm/trigonometric.hpp>
|
||||
#include <glm/vec3.hpp>
|
||||
#include <glm/vec4.hpp>
|
||||
#include <glm/mat4x4.hpp>
|
||||
#include <glm/trigonometric.hpp>
|
||||
|
||||
// Include GLM extensions
|
||||
\#include <glm/gtc/matrix\_transform.hpp>
|
||||
#include <glm/gtc/matrix_transform.hpp>
|
||||
|
||||
glm::mat4 transform(
|
||||
glm::vec2 const& Orientation,
|
||||
glm::vec3 const& Translate,
|
||||
glm::vec3 const& Up)
|
||||
|
||||
{
|
||||
|
||||
glm::mat4 Proj = glm::perspective(glm::radians(45.f), 1.33f, 0.1f, 10.f);
|
||||
|
||||
glm::mat4 ViewTranslate = glm::translate(glm::mat4(1.f), Translate);
|
||||
|
||||
glm::mat4 ViewRotateX = glm::rotate(ViewTranslate, Orientation.y, Up);
|
||||
|
||||
glm::mat4 View = glm::rotate(ViewRotateX, Orientation.x, Up);
|
||||
|
||||
glm::mat4 Model = glm::mat4(1.0f);
|
||||
|
||||
return Proj \* View \* Model;
|
||||
|
||||
}
|
||||
glm::mat4 transform(glm::vec2 const& Orientation, glm::vec3 const& Translate, glm::vec3 const& Up)
|
||||
{
|
||||
glm::mat4 Proj = glm::perspective(glm::radians(45.f), 1.33f, 0.1f, 10.f);
|
||||
glm::mat4 ViewTranslate = glm::translate(glm::mat4(1.f), Translate);
|
||||
glm::mat4 ViewRotateX = glm::rotate(ViewTranslate, Orientation.y, Up);
|
||||
glm::mat4 View = glm::rotate(ViewRotateX, Orientation.x, Up);
|
||||
glm::mat4 Model = glm::mat4(1.0f);
|
||||
return Proj * View * Model;
|
||||
}
|
||||
```
|
||||
|
||||
### 1.4. Dependencies {#dependencies .HeadingB}
|
||||
-----------------
|
||||
### 1.4. Dependencies
|
||||
|
||||
When <glm/glm.hpp> is included, GLM provides all the GLSL features
|
||||
it implements in C++.
|
||||
@ -203,8 +191,7 @@ GLM is built with a C++ 11 compiler in which case
|
||||
If neither are detected, GLM will rely on its own implementation of
|
||||
static assert.
|
||||
|
||||
2. Swizzle operators {#swizzle-operators .HeadingA}
|
||||
====================
|
||||
## 2. Swizzle operators
|
||||
|
||||
A common feature of shader languages like GLSL is the swizzle operators.
|
||||
Those allow selecting multiple components of a vector and change their
|
||||
@ -214,20 +201,16 @@ components vector. With GLSL, swizzle operators can be both R-values and
|
||||
L-values. Finally, vector components can be accessed using “xyzw”,
|
||||
“rgba” or “stpq”.
|
||||
|
||||
-----------------
|
||||
vec4 A;
|
||||
```cpp
|
||||
vec4 A;
|
||||
vec2 B;
|
||||
...
|
||||
|
||||
vec2 B;
|
||||
B.yx = A.wy;
|
||||
B = A.xx;
|
||||
|
||||
...
|
||||
|
||||
B.yx = A.wy;
|
||||
|
||||
B = A.xx;
|
||||
|
||||
Vec3 C = A.bgr;
|
||||
-----------------
|
||||
-----------------
|
||||
vec3 C = A.bgr;
|
||||
```
|
||||
|
||||
GLM supports a subset of this functionality as described in the
|
||||
following sub-sections. Swizzle operators are disabled by default. To
|
||||
@ -235,71 +218,50 @@ enable them GLM\_SWIZZLE must be defined before any inclusion of
|
||||
<glm/glm.hpp>. Enabling swizzle operators will massively increase
|
||||
the size of compiled files and the compilation time.
|
||||
|
||||
2.1. Default C++98 implementation {#default-c98-implementation .HeadingB}
|
||||
---------------------------------
|
||||
### 2.1. Default C++98 implementation {#default-c98-implementation .HeadingB}
|
||||
|
||||
The C++98 implementation exposes the R-value swizzle operators as member
|
||||
functions of vector types.
|
||||
|
||||
----------------------------------------------------
|
||||
\#define GLM\_SWIZZLE
|
||||
```cpp
|
||||
#define GLM_SWIZZLE
|
||||
#include <glm/glm.hpp>
|
||||
|
||||
\#include <glm/glm.hpp>
|
||||
void foo()
|
||||
{
|
||||
glm::vec4 ColorRGBA(1.0f, 0.5f, 0.0f, 1.0f);
|
||||
glm::vec3 ColorBGR = ColorRGBA.bgr();
|
||||
...
|
||||
|
||||
void foo()
|
||||
glm::vec3 PositionA(1.0f, 0.5f, 0.0f, 1.0f);
|
||||
glm::vec3 PositionB = PositionXYZ.xyz() \* 2.0f;
|
||||
...
|
||||
|
||||
{
|
||||
|
||||
> glm::vec4 ColorRGBA(1.0f, 0.5f, 0.0f, 1.0f);
|
||||
>
|
||||
> glm::vec3 ColorBGR = ColorRGBA.bgr();
|
||||
>
|
||||
> …
|
||||
>
|
||||
> glm::vec3 PositionA(1.0f, 0.5f, 0.0f, 1.0f);
|
||||
>
|
||||
> glm::vec3 PositionB = PositionXYZ.xyz() \* 2.0f;
|
||||
>
|
||||
> …
|
||||
>
|
||||
> glm::vec2 TexcoordST(1.0f, 0.5f);
|
||||
>
|
||||
> glm::vec4 TexcoordSTPQ = TexcoordST.stst();
|
||||
>
|
||||
> …
|
||||
|
||||
}
|
||||
----------------------------------------------------
|
||||
----------------------------------------------------
|
||||
glm::vec2 TexcoordST(1.0f, 0.5f);
|
||||
glm::vec4 TexcoordSTPQ = TexcoordST.stst();
|
||||
...
|
||||
}
|
||||
```
|
||||
|
||||
Swizzle operators return a copy of the component values hence they can’t
|
||||
be used as L-values to change the value of the variables.
|
||||
|
||||
----------------------------------------------------------------
|
||||
\#define GLM\_FORCE\_SWIZZLE
|
||||
```cpp
|
||||
#define GLM_FORCE_SWIZZLE
|
||||
#include <glm/glm.hpp>
|
||||
|
||||
\#include <glm/glm.hpp>
|
||||
void foo()
|
||||
{
|
||||
glm::vec3 A(1.0f, 0.5f, 0.0f);
|
||||
|
||||
void foo()
|
||||
// /!\\ No compiler error but A is not affected
|
||||
// This code modify the components of an anonymous copy.
|
||||
A.bgr() = glm::vec3(2.0f, 1.5f, 1.0f); // A is not modified!
|
||||
...
|
||||
}
|
||||
```
|
||||
|
||||
{
|
||||
|
||||
> glm::vec3 A(1.0f, 0.5f, 0.0f);
|
||||
|
||||
// /!\\ No compiler error but A is not affected
|
||||
|
||||
// This code modify the components of an anonymous copy.
|
||||
|
||||
> A.bgr() = glm::vec3(2.0f, 1.5f, 1.0f); // A is not modified!
|
||||
>
|
||||
> …
|
||||
|
||||
}
|
||||
----------------------------------------------------------------
|
||||
----------------------------------------------------------------
|
||||
|
||||
2.2. Anonymous union member implementation {#anonymous-union-member-implementation .HeadingB}
|
||||
-------------------------------------------
|
||||
### 2.2. Anonymous union member implementation
|
||||
|
||||
Visual C++ supports anonymous structures in union, which is a
|
||||
non-standard language extension, but it enables a very powerful
|
||||
@ -308,34 +270,25 @@ swizzle operators and a syntax that doesn’t require parentheses in some
|
||||
cases. This implementation is only enabled when the language extension
|
||||
is enabled and GLM\_SWIZZLE is defined.
|
||||
|
||||
------------------------------------------------
|
||||
\#define GLM\_FORCE\_SWIZZLE
|
||||
```cpp
|
||||
#define GLM_FORCE_SWIZZLE
|
||||
#include <glm/glm.hpp>
|
||||
|
||||
\#include <glm/glm.hpp>
|
||||
void foo()
|
||||
{
|
||||
glm::vec4 ColorRGBA(1.0f, 0.5f, 0.0f, 1.0f);
|
||||
|
||||
void foo()
|
||||
// l-value:
|
||||
glm::vec4 ColorBGRA = ColorRGBA.bgra;
|
||||
|
||||
{
|
||||
// r-value:
|
||||
ColorRGBA.bgra = ColorRGBA;
|
||||
|
||||
> glm::vec4 ColorRGBA(1.0f, 0.5f, 0.0f, 1.0f);
|
||||
|
||||
// l-value:
|
||||
|
||||
> glm::vec4 ColorBGRA = ColorRGBA.bgra;
|
||||
|
||||
// r-value:
|
||||
|
||||
> ColorRGBA.bgra = ColorRGBA;
|
||||
|
||||
// Both l-value and r-value
|
||||
|
||||
> ColorRGBA.bgra = ColorRGBA.rgba;
|
||||
>
|
||||
> …
|
||||
|
||||
}
|
||||
------------------------------------------------
|
||||
------------------------------------------------
|
||||
// Both l-value and r-value
|
||||
ColorRGBA.bgra = ColorRGBA.rgba;
|
||||
...
|
||||
}
|
||||
```
|
||||
|
||||
Anonymous union member swizzle operators don’t return vector types
|
||||
(glm::vec2, glm::vec3 and glm::vec4) but implementation specific objects
|
||||
|
||||
Loading…
Reference in New Issue
Block a user