libs/hwui/AssetAtlas.cpp

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "AssetAtlas.h"
#include "Caches.h"
#include "Image.h"

#include <GLES2/gl2ext.h>

namespace android {
namespace uirenderer {

///////////////////////////////////////////////////////////////////////////////
// Lifecycle
///////////////////////////////////////////////////////////////////////////////

void AssetAtlas::init(sp<GraphicBuffer> buffer, int64_t* map, int count) {
    if (mImage) {
        return;
    }

    ATRACE_NAME("AssetAtlas::init");

    mImage = new Image(buffer);
    if (mImage->getTexture()) {
        if (!mTexture) {
            Caches& caches = Caches::getInstance();
            mTexture = new Texture(caches);
            mTexture->width = buffer->getWidth();
            mTexture->height = buffer->getHeight();
            createEntries(caches, map, count);
        }
    } else {
        ALOGW("Could not create atlas image");
        delete mImage;
        mImage = nullptr;
    }

    updateTextureId();
}

void AssetAtlas::terminate() {
    if (mImage) {
        delete mImage;
        mImage = nullptr;
        updateTextureId();
    }
}


void AssetAtlas::updateTextureId() {
    mTexture->id = mImage ? mImage->getTexture() : 0;
    if (mTexture->id) {
        // Texture ID changed, force-set to defaults to sync the wrapper & GL
        // state objects
        mTexture->setWrap(GL_CLAMP_TO_EDGE, false, true);
        mTexture->setFilter(GL_NEAREST, false, true);
    }
    for (size_t i = 0; i < mEntries.size(); i++) {
        AssetAtlas::Entry* entry = mEntries.valueAt(i);
        entry->texture->id = mTexture->id;
    }
}

///////////////////////////////////////////////////////////////////////////////
// Entries
///////////////////////////////////////////////////////////////////////////////

AssetAtlas::Entry* AssetAtlas::getEntry(const SkBitmap* bitmap) const {
    ssize_t index = mEntries.indexOfKey(bitmap->pixelRef());
    return index >= 0 ? mEntries.valueAt(index) : nullptr;
}

Texture* AssetAtlas::getEntryTexture(const SkBitmap* bitmap) const {
    ssize_t index = mEntries.indexOfKey(bitmap->pixelRef());
    return index >= 0 ? mEntries.valueAt(index)->texture : nullptr;
}

/**
 * Delegates changes to wrapping and filtering to the base atlas texture
 * instead of applying the changes to the virtual textures.
 */
struct DelegateTexture: public Texture {
    DelegateTexture(Caches& caches, Texture* delegate): Texture(caches), mDelegate(delegate) { }

    virtual void setWrapST(GLenum wrapS, GLenum wrapT, bool bindTexture = false,
            bool force = false, GLenum renderTarget = GL_TEXTURE_2D) override {
        mDelegate->setWrapST(wrapS, wrapT, bindTexture, force, renderTarget);
    }

    virtual void setFilterMinMag(GLenum min, GLenum mag, bool bindTexture = false,
            bool force = false, GLenum renderTarget = GL_TEXTURE_2D) override {
        mDelegate->setFilterMinMag(min, mag, bindTexture, force, renderTarget);
    }

private:
    Texture* const mDelegate;
}; // struct DelegateTexture

void AssetAtlas::createEntries(Caches& caches, int64_t* map, int count) {
    const float width = float(mTexture->width);
    const float height = float(mTexture->height);

    for (int i = 0; i < count; ) {
        SkPixelRef* pixelRef = reinterpret_cast<SkPixelRef*>(map[i++]);
        // NOTE: We're converting from 64 bit signed values to 32 bit
        // signed values. This is guaranteed to be safe because the "x"
        // and "y" coordinate values are guaranteed to be representable
        // with 32 bits. The array is 64 bits wide so that it can carry
        // pointers on 64 bit architectures.
        const int x = static_cast<int>(map[i++]);
        const int y = static_cast<int>(map[i++]);

        // Bitmaps should never be null, we're just extra paranoid
        if (!pixelRef) continue;

        const UvMapper mapper(
                x / width, (x + pixelRef->info().width()) / width,
                y / height, (y + pixelRef->info().height()) / height);

        Texture* texture = new DelegateTexture(caches, mTexture);
        texture->blend = !SkAlphaTypeIsOpaque(pixelRef->info().alphaType());
        texture->width = pixelRef->info().width();
        texture->height = pixelRef->info().height();

        Entry* entry = new Entry(pixelRef, texture, mapper, *this);
        texture->uvMapper = &entry->uvMapper;

        mEntries.add(entry->pixelRef, entry);
    }
}

}; // namespace uirenderer
}; // namespace android