/*****************************************************************************************
 *                                                                                       *
 * OpenSpace                                                                             *
 *                                                                                       *
 * Copyright (c) 2014-2017                                                               *
 *                                                                                       *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
 * software and associated documentation files (the "Software"), to deal in the Software *
 * without restriction, including without limitation the rights to use, copy, modify,    *
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    *
 * permit persons to whom the Software is furnished to do so, subject to the following   *
 * conditions:                                                                           *
 *                                                                                       *
 * The above copyright notice and this permission notice shall be included in all copies *
 * or substantial portions of the Software.                                              *
 *                                                                                       *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT    *
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF  *
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE  *
 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
 ****************************************************************************************/

#include <modules/globebrowsing/globes/pointglobe.h>

#include <modules/globebrowsing/globes/renderableglobe.h>

#include <openspace/engine/openspaceengine.h>
#include <openspace/engine/wrapper/windowwrapper.h>
#include <openspace/rendering/renderengine.h>
#include <openspace/util/updatestructures.h>

#include <ghoul/opengl/programobject.h>

namespace openspace {
namespace globebrowsing {

PointGlobe::PointGlobe(const RenderableGlobe& owner)
    : _owner(owner)
{}

PointGlobe::~PointGlobe() {
    glDeleteBuffers(1, &_vertexBufferID);
    glDeleteVertexArrays(1, &_vaoID);
}

bool PointGlobe::initialize() {
    _programObject = OsEng.renderEngine().buildRenderProgram(
        "PointGlobe",
        "${MODULE_GLOBEBROWSING}/shaders/pointglobe_vs.glsl",
        "${MODULE_GLOBEBROWSING}/shaders/pointglobe_fs.glsl");

    glGenVertexArrays(1, &_vaoID);
    glGenBuffers(1, &_vertexBufferID);

    glBindVertexArray(_vaoID);

    // Vertex data is only one point in the origin
    glm::vec3 data = glm::vec3(0,0,0);

    // Vertex buffer
    glBindBuffer(GL_ARRAY_BUFFER, _vertexBufferID);
    glBufferData(
        GL_ARRAY_BUFFER,
        sizeof(glm::vec3),
        &data,
        GL_STATIC_DRAW
    );

    // Position at location 0
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(glm::vec3), 0);

    glBindVertexArray(0);

    return isReady();
}

bool PointGlobe::deinitialize() {
    return true;
}

bool PointGlobe::isReady() const {
    return (_vaoID != 0) && (_vertexBufferID != 0);
}
    
void PointGlobe::render(const RenderData& data) {
    _programObject->activate();

    // Calculate variables to be used as uniform variables in shader
    glm::dvec3 bodyPosition = data.modelTransform.translation;

    // Model transform and view transform needs to be in double precision
    glm::dmat4 modelTransform =
        glm::translate(glm::dmat4(1.0), bodyPosition) * // Translation
        glm::scale(glm::dmat4(1.0), glm::dvec3(data.modelTransform.scale)); // Scale
    glm::dmat4 modelViewTransform = data.camera.combinedViewMatrix() * modelTransform;
    glm::vec3 directionToSun = glm::normalize(glm::vec3(0) - glm::vec3(bodyPosition));
    glm::vec3 directionToSunViewSpace = glm::mat3(data.camera.combinedViewMatrix()) * directionToSun;
        
    int windowWidth = OsEng.windowWrapper().currentWindowSize().x;
    float avgRadius = _owner.ellipsoid().averageRadius();
        
    _programObject->setUniform("windowWidth", windowWidth);
    _programObject->setUniform("globeRadius", avgRadius);
    _programObject->setUniform("directionToSunViewSpace", directionToSunViewSpace);
    _programObject->setUniform("modelViewTransform", glm::mat4(modelViewTransform));
    _programObject->setUniform("projectionTransform", data.camera.projectionMatrix());

    glEnable(GL_VERTEX_PROGRAM_POINT_SIZE);

    glBindVertexArray(_vaoID);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _vertexBufferID);
    glDrawArrays(GL_POINTS, 0, 1);
    glBindVertexArray(0);

    glDisable(GL_VERTEX_PROGRAM_POINT_SIZE);

    _programObject->deactivate();
}

} // namespace globebrowsing
} // namespace openspace