How to Build & Use OpenCL on Android Studio

©SIProp Project, 2006-2008 1
How to Build & Use OpenCL on Android
Studio
Noritsuna Imamura
noritsuna@siprop.org

Goal
Making OpenCL programming Environment on
Android Studio
Android Studio 1.3 or later
C Language (Android NDK)
OpenCL 1.1 (ARM-Mali)

Why?
OpenCL source code is separated “host source
code” as C Language file & “kernel(device)
source code” as CL file.
But Android’s APK can NOT include “kernel(device)
source code” as CL file in APK file.
Solution
Convert CL file to const char* in Single C header file

Setup NDK on Android Studio1.3
Requited
Gradle2.5 or later
AS1.3’s Gradel is 2.4.
MUST update 2.4 -> 2.5 .
Setup NDK
Settings->System Setting->Android SDK
Modify “build.gradle”
http://tools.android.com/tech-docs/new-build-
system/gradle-experimental
Informations
Android NDK Support for Android Studio
http://tools.android.com/tech-docs/android-ndk-preview
NDK Samples
https://github.com/googlesamples/android-ndk

Setup OpenCL on Android Studio1.3
Setup Header files of OpenCL
Download from ARM-Mali’s OpenCL Dev Site
http://malideveloper.arm.com/resources/sdks/mali-opencl-
sdk/
Copy “[ARM-Mali dir]/include/CL/*.h” to “[your
project dir]/app/main/src/jni/CL/”
Load Shared Lib of OpenCL
Copy “libOpenCL.so” from your Android Device
to “[your Android Studio Dir]/sdk/ndk-
bundle/platforms/android-[your target system]/arch-
arm/usr/lib/”

Setup OpenCL on Android Studio1.3
Setup Header files & Shared Lib on Android
Studio
Add “Cflags” & “ldLibs” in “build.gradle”
1. build.gradle : app, android.ndk section
1. android.ndk {
2. moduleName = "openclsample-jni"
3. CFlags += "-I${file("src/main/jni/CL")}".toString()
4. ldLibs = ["android", "log", "OpenCL"]
5. (snip)

Setup Plugin “OpenCL CL Generator”
Install Plugin to Android Studio
Select “Setting->plugins”
Click “Browse Repositories”
Search Plugin by “OpenCL” as keyword
Target Plugin URL
https://plugins.jetbrains.com/plugin/7888?pr=androidstudio
Click “Install Plugin”
Restart Android Studio

Use Plugin “OpenCL CL Generator”
Click “Tools->Generate OpenCL’s CL files
header”

How to Use Plugin: Host Side
Host side programming: standard OpenCL
CL file(kernel side source code) is loaded as “file”.
1. #include “opencl_cl_files.h”
2. (snip)
3. /* Create Kernel Program from the source */
4. program = clCreateProgramWithSource(context, 1, (const char **)&CLCL_HELLO,
(const size_t *)&strlen(CLCL_HELLO), &ret);
1. FILE *fp;
2. char fileName[] = "./hello.cl";
3. char *source_str;
4. size_t source_size;
5. fp = fopen(fileName, "r");
6. source_str = (char*)malloc(MAX_SOURCE_SIZE);
7. source_size = fread( source_str, 1, MAX_SOURCE_SIZE, fp);
8. fclose( fp );
9. (snip)
10. /* Create Kernel Program from the source */
11. program = clCreateProgramWithSource(context, 1, (const char **)&source_str, (const
size_t *)&source_size, &ret);
Host side programming: with Android Plugin
CL file is loaded as “const char*”.

How to Use Plugin: Kernel Side
1. Converted Original File: opencl_cl_files.h
1. const char *CLCL_HELLO =
2. "#pragma OPENCL EXTENSION
cl_khr_byte_addressable_store : enablen"
3. "n"
4. "__kernel void hello(__global char*
string)n"
5. "{n"
6. " string[0] = 'H';n"
7. " string[1] = 'e';n"
8. " string[2] = 'l';n"
9. " string[3] = 'l';n"
10. " string[4] = 'o';n"
11. " string[5] = '0';n"
12. "}n"
13. "";
1. Kernel Source Code File: hello.cl
1. #pragma OPENCL EXTENSION
cl_khr_byte_addressable_store : enable
2. __kernel void hello(__global char* string)
3. {
4. string[0] = 'H';
5. string[1] = 'e';
6. string[2] = 'l';
7. string[3] = 'l';
8. string[4] = 'o';
9. string[5] = '0';
10. }
Kernel side programming
1. Write Source Code as CL file(Kernel Source Code)
2. Convert CL file(Kernel Source Code) to Original
Header File as “opencl_cl_files.h”

Setup libOpenCL.so on Android
If you(or your Android Device) don’t have
libOpenCL.so in “/system/lib” or
“/system/vendor/lib”, you can download
libOpenCL.so.
Support GPUs
adreno-3xx: Qualcomm's Adreno 3xx GPUs
mali-t6xx: ARM's Mali-T6xx GPUs
Download from:
https://github.com/madeye/opencl-android-proprietary
Setup
Copy All SO files to “/system/lib” or “/system/vendor/lib”
on your Android Device.

Appendix

Download the Sample Project for AS
The Sample Project for AS that I use in this
slide.
https://github.com/noritsuna/OpenCLCLGenerator_
Sample
Features
“build.gradle” for NDK Support
Setup Plugin
OpenCL Headers & SO lib
The Sample Source Code for OpenCL

How to Build & Use OpenCL on Android Studio

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