OpenSpace/modules/globebrowsing/src/tiletextureinitdata.cpp

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 * OpenSpace                                                                             *
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 * Copyright (c) 2014-2023                                                               *
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#include <modules/globebrowsing/src/tiletextureinitdata.h>

namespace {

size_t numberOfRasters(ghoul::opengl::Texture::Format format) {
    switch (format) {
        case ghoul::opengl::Texture::Format::Red:
            return 1;
        case ghoul::opengl::Texture::Format::RG:
            return 2;
        case ghoul::opengl::Texture::Format::RGB:
        case ghoul::opengl::Texture::Format::BGR:
            return 3;
        case ghoul::opengl::Texture::Format::RGBA:
        case ghoul::opengl::Texture::Format::BGRA:
            return 4;
        default:
            ghoul_assert(false, "Unknown format");
            throw ghoul::MissingCaseException();
    }
}

size_t numberOfBytes(GLenum glType) {
    switch (glType) {
        case GL_UNSIGNED_BYTE:  return sizeof(GLubyte);
        case GL_BYTE:           return sizeof(GLbyte);
        case GL_UNSIGNED_SHORT: return sizeof(GLushort);
        case GL_SHORT:          return sizeof(GLshort);
        case GL_UNSIGNED_INT:   return sizeof(GLuint);
        case GL_INT:            return sizeof(GLint);
        case GL_HALF_FLOAT:     return sizeof(GLhalf);
        case GL_FLOAT:          return sizeof(GLfloat);
        case GL_DOUBLE:         return sizeof(GLdouble);
        default:
            ghoul_assert(false, "Unknown data type");
            throw ghoul::MissingCaseException();
    }
}

unsigned int uniqueIdForTextureFormat(ghoul::opengl::Texture::Format textureFormat) {
    switch (textureFormat) {
        case ghoul::opengl::Texture::Format::Red:            return 0;
        case ghoul::opengl::Texture::Format::RG:             return 1;
        case ghoul::opengl::Texture::Format::RGB:            return 2;
        case ghoul::opengl::Texture::Format::BGR:            return 3;
        case ghoul::opengl::Texture::Format::RGBA:           return 4;
        case ghoul::opengl::Texture::Format::BGRA:           return 5;
        case ghoul::opengl::Texture::Format::DepthComponent: return 6;
        default:                                      throw ghoul::MissingCaseException();
    }
}

openspace::globebrowsing::TileTextureInitData::HashKey calculateHashKey(
                                                             const glm::ivec3& dimensions,
                                             const ghoul::opengl::Texture::Format& format,
                                                                     const GLenum& glType)
{
    ghoul_assert(dimensions.x > 0, "Incorrect dimension");
    ghoul_assert(dimensions.y > 0, "Incorrect dimension");
    ghoul_assert(dimensions.x <= 1024, "Incorrect dimension");
    ghoul_assert(dimensions.y <= 1024, "Incorrect dimension");
    ghoul_assert(dimensions.z == 1, "Incorrect dimension");
    unsigned int formatId = uniqueIdForTextureFormat(format);
    ghoul_assert(formatId < 256, "Incorrect format");

    openspace::globebrowsing::TileTextureInitData::HashKey res = 0ULL;

    res |= dimensions.x;
    res |= dimensions.y << 10;
    res |= static_cast<std::underlying_type_t<GLenum>>(glType) << (10 + 16);
    res |= formatId << (10 + 16 + 4);

    return res;
}

} // namespace

namespace openspace::globebrowsing {

TileTextureInitData tileTextureInitData(layers::Group::ID id,
                                        size_t preferredTileSize)
{
    switch (id) {
        case layers::Group::ID::HeightLayers: {
            const size_t tileSize = preferredTileSize ? preferredTileSize : 512;
            return TileTextureInitData(
                tileSize,
                tileSize,
                GL_FLOAT,
                ghoul::opengl::Texture::Format::Red,
                TileTextureInitData::ShouldAllocateDataOnCPU::Yes
            );
        }
        case layers::Group::ID::ColorLayers: {
            const size_t tileSize = preferredTileSize ? preferredTileSize : 512;
            return TileTextureInitData(
                tileSize,
                tileSize,
                GL_UNSIGNED_BYTE,
                ghoul::opengl::Texture::Format::BGRA
            );
        }
        case layers::Group::ID::Overlays: {
            const size_t tileSize = preferredTileSize ? preferredTileSize : 512;
            return TileTextureInitData(
                tileSize,
                tileSize,
                GL_UNSIGNED_BYTE,
                ghoul::opengl::Texture::Format::BGRA
            );
        }
        case layers::Group::ID::NightLayers: {
            const size_t tileSize = preferredTileSize ? preferredTileSize : 512;
            return TileTextureInitData(
                tileSize,
                tileSize,
                GL_UNSIGNED_BYTE,
                ghoul::opengl::Texture::Format::BGRA
            );
        }
        case layers::Group::ID::WaterMasks: {
            const size_t tileSize = preferredTileSize ? preferredTileSize : 512;
            return TileTextureInitData(
                tileSize,
                tileSize,
                GL_UNSIGNED_BYTE,
                ghoul::opengl::Texture::Format::BGRA
            );
        }
        default: {
            throw ghoul::MissingCaseException();
        }
    }
}

TileTextureInitData::TileTextureInitData(size_t width, size_t height, GLenum type,
                                         ghoul::opengl::Texture::Format textureFormat,
                                         ShouldAllocateDataOnCPU allocCpu)
    : dimensions(width, height, 1)
    , glType(type)
    , ghoulTextureFormat(textureFormat)
    , nRasters(numberOfRasters(ghoulTextureFormat))
    , bytesPerDatum(numberOfBytes(glType))
    , bytesPerPixel(nRasters * bytesPerDatum)
    , bytesPerLine(bytesPerPixel * width)
    , totalNumBytes(bytesPerLine * height)
    , shouldAllocateDataOnCPU(allocCpu)
    , hashKey(calculateHashKey(dimensions, ghoulTextureFormat, glType))
{}

TileTextureInitData TileTextureInitData::operator=(const TileTextureInitData& rhs) {
    if (this == &rhs) {
        return *this;
    }

    return rhs;
}

TileTextureInitData TileTextureInitData::operator=(TileTextureInitData&& rhs) noexcept {
    if (this == &rhs) {
        return *this;
    }

    return std::move(rhs);
}

} // namespace openspace::globebrowsing