Implement a new Shader API, which can run custom code on GPU

Add RuntimeShader hidden API, which calculates pixel output with
a fragment shader running on GPU.
Extend ColorFiltersMutateActivity HWUI test to use new API and
show how to animate uniforms on UI thread.

Test: Updated HwAccelerationTest
Change-Id: Ia26e44259b12099924facba250880cbbd9be21c7

core/jni/android/graphics/Shader.cpp

@@ -5,6 +5,7 @@
 #include "SkShader.h"
 #include "SkBlendMode.h"
 #include "core_jni_helpers.h"
+#include "src/shaders/SkRTShader.h"
 
 #include <jni.h>
 
@@ -212,6 +213,44 @@ static jlong ComposeShader_create(JNIEnv* env, jobject o, jlong matrixPtr,
 
 ///////////////////////////////////////////////////////////////////////////////////////////////
 
+static jlong RuntimeShader_create(JNIEnv* env, jobject, jlong shaderFactory, jlong matrixPtr,
+        jbyteArray inputs, jlong colorSpaceHandle) {
+    SkRuntimeShaderFactory* factory = reinterpret_cast<SkRuntimeShaderFactory*>(shaderFactory);
+    AutoJavaByteArray arInputs(env, inputs);
+
+    sk_sp<SkData> fData;
+    fData = SkData::MakeWithCopy(arInputs.ptr(), arInputs.length());
+    const SkMatrix* matrix = reinterpret_cast<const SkMatrix*>(matrixPtr);
+    sk_sp<SkShader> shader = factory->make(fData, matrix);
+    ThrowIAE_IfNull(env, shader);
+
+    return reinterpret_cast<jlong>(shader.release());
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////
+
+static jlong RuntimeShader_createShaderFactory(JNIEnv* env, jobject, jstring sksl,
+        jboolean isOpaque) {
+    ScopedUtfChars strSksl(env, sksl);
+    SkRuntimeShaderFactory* shaderFactory = new SkRuntimeShaderFactory(SkString(strSksl.c_str()),
+            isOpaque == JNI_TRUE);
+    ThrowIAE_IfNull(env, shaderFactory);
+
+    return reinterpret_cast<jlong>(shaderFactory);
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////
+
+static void RuntimeShader_delete(SkRuntimeShaderFactory* shaderFactory) {
+    delete shaderFactory;
+}
+
+static jlong RuntimeShader_getNativeFinalizer(JNIEnv*, jobject) {
+    return static_cast<jlong>(reinterpret_cast<uintptr_t>(&RuntimeShader_delete));
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////
+
 static const JNINativeMethod gColorMethods[] = {
     { "nativeRGBToHSV",    "(III[F)V", (void*)Color_RGBToHSV   },
     { "nativeHSVToColor",  "(I[F)I",   (void*)Color_HSVToColor }
@@ -241,6 +280,13 @@ static const JNINativeMethod gComposeShaderMethods[] = {
     { "nativeCreate",      "(JJJI)J",   (void*)ComposeShader_create     },
 };
 
+static const JNINativeMethod gRuntimeShaderMethods[] = {
+    { "nativeGetFinalizer",   "()J",    (void*)RuntimeShader_getNativeFinalizer },
+    { "nativeCreate",     "(JJ[BJ)J",  (void*)RuntimeShader_create     },
+    { "nativeCreateShaderFactory",     "(Ljava/lang/String;Z)J",
+      (void*)RuntimeShader_createShaderFactory     },
+};
+
 int register_android_graphics_Shader(JNIEnv* env)
 {
     android::RegisterMethodsOrDie(env, "android/graphics/Color", gColorMethods,
@@ -257,6 +303,8 @@ int register_android_graphics_Shader(JNIEnv* env)
                                   NELEM(gSweepGradientMethods));
     android::RegisterMethodsOrDie(env, "android/graphics/ComposeShader", gComposeShaderMethods,
                                   NELEM(gComposeShaderMethods));
+    android::RegisterMethodsOrDie(env, "android/graphics/RuntimeShader", gRuntimeShaderMethods,
+                                  NELEM(gRuntimeShaderMethods));
 
     return 0;
 }

graphics/java/android/graphics/RuntimeShader.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2019 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 android.graphics;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+
+import libcore.util.NativeAllocationRegistry;
+
+/**
+ * Shader that calculates pixel output with a program (fragment shader) running on a GPU.
+ * @hide
+ */
+public class RuntimeShader extends Shader {
+
+    private static class NoImagePreloadHolder {
+        public static final NativeAllocationRegistry sRegistry =
+                NativeAllocationRegistry.createMalloced(
+                RuntimeShader.class.getClassLoader(), nativeGetFinalizer());
+    }
+
+    private byte[] mUniforms;
+
+    /**
+     * Current native shader factory instance.
+     */
+    private long mNativeInstanceRuntimeShaderFactory;
+
+    /**
+     * Creates a new RuntimeShader.
+     *
+     * @param sksl The text of SKSL program to run on the GPU.
+     * @param uniforms Array of parameters passed by the SKSL shader. Array size depends
+     *                 on number of uniforms declared by sksl.
+     * @param isOpaque True if all pixels have alpha 1.0f.
+     */
+    public RuntimeShader(@NonNull String sksl, @Nullable byte[] uniforms, boolean isOpaque) {
+        this(sksl, uniforms, isOpaque, ColorSpace.get(ColorSpace.Named.SRGB));
+    }
+
+    private RuntimeShader(@NonNull String sksl, @Nullable byte[] uniforms, boolean isOpaque,
+            ColorSpace colorSpace) {
+        super(colorSpace);
+        mUniforms = uniforms;
+        mNativeInstanceRuntimeShaderFactory = nativeCreateShaderFactory(sksl, isOpaque);
+        NoImagePreloadHolder.sRegistry.registerNativeAllocation(this,
+                mNativeInstanceRuntimeShaderFactory);
+    }
+
+    /**
+     * Sets new value for shader parameters.
+     *
+     * @param uniforms Array of parameters passed by the SKSL shader. Array size depends
+     *                 on number of uniforms declared by mSksl.
+     */
+    public void updateUniforms(@Nullable byte[] uniforms) {
+        mUniforms = uniforms;
+        discardNativeInstance();
+    }
+
+    @Override
+    long createNativeInstance(long nativeMatrix) {
+        return nativeCreate(mNativeInstanceRuntimeShaderFactory, nativeMatrix, mUniforms,
+                colorSpace().getNativeInstance());
+    }
+
+    private static native long nativeCreate(long shaderFactory, long matrix, byte[] inputs,
+            long colorSpaceHandle);
+
+    private static native long nativeCreateShaderFactory(String sksl, boolean isOpaque);
+
+    private static native long nativeGetFinalizer();
+}
+

tests/HwAccelerationTest/src/com/android/test/hwui/ColorFiltersMutateActivity.java

@@ -29,9 +29,13 @@ import android.graphics.LightingColorFilter;
 import android.graphics.Paint;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffColorFilter;
+import android.graphics.RuntimeShader;
 import android.os.Bundle;
 import android.view.View;
 
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+
 @SuppressWarnings({"UnusedDeclaration"})
 public class ColorFiltersMutateActivity extends Activity {
     @Override
@@ -47,12 +51,21 @@ public class ColorFiltersMutateActivity extends Activity {
         private final Paint mColorMatrixPaint;
         private final Paint mLightingPaint;
         private final Paint mBlendPaint;
+        private final Paint mShaderPaint;
 
         private float mSaturation = 0.0f;
         private int mLightAdd = 0;
         private int mLightMul = 0;
         private int mPorterDuffColor = 0;
 
+        static final String sSkSL =
+                "uniform float param1;\n"
+                + "void main(float x, float y, inout half4 color) {\n"
+                + "color = half4(color.r, half(param1), color.b, 1.0);\n"
+                + "}\n";
+
+        private byte[] mUniforms = new byte[4];
+
         BitmapsView(Context c) {
             super(c);
 
@@ -70,6 +83,10 @@ public class ColorFiltersMutateActivity extends Activity {
             mBlendPaint = new Paint();
             mBlendPaint.setColorFilter(new PorterDuffColorFilter(0, PorterDuff.Mode.SRC_OVER));
 
+            mShaderPaint = new Paint();
+            mShaderPaint.setShader(new RuntimeShader(sSkSL, mUniforms, true));
+            setShaderParam1(0.0f);
+
             ObjectAnimator sat = ObjectAnimator.ofFloat(this, "saturation", 1.0f);
             sat.setDuration(1000);
             sat.setRepeatCount(ObjectAnimator.INFINITE);
@@ -96,6 +113,12 @@ public class ColorFiltersMutateActivity extends Activity {
             color.setRepeatCount(ObjectAnimator.INFINITE);
             color.setRepeatMode(ObjectAnimator.REVERSE);
             color.start();
+
+            ObjectAnimator shaderUniform = ObjectAnimator.ofFloat(this, "shaderParam1", 1.0f);
+            shaderUniform.setDuration(1000);
+            shaderUniform.setRepeatCount(ObjectAnimator.INFINITE);
+            shaderUniform.setRepeatMode(ObjectAnimator.REVERSE);
+            shaderUniform.start();
         }
 
         public int getPorterDuffColor() {
@@ -148,6 +171,23 @@ public class ColorFiltersMutateActivity extends Activity {
             return mSaturation;
         }
 
+        public void setShaderParam1(float value) {
+            RuntimeShader shader = (RuntimeShader) mShaderPaint.getShader();
+            ByteBuffer buffer = ByteBuffer.wrap(mUniforms);
+            buffer.order(ByteOrder.LITTLE_ENDIAN);
+            buffer.putFloat(value);
+            shader.updateUniforms(mUniforms);
+            invalidate();
+        }
+
+        // If either valueFrom or valueTo is null, then a getter function will also be derived
+        // and called by the animator class.
+        public float getShaderParam1() {
+            ByteBuffer buffer = ByteBuffer.wrap(mUniforms);
+            buffer.order(ByteOrder.LITTLE_ENDIAN);
+            return buffer.getFloat();
+        }
+
         @Override
         protected void onDraw(Canvas canvas) {
             super.onDraw(canvas);
@@ -163,6 +203,10 @@ public class ColorFiltersMutateActivity extends Activity {
 
             canvas.translate(0.0f, 50.0f + mBitmap1.getHeight());
             canvas.drawBitmap(mBitmap1, 0.0f, 0.0f, mBlendPaint);
+
+            canvas.translate(0.0f, 50.0f + mBitmap1.getHeight());
+            canvas.drawRect(0.0f, 0.0f, mBitmap1.getWidth(), mBitmap1.getHeight(),
+                    mShaderPaint);
             canvas.restore();
 
             canvas.save();
@@ -174,6 +218,10 @@ public class ColorFiltersMutateActivity extends Activity {
 
             canvas.translate(0.0f, 50.0f + mBitmap2.getHeight());
             canvas.drawBitmap(mBitmap2, 0.0f, 0.0f, mBlendPaint);
+
+            canvas.translate(0.0f, 50.0f + mBitmap2.getHeight());
+            canvas.drawRoundRect(0.0f, 0.0f, mBitmap2.getWidth(), mBitmap2.getHeight(), 20, 20,
+                    mShaderPaint);
             canvas.restore();
         }
     }