Question

I am using OpenGL ES in JNI to draw the frame (RGB data) returned from the C source code (MPEG2 Codec). For this I have created one texture and draw RGB data using glTexSubImage2D() function of OpenGL. But Using this function I am not getting even 7 FPS. While As I have studied that using OpenGL we can get 22 FPS.

Is there any other specific function to display an image through android-ndk which will give better performance than that function (glTexSubImage2D()).
I have referred to this link to draw frame returned from codec.

Thanks in advance.

Answer 1

There are a set of native bitmap functions added in Android 2.2 which allow you to get direct access to the bits of a bitmap without making a copy of it. In your C code you will use:

#include <android/bitmap.h>

JNIEXPORT jint JNICALL Java_com_somecompany_someapp_someclass_drawonbitmap(JNIEnv *env, jobject obj, jobject bitmap)
{
int iReturn;
AndroidBitmapInfo info;
void *pixels;

   iReturn = AndroidBitmap_getInfo(env, bitmap, &info);
   if (iReturn < 0)
   {
       return <some error>;
   }
   iReturn = AndroidBitmap_lockPixels(env, bitmap, &pixels);
   if (iReturn < 0)
   {
       return <some error>;
   }

   // Draw directly into the bitmap here
   //
   // use the structure members:
   // info.stride
   // info.width
   // info.height
   // info.format (e.g. ANDROID_BITMAP_FORMAT_RGB_565)

   if (pixels != NULL) // we previously locked the pixels
   {
       AndroidBitmap_unlockPixels(env, bitmap);
   }
   return 0;
}