I need to show a square polygon with the 100% of the width of the
screen, then, i supose that i must zoom it (with Z axis) until the
polygon borders are tounching the screen borders.
I'm trying to achieve this using gluProject to project a coordinate in
3D into a 2D screen coordinate. If the screen coordinate is either 0
or matches the width or height, then it is touching a screen border.
The problem is that something is going wrong, the `outputCoords` array
returned with gluProject is giving me these values: 0,0,0.5, but my
square is centered on the sreen, and with Z=-5.0f!!!!
I dont understand these values...
This is the code i'm using to obtain the 2D Projection of my square
poligon on the screen:
/////////////// NEW CODE FOR SCALING THE AR IMAGE TO THE DESIRED
WIDTH /////////////////
mg.getCurrentModelView(gl);
mg.getCurrentProjection(gl);
float [] modelMatrix = new float[16];
float [] projMatrix = new float[16];
modelMatrix=mg.mModelView;
projMatrix=mg.mProjection;
int [] mView = new int[4];
// Fill this with your window width and height
mView[0] = 0;
mView[1] = 0;
mView[2] = 800; //width
mView[3] = 480; //height
// Make sure you have 3 components in this array even if the
screen only needs 2
float [] outputCoords = new float[3];
// objX, objY, objZ are the coordinates of one of the borders
GLU.gluProject(-1.0f, -1.0f, 0.0f, modelMatrix, 0,
projMatrix, 0, mView, 0, outputCoords, 0);
This is my square class:
public class Square {
//Buffer de vertices
private FloatBuffer vertexBuffer;
//Buffer de coordenadas de texturas
private FloatBuffer textureBuffer;
//Puntero de texturas
private int[] textures = new int[3];
//El item a representar
private Bitmap image;
//Definición de vertices
private float vertices[] =
{
-1.0f, -1.0f, 0.0f, //Bottom Left
1.0f, -1.0f, 0.0f, //Bottom Right
-1.0f, 1.0f, 0.0f, //Top Left
1.0f, 1.0f, 0.0f //Top Right
};
private float texture[] =
{
//Mapping coordinates for the vertices
0.0f, 1.0f,
1.0f, 1.0f,
0.0f, 0.0f,
1.0f, 0.0f
};
//Inicializamos los buffers
public Square(Bitmap image) {
ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length
* 4);
byteBuf.order(ByteOrder.nativeOrder());
vertexBuffer = byteBuf.asFloatBuffer();
vertexBuffer.put(vertices);
vertexBuffer.position(0);
byteBuf = ByteBuffer.allocateDirect(texture.length * 4);
byteBuf.order(ByteOrder.nativeOrder());
textureBuffer = byteBuf.asFloatBuffer();
textureBuffer.put(texture);
textureBuffer.position(0);
this.image=image;
}
//Funcion de dibujado
public void draw(GL10 gl) {
gl.glFrontFace(GL10.GL_CCW);
//gl.glEnable(GL10.GL_BLEND);
//Bind our only previously generated texture in this case
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
//Point to our vertex buffer
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);
//Enable vertex buffer
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
//Draw the vertices as triangle strip
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, vertices.length / 3);
//Disable the client state before leaving
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
//gl.glDisable(GL10.GL_BLEND);
}
//Carga de texturas
public void loadGLTexture(GL10 gl, Context context) {
//Generamos un puntero de texturas
gl.glGenTextures(1, textures, 0);
//y se lo asignamos a nuestro array
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
//Creamos filtros de texturas
gl.glTexParameterf(GL10.GL_TEXTURE_2D,
GL10.GL_TEXTURE_MIN_FILTER,
GL10.GL_NEAREST);
gl.glTexParameterf(GL10.GL_TEXTURE_2D,
GL10.GL_TEXTURE_MAG_FILTER,
GL10.GL_LINEAR);
//Diferentes parametros de textura posibles
GL10.GL_CLAMP_TO_EDGE
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S,
GL10.GL_REPEAT);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T,
GL10.GL_REPEAT);
/*
String imagePath = "radiocd5.png";
AssetManager mngr = context.getAssets();
InputStream is=null;
try {
is = mngr.open(imagePath);
} catch (IOException e1) { e1.printStackTrace(); }
*/
//Get the texture from the Android resource directory
InputStream is=null;
/*
if (item.equals("rim"))
is = context.getResources().openRawResource(R.drawable.rueda);
else if (item.equals("selector"))
is =
context.getResources().openRawResource(R.drawable.selector);
*/
/*
is = context.getResources().openRawResource(resourceId);
Bitmap bitmap = null;
try {
bitmap = BitmapFactory.decodeStream(is);
} finally {
try {
is.close();
is = null;
} catch (IOException e) {
}
}
*/
Bitmap bitmap =image;
//con el siguiente código redimensionamos las imágenes que sean
mas
grandes de 256x256.
int newW=bitmap.getWidth();
int newH=bitmap.getHeight();
float fact;
if (newH>256 || newW>256)
{
if (newH>256)
{
fact=(float)255/(float)newH; //porcentaje por
el que multiplicar
para ser tamaño 256
newH=(int)(newH*fact); //altura reducida al
porcentaje necesario
newW=(int)(newW*fact); //anchura reducida al
porcentaje necesario
}
if (newW>256)
{
fact=(float)255/(float)newW; //porcentaje por
el que multiplicar
para ser tamaño 256
newH=(int)(newH*fact); //altura reducida al
porcentaje necesario
newW=(int)(newW*fact); //anchura reducida al
porcentaje necesario
}
bitmap=Bitmap.createScaledBitmap(bitmap, newW, newH,
true);
}
//con el siguiente código transformamos imágenes no potencia de
2 en
imágenes potencia de 2 (pot)
//meto el bitmap NOPOT en un bitmap POT para que no aparezcan
texturas blancas.
int nextPot=256;
int h = bitmap.getHeight();
int w = bitmap.getWidth();
int offx=(nextPot-w)/2; //distancia respecto a la izquierda,
para
que la imagen quede centrada en la nueva imagen POT
int offy=(nextPot-h)/2; //distancia respecto a arriba, para que
la
imagen quede centrada en la nueva imagen POT
Bitmap bitmap2 = Bitmap.createBitmap(nextPot, nextPot,
Bitmap.Config.ARGB_8888); //crea un bitmap transparente gracias al
ARGB_8888
Canvas comboImage = new Canvas(bitmap2);
comboImage.drawBitmap(bitmap, offx, offy, null);
comboImage.save();
//Usamos Android GLUtils para espcificar una textura de 2
dimensiones para nuestro bitmap
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap2, 0);
//Checkeamos si el GL context es versión 1.1 y generamos los
Mipmaps
por Flag. Si no, llamamos a nuestra propia implementación
if(gl instanceof GL11) {
gl.glTexParameterf(GL11.GL_TEXTURE_2D,
GL11.GL_GENERATE_MIPMAP,
GL11.GL_TRUE);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap2, 0);
} else {
buildMipmap(gl, bitmap2);
}
//Limpiamos los bitmaps
bitmap.recycle();
bitmap2.recycle();
}
//Nuestra implementación de MipMap. Escalamos el bitmap original
hacia abajo por factor de 2 y lo asignamos como nuevo nivel de mipmap
private void buildMipmap(GL10 gl, Bitmap bitmap) {
int level = 0;
int height = bitmap.getHeight();
int width = bitmap.getWidth();
while(height >= 1 || width >= 1) {
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, level, bitmap,
0);
if(height == 1 || width == 1) {
break;
}
level++;
height /= 2;
width /= 2;
Bitmap bitmap2 = Bitmap.createScaledBitmap(bitmap,
width, height,
true);
bitmap.recycle();
bitmap = bitmap2;
}
}
}
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