FrameBufferObject.cpp

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#include "FrameBufferObject.h"
#include "ngl/Types.h"
#include "iostream"

FrameBufferObject::FrameBufferObject(unsigned int _width, unsigned int _height):
        m_width(_width),m_height(_height)
{
}

FrameBufferObject::~FrameBufferObject()
{}

void FrameBufferObject::bind()
{
    glBindFramebuffer(GL_FRAMEBUFFER_EXT, m_FBOid);
    glBindRenderbuffer(GL_RENDERBUFFER_EXT, m_RBid);

    glPushAttrib(GL_VIEWPORT_BIT | GL_DEPTH_BUFFER_BIT);
    glViewport(0, 0, m_width, m_height);

}

void FrameBufferObject::unbind()
{
    glPopAttrib();
    glBindFramebuffer(GL_FRAMEBUFFER_EXT, 0);
    glBindRenderbuffer(GL_RENDERBUFFER_EXT, 0);
}

void FrameBufferObject::checkStatus()
{
    GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);

    switch(status)
    {
    case GL_FRAMEBUFFER_COMPLETE:
        std::cout << "Complete FBO" << std::endl;
        break;
    case GL_FRAMEBUFFER_UNSUPPORTED:
        std::cout << "Unsupported FBO" << std::endl;
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
        std::cout << "Incomplete Attatchments" << std::endl;
        break;
    case GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
        std::cout << "Missing attatchment" << std::endl;
        break;
    default:
        std::cout << "Weirdness afoot" << std::endl;
        break;
    }
}

void FrameBufferObject::bindTextureSlot(unsigned int _slot, GLuint _id)
{
    glBindFramebuffer(GL_FRAMEBUFFER, m_FBOid);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0+_slot,GL_TEXTURE_2D, _id, 0);
}

void FrameBufferObject::bindDepthTexture( GLuint textureId )
{
    glBindFramebuffer( GL_FRAMEBUFFER, m_FBOid);
    glFramebufferTexture2D( GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, textureId, 0 );
}

void FrameBufferObject::create(GLuint _textureId){
    // create a renderbuffer object to store depth info
    glGenRenderbuffers(1, &m_RBid);
    glBindRenderbuffer(GL_RENDERBUFFER, m_RBid);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT,
                             m_width, m_height);
    glBindRenderbuffer(GL_RENDERBUFFER, 0);

    // create a framebuffer object
    glGenFramebuffers(1, &m_FBOid);
    glBindFramebuffer(GL_FRAMEBUFFER, m_FBOid);

    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,GL_TEXTURE_2D, _textureId, 0);

    // attach the renderbuffer to depth attachment point
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
                                 GL_RENDERBUFFER, m_RBid);

    checkStatus();
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glBindRenderbuffer(GL_RENDERBUFFER, 0);
}

void FrameBufferObject::activateAllTargets()
{
    GLenum buffers[] = {
        GL_COLOR_ATTACHMENT0,
        GL_COLOR_ATTACHMENT1,
        GL_COLOR_ATTACHMENT2,
        GL_COLOR_ATTACHMENT3
    };

    glDrawBuffers(4, buffers);
}

void FrameBufferObject::activateTarget(unsigned int _id)
{
    glDrawBuffer(GL_COLOR_ATTACHMENT0 + _id);
}