SingleFrameGlTextureProcessor.java
/*
* Copyright 2022 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.
*/
package androidx.media3.transformer;
import android.content.Context;
import android.util.Size;
import androidx.media3.common.util.UnstableApi;
import java.io.IOException;
/**
* Manages a GLSL shader program for processing a frame. Implementations generally copy input pixels
* into an output frame, with changes to pixels specific to the implementation.
*
* <p>Methods must be called in the following order:
*
* <ol>
* <li>The constructor, for implementation-specific arguments.
* <li>{@link #initialize(Context, int, int, int)}, to set up graphics initialization.
* <li>{@link #drawFrame(long)}, to process one frame.
* <li>{@link #release()}, upon conclusion of processing.
* </ol>
*/
@UnstableApi
// TODO(b/227625423): Add GlTextureProcessor interface for async texture processors and make this an
// abstract class with a default implementation of GlTextureProcessor methods.
public interface SingleFrameGlTextureProcessor {
/**
* Performs all initialization that requires OpenGL, such as, loading and compiling a GLSL shader
* program.
*
* <p>This method may only be called if there is a current OpenGL context.
*
* @param context The {@link Context}.
* @param inputTexId Identifier of a 2D OpenGL texture.
* @param inputWidth The input width, in pixels.
* @param inputHeight The input height, in pixels.
* @throws IOException If an error occurs while reading resources.
*/
void initialize(Context context, int inputTexId, int inputWidth, int inputHeight)
throws IOException;
/**
* Returns the output {@link Size} of frames processed through {@link #drawFrame(long)}.
*
* <p>This method may only be called after the texture processor has been {@link
* #initialize(Context, int, int, int) initialized}.
*/
Size getOutputSize();
/**
* Draws one frame.
*
* <p>This method may only be called after the texture processor has been {@link
* #initialize(Context, int, int, int) initialized}. The caller is responsible for focussing the
* correct render target before calling this method.
*
* <p>A minimal implementation should tell OpenGL to use its shader program, bind the shader
* program's vertex attributes and uniforms, and issue a drawing command.
*
* @param presentationTimeUs The presentation timestamp of the current frame, in microseconds.
* @throws FrameProcessingException If an error occurs while processing or drawing the frame.
*/
void drawFrame(long presentationTimeUs) throws FrameProcessingException;
/** Releases all resources. */
void release();
}