/*****************************************************************************************
*                                                                                       *
* OpenSpace                                                                             *
*                                                                                       *
* Copyright (c) 2014-2016                                                               *
*                                                                                       *
* 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/meshes/skirtedgrid.h>

namespace {
    const std::string _loggerCat = "SkirtedGrid";
}

namespace openspace {

    SkirtedGrid::SkirtedGrid(
        unsigned int xSegments,
        unsigned int ySegments,
        TriangleSoup::Positions usePositions,
        TriangleSoup::TextureCoordinates useTextureCoordinates,
        TriangleSoup::Normals useNormals)
        : Grid(
            xSegments,
            ySegments,
            usePositions,
            useTextureCoordinates,
            useNormals)
    {
        _geometry = std::unique_ptr<TriangleSoup>(new TriangleSoup(
            CreateElements(xSegments, ySegments),
            usePositions,
            useTextureCoordinates,
            useNormals));

        if (usePositions == TriangleSoup::Positions::Yes) {
            _geometry->setVertexPositions(CreatePositions(_xSegments, _ySegments));
        }
        if (useTextureCoordinates == TriangleSoup::TextureCoordinates::Yes) {
            _geometry->setVertexTextureCoordinates(CreateTextureCoordinates(_xSegments, _ySegments));
        }
        if (useNormals == TriangleSoup::Normals::Yes) {
            _geometry->setVertexNormals(CreateNormals(_xSegments, _ySegments));
        }
    }

    SkirtedGrid::~SkirtedGrid()
    {

    }

    int SkirtedGrid::xSegments() const {
        return _xSegments;
    }

    int SkirtedGrid::ySegments() const {
        return _ySegments;
    }

    void SkirtedGrid::validate(int xSegments, int ySegments) {
        ghoul_assert(xSegments > 0 && ySegments > 0,
            "Resolution must be at least 1x1. (" << xSegments << ", " << ySegments << ")");
    }

    inline size_t SkirtedGrid::numElements(int xSegments, int ySegments) {
        return 3 * 2 * xSegments * ySegments;
    }

    inline size_t SkirtedGrid::numVertices(int xSegments, int ySegments) {
        return (xSegments + 1) * (ySegments + 1);
    }

    std::vector<GLuint> SkirtedGrid::CreateElements(int xSegments, int ySegments) {
        validate(xSegments, ySegments);

        std::vector<GLuint> elements;
        elements.reserve(numElements(xSegments + 2, ySegments + 2));
        for (unsigned int y = 0; y < ySegments + 2; y++) {
            for (unsigned int x = 0; x < xSegments + 2; x++) {

                // x    v01---v11   x ..
                //       |  /  |
                // x    v00---v10   x ..
                //
                // x	x     x     x ..
                // :    :     :     :

                GLuint v00 = (y + 0) * (xSegments + 2 + 1) + x + 0;
                GLuint v10 = (y + 0) * (xSegments + 2 + 1) + x + 1;
                GLuint v01 = (y + 1) * (xSegments + 2 + 1) + x + 0;
                GLuint v11 = (y + 1) * (xSegments + 2 + 1) + x + 1;

                // add upper triangle
                elements.push_back(v00);
                elements.push_back(v10);
                elements.push_back(v11);

                // add lower triangle
                elements.push_back(v00);
                elements.push_back(v11);
                elements.push_back(v01);
            }
        }

        return elements;
    }

    std::vector<glm::vec4> SkirtedGrid::CreatePositions(
        int xSegments,
        int ySegments)
    {
        validate(xSegments, ySegments);
        std::vector<glm::vec4> positions;
        positions.reserve(numVertices(xSegments, ySegments));

        // Copy from 2d texture coordinates and use as template to create positions
        std::vector<glm::vec2> templateTextureCoords = CreateTextureCoordinates(xSegments, ySegments);
        for (unsigned int i = 0; i < templateTextureCoords.size(); i++)
        {
            positions.push_back(glm::vec4(
                templateTextureCoords[i],
                0.0f,
                1.0f
                ));
        }
        return positions;
    }

    std::vector<glm::vec2> SkirtedGrid::CreateTextureCoordinates(int xSegments, int ySegments) {
        validate(xSegments, ySegments);
        std::vector<glm::vec2> textureCoordinates;
        textureCoordinates.reserve(numVertices(xSegments + 2, ySegments + 2));

        for (int y = -1; y < ySegments + 2; y++) {
            for (int x = -1; x < xSegments + 2; x++) {
                textureCoordinates.push_back(glm::vec2(
                    glm::clamp(static_cast<float>(x) / static_cast<float>(xSegments), 0 - 1.0f / (2 * xSegments), 1 + 1.0f / (2 * xSegments)),
                    glm::clamp(static_cast<float>(y) / static_cast<float>(ySegments), 0 - 1.0f / (2 * ySegments), 1 + 1.0f / (2 * ySegments))
                    ));
            }
        }
        return textureCoordinates;
    }

    std::vector<glm::vec3> SkirtedGrid::CreateNormals(int xSegments, int ySegments) {
        validate(xSegments, ySegments);
        std::vector<glm::vec3> normals;
        normals.reserve(numVertices(xSegments + 2, ySegments + 2));

        for (int y = -1; y < ySegments + 2; y++) {
            for (int x = -1; x < xSegments + 2; x++) {
                normals.push_back(glm::vec3(0, 0, 1));
            }
        }

        return normals;
    }
}// namespace openspace