CODEWITHSUNDEEP
javaandroidbitmapopengl-es
TheMagicDon
TheMagicDon

Reputation: 31

OpenGL on Android - Convert a Bitmap to a Texture, and save a Texture

Me and my team are currently developping an Android app to do fast live and non-live image processing.

We are facing two problems:

First, we would like to convert a Bitmap into a Texture to process the picture with OpenGL shaders, and then convert it back into a Bitmap. We tried some implementations unsuccesfully, as using the GLUtils.texImage2D function inside a SurfaceTexture and a Renderer.

Our second problem is that we don't currently know how to save a Texture on our live camera activity. We use an OnFrameAvailableListener in which we process the images. But as for now, we can't keep the original Texture.

We hope someone can provide an answer to our problem. Thanks in advance !

Upvotes: 3

Views: 8287

Answers (2)

Michael N
Michael N

Reputation: 559

Here's a Kotlin version of Mohamed's answer

/**
 * Load Texture from Bitmap
 **/

fun loadTexture(context: Context, resourceId: Int) : Int {

    val textureHandle : IntArray = IntArray(1)

    GLES20.glGenTextures(1, textureHandle, 0)

    if (textureHandle[0] != 0)
    {
        val options : BitmapFactory.Options = BitmapFactory.Options()
        
        options.inScaled = false   // No pre-scaling

        // Read in the resource
        
        val bitmap = BitmapFactory.decodeResource(context.getResources(), resourceId, options)

        // Bind to the texture in OpenGL
        
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle[0])

        // Set filtering

        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST)
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST)

        // Load the bitmap into the bound texture.

        GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0)

        // Recycle the bitmap, since its data has been loaded into OpenGL.

        bitmap.recycle()

    }

    if (textureHandle[0] == 0) {

        throw RuntimeException("Error loading texture.")

    }

    return textureHandle[0]

}

Upvotes: 0

andras
andras

Reputation: 3645

First

Bitmap to texture

Source:

http://www.learnopengles.com/android-lesson-four-introducing-basic-texturing/


  public static int loadTexture(final Context context, final int resourceId){

    final int[] textureHandle = new int[1];
 
    GLES20.glGenTextures(1, textureHandle, 0);
 
    if (textureHandle[0] != 0)
    {
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inScaled = false;   // No pre-scaling
 
        // Read in the resource
        final Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), resourceId, options);
 
        // Bind to the texture in OpenGL
        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle[0]);
 
        // Set filtering
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST);
        GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST);
 
        // Load the bitmap into the bound texture.
        GLUtils.texImage2D(GLES20.GL_TEXTURE_2D, 0, bitmap, 0);
 
        // Recycle the bitmap, since its data has been loaded into OpenGL.
        bitmap.recycle();
    }
 
    if (textureHandle[0] == 0)
    {
        throw new RuntimeException("Error loading texture.");
    }
 
    return textureHandle[0];
}

Texture to bitmap:

Source:

How do you convert opengl texture back to bitmap in android?

Second

There is also a save option in the SO link I linked.

Upvotes: 8

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