ShaderProvider.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.camera.core.processing;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RestrictTo;
/**
* A provider that supplies OpenGL shader code.
*
* @hide
*/
@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
public interface ShaderProvider {
/**
* Creates the fragment shader code with the given variable names.
*
* <p>The provider must use the variable names to construct the shader code, or it will fail
* to create the OpenGL program when the provider is used. For example:
* <pre>{@code
* #extension GL_OES_EGL_image_external : require
* precision mediump float;
* uniform samplerExternalOES {$samplerVarName};
* varying vec2 {$fragCoordsVarName};
* void main() {
* vec4 sampleColor = texture2D({$samplerVarName}, {$fragCoordsVarName});
* gl_FragColor = vec4(
* sampleColor.r * 0.5 + sampleColor.g * 0.8 + sampleColor.b * 0.3,
* sampleColor.r * 0.4 + sampleColor.g * 0.7 + sampleColor.b * 0.2,
* sampleColor.r * 0.3 + sampleColor.g * 0.5 + sampleColor.b * 0.1,
* 1.0);
* }
* }</pre>
*
* @param samplerVarName the variable name of the samplerExternalOES.
* @param fragCoordsVarName the variable name of the fragment coordinates.
* @return the shader code. Return null to use the default shader.
*/
@Nullable
default String createFragmentShader(
@NonNull String samplerVarName,
@NonNull String fragCoordsVarName) {
return null;
}
/** A default provider that will use the default shader code without any post-processing. */
ShaderProvider DEFAULT = new ShaderProvider() {
// Use default implementation.
};
}