FrameBufferObject.cc

////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2011, Computer Graphics Group RWTH Aachen University         //
// All rights reserved.                                                       //
////////////////////////////////////////////////////////////////////////////////

#include <ACGL/OpenGL/Objects/FrameBufferObject.hh>

using namespace ACGL;
using namespace ACGL::OpenGL;

int_t FrameBufferObject::getColorAttachmentIndexByName(const std::string& _name) const
{
     for(AttachmentVec::size_type i = 0; i < mColorAttachments.size(); i++)
     {
         if(mColorAttachments[i].name == _name)
             return (int_t) i;
     }

     return -1;
 }

bool FrameBufferObject::isFrameBufferObjectComplete() const
{
    bind();
    GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
    if (status != GL_FRAMEBUFFER_COMPLETE)
    {
        Utils::error() << "Failed to make complete FrameBufferObject object: ";
        if (status == GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT) {
            Utils::error() << "GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT";
        } else if (status == GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT) {
            Utils::error() << "GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT";
        } else if (status == GL_FRAMEBUFFER_UNSUPPORTED) {
            Utils::error() << "GL_FRAMEBUFFER_UNSUPPORTED";
        } else if (status == GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE) {
            Utils::error() << "GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE";
        } else {
            Utils::error() << status;
        }
        Utils::error() << std::endl;
        return false;
    }
    return true;
}

void FrameBufferObject::validate(void) const
{
    // if OpenGL says were ok, return
    if (isFrameBufferObjectComplete()) return;

    // the above call will create some output, but let's try to get more infos:
    if(mColorAttachments.size() > 0)
    {
        int width  = -1;
        int height = -1;

        if(mColorAttachments[0].texture)
        {
            width  = mColorAttachments[0].texture->getWidth();
            height = mColorAttachments[0].texture->getHeight();
        }
        else
        {
            width  = mColorAttachments[0].renderBuffer->getWidth();
            height = mColorAttachments[0].renderBuffer->getHeight();
        }

        for(AttachmentVec::size_type k = 0; k < mColorAttachments.size(); k++)
        {
            bool fail = false;

            if(mColorAttachments[k].texture)
                fail = (mColorAttachments[k].texture->getWidth() != width || mColorAttachments[k].texture->getHeight() != height);
            else //otherwise its a RenderBuffer
                fail = (mColorAttachments[k].renderBuffer->getWidth() != width || mColorAttachments[k].renderBuffer->getHeight() != height);

            if(fail)
                Utils::error() << "FrameBufferObject validation failed: Color attachment "<< k << " has different size." << std::endl;
        }
    }
    else
        Utils::error() << "FrameBufferObject validation failed: No color attachments."<< std::endl;
}

bool FrameBufferObject::attachColorAttachment( const Attachment &_attachment )
{
    int realLocation = -1;

    for (unsigned int i = 0; i < mColorAttachments.size(); ++i) {
        if (mColorAttachments[i].name == _attachment.name) {
            // replace this attachment
            mColorAttachments[i] = _attachment;
            realLocation = i;
        }
    }
    if (realLocation == -1) {
        // it's a new attachment
        realLocation = (int) mColorAttachments.size();
        mColorAttachments.push_back(_attachment);
    }

    // attach it to the OpenGL object:
    bind();
    openGLCriticalErrorOccured();
    if (_attachment.renderBuffer) {
        // it's a renderBuffer
        glFramebufferRenderbuffer( GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + realLocation, GL_RENDERBUFFER, _attachment.renderBuffer->getObjectName() );
    } else {
        // it's a texture
        glFramebufferTexture2D(    GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + realLocation, _attachment.texture->getTarget(), _attachment.texture->getObjectName(), 0 );
        //Utils::debug() << "glFramebufferTexture2D( " << _attachment.name << " to " << realLocation <<" )" << std::endl;
    }
    if (openGLCommonErrorOccured())
    {
        Utils::error() << "Attaching of render target to the FBO failed" << std::endl;
        return false;
    }

    remapAttachments();
    return true;
}

void FrameBufferObject::remapAttachments()
{
    GLint maxColorBuffers;
    glGetIntegerv(GL_MAX_DRAW_BUFFERS, &maxColorBuffers);
    GLenum* bufferMappings = new GLenum[maxColorBuffers];

    int attachments = std::min( maxColorBuffers, (int) mColorAttachments.size() );

    for (int i = 0; i < maxColorBuffers; ++i) {
        bufferMappings[i] = GL_NONE;
    }
    for (int i = 0; i < attachments; ++i) {
        if (bufferMappings[ mColorAttachments[i].location ] != GL_NONE) {
            Utils::warning() << "FBO: Attachment mapping collision: Location " << mColorAttachments[i].location;
            Utils::warning() << " maps to both attachments " << mColorAttachments[i].name;
            Utils::warning() << " and " << mColorAttachments[bufferMappings[mColorAttachments[i].location] - GL_COLOR_ATTACHMENT0].name << std::endl;
        }
        bufferMappings[ mColorAttachments[i].location ] = GL_COLOR_ATTACHMENT0 + i;
    }

    // debug:
    /*
    Utils::debug() << "remapAttachments: " << std::endl;
    for (unsigned int i = 0; i < maxColorBuffers; ++i) {
        if (bufferMappings[i] == GL_NONE) {
            Utils::debug() << "bufferMappings["<<i<<"] GL_NONE" << std::endl;
        } else {
            Utils::debug() << "bufferMappings["<<i<<"] "<< bufferMappings[i]-GL_COLOR_ATTACHMENT0 << std::endl;
        }
    }
    */
    // end debug

    bind(); // glDrawBuffers will get part of the FBO state!

#ifdef __APPLE__
    // Somehow, Apple's current (OSX 10.7) OpenGL implementation skips over all
    // GL_NONE entries in the bufferMappings array if the only color attachment
    // specified is GL_COLOR_ATTACHMENT0.
    // This however causes that no change from the initial FBO state is
    // detected when the only color attachment should be assigned to a FragData
    // location other than 0.
    // Hotfix: Temporarily set all draw buffers to GL_NONE before setting the
    // actual configuration:
    glDrawBuffers(0, (GLenum*)NULL);
#endif // __APPLE__

    glDrawBuffers( maxColorBuffers, bufferMappings );

    delete[] bufferMappings;
}


void FrameBufferObject::setAttachmentLocations(ConstSharedLocationMappings _locationMappings)
{
    bool needsUpdate = false;

    for(AttachmentVec::size_type i = 0; i < mColorAttachments.size(); i++)
    {
        int_t location = _locationMappings->getLocation(mColorAttachments[i].name);

        if (location != -1) // is a mapping by that name specified?
        {
            mColorAttachments[i].location = location;
            needsUpdate = true;
        }
    }

    if(needsUpdate) remapAttachments();
}


SharedLocationMappings FrameBufferObject::getAttachmentLocations() const
{
    SharedLocationMappings locationMap = SharedLocationMappings( new LocationMappings() );

    for (AttachmentVec::size_type i = 0; i < mColorAttachments.size(); i++)
    {
        locationMap->setLocation( mColorAttachments[i].name, mColorAttachments[i].location );
        //ACGL::Utils::debug() << "locationMap->setLocation( "<<mColorAttachments[i].name<<", "<<mColorAttachments[i].location<<" );"<<std::endl;
    }

    return locationMap;
}

SharedTextureData FrameBufferObject::getImageData(GLsizei _width, GLsizei _height, GLint _x, GLint _y, GLenum _readBuffer)
{
    GLubyte* frameBufferData = new GLubyte[_width * _height * 3];

    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    if(_readBuffer != GL_INVALID_ENUM)
        glReadBuffer(_readBuffer);

    glReadPixels(_x, _y, _width, _height, GL_RGB, GL_UNSIGNED_BYTE, frameBufferData);

    SharedTextureData texData = SharedTextureData(new TextureData());
    texData->setWidth(_width);
    texData->setHeight(_height);
    texData->setFormat(GL_RGB);
    texData->setType(GL_UNSIGNED_BYTE);
    texData->setData(frameBufferData); // frameBufferData memory will be managed by texData

    openGLRareError();

    return texData;
}