如何通过JNI将图像从Java传递到Cocos2d-x？

Question

我需要通过JNI将图像数据从java端传递给cocos2d-x。我如何实现它？ JNI函数的参数应该是什么以及如何在cocos2d-x一侧投射？

Answer 1

1. 创建Java接口forJNI像：

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

在C

2. ++代码做：

   //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); 
   } 
   

然后调用以下方法某处持续时间层init或其他cocos2d- x代码：

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对象来创建一个精灵或做任何你想做

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

我只是从cocos2d-x发送图像数据到Java，所以你需要找到一种方法来颠倒这种方法。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方面看起来是这样的：

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

我认为这样做会用Java来保存它，然后访问来自CPP文件，然后使用后删除它最好的，简单的方法。