OpenSpace/modules/globebrowsing/meshes/trianglesoup.cpp

/*****************************************************************************************
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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2018                                                               *
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#include <modules/globebrowsing/meshes/trianglesoup.h>

#include <ghoul/logging/logmanager.h>

namespace {
    constexpr const char* _loggerCat = "TriangleSoup";
} // namespace

namespace openspace::globebrowsing {

TriangleSoup::TriangleSoup(std::vector<unsigned int> elements, Positions usePositions,
                           TextureCoordinates useTextures, Normals useNormals)
    : _useVertexPositions(usePositions)
    , _useTextureCoordinates(useTextures)
    , _useVertexNormals(useNormals)
{
    setElements(std::move(elements));
}

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

void TriangleSoup::setVertexPositions(std::vector<glm::vec4> positions) {
    _useVertexPositions = true;
    _gpuDataNeedUpdate = true;
    _vertexData.resize(positions.size());
    for (size_t i = 0; i < positions.size(); ++i) {
        _vertexData[i].position[0] = positions[i][0];
        _vertexData[i].position[1] = positions[i][1];
        _vertexData[i].position[2] = positions[i][2];
        //_vertexData[i].position[3] = positions[i][3];
    }
}

void TriangleSoup::setVertexTextureCoordinates(std::vector<glm::vec2> textures) {
    _useTextureCoordinates = true;
    _gpuDataNeedUpdate = true;
    _vertexData.resize(textures.size());
    for (size_t i = 0; i < textures.size(); ++i) {
        _vertexData[i].texture[0] = textures[i][0];
        _vertexData[i].texture[1] = textures[i][1];
    }
}

void TriangleSoup::setVertexNormals(std::vector<glm::vec3> normals) {
    _useVertexNormals = true;
    _gpuDataNeedUpdate = true;
    _vertexData.resize(normals.size());
    for (size_t i = 0; i < normals.size(); ++i) {
        _vertexData[i].normal[0] = normals[i][0];
        _vertexData[i].normal[1] = normals[i][1];
        _vertexData[i].normal[2] = normals[i][2];
    }
}

void TriangleSoup::setElements(std::vector<unsigned int> elements) {
    _gpuDataNeedUpdate = true;
    _elementData = std::move(elements);
}

bool TriangleSoup::updateDataOnGPU() {
    // Create VAO
    if (_vaoID == 0) {
        glGenVertexArrays(1, &_vaoID);
    }

    // Create VBOs
    if (_vertexBufferID == 0 && !_vertexData.empty()) {
        glGenBuffers(1, &_vertexBufferID);
        if (_vertexBufferID == 0) {
            LERROR("Could not create vertex buffer");
            return false;
        }
    }
    if (_elementBufferID == 0 && !_elementData.empty()) {
        glGenBuffers(1, &_elementBufferID);
        if (_elementBufferID == 0) {
            LERROR("Could not create vertex element buffer");
            return false;
        }
    }

    // First VAO setup
    glBindVertexArray(_vaoID);

    // Vertex buffer
    glBindBuffer(GL_ARRAY_BUFFER, _vertexBufferID);
    glBufferData(
        GL_ARRAY_BUFFER,
        _vertexData.size() * sizeof(Vertex),
        &_vertexData[0],
        GL_STATIC_DRAW
    );

    // Positions at location 0
    if (_useVertexPositions) {
        glEnableVertexAttribArray(0);
        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), nullptr);
    }
    // Textures at location 1
    if (_useTextureCoordinates) {
        glEnableVertexAttribArray(1);
        glVertexAttribPointer(
            1,
            2,
            GL_FLOAT,
            GL_FALSE,
            sizeof(Vertex),
            reinterpret_cast<const GLvoid*>(offsetof(Vertex, texture)) // NOLINT
        );
    }
    // Normals at location 2
    if (_useVertexNormals) {
        glEnableVertexAttribArray(2);
        glVertexAttribPointer(
            2,
            3,
            GL_FLOAT,
            GL_FALSE,
            sizeof(Vertex),
            reinterpret_cast<const GLvoid*>(offsetof(Vertex, normal))  // NOLINT
        );
    }

    // Element buffer
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _elementBufferID);
    glBufferData(
        GL_ELEMENT_ARRAY_BUFFER,
        _elementData.size() * sizeof(GLint),
        &_elementData[0],
        GL_STATIC_DRAW);

    glBindVertexArray(0);

    _gpuDataNeedUpdate = false;

    return true;
}

void TriangleSoup::drawUsingActiveProgram() {
    if (_gpuDataNeedUpdate) {
        updateDataOnGPU();
    }
    glBindVertexArray(_vaoID);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _elementBufferID);
    glDrawElements(
        GL_TRIANGLES,
        static_cast<GLsizei>(_elementData.size()),
        GL_UNSIGNED_INT,
        nullptr
    );
    glBindVertexArray(0);
}

} // namespace openspace::globebrowsing