smk::Shader Class Reference

#include <Shader.hpp>

A Shader is a little program that rest on the GPU. They are run on a specific section of the graphic pipeline. More...

Description

A Shader is a little program that rest on the GPU. They are run on a specific section of the graphic pipeline.

This class is movable and copyable (via internal ref-count).

See also

https://learnopengl.com/Getting-started/Shaders

This class is independant from SMK.

Example:

auto vertex_shader = smk::Shader::FromString(R"(
  layout(location = 0) in vec2 space_position;
  layout(location = 1) in vec2 texture_position;
  uniform mat4 projection;
  uniform mat4 view;
  out vec2 f_texture_position;
  void main() {
    f_texture_position = texture_position;
    gl_Position = projection * view * vec4(space_position, 0.0, 1.0);
  }
)", GL_VERTEX_SHADER);
 
auto fragment_shader = smk::Shader::FromString(R"(
  in vec2 f_texture_position;
  uniform sampler2D texture_0;
  uniform vec4 color;
  out vec4 out_color;
  void main() {
    vec4 color = texture(texture_0, f_texture_position) * color;
    vec3 inverted_color = vec3(1.0) - color.rgb;
    out_color = vec4(inverted_color, color.a);
  }
)", GL_FRAGMENT_SHADER);
 
auto shader_program = smk::ShaderProgram();
shader_program.AddShader(vertex_shader);
shader_program.AddShader(fragment_shader);
shader_program.Link();
 
window.SetShaderProgram(shader_program);

See also

ShaderProgram

Definition at line 66 of file Shader.hpp.

Public Member Functions
bool	IsReady () const
	Check the status of a Shader. Linking shader is an asynchronous process. Using the shader can causes the CPU to wait until its completion. If you need to do some work before the completion, you can use this function and use the Shader only after it becomes ready. More...
bool	CompileStatus () const
	Wait until the Shader to be ready. More...
GLuint	id () const
	The GPU shader id. More...
	Shader (Shader &&) noexcept
	Shader (const Shader &) noexcept
Shader &	operator= (Shader &&) noexcept
Shader &	operator= (const Shader &) noexcept

Static Public Member Functions
static Shader	FromFile (const std::string &filename, GLenum type)
	Load a shader from a file. More...
static Shader	FromString (const std::string &content, GLenum type)
	Load a shader from a std::string. More...

Constructor & Destructor Documentation

~Shader()

smk::Shader::~Shader

(

)

Definition at line 132 of file Shader.cpp.

                {
  Release();
}

Shader() [1/2]

smk::Shader::Shader ( Shader &&  other )

noexcept

Definition at line 140 of file Shader.cpp.

                                      {
  this->operator=(std::move(other));
}

Shader() [2/2]

smk::Shader::Shader ( const Shader &  other )

noexcept

Definition at line 136 of file Shader.cpp.

                                           {
  this->operator=(other);
}

Member Function Documentation

CompileStatus()

bool smk::Shader::CompileStatus

(

)

const

Wait until the Shader to be ready.

Returns

True if it suceeded, false otherwise.

Definition at line 113 of file Shader.cpp.

                                 {
  GLint compile_status = {};
  glGetShaderiv(id_, GL_COMPILE_STATUS, &compile_status);
  if (compile_status == GL_TRUE) {
    return true;
  }
 
  GLsizei logsize = 0;
  glGetShaderiv(id_, GL_INFO_LOG_LENGTH, &logsize);
 
  std::vector<char> log(logsize + 1);
  glGetShaderInfoLog(id_, logsize, &logsize, log.data());
 
  std::cout << "[Error] compilation error: " << std::endl;
  std::cout << log.data() << std::endl;
 
  return false;
}

FromFile()

Shader smk::Shader::FromFile ( const std::string &  filename, GLenum  type  )

static

Load a shader from a file.

Parameters

filename	The text filename where the shader is written.
type	Either GL_VERTEX_SHADER or GL_FRAGMENT_SHADER. It can also be any other shader type defined by OpenGL. See https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glCreateShader.xhtml

See also

Shader::FromString

Shader::FromFile

Definition at line 42 of file Shader.cpp.

                                                              {
  std::ifstream file(filename);
  return Shader::FromString(std::string(std::istreambuf_iterator<char>(file),
                                        std::istreambuf_iterator<char>()),
                            type);
}

FromString()

Shader smk::Shader::FromString ( const std::string &  content, GLenum  type  )

static

Load a shader from a std::string.

Parameters

content	The string representing the shader.
type	Either GL_VERTEX_SHADER or GL_FRAGMENT_SHADER. It can also be any other shader type defined by OpenGL. See https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glCreateShader.xhtml

See also

Shader::FromString

Shader::FromFile

Definition at line 60 of file Shader.cpp.

                                                               {
  std::vector<char> buffer;
  for (const auto& c : kShaderHeader) {
    buffer.push_back(c);
  }
  for (const auto& c : content) {
    buffer.push_back(c);
  }
  buffer.push_back('\0');
  return Shader(buffer, type);
}

id()

GLuint smk::Shader::id

(

)

const

The GPU shader id.

Returns

The OpenGL shader id. If the Shader is invalid, returns zero.

Definition at line 74 of file Shader.cpp.

                        {
  return id_;
}

IsReady()

bool smk::Shader::IsReady

(

)

const

Check the status of a Shader. Linking shader is an asynchronous process. Using the shader can causes the CPU to wait until its completion. If you need to do some work before the completion, you can use this function and use the Shader only after it becomes ready.

Definition at line 100 of file Shader.cpp.

                           {
  if (g_khr_parallel_shader) {
    GLint completion_status = {};
    glGetShaderiv(id_, GL_COMPLETION_STATUS_KHR, &completion_status);
    return completion_status == GL_TRUE;
  }
 
  std::cerr << "Used bad path" << std::endl;
  return true;
}

operator=() [1/2]

Shader & smk::Shader::operator= ( const Shader &  other )

noexcept

Definition at line 144 of file Shader.cpp.

                                                      {
  if (this == &other) {
    return *this;
  }
  Release();
  if (!other.id_) {
    return *this;
  }
 
  if (!other.ref_count_) {
    other.ref_count_ = new int(1); // NOLINT
  }
 
  id_ = other.id_;
  ref_count_ = other.ref_count_;
 
  (*ref_count_)++;
  return *this;
}

operator=() [2/2]

Shader & smk::Shader::operator= ( Shader &&  other )

noexcept

Definition at line 164 of file Shader.cpp.

                                                 {
  std::swap(id_, other.id_);
  std::swap(ref_count_, other.ref_count_);
  return *this;
}

---

The documentation for this class was generated from the following files:

• /home/arthursonzogni/programmation/real/smk/include/smk/Shader.hpp
• /home/arthursonzogni/programmation/real/smk/src/smk/Shader.cpp