OpenSpace/modules/base/rendering/grids/renderablesphericalgrid.cpp

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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2024                                                               *
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#include <modules/base/rendering/grids/renderablesphericalgrid.h>

#include <modules/base/basemodule.h>
#include <openspace/engine/globals.h>
#include <openspace/rendering/renderengine.h>
#include <openspace/util/updatestructures.h>
#include <openspace/documentation/verifier.h>
#include <ghoul/glm.h>
#include <ghoul/filesystem/filesystem.h>
#include <ghoul/opengl/openglstatecache.h>
#include <ghoul/opengl/programobject.h>
#include <optional>

namespace {
    constexpr openspace::properties::Property::PropertyInfo ColorInfo = {
        "Color",
        "Color",
        "The color of the grid lines.",
        openspace::properties::Property::Visibility::NoviceUser
    };

    constexpr openspace::properties::Property::PropertyInfo SegmentsInfo = {
        "Segments",
        "Number of Segments",
        "The number of segments the sphere is split into. Determines the resolution "
        "of the rendered sphere. Should be an even value (if an odd value is provided, "
        "the value will be set to the new value minus one).",
        openspace::properties::Property::Visibility::User
    };

    constexpr openspace::properties::Property::PropertyInfo LineWidthInfo = {
        "LineWidth",
        "Line Width",
        "The width of the grid lines. The larger number, the thicker the lines.",
        openspace::properties::Property::Visibility::NoviceUser
    };

    const openspace::properties::PropertyOwner::PropertyOwnerInfo LabelsInfo = {
        "Labels",
        "Labels",
        "The labels for the grid."
    };

    struct [[codegen::Dictionary(RenderableSphericalGrid)]] Parameters {
        // [[codegen::verbatim(ColorInfo.description)]]
        std::optional<glm::vec3> color [[codegen::color()]];

        // [[codegen::verbatim(SegmentsInfo.description)]]
        std::optional<int> segments;

        // [[codegen::verbatim(LineWidthInfo.description)]]
        std::optional<float> lineWidth;

        // [[codegen::verbatim(LabelsInfo.description)]]
        std::optional<ghoul::Dictionary> labels
            [[codegen::reference("labelscomponent")]];
    };
#include "renderablesphericalgrid_codegen.cpp"
} // namespace

namespace openspace {

documentation::Documentation RenderableSphericalGrid::Documentation() {
    return codegen::doc<Parameters>("base_renderable_sphericalgrid");
}

RenderableSphericalGrid::RenderableSphericalGrid(const ghoul::Dictionary& dictionary)
    : Renderable(dictionary)
    , _gridProgram(nullptr)
    , _color(ColorInfo, glm::vec3(0.5f), glm::vec3(0.f), glm::vec3(1.f))
    , _segments(SegmentsInfo, 36, 4, 200)
    , _lineWidth(LineWidthInfo, 0.5f, 1.f, 20.f)
{
    const Parameters p = codegen::bake<Parameters>(dictionary);

    addProperty(Fadeable::_opacity);

    _color = p.color.value_or(_color);
    _color.setViewOption(properties::Property::ViewOptions::Color);
    addProperty(_color);

    _segments = p.segments.value_or(_segments);
    _segments.onChange([this]() {
        if (_segments.value() % 2 == 1) {
            _segments = _segments - 1;
        }
        _gridIsDirty = true;
    });
    addProperty(_segments);

    _lineWidth = p.lineWidth.value_or(_lineWidth);
    addProperty(_lineWidth);

    // Radius is always 1
    setBoundingSphere(1.0);

    if (p.labels.has_value()) {
        _labels = std::make_unique<LabelsComponent>(*p.labels);
        _hasLabels = true;
        addPropertySubOwner(_labels.get());
        // Fading of the labels should also depend on the fading of the renderable
        _labels->setParentFadeable(this);
    }
}

bool RenderableSphericalGrid::isReady() const {
    return _hasLabels ? _gridProgram && _labels->isReady() : _gridProgram != nullptr;
}

void RenderableSphericalGrid::initialize() {
    if (_hasLabels) {
        _labels->initialize();
    }
}

void RenderableSphericalGrid::initializeGL() {
    _gridProgram = BaseModule::ProgramObjectManager.request(
        "GridProgram",
        []() -> std::unique_ptr<ghoul::opengl::ProgramObject> {
            return global::renderEngine->buildRenderProgram(
                "GridProgram",
                absPath("${MODULE_BASE}/shaders/grid_vs.glsl"),
                absPath("${MODULE_BASE}/shaders/grid_fs.glsl")
            );
        }
    );

    glGenVertexArrays(1, &_vaoID);
    glGenBuffers(1, &_vBufferID);
    glGenBuffers(1, &_iBufferID);

    glBindVertexArray(_vaoID);
    glBindBuffer(GL_ARRAY_BUFFER, _vBufferID);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _iBufferID);
    glEnableVertexAttribArray(0);
    glBindVertexArray(0);
}

void RenderableSphericalGrid::deinitializeGL() {
    glDeleteVertexArrays(1, &_vaoID);
    _vaoID = 0;

    glDeleteBuffers(1, &_vBufferID);
    _vBufferID = 0;

    glDeleteBuffers(1, &_iBufferID);
    _iBufferID = 0;

    BaseModule::ProgramObjectManager.release(
        "GridProgram",
        [](ghoul::opengl::ProgramObject* p) {
            global::renderEngine->removeRenderProgram(p);
        }
    );
    _gridProgram = nullptr;
}

void RenderableSphericalGrid::render(const RenderData& data, RendererTasks&){
    _gridProgram->activate();

    auto [modelTransform, modelViewTransform, modelViewProjectionTransform] =
        calcAllTransforms(data);

    _gridProgram->setUniform("modelViewTransform", modelViewTransform);
    _gridProgram->setUniform("MVPTransform", modelViewProjectionTransform);
    _gridProgram->setUniform("opacity", opacity());
    _gridProgram->setUniform("gridColor", _color);

    // Change GL state:
#ifndef __APPLE__
    glLineWidth(_lineWidth);
#else
    glLineWidth(1.f);
#endif
    glEnablei(GL_BLEND, 0);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glEnable(GL_LINE_SMOOTH);
    glDepthMask(false);

    glBindVertexArray(_vaoID);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _iBufferID);
    glDrawElements(_mode, _isize, GL_UNSIGNED_INT, nullptr);
    glBindVertexArray(0);

    _gridProgram->deactivate();

    // Restore GL State
    global::renderEngine->openglStateCache().resetBlendState();
    global::renderEngine->openglStateCache().resetLineState();
    global::renderEngine->openglStateCache().resetDepthState();

    // Draw labels
    if (_hasLabels && _labels->enabled()) {
        const glm::vec3 lookup = data.camera.lookUpVectorWorldSpace();
        const glm::vec3 viewDirection = data.camera.viewDirectionWorldSpace();
        glm::vec3 right = glm::cross(viewDirection, lookup);
        const glm::vec3 up = glm::cross(right, viewDirection);

        const glm::dmat4 worldToModelTransform = glm::inverse(modelTransform);
        glm::vec3 orthoRight = glm::normalize(
            glm::vec3(worldToModelTransform * glm::vec4(right, 0.0))
        );

        if (orthoRight == glm::vec3(0.0)) {
            const glm::vec3 otherVector = glm::vec3(lookup.y, lookup.x, lookup.z);
            right = glm::cross(viewDirection, otherVector);
            orthoRight = glm::normalize(
                glm::vec3(worldToModelTransform * glm::vec4(right, 0.0))
            );
        }
        const glm::vec3 orthoUp = glm::normalize(
            glm::vec3(worldToModelTransform * glm::dvec4(up, 0.0))
        );
        _labels->render(data, modelViewProjectionTransform, orthoRight, orthoUp);
    }
}

void RenderableSphericalGrid::update(const UpdateData&) {
    if (!_gridIsDirty) {
        return;
    }

    _isize = 6 * _segments * _segments;
    _vsize = (_segments + 1) * (_segments + 1);
    _varray.resize(_vsize);
    constexpr Vertex v = { 0.f, 0.f, 0.f };
    std::fill(_varray.begin(), _varray.end(), v);
    _iarray.resize(_isize);
    std::fill(_iarray.begin(), _iarray.end(), 0);

    int nr = 0;
    const float fsegments = static_cast<float>(_segments);

    for (int nSegment = 0; nSegment <= _segments; ++nSegment) {
        // define an extra vertex around the y-axis due to texture mapping
        for (int j = 0; j <= _segments; j++) {
            const float fi = static_cast<float>(nSegment);
            const float fj = static_cast<float>(j);

            // inclination angle (north to south)
            const float theta = fi * glm::pi<float>() / fsegments * 2.f;  // 0 -> PI

            // azimuth angle (east to west)
            const float phi = fj * glm::pi<float>() * 2.0f / fsegments;  // 0 -> 2*PI

            const float x = std::sin(phi) * std::sin(theta);  //
            const float y = std::cos(theta);                  // up
            const float z = std::cos(phi) * std::sin(theta);  //

            glm::vec3 normal = glm::vec3(x, y, z);
            if (x != 0.f || y != 0.f || z != 0.f) {
                normal = glm::normalize(normal);
            }

            glm::vec4 tmp(x, y, z, 1.f);
            const glm::mat4 rot = glm::rotate(
                glm::mat4(1.f),
                glm::half_pi<float>(),
                glm::vec3(1.f, 0.f, 0.f)
            );
            tmp = glm::vec4(glm::dmat4(rot) * glm::dvec4(tmp));

            for (int i = 0; i < 3; i++) {
                _varray[nr].location[i] = tmp[i];
            }
            ++nr;
        }
    }
    nr = 0;
    // define indices for all triangles
    for (int i = 1; i <= _segments; i++) {
        for (int j = 0; j < _segments; j++) {
            const int t = _segments + 1;
            _iarray[nr] = t * (i - 1) + j + 0; ++nr;
            _iarray[nr] = t * (i + 0) + j + 0; ++nr;
            _iarray[nr] = t * (i + 0) + j + 1; ++nr;
            _iarray[nr] = t * (i - 1) + j + 1; ++nr;
            _iarray[nr] = t * (i - 1) + j + 0; ++nr;
        }
    }

    glBindVertexArray(_vaoID);
    glBindBuffer(GL_ARRAY_BUFFER, _vBufferID);
    glBufferData(
        GL_ARRAY_BUFFER,
        _vsize * sizeof(Vertex),
        _varray.data(),
        GL_STATIC_DRAW
    );

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), nullptr);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _iBufferID);
    glBufferData(
        GL_ELEMENT_ARRAY_BUFFER,
        _isize * sizeof(int),
        _iarray.data(),
        GL_STATIC_DRAW
    );

    _gridIsDirty = false;
}

} // namespace openspace