Sphere in an android App
Saturday, September 21, 2024
Sunday, September 15, 2024
Sierpinki Gasket in an Android App
This project is a modification of an existing app I created earlier.
~TLDR: clone the repo https://github.com/bmkamath2000/mukBoApps and open in android studio to run.
Upon creating an android project in android studio there was a MainActivity.java automatically created in the src folder.
I instinctively guessed that I needed to declare a MyGLSurfaceView which extends a GLSurfaceView.
My guess turned true as I got a surface in the app when I created a run configuration and
launched the app using it.
I had some experience with rudimentary android app development over several years in the past.
package com.example.mukesh.seirpinskigasketandroid;
import android.opengl.GLSurfaceView;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MotionEvent;
import java.lang.Runnable;
public class MainActivity extends AppCompatActivity {
private MyGLSurfaceView mGLView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mGLView = new MyGLSurfaceView(this);
setContentView(mGLView);
}
}
As you can see onCreate of the MainActivity the view is set as content view.
In MyGLSurfaceView
I created a MyGLRenderer instance which is derived from GLSurfaceView.Renderer.
package com.example.mukesh.seirpinskigasketandroid;
import android.content.Context;
import android.opengl.GLSurfaceView;
import android.view.MotionEvent;
import android.view.KeyEvent;
public class MyGLSurfaceView extends GLSurfaceView {
private final MyGLRenderer mRenderer;
//variable for storing the time of first click
long startTime;
public MyGLSurfaceView(Context context) {
super(context);
// Create an OpenGL ES 2.0 context
setEGLContextClientVersion(2);
mRenderer = new MyGLRenderer();
// Set the Renderer for drawing on the GLSurfaceView
setRenderer(mRenderer);
// Render the view only when there is a change in the drawing data
setRenderMode(GLSurfaceView.RENDERMODE_CONTINUOUSLY);
}
@Override
public boolean onTouchEvent(MotionEvent e) {
// MotionEvent reports input details from the touch screen
// and other input controls. In this case, you are only
// interested in events where the touch position changed.
//constant for defining the time duration between the click that can be
//considered as double-tap
final int MAX_DURATION = 200;
if (e.getAction() == MotionEvent.ACTION_DOWN) {
startTime = System.currentTimeMillis();
}
else if (e.getAction() == MotionEvent.ACTION_UP) {
if(System.currentTimeMillis() - startTime >= MAX_DURATION)
{
//DOUBLE TAP
mRenderer.mTriangle.n++;
requestRender();
}
else {
//SINGLE TAP
if(mRenderer.mTriangle.n>0) {
mRenderer.mTriangle.n--;
requestRender();
}
}
}
return true;
}
}
The MyGLRenderer declares a Triangle and draws it onDrawFrame.
package com.example.mukesh.seirpinskigasketandroid;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
public class MyGLRenderer implements GLSurfaceView.Renderer {
public Triangle mTriangle;
@Override
public void onSurfaceCreated(GL10 gl10, EGLConfig eglConfig) {
GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
// initialize a triangle
mTriangle = new Triangle();
// initialize a square
}
@Override
public void onSurfaceChanged(GL10 gl10, int width, int height) {
GLES20.glViewport(0, 0, width, height);
}
@Override
public void onDrawFrame(GL10 gl10) {
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
mTriangle.draw();
}
public static int loadShader(int type, String shaderCode){
// create a vertex shader type (GLES20.GL_VERTEX_SHADER)
// or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
int shader = GLES20.glCreateShader(type);
// add the source code to the shader and compile it
GLES20.glShaderSource(shader, shaderCode);
GLES20.glCompileShader(shader);
return shader;
}
}
I have Created the Triangle class which is based on the android official site:
https://developer.android.com/develop/ui/views/graphics/opengl/draw
package com.example.mukesh.seirpinskigasketandroid;
import android.opengl.GLES20;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
public class Triangle {
private final int mProgram;
private FloatBuffer vertexBuffer;
// number of coordinates per vertex in this array
static final int COORDS_PER_VERTEX = 3;
static float triangleCoords[] = { // in counterclockwise order:
0.0f, 0.622008459f, 0.0f, // top
-0.5f, -0.311004243f, 0.0f, // bottom left
0.5f, -0.311004243f, 0.0f // bottom right
};
float v[][]={{-1.0f,-0.5f,0.0f},{1.0f,-0.5f,0.0f},
{0.0f,1.0f,0.0f}};
float colors[][]={{1.0f,0.0f,0.0f},{0.0f,1.0f,0.0f},{0.0f,0.0f,1.0f},
{0.0f,0.0f,0.0f}};
public int n=4, prevn=0;
int vc1=0;
// Set color with red, green, blue and alpha (opacity) values
float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 1.0f };
public Triangle() {
// create empty OpenGL ES Program
mProgram = GLES20.glCreateProgram();
}
void triangle(FloatBuffer fb,float a[],float b[],float c[])
{
fb.put(a);
fb.put(b);
fb.put(c);
vc1+=3;
}
public int findnoofnodes(int nt)
{
if(nt<=1)
return 3;
else return ((findnoofnodes(nt-1) * 3) - 3);
}
void divide_tetra(FloatBuffer fb,float a[],float b[],float c[],int m)
{
float v1[]=new float[3],v2[]=new float[3],v3[]=new float[3];
int j;
if(m>0)
{ /*compute three midpoints*/
for(j=0;j<3;j++)
v1[j]=(a[j]+b[j])/2;
for(j=0;j<3;j++)
v2[j]=(a[j]+c[j])/2;
for(j=0;j<3;j++)
v3[j]=(c[j]+b[j])/2;
divide_tetra(fb,a,v2,v1,m-1);
divide_tetra(fb,c,v3,v2,m-1);
divide_tetra(fb,b,v1,v3,m-1);
}
else
triangle(fb, a, b, c); //draw triangle at end of recursion//
}
private final String vertexShaderCode =
"attribute vec4 vPosition;" +
"void main() {" +
" gl_Position = vPosition;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
" gl_FragColor = vColor;" +
"}";
private int mPositionHandle;
private int mColorHandle;
private final int vertexCount = triangleCoords.length / COORDS_PER_VERTEX;
private final int vertexStride = COORDS_PER_VERTEX *4; // 4 bytes per vertex
public void PopulateVBO()
{
final int nodesN = findnoofnodes(n+2);
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.allocateDirect(
// (number of coordinate values * 4 bytes per float)
(nodesN* 16 ) +100
//90000
);
// use the device hardware's native byte order
bb.order(ByteOrder.nativeOrder());
// create a floating point buffer from the ByteBuffer
vertexBuffer = bb.asFloatBuffer();
// add the coordinates to the FloatBuffer
//vertexBuffer.put(triangleCoords);
// set the buffer to read the first coordinate
vc1=0;
divide_tetra(vertexBuffer,v[0],v[1],v[2],n);
System.out.println("Length of VB"+ vertexBuffer.capacity()+ "VC1"+vc1);
vertexBuffer.position(0);
int vertexShader = MyGLRenderer.loadShader(GLES20.GL_VERTEX_SHADER,
vertexShaderCode);
int fragmentShader = MyGLRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER,
fragmentShaderCode);
// add the vertex shader to program
GLES20.glAttachShader(mProgram, vertexShader);
// add the fragment shader to program
GLES20.glAttachShader(mProgram, fragmentShader);
// creates OpenGL ES program executables
GLES20.glLinkProgram(mProgram);
}
public void draw() {
if(prevn != n && n > 0)
{
prevn = n;
PopulateVBO();
}
// Add program to OpenGL ES environment
GLES20.glUseProgram(mProgram);
// get handle to vertex shader's vPosition member
mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
// Enable a handle to the triangle vertices
GLES20.glEnableVertexAttribArray(mPositionHandle);
// Prepare the triangle coordinate data
GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
GLES20.GL_FLOAT, false,
vertexStride, vertexBuffer);
// get handle to fragment shader's vColor member
mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
// Set color for drawing the triangle
GLES20.glUniform4fv(mColorHandle, 1, color, 0);
// Draw the triangle
GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0,vc1);
// Disable vertex array
GLES20.glDisableVertexAttribArray(mPositionHandle);
}
}
The triangle is subdivided and on single or delayed click the number of triangles
triples or divides by a factor of 3.
Here is how it looks:
Thanks
Saturday, September 14, 2024
protobuf.dev getting started with protocol buffer example
Head over to the site https://protobuf.dev
In that site you will find things to compile a C++ and many other language projects with address book. Now just take a deep breath and dive in.
Warning: This is easy in Linux and verry verry difficult in Windows
If you find the going tough in that site, come here for I will get you some personal touch.
write_to_file.cpp
#include <iostream>
#include <fstream>
#include <string>
#include "./proto/addressbook.pb.h"
using namespace std;
// This function fills in a Person message based on user input.
void PromptForAddress(tutorial::Person* person) {
cout << "Enter person ID number: ";
int id;
cin >> id;
person->set_id(id);
cin.ignore(256, '\n');
cout << "Enter name: ";
getline(cin, *person->mutable_name());
cout << "Enter email address (blank for none): ";
string email;
getline(cin, email);
if (!email.empty()) {
person->set_email(email);
}
while (true) {
cout << "Enter a phone number (or leave blank to finish): ";
string number;
getline(cin, number);
if (number.empty()) {
break;
}
tutorial::Person::PhoneNumber* phone_number = person->add_phones();
phone_number->set_number(number);
cout << "Is this a mobile, home, or work phone? ";
string type;
getline(cin, type);
if (type == "mobile") {
phone_number->set_type(tutorial::Person::PHONE_TYPE_MOBILE);
} else if (type == "home") {
phone_number->set_type(tutorial::Person::PHONE_TYPE_HOME);
} else if (type == "work") {
phone_number->set_type(tutorial::Person::PHONE_TYPE_WORK);
} else {
cout << "Unknown phone type. Using default." << endl;
}
}
}
// Main function: Reads the entire address book from a file,
// adds one person based on user input, then writes it back out to the same
// file.
int main(int argc, char* argv[]) {
// Verify that the version of the library that we linked against is
// compatible with the version of the headers we compiled against.
GOOGLE_PROTOBUF_VERIFY_VERSION;
if (argc != 2) {
cerr << "Usage: " << argv[0] << " ADDRESS_BOOK_FILE" << endl;
return -1;
}
tutorial::AddressBook address_book;
{
// Read the existing address book.
fstream input(argv[1], ios::in | ios::binary);
if (!input) {
cout << argv[1] << ": File not found. Creating a new file." << endl;
} else if (!address_book.ParseFromIstream(&input)) {
cerr << "Failed to parse address book." << endl;
return -1;
}
}
// Add an address.
PromptForAddress(address_book.add_people());
{
// Write the new address book back to disk.
fstream output(argv[1], ios::out | ios::trunc | ios::binary);
if (!address_book.SerializeToOstream(&output)) {
cerr << "Failed to write address book." << endl;
return -1;
}
}
// Optional: Delete all global objects allocated by libprotobuf.
google::protobuf::ShutdownProtobufLibrary();
return 0;
}
read_from_file.cpp
#include <iostream>
#include <fstream>
#include <string>
#include "addressbook.pb.h"
using namespace std;
// Iterates though all people in the AddressBook and prints info about them.
void ListPeople(const tutorial::AddressBook& address_book) {
for (int i = 0; i < address_book.people_size(); i++) {
const tutorial::Person& person = address_book.people(i);
cout << "Person ID: " << person.id() << endl;
cout << " Name: " << person.name() << endl;
if (person.has_email()) {
cout << " E-mail address: " << person.email() << endl;
}
for (int j = 0; j < person.phones_size(); j++) {
const tutorial::Person::PhoneNumber& phone_number = person.phones(j);
switch (phone_number.type()) {
case tutorial::Person::PHONE_TYPE_MOBILE:
cout << " Mobile phone #: ";
break;
case tutorial::Person::PHONE_TYPE_HOME:
cout << " Home phone #: ";
break;
case tutorial::Person::PHONE_TYPE_WORK:
cout << " Work phone #: ";
break;
}
cout << phone_number.number() << endl;
}
}
}
// Main function: Reads the entire address book from a file and prints all
// the information inside.
int main(int argc, char* argv[]) {
// Verify that the version of the library that we linked against is
// compatible with the version of the headers we compiled against.
GOOGLE_PROTOBUF_VERIFY_VERSION;
if (argc != 2) {
cerr << "Usage: " << argv[0] << " ADDRESS_BOOK_FILE" << endl;
return -1;
}
tutorial::AddressBook address_book;
{
// Read the existing address book.
fstream input(argv[1], ios::in | ios::binary);
if (!address_book.ParseFromIstream(&input)) {
cerr << "Failed to parse address book." << endl;
return -1;
}
}
ListPeople(address_book);
// Optional: Delete all global objects allocated by libprotobuf.
google::protobuf::ShutdownProtobufLibrary();
return 0;
}
Thursday, September 5, 2024
Compile and execute a Simple example of working with Protobuf in C++
You can learn a lot by doing.
Ditto with CMake project building and running in Ubuntu.
An example cpp-protobuf-example in the github site https://github.com/afiskon/cpp-protobuf-example
comes up often in the google search and I tried compiling it in windows and it gave error.
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Could NOT find Protobuf (missing: Protobuf_INCLUDE_DIR)
Its difficult to install protobuf in windows but I did it in Ubuntu(which is just an app in windows now with technology of windows subsystem for linux-WSL).
First I did a git clone with this cmd:
git clone https://github.com/afiskon/cpp-protobuf-example.git
then I changed directory to
cd cpp-protobuf-example/
After that I created a build directory by
mkdir build
followed by
cd build
followed by
cmake ..
which gave the same error as in windows. In ubuntu its much easier to install required libraries.
sudo apt-get install protobuf-compiler libprotobuf-dev
this command installed everything for me and I was good to go build the app.
cmake ..
worked like charm with following output:
-- Found Protobuf: /usr/lib/x86_64-linux-gnu/libprotobuf.so (found version "3.12.4")
-- Configuring done
-- Generating done
-- Build files have been written to: /home/kamathbol/GitHub/cpp-protobuf-example/build
then the command
cmake --build .
[ 20%] Running cpp protocol buffer compiler on src/proto/Game.proto
[ 40%] Building CXX object CMakeFiles/proto.dir/Game.pb.cc.o
[ 60%] Linking CXX static library libproto.a
[ 60%] Built target proto
[ 80%] Building CXX object CMakeFiles/main.dir/src/Main.cpp.o
[100%] Linking CXX executable main
[100%] Built target main
then upon running the main
./main
Saving heroes...
Loading heroes...
Name: eax
HP: 50
XP: 256
Class: warrior
Weapon: sword
Arrows: 15
Name: afiskon
HP: 25
XP: 1024
Class: mage
Spellbook: fireball, thunderbolt,
Mana: 100
BTW here is the Main.cpp source that gets you this Output:
#include <iostream>
#include <fstream>
#include <stdexcept>
#include <Game.pb.h>
using namespace std;
using namespace me::eax::examples::game;
void saveHero(const char* fname, const Hero& hero) {
fstream out(fname, ios::out | ios::trunc | ios::binary);
if(!hero.SerializeToOstream(&out))
throw runtime_error("saveHero() failed");
}
void loadHero(const char* fname, Hero& hero) {
fstream in(fname, ios::in | ios::binary);
if(!hero.ParseFromIstream(&in))
throw runtime_error("loadHero() failed");
}
void printHero(const Hero& hero) {
cout << "Name: " << hero.name() << endl;
cout << "HP: " << hero.hp() << endl;
cout << "XP: " << hero.xp() << endl;
if(hero.has_mage_info()) {
cout << "Class: mage" << endl;
cout << "Spellbook: ";
for(int i = 0; i < hero.mage_info().spellbook_size(); i++) {
switch(hero.mage_info().spellbook(i)) {
case Spell::FIREBALL:
cout << "fireball, ";
break;
case Spell::THUNDERBOLT:
cout << "thunderbolt, ";
break;
default:
cout << "(unknown spell), ";
break;
}
}
cout << endl;
cout << "Mana: " << hero.mage_info().mana() << endl;
} else if(hero.has_warrior_info()) {
cout << "Class: warrior" << endl;
cout << "Weapon: " << (
hero.warrior_info().weapon() == Weapon::SWORD ? "sword" :
hero.warrior_info().weapon() == Weapon::BOW ? "bow" :
"(unknown weapon)"
) << endl;
cout << "Arrows: " << hero.warrior_info().arrows_number() << endl;
} else {
cout << "Class: (unknown class)" << endl;
}
cout << endl;
}
int main() {
// Verify that the version of the library that we linked against is
// compatible with the version of the headers we compiled against.
GOOGLE_PROTOBUF_VERIFY_VERSION;
Hero warrior;
warrior.set_name("eax");
warrior.set_hp(50);
warrior.set_xp(256);
warrior.mutable_warrior_info()->set_weapon(Weapon::SWORD);
warrior.mutable_warrior_info()->set_arrows_number(15);
Hero mage;
mage.set_name("afiskon");
mage.set_hp(25);
mage.set_xp(1024);
mage.mutable_mage_info()->add_spellbook(Spell::FIREBALL);
mage.mutable_mage_info()->add_spellbook(Spell::THUNDERBOLT);
mage.mutable_mage_info()->set_mana(100);
cout << "Saving heroes..." << endl;
saveHero("eax.dat", warrior);
saveHero("afiskon.dat", mage);
cout << "Loading heroes..." << endl;
Hero warrior2;
Hero mage2;
loadHero("eax.dat", warrior2);
loadHero("afiskon.dat", mage2);
cout << endl;
printHero(warrior2);
printHero(mage2);
}
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