Question

我需要通过JNI将类似drawable的图像数据从java端传递到cocos2d-x。我该如何实现它？ JNI函数的参数应该是什么以及如何在cocos2d-x中投射？

Answer 1

为JNI创建一个Java接口，如：

public static native void setBG(int[] raw, int width, int height);

在c ++代码中执行：

//Use static variable here for simplicity

int *imagedata;
int staticwidth;
int staticheight;
Texture2D *userBackgroundImage;



void Java_com_my_company_JniHelper_setBG(JNIEnv*  env, jobject thiz, jintArray raw, jint width, jint height)
{
    jint *carr;
    carr = env->GetIntArrayElements(raw, 0);
    if(carr == NULL) {
        return; /* exception occurred */
    }
    ssize_t dataLen = (int)width * (int)height;
    int *data = new int[dataLen];
    for (long i = 0; i < dataLen; i++)
    {
        data[i] = carr[i];
    }
    imagedata = data;//Make a copy because it need to be done in GLThread
    staticwidth = (int)width;
    staticheight = (int)height;
    env->ReleaseIntArrayElements(raw, carr, 0);
    LOGD("set image: %d * %d", width, height);
}

然后在某个持续时间层init或其他cocos2d-x代码中调用以下方法：

    void createImage(const void *data, ssize_t dataLen, int width, int height)
    {
        Texture2D *image = new Texture2D();
        if (!image->initWithData(data, dataLen, Texture2D::PixelFormat::BGRA8888, width,      height, Size(width, height)))
        {
            delete image;
            delete imagedata;
            image = NULL;
            imagedata = NULL;
            userBackgroundImage = NULL;
            return;
        }
        delete imagedata;
        imagedata = NULL;
        userBackgroundImage = image;
    }

然后，您可以使用Texture2D对象创建精灵或执行任何您想要的操作

从java调用此代码：

public static int[] BitmapToRaw(Bitmap bitmap) {
    Bitmap image = bitmap.copy(Bitmap.Config.ARGB_8888, false);
    int width = image.getWidth();
    int height = image.getHeight();
    int[] raw = new int[width * height];
    image.getPixels(raw, 0, width, 0, 0, width, height);
    return raw;
}

Bitmap image = BitmapFactory.decodeResource(getResources(), R.drawable.bg);
JniHelper.setBG(BitmapToRaw(image), image.getWidth(), image.getHeight());

Answer 2

我只是将图像数据从cocos2d-x发送到Java，所以你需要找到一种方法来反转这种方法。它用于捕获节点并将其传递给屏幕截图。

CCNode* node = <some node>;
const CCSize& size(node->getContentSize());
CCRenderTexture* render = CCRenderTexture::create(size.width, size.height);

// render node to the texturebuffer
render->clear(0, 0, 0, 1);
render->begin();
node->visit();
render->end();

CCImage* image = render->newCCImage();

// If we don't clear then the JNI call gets corrupted.
render->clear(0, 0, 0, 1);

// Create the array to pass in
jsize length = image->getDataLen();
jintArray imageBytes = t.env->NewIntArray(length);
unsigned char* imageData = image->getData();
t.env->SetIntArrayRegion(imageBytes, 0, length, const_cast<const jint*>(reinterpret_cast<jint*>(imageData)));

t.env->CallStaticVoidMethod(t.classID, t.methodID, imageBytes, (jint)image->getWidth(), (jint)image->getHeight());

image->release();
t.env->DeleteLocalRef(imageBytes);
t.env->DeleteLocalRef(t.classID);

Java端看起来像这样：

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;

public static Bitmap getImage(int[] imageData, int width, int height) {
   Bitmap image = Bitmap.createBitmap(width, height, Config.ARGB_8888);
   image.setPixels(imageData, 0, width, 0, 0, width, height);
   return image;
}

Answer 3

我认为最好和最简单的方法是将其保存在Java中，然后从cpp访问该文件，然后在使用后将其删除。

如何通过JNI将图像从Java传递到Cocos2d-x？

3 个答案: