Recently I worked on a 2D Game using SurfaceView and I learned a lot about game loops and everything. But now I want to make the same game using OpenGL. I read that the GLSurfaceView is the class that would be relative to what SurfaceView was. But I'm not sure about other things as:
Using SurfaceView, I used the Bitmap class to load a image resource that would be lets say a character. And that bitmap would be a property of my Character class. And for the gameloop I used a different Thread
I'm new to OpenGL so I'd like to know how to load image resources (do I load them using the Bitmap class?), or what to use instead of a Thread for the game loop?
do I load them using the Bitmap class?
Yes, you can load bitmap and use it as textImage2D.
Example:
public void loadTextures(GL10 gl, Context context) {
Log.e(LOG_TAG, "ExplosionSprite :: loadTextures");
mFrame = 0;
InputStream is;
Bitmap bitmap;
is = context.getResources().openRawResource(DRAW_SOURCE);
bitmap = BitmapFactory.decodeStream(is);
try {
is.close();
is = null;
} catch (IOException e) {
}
gl.glGenTextures(TEXTURE_COUNT, textures, 0);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_LINEAR);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
bitmap.recycle();
}
Before 4 month I did the same, because of performance switched to OpenGL ES 2D.
Its a bit complicated but after some time seems easy enough.
I don't have right now example for single image but have pretty good example for sprite sheet where I animate my Image. I'm sure you can remove not relevant data to make it for one static image. Google has enough resources "how to" so I'll point what I used for my purposes:
Cast_001_Sprite_.java
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import javax.microedition.khronos.opengles.GL10;
import net.obviam.droidz.R;
import net.obviam.droidz.model.components.ESpriteDirection;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.opengl.GLUtils;
import android.util.Log;
public class Cast_001_Sprite_ {
private static final String LOG_TAG = Cast_001_Sprite.class.getSimpleName();
/** Sprite sheet definition */
private static final int SPRITE_WIDTH = 5;
private static final int SPRITE_HEIGHT = 4;
private int DRAW_SOURCE = R.drawable.a1;
private int mX = Location._1[0]; // 100;
private int mY = Location._1[1]; // 100;
private float mScreenWidth, mScreenHeight, wRatio, hRatio;
private int mFrame = 0;
private int mSwitcher = 0;
private final static int TEXTURE_COUNT = 1; // for sprite sheet we use 1 image all the time.
private int[] textures = new int[TEXTURE_COUNT]; // frame animation
protected FloatBuffer vertexBuffer;
private final static ESpriteDirection mDirection = ESpriteDirection.TOP_TO_DOWN_LEFT_TO_RIGHT;
public float x, y, initPos, finalPos, initSpeed, currentPos;
private ByteBuffer bb1;
private final static int TOTAL_IMAGE_COUNT_IN_SPRITE = SPRITE_WIDTH * SPRITE_HEIGHT;
private FloatBuffer[] floatBufferArray = new FloatBuffer[TOTAL_IMAGE_COUNT_IN_SPRITE];
private float xOffset = 1.0f/SPRITE_WIDTH;
private float yOffset = 1.0f/SPRITE_HEIGHT;
float[] vertices = new float[] {
-1.0f, -1.0f, 0.0f,
-1.0f, 1.0f, 0.0f,
1.0f, -1.0f, 0.0f,
1.0f, 1.0f, 0.0f };
private float storage[][] = new float[TOTAL_IMAGE_COUNT_IN_SPRITE][];
private int[] sprite_X_Indexes = new int[SPRITE_WIDTH];//{1,2,3,4};
private int[] sprite_Y_Indexes = new int[SPRITE_HEIGHT];//{1,2,3,4};
public Cast_001_Sprite_(float screenWidth, float screenHeight){
generateSpriteIndexes();
updateScreenData(screenWidth, screenHeight);
int index = 0;
switch (mDirection) {
case TOP_TO_DOWN_LEFT_TO_RIGHT:
for(int row = 0; row<SPRITE_HEIGHT; row++){
for(int column = 0; column<SPRITE_WIDTH; column++){
storage[index] = generateTextures(column, row);
index++;
}
}
break;
case DOWN_TO_TOP_LEFT_TO_RIGHT:
//TODO
// for(int row = spriteLength; row>0; row--){
// for(int column = 0; column<spriteHeight; column++){
// storage[index] = generateTextures( row-1, column);
// index++;
// }
// }
break;
default:
break;
}
// vertices buffer
bb1 = ByteBuffer.allocateDirect(vertices.length * 4);
bb1.order(ByteOrder.nativeOrder());
vertexBuffer = bb1.asFloatBuffer();
vertexBuffer.put(vertices);
vertexBuffer.position(0);
for(int i=0; i<TOTAL_IMAGE_COUNT_IN_SPRITE; i++){
bb1 = ByteBuffer.allocateDirect(storage[i].length * 4);
bb1.order(ByteOrder.nativeOrder());
FloatBuffer textureBuffer = bb1.asFloatBuffer();
textureBuffer.put(storage[i]);
textureBuffer.position(0);
floatBufferArray[i] = textureBuffer;
}
}
private void generateSpriteIndexes() {
for(int indexX = 0; indexX<SPRITE_WIDTH; indexX++){
sprite_X_Indexes[indexX] = indexX+1;
}
for(int indexY = 0; indexY<SPRITE_HEIGHT; indexY++){
sprite_Y_Indexes[indexY] = indexY+1;
}
}
public void updateScreenData(float screenWidth, float screenHeight){
// takes screen Height and Width
this.mScreenWidth = (screenWidth > 0) ? screenWidth : 1f;
this.mScreenHeight = screenHeight;
wRatio = 10f/mScreenWidth;
hRatio = mScreenHeight/10f;
addExplosion(mX,mY);
}
public void addExplosion(float x, float y) {
this.x = x;
this.y = y;
this.initPos = y;
}
/**
* Generates texture by location
*
* @param texture - fill current texture
* @param placeX - image place in sprite scale X
* @param placeY - image place in sprite scale Y
* @return
*/
private float[] generateTextures(int placeX, int placeY) {
float texture[] = new float[8];
/*
V1 _____ V3
| |
| |
V2|_____|V4
*/
//StringBuffer buff = new StringBuffer();
/** V1 */
texture[0] = (placeX == 0)?0.0f : xOffset*sprite_X_Indexes[placeX-1];
texture[1] = yOffset*sprite_Y_Indexes[placeY];
/** V2 */
texture[2] = (placeX == 0)?0.0f : xOffset*sprite_X_Indexes[placeX-1];
texture[3] = (placeY == 0)?0.0f : yOffset*sprite_Y_Indexes[placeY-1];
/** V3 */
texture[4] = xOffset*sprite_X_Indexes[placeX];
texture[5] = yOffset*sprite_Y_Indexes[placeY];
/** V4 */
texture[6] = xOffset*sprite_X_Indexes[placeX];
texture[7] = (placeY == 0)?0.0f : yOffset*sprite_Y_Indexes[placeY-1];
return texture;
}
private void update() {
if(mSwitcher == 1){
mFrame = ++mFrame % TOTAL_IMAGE_COUNT_IN_SPRITE;
mSwitcher = 0;
// Log.e(LOG_TAG, "DevQuestSpriteBase :: " + mFrame);
}
else{
mSwitcher++;
}
}
public void reset(){
mFrame = 0;
}
public void loadTextures(GL10 gl, Context context) {
Log.e(LOG_TAG, "ExplosionSprite :: loadTextures");
mFrame = 0;
InputStream is;
Bitmap bitmap;
is = context.getResources().openRawResource(DRAW_SOURCE);
bitmap = BitmapFactory.decodeStream(is);
try {
is.close();
is = null;
} catch (IOException e) {
}
gl.glGenTextures(TEXTURE_COUNT, textures, 0);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_LINEAR);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
bitmap.recycle();
}
public void draw(GL10 gl){
// if(mFrame == TOTAL_IMAGE_COUNT_IN_SPRITE - 1){
// return;
// }
gl.glPushMatrix();
try {
float transx = + (wRatio * x);
float transy = + (mScreenHeight*wRatio) - (wRatio * y) - 1/hRatio;
// Log.e(LOG_TAG, "transx: " + transx + "; transy: " + transy + "; sprite.x: "+ sprite.x + "; sprite.y: " + sprite.y);
gl.glTranslatef(transx, transy, 0.0f);
//########### draw ##############
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_LINEAR);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_CLAMP_TO_EDGE);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_CLAMP_TO_EDGE);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, floatBufferArray[mFrame]);
update();
gl.glColor4f(1f, 1f, 1f, 0.2f);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, vertices.length / 3);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
//###############################
} catch (NullPointerException e) {
}
gl.glPopMatrix();
}
}
DevQuest1Activity.java
public class DevQuest1Activity extends Activity {
private DevQuestGLSurfaceView mGLView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
mGLView = new DevQuestGLSurfaceView(this);
setContentView(mGLView);
}
@Override
protected void onPause() {
super.onPause();
mGLView.onPause();
}
@Override
protected void onResume() {
super.onResume();
mGLView.onResume();
}
}
DevQuestGLRenderer.java
public class DevQuestGLRenderer implements GLSurfaceView.Renderer {
private static final String LOG_TAG = "Fess";//DevQuestGLRenderer.class.getSimpleName();
private Context context;
private float ratio;
private int screenWidth, screenHeight;
public Cast_001_Sprite Cast_001_Sprite;
public DevQuestGLRenderer(Context context){
this.context = context;
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig confid) {
gl.glEnable(GL10.GL_TEXTURE_2D);
gl.glShadeModel(GL10.GL_SMOOTH);
gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
gl.glClearDepthf(1.0f);
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);
gl.glEnable(GL10.GL_BLEND);
gl.glDisable(GL10.GL_DEPTH_TEST);
gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);
gl.glTexEnvf(GL10.GL_TEXTURE_ENV, GL10.GL_TEXTURE_ENV_MODE, /*GL10.GL_REPLACE*/ GL10.GL_MODULATE);
}
@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
Log.e(LOG_TAG, "onSurfaceChanged");
// prevent 0 divise
if(height == 0) { height=1;}
screenWidth = width; screenHeight = height;
ratio = (float) width/height;
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
gl.glOrthof(0, width, 0, height, -10f, 10f);
gl.glViewport(0, 0, screenWidth, screenHeight);
Cast_001_Sprite = new Cast_001_Sprite(width, height);
Cast_001_Sprite.loadTextures(gl, context);
}
@Override
public void onDrawFrame(GL10 gl) {
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
gl.glPushMatrix();
gl.glScalef((screenWidth)/10, (screenHeight*ratio)/10, 1.0f);
Cast_001_Sprite.draw(gl);
gl.glPopMatrix();
}
}
DevQuestGLSurfaceView.java
public class DevQuestGLSurfaceView extends GLSurfaceView {
private DevQuestGLRenderer mRenderer;
private int count = 0;
public DevQuestGLSurfaceView(Context context) {
super(context);
mRenderer = new DevQuestGLRenderer(context);
setRenderer(mRenderer);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
return true;
}
}
ESpriteDirection.java
public enum ESpriteDirection {
TOP_TO_DOWN_LEFT_TO_RIGHT,
DOWN_TO_TOP_LEFT_TO_RIGHT,
TOP_TO_DOWN_RIGHT_TO_LEFT,
DOWN_TO_TOP_RIGHT_TO_LEFT
}
And this is an image I used:
USE THIS CODE TO LOAD YOUR IMAGE..
public static int loadTexture(Context context, int resourceId) {
final int[] textureObjectIds = new int[1];
glGenTextures(1, textureObjectIds, 0);
if (textureObjectIds[0] == 0) {
if (LoggerConfig.ON) {
Log.w(TAG, "Could not generate a new OpenGL texture object.");
}
return 0;
}
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inScaled = false;
// Read in the resource
final Bitmap bitmap = BitmapFactory.decodeResource(
context.getResources(), resourceId, options);
if (bitmap == null) {
if (LoggerConfig.ON) {
Log.w(TAG, "Resource ID " + resourceId + " could not be decoded.");
}
glDeleteTextures(1, textureObjectIds, 0);
return 0;
}
// Bind to the texture in OpenGL
glBindTexture(GL_TEXTURE_2D, textureObjectIds[0]);
// Set filtering: a default must be set, or the texture will be
// black.
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// Load the bitmap into the bound texture.
texImage2D(GL_TEXTURE_2D, 0, bitmap, 0);
// Note: Following code may cause an error to be reported in the
// ADB log as follows: E/IMGSRV(20095): :0: HardwareMipGen:
// Failed to generate texture mipmap levels (error=3)
// No OpenGL error will be encountered (glGetError() will return
// 0). If this happens, just squash the source image to be
// square. It will look the same because of texture coordinates,
// and mipmap generation will work.
glGenerateMipmap(GL_TEXTURE_2D);
// Recycle the bitmap, since its data has been loaded into
// OpenGL.
bitmap.recycle();
// Unbind from the texture.
glBindTexture(GL_TEXTURE_2D, 0);
return textureObjectIds[0];
}
来源：https://stackoverflow.com/questions/18791983/android-2d-game-with-opengl