// ================================================================================================
// 
// This file is part of the CAMPVis Software Framework.
// 
// If not explicitly stated otherwise: Copyright (C) 2012-2015, all rights reserved,
//      Christian Schulte zu Berge <christian.szb@in.tum.de>
//      Chair for Computer Aided Medical Procedures
//      Technische Universitaet Muenchen
//      Boltzmannstr. 3, 85748 Garching b. Muenchen, Germany
// 
// For a full list of authors and contributors, please refer to the file "AUTHORS.txt".
// 
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file 
// except in compliance with the License. You may obtain a copy of the License at
// 
// http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software distributed under the 
// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, 
// either express or implied. See the License for the specific language governing permissions 
// and limitations under the License.
// 
// ================================================================================================

#include "visualizationprocessor.h"

#include "cgt/textureunit.h"
#include "core/datastructures/imagedata.h"
#include "core/datastructures/renderdata.h"
#include "core/datastructures/imagerepresentationgl.h"

namespace campvis {

    const std::string VisualizationProcessor::loggerCat_ = "CAMPVis.core.datastructures.VisualizationProcessor";

// ================================================================================================

    VisualizationProcessor::VisualizationProcessor(IVec2Property* viewportSizeProp)
        : AbstractProcessor()
        , p_lqMode("LqMode", "Low Quality Mode", false)
        , _fbo(0)
        , _viewportSizeProperty(viewportSizeProp)
    {
        if (_viewportSizeProperty) {
            _viewportSizeProperty->s_changed.connect<VisualizationProcessor>(this, &VisualizationProcessor::onPropertyChanged);
            setPropertyInvalidationLevel(*_viewportSizeProperty, INVALID_RESULT);
        }
    }

    VisualizationProcessor::~VisualizationProcessor() {
    }

    void VisualizationProcessor::init() {
        AbstractProcessor::init();

        cgtAssert(_viewportSizeProperty != 0, "The pointer to the viewport size property must not be 0!");
        addProperty(p_lqMode);

        _fbo = new cgt::FramebufferObject();
    }

    void VisualizationProcessor::deinit() {
        if (_viewportSizeProperty) {
            _viewportSizeProperty->s_changed.disconnect(this);
            _viewportSizeProperty = nullptr;
        }

        delete _fbo;
        AbstractProcessor::deinit();
    }

    void VisualizationProcessor::createAndAttachTexture(GLint internalFormat, GLenum attachment, ScopedTypedData<RenderData, true>* renderData /*= nullptr*/) {
        cgtAssert(_fbo->isActive(), "Trying to attach a texture while FBO is not bound!");

        // acquire a new TextureUnit, so that we don't mess with other currently bound textures during texture upload...
        cgt::TextureUnit rtUnit;
        rtUnit.activate();

        // Set OpenGL pixel alignment to 1 to avoid problems with NPOT textures
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

        // Check the render data if we can reuse a texture
        cgt::Texture* tex = nullptr;
        if (renderData) {`
            // check if we can get a GL representation of the desired texture
            ImageRepresentationGL* glRep;
            if (attachment == GL_DEPTH_ATTACHMENT)
                if(auto id = (*renderData)->getDepthTexture())
                    glRep = const_cast<ImageRepresentationGL*>(id->getRepresentation<ImageRepresentationGL>(false));
            else 
                if(auto id =(*renderData)->getColorTexture(_fbo->getNumColorAttachments())) //_fbo->getNumColorAttachments() is the index of the texture that is to be created
                    glRep = const_cast<ImageRepresentationGL*>(id->getRepresentation<ImageRepresentationGL>(false));

            // check if the texture is compatible with what we want, and in that case detach from the old RenderTargetData
            if (glRep) {
                tex = const_cast<cgt::Texture*>(glRep->getTexture());
                if (tex->getType() != GL_TEXTURE_2D || tex->getDimensions() != getRenderTargetSize()
                    || tex->getInternalFormat() != internalFormat)
                    tex = nullptr;
                else {
                    // somehow detach the cgt::Texture from the ImageRepresentationGL
                    // yes this is horrible - however, we know that renderData has write access, ergo
                    // we can safely do this const_cast
                    const_cast<ImageData*>(glRep->getParent())->removeRepresentationUnsafe<ImageRepresentationGL>();
                }

            }
        }

        // if we could not get the texture from a previous render target, create a new one
        if (!tex) {
            // create texture
            tex = new cgt::Texture(GL_TEXTURE_2D, getRenderTargetSize(), internalFormat, cgt::Texture::LINEAR);
        }
        tex->setWrapping(cgt::Texture::CLAMP_TO_EDGE);

        // attach texture to FBO
        _fbo->attachTexture(tex, attachment);
    }

    void VisualizationProcessor::createAndAttachTexture(GLint internalFormat, ScopedTypedData<RenderData, true>* renderData /*= nullptr*/) {
        GLenum attachment = 0;
        switch(internalFormat) {
            case GL_R32F:
            case GL_RGB:
            case GL_RGB16F_ARB:
            case GL_RGBA:
            case GL_RGBA8:
            case GL_RGBA16:
            case GL_RGBA16F:
            case GL_RGBA32F:
                if (_fbo->getNumColorAttachments() >= static_cast<size_t>(GpuCaps.getMaxColorAttachments())) {
                    cgtAssert(false, "Tried to attach more color textures to FBO than supported!");
                    LWARNING("Tried to attach more color textures to FBO than supported, aborted.");
                    return;
                }
                attachment = static_cast<GLenum>(GL_COLOR_ATTACHMENT0 + _fbo->getNumColorAttachments());
                break;

            case GL_DEPTH_COMPONENT16:
            case GL_DEPTH_COMPONENT24:
#ifdef GL_DEPTH_COMPONENT32F
            case GL_DEPTH_COMPONENT32F:
#endif
                cgtAssert(_fbo->getDepthAttachment() == 0, "Tried to attach more than one depth texture.");
                attachment = GL_DEPTH_ATTACHMENT;
                break;

            default:
                cgtAssert(false, "Unknown internal format!");
        }
        createAndAttachTexture(internalFormat, attachment);
    }

    cgt::ivec2 VisualizationProcessor::getEffectiveViewportSize() const {
        return (p_lqMode.getValue() ? _viewportSizeProperty->getValue() / 2 : _viewportSizeProperty->getValue());
    }

    cgt::ivec3 VisualizationProcessor::getRenderTargetSize() const {
        return cgt::ivec3(getEffectiveViewportSize(), 1);
    }

    void VisualizationProcessor::createAndAttachColorTexture(ScopedTypedData<RenderData, true>* renderData /*= nullptr*/) {
        createAndAttachTexture(GL_RGBA8, renderData);
    }

    void VisualizationProcessor::createAndAttachDepthTexture(ScopedTypedData<RenderData, true>* renderData /*= nullptr*/) {
        createAndAttachTexture(GL_DEPTH_COMPONENT24, renderData);
    }

    void VisualizationProcessor::setViewportSizeProperty(IVec2Property* viewportSizeProp) {
        cgtAssert(viewportSizeProp != nullptr, "Pointer must not be nullptr.");

        if (_viewportSizeProperty != nullptr) {
            _viewportSizeProperty->s_changed.disconnect(this);
        }

        _viewportSizeProperty = viewportSizeProp;
        _viewportSizeProperty->s_changed.connect<VisualizationProcessor>(this, &VisualizationProcessor::onPropertyChanged);
        setPropertyInvalidationLevel(*viewportSizeProp, INVALID_RESULT);
        invalidate(INVALID_RESULT);
    }

}