Transformer GL: Simplify GL program handling.

Relanding http://https://github.com/google/ExoPlayer/commit/9788750ddb23b2064dddf99d6e1ea491b2e45cea, with some changes
applied to improve primarily readability, naming,
and nullness checks.

PiperOrigin-RevId: 406101742

demos/gl/src/main/java/com/google/android/exoplayer2/gldemo/BitmapOverlayVideoProcessor.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.gldemo;
 
+import static com.google.android.exoplayer2.util.Assertions.checkNotNull;
+
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.graphics.Bitmap;
@@ -26,11 +28,11 @@ import android.opengl.GLES20;
 import android.opengl.GLUtils;
 import androidx.annotation.Nullable;
 import com.google.android.exoplayer2.C;
-import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.GlUtil;
 import java.io.IOException;
 import java.util.Locale;
 import javax.microedition.khronos.opengles.GL10;
+import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
 /**
  * Video processor that demonstrates how to overlay a bitmap on video output using a GL shader. The
@@ -49,7 +51,7 @@ import javax.microedition.khronos.opengles.GL10;
   private final Bitmap logoBitmap;
   private final Canvas overlayCanvas;
 
-  private int program;
+  private GlUtil.@MonotonicNonNull Program program;
   @Nullable private GlUtil.Attribute[] attributes;
   @Nullable private GlUtil.Uniform[] uniforms;
 
@@ -77,27 +79,39 @@ import javax.microedition.khronos.opengles.GL10;
 
   @Override
   public void initialize() {
-    String vertexShaderCode;
-    String fragmentShaderCode;
     try {
-      vertexShaderCode = GlUtil.loadAsset(context, "bitmap_overlay_video_processor_vertex.glsl");
-      fragmentShaderCode =
-          GlUtil.loadAsset(context, "bitmap_overlay_video_processor_fragment.glsl");
+      program =
+          new GlUtil.Program(
+              context,
+              /* vertexShaderFilePath= */ "bitmap_overlay_video_processor_vertex.glsl",
+              /* fragmentShaderFilePath= */ "bitmap_overlay_video_processor_fragment.glsl");
     } catch (IOException e) {
       throw new IllegalStateException(e);
     }
-    program = GlUtil.compileProgram(vertexShaderCode, fragmentShaderCode);
-    GlUtil.Attribute[] attributes = GlUtil.getAttributes(program);
-    GlUtil.Uniform[] uniforms = GlUtil.getUniforms(program);
+    GlUtil.Attribute[] attributes = program.getAttributes();
     for (GlUtil.Attribute attribute : attributes) {
       if (attribute.name.equals("a_position")) {
-        attribute.setBuffer(new float[] {-1, -1, 0, 1, 1, -1, 0, 1, -1, 1, 0, 1, 1, 1, 0, 1}, 4);
+        attribute.setBuffer(
+            new float[] {
+              -1, -1, 0, 1,
+              1, -1, 0, 1,
+              -1, 1, 0, 1,
+              1, 1, 0, 1
+            },
+            4);
       } else if (attribute.name.equals("a_texcoord")) {
-        attribute.setBuffer(new float[] {0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1}, 4);
+        attribute.setBuffer(
+            new float[] {
+              0, 0, 0, 1,
+              1, 0, 0, 1,
+              0, 1, 0, 1,
+              1, 1, 0, 1
+            },
+            4);
       }
     }
     this.attributes = attributes;
-    this.uniforms = uniforms;
+    this.uniforms = program.getUniforms();
     GLES20.glGenTextures(1, textures, 0);
     GLES20.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
     GLES20.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);
@@ -126,9 +140,9 @@ import javax.microedition.khronos.opengles.GL10;
     GlUtil.checkGlError();
 
     // Run the shader program.
-    GlUtil.Uniform[] uniforms = Assertions.checkNotNull(this.uniforms);
-    GlUtil.Attribute[] attributes = Assertions.checkNotNull(this.attributes);
-    GLES20.glUseProgram(program);
+    GlUtil.Uniform[] uniforms = checkNotNull(this.uniforms);
+    GlUtil.Attribute[] attributes = checkNotNull(this.attributes);
+    checkNotNull(program).use();
     for (GlUtil.Uniform uniform : uniforms) {
       switch (uniform.name) {
         case "tex_sampler_0":

library/core/src/main/java/com/google/android/exoplayer2/video/VideoDecoderGLSurfaceView.java

@@ -15,6 +15,8 @@
  */
 package com.google.android.exoplayer2.video;
 
+import static com.google.android.exoplayer2.util.Assertions.checkNotNull;
+
 import android.content.Context;
 import android.opengl.GLES20;
 import android.opengl.GLSurfaceView;
@@ -30,6 +32,7 @@ import javax.microedition.khronos.egl.EGLConfig;
 import javax.microedition.khronos.opengles.GL10;
 import org.checkerframework.checker.nullness.compatqual.NullableType;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
+import org.checkerframework.checker.nullness.qual.RequiresNonNull;
 
 /**
  * GLSurfaceView implementing {@link VideoDecoderOutputBufferRenderer} for rendering {@link
@@ -141,7 +144,7 @@ public final class VideoDecoderGLSurfaceView extends GLSurfaceView
     // glDrawArrays uses it.
     private final FloatBuffer[] textureCoords;
 
-    private int program;
+    private GlUtil.@MonotonicNonNull Program program;
     private int colorMatrixLocation;
 
     // Accessed only from the GL thread.
@@ -162,9 +165,9 @@ public final class VideoDecoderGLSurfaceView extends GLSurfaceView
 
     @Override
     public void onSurfaceCreated(GL10 unused, EGLConfig config) {
-      program = GlUtil.compileProgram(VERTEX_SHADER, FRAGMENT_SHADER);
-      GLES20.glUseProgram(program);
-      int posLocation = GLES20.glGetAttribLocation(program, "in_pos");
+      program = new GlUtil.Program(VERTEX_SHADER, FRAGMENT_SHADER);
+      program.use();
+      int posLocation = program.getAttribLocation("in_pos");
       GLES20.glEnableVertexAttribArray(posLocation);
       GLES20.glVertexAttribPointer(
           posLocation,
@@ -173,14 +176,14 @@ public final class VideoDecoderGLSurfaceView extends GLSurfaceView
           /* normalized= */ false,
           /* stride= */ 0,
           TEXTURE_VERTICES);
-      texLocations[0] = GLES20.glGetAttribLocation(program, "in_tc_y");
+      texLocations[0] = program.getAttribLocation("in_tc_y");
       GLES20.glEnableVertexAttribArray(texLocations[0]);
-      texLocations[1] = GLES20.glGetAttribLocation(program, "in_tc_u");
+      texLocations[1] = program.getAttribLocation("in_tc_u");
       GLES20.glEnableVertexAttribArray(texLocations[1]);
-      texLocations[2] = GLES20.glGetAttribLocation(program, "in_tc_v");
+      texLocations[2] = program.getAttribLocation("in_tc_v");
       GLES20.glEnableVertexAttribArray(texLocations[2]);
       GlUtil.checkGlError();
-      colorMatrixLocation = GLES20.glGetUniformLocation(program, "mColorConversion");
+      colorMatrixLocation = program.getUniformLocation("mColorConversion");
       GlUtil.checkGlError();
       setupTextures();
       GlUtil.checkGlError();
@@ -207,7 +210,7 @@ public final class VideoDecoderGLSurfaceView extends GLSurfaceView
         renderedOutputBuffer = pendingOutputBuffer;
       }
 
-      VideoDecoderOutputBuffer outputBuffer = Assertions.checkNotNull(renderedOutputBuffer);
+      VideoDecoderOutputBuffer outputBuffer = checkNotNull(renderedOutputBuffer);
 
       // Set color matrix. Assume BT709 if the color space is unknown.
       float[] colorConversion = kColorConversion709;
@@ -230,8 +233,8 @@ public final class VideoDecoderGLSurfaceView extends GLSurfaceView
           colorConversion,
           /* offset= */ 0);
 
-      int[] yuvStrides = Assertions.checkNotNull(outputBuffer.yuvStrides);
-      ByteBuffer[] yuvPlanes = Assertions.checkNotNull(outputBuffer.yuvPlanes);
+      int[] yuvStrides = checkNotNull(outputBuffer.yuvStrides);
+      ByteBuffer[] yuvPlanes = checkNotNull(outputBuffer.yuvPlanes);
 
       for (int i = 0; i < 3; i++) {
         int h = (i == 0) ? outputBuffer.height : (outputBuffer.height + 1) / 2;
@@ -294,10 +297,11 @@ public final class VideoDecoderGLSurfaceView extends GLSurfaceView
       surfaceView.requestRender();
     }
 
+    @RequiresNonNull("program")
     private void setupTextures() {
       GLES20.glGenTextures(3, yuvTextures, /* offset= */ 0);
       for (int i = 0; i < 3; i++) {
-        GLES20.glUniform1i(GLES20.glGetUniformLocation(program, TEXTURE_UNIFORMS[i]), i);
+        GLES20.glUniform1i(program.getUniformLocation(TEXTURE_UNIFORMS[i]), i);
         GLES20.glActiveTexture(GLES20.GL_TEXTURE0 + i);
         GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, yuvTextures[i]);
         GLES20.glTexParameterf(

library/core/src/main/java/com/google/android/exoplayer2/video/spherical/ProjectionRenderer.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.video.spherical;
 
+import static com.google.android.exoplayer2.util.Assertions.checkNotNull;
 import static com.google.android.exoplayer2.util.GlUtil.checkGlError;
 
 import android.opengl.GLES11Ext;
@@ -92,9 +93,9 @@ import java.nio.FloatBuffer;
   private int stereoMode;
   @Nullable private MeshData leftMeshData;
   @Nullable private MeshData rightMeshData;
+  @Nullable private GlUtil.Program program;
 
-  // Program related GL items. These are only valid if program != 0.
-  private int program;
+  // Program related GL items. These are only valid if program is non-null.
   private int mvpMatrixHandle;
   private int uTexMatrixHandle;
   private int positionHandle;
@@ -119,12 +120,12 @@ import java.nio.FloatBuffer;
 
   /** Initializes of the GL components. */
   /* package */ void init() {
-    program = GlUtil.compileProgram(VERTEX_SHADER_CODE, FRAGMENT_SHADER_CODE);
-    mvpMatrixHandle = GLES20.glGetUniformLocation(program, "uMvpMatrix");
-    uTexMatrixHandle = GLES20.glGetUniformLocation(program, "uTexMatrix");
-    positionHandle = GLES20.glGetAttribLocation(program, "aPosition");
-    texCoordsHandle = GLES20.glGetAttribLocation(program, "aTexCoords");
-    textureHandle = GLES20.glGetUniformLocation(program, "uTexture");
+    program = new GlUtil.Program(VERTEX_SHADER_CODE, FRAGMENT_SHADER_CODE);
+    mvpMatrixHandle = program.getUniformLocation("uMvpMatrix");
+    uTexMatrixHandle = program.getUniformLocation("uTexMatrix");
+    positionHandle = program.getAttribLocation("aPosition");
+    texCoordsHandle = program.getAttribLocation("aTexCoords");
+    textureHandle = program.getUniformLocation("uTexture");
   }
 
   /**
@@ -143,7 +144,7 @@ import java.nio.FloatBuffer;
     }
 
     // Configure shader.
-    GLES20.glUseProgram(program);
+    checkNotNull(program).use();
     checkGlError();
 
     GLES20.glEnableVertexAttribArray(positionHandle);
@@ -196,8 +197,9 @@ import java.nio.FloatBuffer;
 
   /** Cleans up the GL resources. */
   /* package */ void shutdown() {
-    if (program != 0) {
-      GLES20.glDeleteProgram(program);
+    if (program != null) {
+      program.delete();
+      program = null;
     }
   }
 

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/TransformerTranscodingVideoRenderer.java

@@ -229,17 +229,19 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
     GlUtil.focusSurface(
         eglDisplay, eglContext, eglSurface, decoderInputFormat.width, decoderInputFormat.height);
     decoderTextureId = GlUtil.createExternalTexture();
-    String vertexShaderCode;
-    String fragmentShaderCode;
+    GlUtil.Program copyProgram;
     try {
-      vertexShaderCode = GlUtil.loadAsset(context, "shaders/blit_vertex_shader.glsl");
-      fragmentShaderCode = GlUtil.loadAsset(context, "shaders/copy_external_fragment_shader.glsl");
+      copyProgram =
+          new GlUtil.Program(
+              context,
+              /* vertexShaderFilePath= */ "shaders/blit_vertex_shader.glsl",
+              /* fragmentShaderFilePath= */ "shaders/copy_external_fragment_shader.glsl");
     } catch (IOException e) {
       throw new IllegalStateException(e);
     }
-    int copyProgram = GlUtil.compileProgram(vertexShaderCode, fragmentShaderCode);
-    GLES20.glUseProgram(copyProgram);
-    GlUtil.Attribute[] copyAttributes = GlUtil.getAttributes(copyProgram);
+
+    copyProgram.use();
+    GlUtil.Attribute[] copyAttributes = copyProgram.getAttributes();
     checkState(copyAttributes.length == 2, "Expected program to have two vertex attributes.");
     for (GlUtil.Attribute copyAttribute : copyAttributes) {
       if (copyAttribute.name.equals("a_position")) {
@@ -265,7 +267,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
       }
       copyAttribute.bind();
     }
-    GlUtil.Uniform[] copyUniforms = GlUtil.getUniforms(copyProgram);
+    GlUtil.Uniform[] copyUniforms = copyProgram.getUniforms();
     checkState(copyUniforms.length == 2, "Expected program to have two uniforms.");
     for (GlUtil.Uniform copyUniform : copyUniforms) {
       if (copyUniform.name.equals("tex_sampler")) {