GL: Update BitmapOverlayVideoProcessor naming conventions.

To be more readable and consistent with Transformer GL.

Tested by running gl-demo with no crash.

PiperOrigin-RevId: 421815519

demos/gl/src/main/assets/bitmap_overlay_video_processor_fragment.glsl

@@ -15,19 +15,19 @@
 #extension GL_OES_EGL_image_external : require
 precision mediump float;
 // External texture containing video decoder output.
-uniform samplerExternalOES tex_sampler_0;
+uniform samplerExternalOES uTexSampler0;
 // Texture containing the overlap bitmap.
-uniform sampler2D tex_sampler_1;
+uniform sampler2D uTexSampler1;
 // Horizontal scaling factor for the overlap bitmap.
-uniform float scaleX;
+uniform float uScaleX;
 // Vertical scaling factory for the overlap bitmap.
-uniform float scaleY;
-varying vec2 v_texcoord;
+uniform float uScaleY;
+varying vec2 vTexCoords;
 void main() {
-  vec4 videoColor = texture2D(tex_sampler_0, v_texcoord);
-  vec4 overlayColor = texture2D(tex_sampler_1,
-                                vec2(v_texcoord.x * scaleX,
-                                     v_texcoord.y * scaleY));
+  vec4 videoColor = texture2D(uTexSampler0, vTexCoords);
+  vec4 overlayColor = texture2D(uTexSampler1,
+                                vec2(vTexCoords.x * uScaleX,
+                                     vTexCoords.y * uScaleY));
   // Blend the video decoder output and the overlay bitmap.
   gl_FragColor = videoColor * (1.0 - overlayColor.a)
       + overlayColor * overlayColor.a;

demos/gl/src/main/assets/bitmap_overlay_video_processor_vertex.glsl

@@ -11,11 +11,11 @@
 // 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.
-attribute vec4 a_position;
-attribute vec4 a_texcoord;
-uniform mat4 tex_transform;
-varying vec2 v_texcoord;
+attribute vec4 aFramePosition;
+attribute vec4 aTexCoords;
+uniform mat4 uTexTransform;
+varying vec2 vTexCoords;
 void main() {
- gl_Position = a_position;
- v_texcoord = (tex_transform * a_texcoord).xy;
+ gl_Position = aFramePosition;
+ vTexCoords = (uTexTransform * aTexCoords).xy;
 }

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

@@ -86,9 +86,9 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
       throw new IllegalStateException(e);
     }
     program.setBufferAttribute(
-        "a_position", GlUtil.getNormalizedCoordinateBounds(), GlUtil.RECTANGLE_VERTICES_COUNT);
+        "aFramePosition", GlUtil.getNormalizedCoordinateBounds(), GlUtil.RECTANGLE_VERTICES_COUNT);
     program.setBufferAttribute(
-        "a_texcoord", GlUtil.getTextureCoordinateBounds(), GlUtil.RECTANGLE_VERTICES_COUNT);
+        "aTexCoords", GlUtil.getTextureCoordinateBounds(), GlUtil.RECTANGLE_VERTICES_COUNT);
     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);
@@ -118,11 +118,11 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
     // Run the shader program.
     GlUtil.Program program = checkNotNull(this.program);
-    program.setSamplerTexIdUniform("tex_sampler_0", frameTexture, /* unit= */ 0);
-    program.setSamplerTexIdUniform("tex_sampler_1", textures[0], /* unit= */ 1);
-    program.setFloatUniform("scaleX", bitmapScaleX);
-    program.setFloatUniform("scaleY", bitmapScaleY);
-    program.setFloatsUniform("tex_transform", transformMatrix);
+    program.setSamplerTexIdUniform("uTexSampler0", frameTexture, /* unit= */ 0);
+    program.setSamplerTexIdUniform("uTexSampler1", textures[0], /* unit= */ 1);
+    program.setFloatUniform("uScaleX", bitmapScaleX);
+    program.setFloatUniform("uScaleY", bitmapScaleY);
+    program.setFloatsUniform("uTexTransform", transformMatrix);
     program.bindAttributesAndUniforms();
     GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
     GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, /* first= */ 0, /* count= */ 4);