OpenSpace/modules/globebrowsing/meshes/trianglesoup.cpp

/*****************************************************************************************
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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2017                                                               *
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#include <modules/globebrowsing/meshes/trianglesoup.h>

#include <ghoul/logging/logmanager.h>

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

namespace openspace {
namespace globebrowsing {

TriangleSoup::TriangleSoup(std::vector<unsigned int> elements, Positions usePositions,
                           TextureCoordinates useTextures, Normals useNormals)
    : _useVertexPositions(usePositions)
    , _useTextureCoordinates(useTextures)
    , _useVertexNormals(useNormals)
    , _vaoID(0)
    , _vertexBufferID(0)
    , _elementBufferID(0)
{
    setElements(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] = static_cast<GLfloat>(positions[i].x);
        _vertexData[i].position[1] = static_cast<GLfloat>(positions[i].y);
        _vertexData[i].position[2] = static_cast<GLfloat>(positions[i].z);
        _vertexData[i].position[3] = static_cast<GLfloat>(positions[i].w);
    }
}

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] = static_cast<GLfloat>(textures[i].s);
        _vertexData[i].texture[1] = static_cast<GLfloat>(textures[i].t);
    }
}

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] = static_cast<GLfloat>(normals[i].x);
        _vertexData[i].normal[1] = static_cast<GLfloat>(normals[i].y);
        _vertexData[i].normal[2] = static_cast<GLfloat>(normals[i].z);
    }
}

void TriangleSoup::setElements(std::vector<unsigned int> elements) {
    _elementData.resize(elements.size());
    _gpuDataNeedUpdate = true;
    for (size_t i = 0; i < elements.size(); i++) {
        _elementData[i] = static_cast<GLuint>(elements[i]);
    }
}

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

    // Create VBOs
    if (_vertexBufferID == 0 && _vertexData.size() > 0) {
        glGenBuffers(1, &_vertexBufferID);
        if (_vertexBufferID == 0) {
            LERROR("Could not create vertex buffer");
            return false;
        }
    }
    if (_elementBufferID == 0 && _elementData.size() > 0) {
        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, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex),
            reinterpret_cast<const GLvoid*>(offsetof(Vertex, position)));
    }
    // Textures at location 1
    if (_useTextureCoordinates) {
        glEnableVertexAttribArray(1);
        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
            reinterpret_cast<const GLvoid*>(offsetof(Vertex, texture)));
    }
    // Normals at location 2
    if (_useVertexNormals) {
        glEnableVertexAttribArray(2);
        glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
            reinterpret_cast<const GLvoid*>(offsetof(Vertex, normal)));
    }

    // 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, _elementData.size(), GL_UNSIGNED_INT, 0);
    glBindVertexArray(0);
}

} // namespace globebrowsing
} // namespace openspace