OpenSpace/modules/globebrowsing/tile/tile.cpp

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

#include <modules/globebrowsing/tile/rawtiledatareader/rawtiledatareader.h>
#include <modules/globebrowsing/tile/tilemetadata.h>

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

namespace openspace {
namespace globebrowsing {

const Tile Tile::TileUnavailable = Tile(nullptr, nullptr, Tile::Status::Unavailable);

Tile::Tile(std::shared_ptr<ghoul::opengl::Texture> texture,
    std::shared_ptr<TileMetaData> metaData, Status status)
    : MemoryAwareCacheable(
        (sizeof(Tile) +
        (metaData ? sizeof(TileMetaData) : 0) +
        (texture ? sizeof(ghoul::opengl::Texture) + texture->expectedPixelDataSize() * 2 : 0))
        // Multiply by two since double memory is used when creating mip maps.
        / 1000 // Convert from bytes to kilobytes
    )
    , _texture(texture)
    , _metaData(metaData)
    , _status(status)
{}

Tile Tile::createPlainTile(const glm::uvec2& size, const glm::uvec4& color) {
    using namespace ghoul::opengl;
        
    // Create pixel data
    int numBytes = size.x * size.y * 4 * 1;
    char* pixels = new char[numBytes];
    size_t numPixels = size.x * size.y;
    size_t i = 0;
    for (size_t p = 0; p < numPixels; p++){
        pixels[i++] = color.r;
        pixels[i++] = color.g;
        pixels[i++] = color.b;
        pixels[i++] = color.a;
    }

    // Create ghoul texture
    auto texture = std::make_shared<Texture>(glm::uvec3(size, 1));
    texture->setDataOwnership(Texture::TakeOwnership::Yes);
    texture->setPixelData(pixels);
    texture->uploadTexture();
    texture->setFilter(ghoul::opengl::Texture::FilterMode::Linear);

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

glm::vec2 Tile::compensateSourceTextureSampling(glm::vec2 startOffset, glm::vec2 sizeDiff,
                                                glm::uvec2 resolution, glm::vec2 tileUV)
{
    glm::vec2 sourceSize = glm::vec2(resolution) + sizeDiff;
    glm::vec2 currentSize = glm::vec2(resolution);
    glm::vec2 sourceToCurrentSize = currentSize / sourceSize;
    tileUV = sourceToCurrentSize * (tileUV - startOffset / sourceSize);
    return tileUV;
}

glm::vec2 Tile::TileUvToTextureSamplePosition(const TileUvTransform& uvTransform,
                                              glm::vec2 tileUV, glm::uvec2 resolution)
{
    glm::vec2 uv = uvTransform.uvOffset + uvTransform.uvScale * tileUV;
    uv = compensateSourceTextureSampling(
        RawTileDataReader::tilePixelStartOffset,
        RawTileDataReader::tilePixelSizeDifference,
        resolution,
        uv);
    return uv;
}

} // namespace globebrowsing
} // namespace openspace