RenderScript使用教程（二）

NDK中使用RenderScript

编写一个rs脚本文件

实现灰度转换的代码

#pragma version(1)#pragma rs java_package_name(com.example.android.rs.hellocomputendk)const static float3 gMonoMult = {0.299f, 0.587f, 0.114f};void root(const uchar4 *v_in, uchar4 *v_out) {    float4 f4 = rsUnpackColor8888(*v_in);    float3 mono = dot(f4.rgb, gMonoMult);    *v_out = rsPackColorTo8888(mono);}

编写NDK调用代码

#include <jni.h>#include <android/log.h>#include <android/bitmap.h>#include <stdio.h>#include <stdlib.h>#include <math.h>#include <RenderScript.h>#include "ScriptC_mono.h"#include "demo_ndk_rs_wps_cn_rsndkdemo_MainActivity.h"#define  LOG_TAG    "HelloComputeNDK"#define  LOGI(...)  __android_log_print(ANDROID_LOG_INFO,LOG_TAG,__VA_ARGS__)#define  LOGE(...)  __android_log_print(ANDROID_LOG_ERROR,LOG_TAG,__VA_ARGS__)using namespace android::RSC;extern "C" JNIEXPORT void JNICALLJava_demo_ndk_rs_wps_cn_rsndkdemo_MainActivity_nativeMono(JNIEnv * env, jclass, jstring pathObj, jint X, jint Y, jobject jbitmapIn, jobject jbitmapOut) {    void* inputPtr = nullptr;    void* outputPtr = nullptr;    AndroidBitmap_lockPixels(env, jbitmapIn, &inputPtr);    AndroidBitmap_lockPixels(env, jbitmapOut, &outputPtr);    const char * path = env->GetStringUTFChars(pathObj, nullptr);    sp<RS> rs = new RS();    rs->init(path);    env->ReleaseStringUTFChars(pathObj, path);    sp<const Element> e = Element::RGBA_8888(rs);    sp<const Type> t = Type::create(rs, e, X, Y, 0);    sp<Allocation> inputAlloc = Allocation::createTyped(rs, t, RS_ALLOCATION_MIPMAP_NONE,                                                        RS_ALLOCATION_USAGE_SHARED | RS_ALLOCATION_USAGE_SCRIPT,                                                        inputPtr);    sp<Allocation> outputAlloc = Allocation::createTyped(rs, t, RS_ALLOCATION_MIPMAP_NONE,                                                         RS_ALLOCATION_USAGE_SHARED | RS_ALLOCATION_USAGE_SCRIPT,                                                         outputPtr);    inputAlloc->copy2DRangeFrom(0, 0, X, Y, inputPtr);    ScriptC_mono* sc = new ScriptC_mono(rs);    sc->forEach_root(inputAlloc, outputAlloc);    outputAlloc->copy2DRangeTo(0, 0, X, Y, outputPtr);    AndroidBitmap_unlockPixels(env, jbitmapIn);    AndroidBitmap_unlockPixels(env, jbitmapOut);}

编写编译mk文件

android.mk文件如下：

LOCAL_PATH := $(call my-dir)include $(CLEAR_VARS)LOCAL_MODULE := rstest-computeLOCAL_SRC_FILES:=main.cpp mono.rsLOCAL_C_INCLUDES += D:/Android/android-ndk-r14b-windows-x86_64/android-ndk-r14b/toolchains/renderscript/prebuilt/windows-x86_64/platform/rs/cpp \    D:/Android/android-ndk-r14b-windows-x86_64/android-ndk-r14b/toolchains/renderscript/prebuilt/windows-x86_64/platform/rsLOCAL_CFLAGS := -std=c++11LOCAL_LDFLAGS := -Wl,-Bsymbolic#LOCAL_RENDERSCRIPT_COMPATIBILITY := trueLOCAL_SHARED_LIBRARIES := RSSupport blasV8 RSSupportIOLOCAL_STATIC_LIBRARIES := RScpp_staticLOCAL_LDLIBS := -llog -ljnigraphics -lz -ldlinclude $(BUILD_SHARED_LIBRARY)$(call import-module,android/renderscript)

这里注意LOCAL_C_INCLUDES 请写你本地对应NDK有关rs头文件的目录。
application.mk文件如下：

APP_ABI := armeabi-v7aAPP_PLATFORM := android-19APP_STL := stlport_static

编译代码

这里需要注意必须使用linux系统或者babun去编译文件，因为在window命令行下有NDK有一个bug，具体请查看编译以及注意事项请查看该链接。

Java调用测试

private Bitmap mBitmapIn;    private Bitmap mBitmapOut;    private ImageView iv_show;    private ImageView iv_input;    // Used to load the 'native-lib' library on application startup.    static {        System.loadLibrary("rstest-compute");    }    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mBitmapIn = ((BitmapDrawable)getResources().getDrawable(R.drawable.ic_launcher)).getBitmap();        mBitmapOut = Bitmap.createBitmap(mBitmapIn.getWidth(), mBitmapIn.getHeight(), mBitmapIn.getConfig());        nativeMono(this.getCacheDir().toString(),                mBitmapIn.getWidth(), mBitmapIn.getHeight(),                mBitmapIn, mBitmapOut);        iv_show = (ImageView) findViewById(R.id.iv_show);        iv_input = (ImageView) findViewById(R.id.iv_input);        iv_input.setImageBitmap(mBitmapIn);        iv_show.setImageBitmap(mBitmapOut);    }    /**     * A native method that is implemented by the 'native-lib' native library,     * which is packaged with this application.     */    native void nativeMono(String cacheDir, int X, int Y, Bitmap in, Bitmap out);

运行效果如下：