OpenSpace/modules/globebrowsing/tile/tileprovider/texttileprovider.cpp

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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2017                                                               *
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#include <modules/globebrowsing/tile/tileprovider/texttileprovider.h>

#include <modules/globebrowsing/geometry/geodeticpatch.h>
#include <modules/globebrowsing/tile/tileindex.h>
#include <modules/globebrowsing/cache/memoryawaretilecache.h>

#include <openspace/engine/openspaceengine.h>
#include <openspace/engine/moduleengine.h>

#include <ghoul/filesystem/filesystem.h>
#include <ghoul/font/fontmanager.h>
#include <ghoul/font/fontrenderer.h>
#include <ghoul/io/texture/texturereader.h>
#include <ghoul/misc/dictionary.h>

using namespace ghoul::fontrendering;

namespace openspace {
namespace globebrowsing {
namespace tileprovider {
    
TextTileProvider::TextTileProvider(const TileTextureInitData& initData, size_t fontSize)
    : _initData(initData)
    , _fontSize(fontSize)
{
    _tileCache = OsEng.moduleEngine().module<GlobeBrowsingModule>()->tileCache();
    _font = OsEng.fontManager().font("Mono", _fontSize);
        
    _fontRenderer = std::unique_ptr<FontRenderer>(FontRenderer::createDefault());
    _fontRenderer->setFramebufferSize(_initData.dimensionsWithPadding());
    
    glGenFramebuffers(1, &_fbo);
}

TextTileProvider::~TextTileProvider() {
    glDeleteFramebuffers(1, &_fbo);
}

Tile TextTileProvider::getTile(const TileIndex& tileIndex) {
    cache::ProviderTileKey key = { tileIndex, uniqueIdentifier() };

    Tile tile = _tileCache->get(key);

    if (tile.texture() == nullptr) {
        tile = TextTileProvider::createChunkIndexTile(tileIndex);
        _tileCache->put(key, _initData.hashKey(), tile);
    }
    return tile;
}

Tile::Status TextTileProvider::getTileStatus(const TileIndex&) {
    return Tile::Status::OK;
}

TileDepthTransform TextTileProvider::depthTransform() {
    TileDepthTransform transform;
    transform.depthOffset = 0.0f;
    transform.depthScale = 1.0f;
    return transform;
}

void TextTileProvider::update() {}

void TextTileProvider::reset() {
    _tileCache->clear();
}

Tile TextTileProvider::createChunkIndexTile(const TileIndex& tileIndex) {
    ghoul::opengl::Texture* texture = _tileCache->getTexture(_initData);

    // Keep track of defaultFBO and viewport to be able to reset state when done
    GLint defaultFBO;
    GLint viewport[4];
    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &defaultFBO);
    glGetIntegerv(GL_VIEWPORT, viewport);

    // Render to texture
    glBindFramebuffer(GL_FRAMEBUFFER, _fbo);
    glFramebufferTexture2D(
        GL_FRAMEBUFFER,
        GL_COLOR_ATTACHMENT0,
        GL_TEXTURE_2D,
        *texture,
        0
    );

    glViewport(
        0, 0,
        static_cast<GLsizei>(texture->width()),
        static_cast<GLsizei>(texture->height())
    );

    glClearColor(0,0,0,0);
    glClear(GL_COLOR_BUFFER_BIT);
        
    ghoul_assert(_fontRenderer != nullptr, "_fontRenderer must not be null");
    renderText(*_fontRenderer, tileIndex);

    // Reset state: bind default FBO and set viewport to what it was
    glBindFramebuffer(GL_FRAMEBUFFER, defaultFBO);
    glViewport(viewport[0], viewport[1], viewport[2], viewport[3]);

    return Tile(texture, nullptr, Tile::Status::OK);
}

int TextTileProvider::maxLevel() {
    return 1337; // unlimited
}

TileIndex::TileHashKey TextTileProvider::toHash(const TileIndex& tileIndex) const {
    return tileIndex.hashKey();
}

} // namespace tileprovider
} // namespace globebrowsing
} // namespace openspace