OpenSpace/modules/base/rendering/renderabletrail.cpp

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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2025                                                               *
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#include <modules/base/rendering/renderabletrail.h>

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

namespace {
#ifdef __APPLE__
    constexpr std::array<const char*, 16> UniformNames = {
        "opacity", "modelViewTransform", "projectionTransform", "color", "useLineFade",
        "lineLength", "lineFadeAmount", "vertexSortingMethod", "idOffset", "nVertices",
        "stride", "pointSize", "renderPhase", "useSplitRenderMode", "floatingOffset",
        "numberOfUniqueVertices"
    };
#else // ^^^^ __APPLE__ // !__APPLE__ vvvv
    constexpr std::array<const char*, 18> UniformNames = {
        "opacity", "modelViewTransform", "projectionTransform", "color", "useLineFade",
        "lineLength", "lineFadeAmount", "vertexSortingMethod", "idOffset", "nVertices",
        "stride", "pointSize", "renderPhase", "viewport", "lineWidth", "floatingOffset",
        "useSplitRenderMode", "numberOfUniqueVertices"
    };
#endif // __APPLE__

    // The possible values for the _renderingModes property
    enum RenderingMode {
        RenderingModeLines = 0,
        RenderingModePoints,
        RenderingModeLinesPoints
    };

    // Fragile! Keep in sync with documentation
    const std::map<std::string, RenderingMode> RenderingModeConversion = {
        { "Lines", RenderingModeLines },
        { "Points", RenderingModePoints },
        { "Lines+Points", RenderingModeLinesPoints },
        { "Points+Lines", RenderingModeLinesPoints }
    };

    constexpr openspace::properties::Property::PropertyInfo LineColorInfo = {
        "Color",
        "Color",
        "This value determines the RGB main color for the lines and points of the trail.",
        openspace::properties::Property::Visibility::NoviceUser
    };

    constexpr openspace::properties::Property::PropertyInfo EnableFadeInfo = {
        "EnableFade",
        "Enable line fading of old points",
        "Toggles whether the trail should fade older points out. If this value is "
        "true, the 'Fade' parameter determines the speed of fading. If this value is "
        "false, the entire trail is rendered at full opacity and color.",
        openspace::properties::Property::Visibility::NoviceUser
    };

    constexpr openspace::properties::Property::PropertyInfo LineLengthInfo = {
        "LineLength",
        "Line length",
        "The extent of the rendered trail. A value of 0 will result in no trail and a "
        "value of 1 will result in a trail that covers the entire extent. The setting "
        "only applies if 'EnableFade' is true. If it is false, this setting has "
        "no effect.",
        openspace::properties::Property::Visibility::User
    };

    constexpr openspace::properties::Property::PropertyInfo LineFadeAmountInfo = {
        "LineFadeAmount",
        "Line fade amount",
        "The amount of the trail that should be faded. If the value is 0 then the "
        "trail will have no fading applied. A value of 0.6 will result in a trail "
        "where 60% of the extent of the trail will have fading applied to it. In other "
        "words, the 40% closest to the head of the trail will be solid and the rest "
        "will fade until completely transparent at the end of the trail. A value of 1 "
        "will result in a trail that starts fading immediately, becoming fully "
        "transparent by the end of the trail. This setting only applies if the "
        "'EnableFade' value is true. If it is false, this setting has no effect.",
        openspace::properties::Property::Visibility::User
    };

    constexpr openspace::properties::Property::PropertyInfo LineWidthInfo = {
        "LineWidth",
        "Line width",
        "Specifies the line width of the trail lines, if the selected rendering method "
        "includes lines. If the rendering mode is Points, this value is ignored.",
        openspace::properties::Property::Visibility::User
    };

    constexpr openspace::properties::Property::PropertyInfo PointSizeInfo = {
        "PointSize",
        "Point size",
        "Specifies the base size of the points along the line, if the selected rendering "
        "method includes points. If the rendering mode is Lines, this value is ignored. "
        "If a subsampling of the values is performed, the subsampled values are half "
        "this size.",
        openspace::properties::Property::Visibility::User
    };

    constexpr openspace::properties::Property::PropertyInfo RenderingModeInfo = {
        "Rendering",
        "Rendering mode",
        "Determines how the trail should be rendered. If 'Lines' is selected, only the "
        "line part is visible, if 'Points' is selected, only the corresponding points "
        "(and subpoints) are shown. 'Lines+Points' shows both parts.",
        openspace::properties::Property::Visibility::AdvancedUser
    };

    struct [[codegen::Dictionary(RenderableTrail)]] Parameters {
        // A translation used to compute locations along the path.
        ghoul::Dictionary translation
            [[codegen::reference("core_transform_translation")]];

        // [[codegen::verbatim(LineColorInfo.description)]]
        glm::vec3 color [[codegen::color()]];

        // [[codegen::verbatim(EnableFadeInfo.description)]]
        std::optional<bool> enableFade;

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

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

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

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

        enum class RenderingMode {
            Lines,
            Points,
            LinesPoints [[codegen::key("Lines+Points")]],
            PointsLines [[codegen::key("Lines+Points")]]
        };
        // [[codegen::verbatim(RenderingModeInfo.description)]]
        std::optional<RenderingMode> renderingMode [[codegen::key("Rendering")]];
    };
#include "renderabletrail_codegen.cpp"
} // namespace

namespace openspace {

documentation::Documentation RenderableTrail::Documentation() {
    return codegen::doc<Parameters>("base_renderable_renderabletrail");
}

RenderableTrail::Appearance::Appearance()
    : properties::PropertyOwner({
        "Appearance",
        "Appearance",
        "The appearance of the trail"
    })
    , lineColor(LineColorInfo, glm::vec3(1.f), glm::vec3(0.f), glm::vec3(1.f))
    , useLineFade(EnableFadeInfo, true)
    , lineWidth(LineWidthInfo, 10.f, 1.f, 20.f)
    , pointSize(PointSizeInfo, 1, 1, 64)
    , renderingModes(RenderingModeInfo)
    , lineLength(LineLengthInfo, 1.f, 0.f, 1.f)
    , lineFadeAmount(LineFadeAmountInfo, 1.f, 0.f, 1.f)
{
    renderingModes.addOptions({
        { RenderingModeLines, "Lines" },
        { RenderingModePoints, "Points" },
        { RenderingModeLinesPoints, "Lines+Points" }
    });

    lineColor.setViewOption(properties::Property::ViewOptions::Color);
    addProperty(lineColor);
    addProperty(lineWidth);
    addProperty(pointSize);
    addProperty(renderingModes);
    addProperty(useLineFade);
    addProperty(lineLength);
    addProperty(lineFadeAmount);
}

RenderableTrail::RenderableTrail(const ghoul::Dictionary& dictionary)
    : Renderable(dictionary)
{
    const Parameters p = codegen::bake<Parameters>(dictionary);

    setRenderBin(RenderBin::Overlay);
    addProperty(Fadeable::_opacity);

    _translation = Translation::createFromDictionary(p.translation);
    addPropertySubOwner(_translation.get());

    _appearance.lineColor = p.color;
    _appearance.useLineFade = p.enableFade.value_or(_appearance.useLineFade);
    _appearance.lineLength = p.lineLength.value_or(_appearance.lineLength);
    _appearance.lineWidth = p.lineWidth.value_or(_appearance.lineWidth);
    _appearance.pointSize = p.pointSize.value_or(_appearance.pointSize);

    if (p.renderingMode.has_value()) {
        switch (*p.renderingMode) {
            case Parameters::RenderingMode::Lines:
                _appearance.renderingModes = RenderingModeLines;
                break;
            case Parameters::RenderingMode::Points:
                _appearance.renderingModes = RenderingModePoints;
                break;
            case Parameters::RenderingMode::LinesPoints:
            case Parameters::RenderingMode::PointsLines:
                _appearance.renderingModes = RenderingModeLinesPoints;
                break;
        }
    }
    else {
        _appearance.renderingModes = RenderingModeLines;
    }

    addPropertySubOwner(_appearance);
}

void RenderableTrail::initialize() {
    Renderable::initialize();
    _translation->initialize();
}

void RenderableTrail::initializeGL() {
    ZoneScoped;

#ifdef __APPLE__
    _programObject = BaseModule::ProgramObjectManager.request(
        "EphemerisProgram",
        []() -> std::unique_ptr<ghoul::opengl::ProgramObject> {
            return global::renderEngine->buildRenderProgram(
                "EphemerisProgram",
                absPath("${MODULE_BASE}/shaders/renderabletrail_apple_vs.glsl"),
                absPath("${MODULE_BASE}/shaders/renderabletrail_apple_fs.glsl")
            );
        }
    );
#else // ^^^^ __APPLE__ // !__APPLE__ vvvv
    _programObject = BaseModule::ProgramObjectManager.request(
        "EphemerisProgram",
        []() -> std::unique_ptr<ghoul::opengl::ProgramObject> {
            return global::renderEngine->buildRenderProgram(
                "EphemerisProgram",
                absPath("${MODULE_BASE}/shaders/renderabletrail_vs.glsl"),
                absPath("${MODULE_BASE}/shaders/renderabletrail_fs.glsl")
            );
        }
    );
#endif // __APPLE__

    ghoul::opengl::updateUniformLocations(*_programObject, _uniformCache, UniformNames);
}

void RenderableTrail::deinitializeGL() {
    BaseModule::ProgramObjectManager.release(
        "EphemerisProgram",
        [](ghoul::opengl::ProgramObject* p) {
            global::renderEngine->removeRenderProgram(p);
        }
    );
    _programObject = nullptr;
}

bool RenderableTrail::isReady() const {
    return _programObject != nullptr;
}

glm::dvec3 RenderableTrail::translationPosition(Time time) const {
    // Use empty modelTransform (local coordinates) and time 0; previous frame time
    // doesn't matter
    const UpdateData data = { {}, time, Time(0.0) };
    // (2025-06-09, emmbr) No need to call update here, since it's only for caching
    // the position and kills the trail performance. If behavior changes or we add
    // a translation type that needs pre-update, we need add the update and address
    // performance
    //_translation->update(data);
    return _translation->position(data);
}

void RenderableTrail::internalRender(bool renderLines, bool renderPoints,
                                     const RenderData& data,
                                     const glm::dmat4& modelTransform,
                                     RenderInformation& info, int nVertices,
                                     int ringOffset, bool useSplitRenderMode,
                                     int numberOfUniqueVertices, int floatingOffset)
{
    ZoneScoped;

    // We pass in the model view transformation matrix as double in order to maintain
    // high precision for vertices; especially for the trails, a high vertex precision
    // is necessary as they are usually far away from their reference
    const glm::dmat4 modelViewTransform = calcModelViewTransform(data, modelTransform);
    _programObject->setUniform(
        _uniformCache.modelViewTransform,
        modelViewTransform * info._localTransform
    );

    const int sorting = [](RenderInformation::VertexSorting s) {
        switch (s) {
            case RenderInformation::VertexSorting::NewestFirst: return 0;
            case RenderInformation::VertexSorting::OldestFirst: return 1;
            case RenderInformation::VertexSorting::NoSorting:   return 2;
            default:                                  throw ghoul::MissingCaseException();
        }
    }(info.sorting);

    // The vertex sorting method is used to tweak the fading along the trajectory
    _programObject->setUniform(_uniformCache.vertexSortingMethod, sorting);

    // This value is subtracted from the vertex id in the case of a potential ring
    // buffer (as used in RenderableTrailOrbit) to keep the first vertex at its
    // brightest
    _programObject->setUniform(_uniformCache.idOffset, ringOffset);

    _programObject->setUniform(_uniformCache.nVertices, nVertices);
    _programObject->setUniform(_uniformCache.floatingOffset, floatingOffset);
    _programObject->setUniform(_uniformCache.useSplitRenderMode, useSplitRenderMode);
    _programObject->setUniform(_uniformCache.numberOfUniqueVertices,
        numberOfUniqueVertices);

#ifndef __APPLE__
    std::array<GLint, 4> viewport;
    global::renderEngine->openglStateCache().viewport(viewport.data());
    _programObject->setUniform(
        _uniformCache.viewport,
        static_cast<float>(viewport[0]),
        static_cast<float>(viewport[1]),
        static_cast<float>(viewport[2]),
        static_cast<float>(viewport[3])
    );
    _programObject->setUniform(
        _uniformCache.lineWidth,
        std::ceil((2.f * 1.f + _appearance.lineWidth) * std::sqrt(2.f))
    );
#endif // __APPLE__

    if (renderPoints) {
        // The stride parameter determines the distance between larger points and
        // smaller ones
        _programObject->setUniform(_uniformCache.stride, info.stride);
        _programObject->setUniform(_uniformCache.pointSize, _appearance.pointSize);
    }

    // Fragile! Keep in sync with fragment shader
    enum RenderPhase {
        RenderPhaseLines = 0,
        RenderPhasePoints
    };

    glBindVertexArray(info._vaoID);
    if (renderLines) {
        _programObject->setUniform(_uniformCache.renderPhase, RenderPhaseLines);
        // Subclasses of this renderer might be using the index array or might now be
        // so we check if there is data available and if there isn't, we use the
        // glDrawArrays draw call; otherwise the glDrawElements
        if (info._iBufferID == 0) {
            glDrawArrays(
                GL_LINE_STRIP,
                info.first,
                info.count
            );
        }
        else {
            glDrawElements(
                GL_LINE_STRIP,
                info.count,
                GL_UNSIGNED_INT,
                reinterpret_cast<void*>(info.first * sizeof(unsigned int))
            );
        }
    }
    if (renderPoints) {
        // Subclasses of this renderer might be using the index array or might now be
        // so we check if there is data available and if there isn't, we use the
        // glDrawArrays draw call; otherwise the glDrawElements
        _programObject->setUniform(_uniformCache.renderPhase, RenderPhasePoints);
        if (info._iBufferID == 0) {
            glDrawArrays(GL_POINTS, info.first, info.count);
        }
        else {
            glDrawElements(
                GL_POINTS,
                info.count,
                GL_UNSIGNED_INT,
                reinterpret_cast<void*>(info.first * sizeof(unsigned int))
            );
        }
    }
}

void RenderableTrail::render(const RenderData& data, RendererTasks&) {
    ZoneScoped;

    _programObject->activate();
    _programObject->setUniform(_uniformCache.opacity, opacity());

    const glm::dmat4 modelTransform = calcModelTransform(data);

    _programObject->setUniform(
        _uniformCache.projectionTransform,
        data.camera.projectionMatrix()
    );

    _programObject->setUniform(_uniformCache.color, _appearance.lineColor);
    _programObject->setUniform(_uniformCache.useLineFade, _appearance.useLineFade);
    if (_appearance.useLineFade) {
        const float startPoint = 1.f - _appearance.lineLength;
        const float remainingRange = 1.f - startPoint;
        const float delta = remainingRange * _appearance.lineFadeAmount;
        const float endPoint = std::min(startPoint + delta, 1.f);
        _programObject->setUniform(_uniformCache.lineLength, startPoint);
        _programObject->setUniform(_uniformCache.lineFadeAmount, endPoint);
    }

    /*glm::ivec2 resolution = global::renderEngine.renderingResolution();
    _programObject->setUniform(_uniformCache.resolution, resolution);*/

    glDepthMask(false);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE);

    const bool renderLines = (_appearance.renderingModes == RenderingModeLines) ||
                             (_appearance.renderingModes == RenderingModeLinesPoints);

    const bool renderPoints = (_appearance.renderingModes == RenderingModePoints) ||
                              (_appearance.renderingModes == RenderingModeLinesPoints);

    if (renderLines) {
#ifdef __APPLE__
        glLineWidth(1);
#else // ^^^^ __APPLE__ // !__APPLE__ vvvv
        glLineWidth(std::ceil((2.f * 1.f + _appearance.lineWidth) * std::sqrt(2.f)));
#endif // __APPLE__
    }
    if (renderPoints) {
        glEnable(GL_PROGRAM_POINT_SIZE);
    }

    // The combined size of vertices; -1 because we duplicate the penultimate point
    const int totalNumber = _primaryRenderInformation.count +
                            _floatingRenderInformation.count - 1;

    // The primary information might use an index buffer, so we might need to start at an
    // offset
    const int primaryOffset = (_primaryRenderInformation._iBufferID == 0) ?
        0 :
        _primaryRenderInformation.first;

    // Culling
    //const glm::dvec3 trailPosWorld = glm::dvec3(
    //    modelTransform * _primaryRenderInformation._localTransform *
    //    glm::dvec4(0.0, 0.0, 0.0, 1.0)
    //);
    //const double distance = glm::distance(trailPosWorld, data.camera.eyePositionVec3());

    //if (distance > boundingSphere() * DISTANCE_CULLING_RADII) {
    //    // Reset
    //    global::renderEngine->openglStateCache().resetBlendState();
    //    global::renderEngine->openglStateCache().resetDepthState();
    //    return;
    //}

    if (_useSplitRenderMode) {
        // Splits the trail up into three parts for more accurate rendering
        // of renderableTrailTrajectory trails

        internalRender(
            renderLines,
            renderPoints,
            data,
            modelTransform,
            _primaryRenderInformation,
            _primaryRenderInformation.count,
            _primaryRenderInformation.first,
            _useSplitRenderMode,
            _nUniqueVertices
        );

        const int floatingOffset = std::max(0, _primaryRenderInformation.count - 1);
        internalRender(
            renderLines,
            renderPoints,
            data,
            modelTransform,
            _floatingRenderInformation,
            _floatingRenderInformation.count,
            _floatingRenderInformation.first,
            _useSplitRenderMode,
            _nUniqueVertices,
            floatingOffset
        );

        const int offset = (_floatingRenderInformation.count > 0) ? 1 : 0;
        internalRender(
            renderLines,
            renderPoints,
            data,
            modelTransform,
            _secondaryRenderInformation,
            _secondaryRenderInformation.count,
            _secondaryRenderInformation.first,
            _useSplitRenderMode,
            _nUniqueVertices,
            offset
        );

    }
    else {
        // Render the primary batch of vertices
        internalRender(
            renderLines,
            renderPoints,
            data,
            modelTransform,
            _primaryRenderInformation,
            totalNumber,
            primaryOffset
        );

        // The secondary batch is optional. We need to check whether we have any data
        if (_floatingRenderInformation._vaoID != 0 &&
            _floatingRenderInformation.count != 0) {
            internalRender(
                renderLines,
                renderPoints,
                data,
                modelTransform,
                _floatingRenderInformation,
                totalNumber,
                // -1 because we duplicate the penultimate point between the vertices
                -(primaryOffset + _primaryRenderInformation.count - 1)
            );
        }
    }


    if (renderPoints) {
        glDisable(GL_PROGRAM_POINT_SIZE);
    }

    glBindVertexArray(0);

    // Reset
    global::renderEngine->openglStateCache().resetBlendState();
    global::renderEngine->openglStateCache().resetDepthState();

    _programObject->deactivate();
}

} // namespace openspace