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class ffw::GLVertexArray

Class List > ffw :: GLVertexArray

A Vertex Array Object (VAO) More...

Protected Attributes

Type Name
GLuint buffer

Public Functions

Type Name
GLVertexArray ()
Creates an empty OpenGL buffer object.
GLVertexArray (bool create)
Creates an OpenGL vertex array buffer.
GLVertexArray (const GLVertexArray & other) = delete
GLVertexArray (GLVertexArray && other)
void swap (GLVertexArray & other)
virtual ~GLVertexArray ()
bool isCreated () const
Returns true if the object has been allocated.
void destroy ()
Releases the resources.
void bind () const
Binds the buffer object.
void unbind () const
Unbinds the buffer object and sets the current buffer object to zero.
GLuint getHandle () const
Returns the OpenGL named object (the handle)
void enableVertexAttribArray (GLint location) const
Enables a vertex attrib array at a specific location.
void disableVertexAttribArray (GLint location) const
Disables a vertex attrib array at a specific location.
void setAttributePointerf (GLint location, GLint size, GLsizei stride, const GLvoid * offset) const
Specify the location and data format of the array of generic vertex attributes at a specific index.
void setAttributeDivisor (GLuint index, GLuint divisor) const
Modify the rate at which generic vertex attributes advance during instanced rendering.
GLVertexArray & operator= (const GLVertexArray & other) = delete
GLVertexArray & operator= (GLVertexArray && other)

Detailed Description

This is a vertex array object to be used with vertex buffer object (VBO). An example code below:

// Somewhere in your code
ffw::GLVertexBuffer vbo;
ffw::GLVertexArray vao;
ffw::GLProgram program;

// Initialization (only once)
try {
    // Create our shader (optional).
    program = ffw::GLProgram(...);
    
    // This will create the VAO object.
    // Once this line is completed, VAO is bound, so no need to
    // manually bind it.
    vao = ffw::GLVertexArray(true);

    // This will create the VBO object using some random "vertices" data.
    // Similarly as the VAO, this VBO is automatically bound after creation
    // (after the constructor is called)
    vbo = ffw::GLVertexBuffer(vertices, sizeof(vertices), GL_STATIC_DRAW);

    // Because both VAO and VBO are bound (during creation), we can
    // set the properties of the VAO by setting attribute pointers
    vao.setAttributePointerf(program.getAttributeLocation("position"), 3, 6 * sizeof(float), (void*)(0 * sizeof(float)));
    
    // Once we are done, we need to unbind the VAO so we won't
    // accidentally modify it.
    vao.unbind();
} catch (ffw::GLException& e) {
    std::cerr << "Failed to initialize shaders: " << e.what() << std::endl;
    return EXIT_FAILURE;
}

// Rendering (in a loop)
while (true) {
    // Bind the shader program and the VAO.
    // You do not need to bind the VBO! The VAO handles that for you!
    program.bind();
    vao.bind();
    
    // Set the uniforms (if any) and draw the arrays
    // Note that calling any functions that modify attribute values or pointers
    // will also modify the VAO, therefore invaliding what we have done
    // in the initialization. This includes "setAttributePointerf" and so on.
    program.drawArrays(GL_TRIANGLES, 0, ...);

    // Stop the program and unbind the VAO
    program.unbind();
    vao.unbind();
}

Protected Attributes Documentation

variable buffer

GLuint ffw::GLVertexArray::buffer;

Public Functions Documentation

function GLVertexArray (1/4)

ffw::GLVertexArray::GLVertexArray ()

Creates an empty OpenGL buffer object.

function GLVertexArray (2/4)

ffw::GLVertexArray::GLVertexArray (
    bool create
)

Creates an OpenGL vertex array buffer.

Exception:

function GLVertexArray (3/4)

ffw::GLVertexArray::GLVertexArray (
    const GLVertexArray & other
) = delete

function GLVertexArray (4/4)

ffw::GLVertexArray::GLVertexArray (
    GLVertexArray && other
)

function swap

void ffw::GLVertexArray::swap (
    GLVertexArray & other
)

function ~GLVertexArray

virtual ffw::GLVertexArray::~GLVertexArray ()

function isCreated

bool ffw::GLVertexArray::isCreated () const

Returns true if the object has been allocated.

function destroy

void ffw::GLVertexArray::destroy ()

Releases the resources.

function bind

void ffw::GLVertexArray::bind () const

Binds the buffer object.

function unbind

void ffw::GLVertexArray::unbind () const

Unbinds the buffer object and sets the current buffer object to zero.

function getHandle

GLuint ffw::GLVertexArray::getHandle () const

Returns the OpenGL named object (the handle)

function enableVertexAttribArray

void ffw::GLVertexArray::enableVertexAttribArray (
    GLint location
) const

Enables a vertex attrib array at a specific location.

Note:

This method is being called by setAttributePointerf

function disableVertexAttribArray

void ffw::GLVertexArray::disableVertexAttribArray (
    GLint location
) const

Disables a vertex attrib array at a specific location.

function setAttributePointerf

void ffw::GLVertexArray::setAttributePointerf (
    GLint location,
    GLint size,
    GLsizei stride,
    const GLvoid * offset
) const

Specify the location and data format of the array of generic vertex attributes at a specific index.

Note:

This automatically calls enableVertexAttribArray with the location

function setAttributeDivisor

void ffw::GLVertexArray::setAttributeDivisor (
    GLuint index,
    GLuint divisor
) const

Modify the rate at which generic vertex attributes advance during instanced rendering.

function operator= (1/2)

GLVertexArray & ffw::GLVertexArray::operator= (
    const GLVertexArray & other
) = delete

function operator= (2/2)

GLVertexArray & ffw::GLVertexArray::operator= (
    GLVertexArray && other
)

The documentation for this class was generated from the following file: include/ffw/graphics/glvertexarray.h