libreoffice/vcl/opengl/FixedTextureAtlas.cxx

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 */

#include <sal/config.h>
#include <vcl/opengl/OpenGLContext.hxx>
#include <vcl/opengl/OpenGLHelper.hxx>

#include "opengl/framebuffer.hxx"
#include "opengl/texture.hxx"

#include "opengl/FixedTextureAtlas.hxx"

FixedTextureAtlasManager::FixedTextureAtlasManager(int nWidthFactor, int nHeightFactor, int nSubTextureSize)
    : mWidthFactor(nWidthFactor)
    , mHeightFactor(nHeightFactor)
    , mSubTextureSize(nSubTextureSize)
{
}

void FixedTextureAtlasManager::CreateNewTexture()
{
    int nTextureWidth = mWidthFactor  * mSubTextureSize;
    int nTextureHeight = mHeightFactor * mSubTextureSize;
    mpTextures.push_back(std::unique_ptr<ImplOpenGLTexture>(new ImplOpenGLTexture(nTextureWidth, nTextureHeight, true)));
    mpTextures.back()->InitializeSlots(mWidthFactor * mHeightFactor);
}

OpenGLTexture FixedTextureAtlasManager::InsertBuffer(int nWidth, int nHeight, int nFormat, int nType, sal_uInt8* pData)
{
    ImplOpenGLTexture* pTexture = nullptr;

    for (size_t i = 0; i < mpTextures.size(); i++)
    {
        if (mpTextures[i]->mnFreeSlots > 0)
        {
            pTexture = mpTextures[i].get();
        }
    }

    if (!pTexture)
    {
        CreateNewTexture();
        pTexture = mpTextures.back().get();
    }

    int nSlot = pTexture->FindFreeSlot();

    // Calculate coordinates in texture
    int nX = (nSlot % mWidthFactor) * mSubTextureSize;
    int nY = (nSlot / mWidthFactor) * mSubTextureSize;

    Rectangle aRectangle(Point(nX, nY), Size(nWidth, nHeight));

    // If available, copy the image data to the texture
    if (pData)
    {
        if (!pTexture->InsertBuffer(nX, nY, nWidth, nHeight, nFormat, nType, pData))
            return OpenGLTexture();
    }

    return OpenGLTexture(pTexture, aRectangle, nSlot);
}

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