GL Shader Program

Class: kodi::gui::gl::CShaderProgram

Class to manage an OpenGL shader program
With this class the used GL shader code can be defined on the GPU and its variables can be managed between CPU and GPU. More...

Topics
	Child Functions
	Class: kodi::gui::gl::CShaderProgram child functions

Functions
	kodi::gui::gl::CShaderProgram::CShaderProgram ()=default
	Construct a new shader.
	kodi::gui::gl::CShaderProgram::CShaderProgram (const std::string &vert, const std::string &frag)
	Construct a new shader and load defined shader files.
virtual	kodi::gui::gl::CShaderProgram::~CShaderProgram ()
	Destructor.
bool	kodi::gui::gl::CShaderProgram::LoadShaderFiles (const std::string &vert, const std::string &frag)
	To load manually the needed shader files.
bool	kodi::gui::gl::CShaderProgram::CompileAndLink (const std::string &vertexExtraBegin="", const std::string &vertexExtraEnd="", const std::string &fragmentExtraBegin="", const std::string &fragmentExtraEnd="")
	To compile and link the shader to the GL interface.
bool	kodi::gui::gl::CShaderProgram::EnableShader ()
	To activate the shader and use it on the GPU.
void	kodi::gui::gl::CShaderProgram::DisableShader ()
	To deactivate the shader use on the GPU.
ATTR_FORCEINLINE bool	kodi::gui::gl::CShaderProgram::ShaderOK () const
	Used to check if shader has been loaded before.
ATTR_FORCEINLINE CVertexShader &	kodi::gui::gl::CShaderProgram::VertexShader ()
	To get the vertex shader class used by Kodi at the addon.
ATTR_FORCEINLINE CPixelShader &	kodi::gui::gl::CShaderProgram::PixelShader ()
	To get the fragment shader class used by Kodi at the addon.
ATTR_FORCEINLINE GLuint	kodi::gui::gl::CShaderProgram::ProgramHandle ()
	Used to get the definition created in the OpenGL itself.

Detailed Description

Class: kodi::gui::gl::CShaderProgram

Class to manage an OpenGL shader program
With this class the used GL shader code can be defined on the GPU and its variables can be managed between CPU and GPU.

It has the header #include <kodi/gui/gl/Shader.h> be included to enjoy it.

---

Example:

#include <kodi/gui/gl/Shader.h>
...
 
class ATTR_DLL_LOCAL CExample
  : ...,
    public kodi::gui::gl::CShaderProgram
{
public:
  CExample() = default;
 
  bool Start();
  void Render();
 
  // override functions for kodi::gui::gl::CShaderProgram
  void OnCompiledAndLinked() override;
  bool OnEnabled() override;
 
private:
  ...
  GLint m_aPosition = -1;
  GLint m_aColor = -1;
};
 
bool CExample::Start()
{
  // Define shaders and load
  std::string fraqShader = kodi::GetAddonPath("resources/shaders/" GL_TYPE_STRING "/glsl.frag");
  std::string vertShader = kodi::GetAddonPath("resources/shaders/" GL_TYPE_STRING "/glsl.vert");
  if (!LoadShaderFiles(vertShader, fraqShader) || !CompileAndLink())
    return false;
 
  ...
  return true;
}
 
...
 
void CExample::Render()
{
  ...
 
  EnableShader();
  ...
  DO WORK
  ...
  DisableShader();
}
 
void CExample::OnCompiledAndLinked()
{
  ...
  DO YOUR WORK HERE FOR WHAT IS ONE TIME REQUIRED DURING COMPILE OF SHADER, E.G.:
 
  m_aPosition = glGetAttribLocation(ProgramHandle(), "a_position");
  m_aColor = glGetAttribLocation(ProgramHandle(), "a_color");
}
 
bool OnEnabled() override
{
  ...
  DO YOUR WORK HERE FOR WHAT REQUIRED DURING ENABLE OF SHADER
  ...
  return true;
}
 
ADDONCREATOR(CExample);

Function Documentation

CompileAndLink()

bool kodi::gui::gl::CShaderProgram::CompileAndLink ( const std::string & vertexExtraBegin = "", const std::string & vertexExtraEnd = "", const std::string & fragmentExtraBegin = "", const std::string & fragmentExtraEnd = "" )

inline

To compile and link the shader to the GL interface.

Optionally, additional source code can be transferred here, or it can be used independently without any files

Parameters

[in]	vertexExtraBegin	[opt] To additionally add vextex source code to the beginning of the loaded file source code
[in]	vertexExtraEnd	[opt] To additionally add vextex source code to the end of the loaded file source code
[in]	fragmentExtraBegin	[opt] To additionally add fragment source code to the beginning of the loaded file source code
[in]	fragmentExtraEnd	[opt] To additionally add fragment source code to the end of the loaded file source code

Returns

true if compile was successed

Note

In the case of a compile error, it will be written once into the Kodi log and in addition to the console output to quickly detect the errors when writing the damage.

CShaderProgram() [1/2]

kodi::gui::gl::CShaderProgram::CShaderProgram ( )

default

Construct a new shader.

Load must be done later with LoadShaderFiles.

CShaderProgram() [2/2]

kodi::gui::gl::CShaderProgram::CShaderProgram ( const std::string & vert, const std::string & frag )

inline

Construct a new shader and load defined shader files.

Parameters

[in]	vert	Path to used GL vertext shader
[in]	frag	Path to used GL fragment shader

DisableShader()

void kodi::gui::gl::CShaderProgram::DisableShader ( )

inline

To deactivate the shader use on the GPU.

EnableShader()

bool kodi::gui::gl::CShaderProgram::EnableShader ( )

inline

To activate the shader and use it on the GPU.

Returns

true if enable was successfully done

Note

During this call, the OnEnabled stored in the child is also called

LoadShaderFiles()

bool kodi::gui::gl::CShaderProgram::LoadShaderFiles ( const std::string & vert, const std::string & frag )

inline

To load manually the needed shader files.

Parameters

[in]	vert	Path to used GL vertext shader
[in]	frag	Path to used GL fragment shader

Note

The use of the files is optional, but it must either be passed over here or via CompileAndLink, or both of the source code.

PixelShader()

ATTR_FORCEINLINE CPixelShader & kodi::gui::gl::CShaderProgram::PixelShader ( )

inline

To get the fragment shader class used by Kodi at the addon.

Returns

pointer to fragment shader class

ProgramHandle()

ATTR_FORCEINLINE GLuint kodi::gui::gl::CShaderProgram::ProgramHandle ( )

inline

Used to get the definition created in the OpenGL itself.

Returns

GLuint of GL shader program handler

ShaderOK()

ATTR_FORCEINLINE bool kodi::gui::gl::CShaderProgram::ShaderOK ( ) const

inline

Used to check if shader has been loaded before.

Returns

true if enable was successfully done

Note

The CompileAndLink call sets these values

VertexShader()

ATTR_FORCEINLINE CVertexShader & kodi::gui::gl::CShaderProgram::VertexShader ( )

inline

To get the vertex shader class used by Kodi at the addon.

Returns

pointer to vertex shader class

~CShaderProgram()

virtual kodi::gui::gl::CShaderProgram::~CShaderProgram ( )

inlinevirtual

Destructor.