# `glshader`
 
 A C++11 helper for [OpenGL][] >=2.0 [shaders][Shader].
 

 `glshader` can load an arbitrary number of [shaders][Shader] with the type
 autodetected by the file extension (using the same rules as the [OpenGL /

 OpenGL ES Reference Compiler][]). [Uniforms][Uniform] are set with a unified

 interface (using template specialization). Data can be provided by [OpenGL

 Mathematics (GLM)][] objects (which uses [OpenGL Shading Language (GLSL)][]

 naming conventions). For other types of data [uniform blocks][Uniform block]
 are used with (shared, per name) [Uniform Buffer Object (UBO)][] backing
 (beware of alignment). UBOs can also be accessed directly and bound to a
 uniform block by name. The expected usage pattern (as used by
 [`glBufferData`][]) can optionally be specified (defaults to
 `GL_DYNAMIC_DRAW`). For example:

 
 ```cpp
 Shader shader({
     "test.vert",
     "test.frag",
 });
 shader.use();

 
 glm::vec4 color(1, 0, 0, 1);
 shader.uniform("color", color);

 
 struct Matrices {
     glm::mat4 view;
     glm::mat4 projection;
 } matrices;
 // Either:
 shader.uniform("matrices", matrices);
 // or:
 Shader::ubo("matrices", matrices);
 shader.uniform("matrices", "matrices");

 ```
 
 Errors are handled by throwing [`std::runtime_error`][] with a [`what()`][]
 that returns helpful context as well as the OpenGL info log where appropriate.
 See the [tests](#tests) source for an overview of (some of) the generated error
 messages.
 

 [OpenGL]: https://www.opengl.org
 [Shader]: https://www.khronos.org/opengl/wiki/Shader

 [Uniform]: https://www.khronos.org/opengl/wiki/Uniform

 [Uniform block]: https://www.khronos.org/opengl/wiki/Interface_Block_(GLSL)#Uniform_blocks
 [Uniform Buffer Object (UBO)]: https://www.khronos.org/opengl/wiki/Uniform_Buffer_Object
 [`glBufferData`]: https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glBufferData.xhtml

 [OpenGL / OpenGL ES Reference Compiler]: https://www.khronos.org/opengles/sdk/tools/Reference-Compiler/

 [OpenGL Mathematics (GLM)]: https://glm.g-truc.net
 [OpenGL Shading Language (GLSL)]: https://www.khronos.org/opengl/wiki/OpenGL_Shading_Language

 [`std::runtime_error`]: https://en.cppreference.com/w/cpp/error/runtime_error
 [`what()`]: https://en.cppreference.com/w/cpp/error/exception/what
 

 ## Tests
 
 A test, using [GLFW][], is provided in [`test/`](test/) and can be run with
 `make test` from the repository root.
 
 [GLFW]: https://www.glfw.org/
 

 ## Dependencies
 

 The [OpenGL Extension Wrangler (GLEW)][] library is used for extension loading.
 

 [`str.hpp`][] is bundled.
 

 Installing dependencies on a Linux distribution using the [APT package
 manager][] can be done with:
 
 ```sh
 // Library dependencies.
 sudo apt-get install \
     libgl1-mesa-dev \

     libglew-dev \
     libglm-dev

 
 // Test dependencies.
 sudo apt-get install \
     libglfw3-dev
 ```
 
 [OpenGL Extension Wrangler (GLEW)]: http://glew.sourceforge.net

 [`str.hpp`]: https://git.rcrnstn.net/rcrnstn/str.hpp

 [APT package manager]: https://en.wikipedia.org/wiki/APT_(software)

 
 ## License
 
 Licensed under the [ISC license][], see the [`LICENSE`](LICENSE) file.
 
 [ISC license]: https://en.wikipedia.org/wiki/ISC_license