FileDocCategorySizeDatePackage
Grid.javaAPI DocAndroid 1.5 Example4372Tue Aug 09 22:58:17 BST 2011com.example.android.apis.graphics.spritetext

Grid

public class Grid extends Object
A 2D rectangular mesh. Can be drawn textured or untextured.

Fields Summary
private FloatBuffer
mVertexBuffer
private FloatBuffer
mTexCoordBuffer
private CharBuffer
mIndexBuffer
private int
mW
private int
mH
private int
mIndexCount
Constructors Summary
public Grid(int w, int h)

        if (w < 0 || w >= 65536) {
            throw new IllegalArgumentException("w");
        }
        if (h < 0 || h >= 65536) {
            throw new IllegalArgumentException("h");
        }
        if (w * h >= 65536) {
            throw new IllegalArgumentException("w * h >= 65536");
        }

        mW = w;
        mH = h;
        int size = w * h;
        final int FLOAT_SIZE = 4;
        final int CHAR_SIZE = 2;
        mVertexBuffer = ByteBuffer.allocateDirect(FLOAT_SIZE * size * 3)
            .order(ByteOrder.nativeOrder()).asFloatBuffer();
        mTexCoordBuffer = ByteBuffer.allocateDirect(FLOAT_SIZE * size * 2)
            .order(ByteOrder.nativeOrder()).asFloatBuffer();

        int quadW = mW - 1;
        int quadH = mH - 1;
        int quadCount = quadW * quadH;
        int indexCount = quadCount * 6;
        mIndexCount = indexCount;
        mIndexBuffer = ByteBuffer.allocateDirect(CHAR_SIZE * indexCount)
            .order(ByteOrder.nativeOrder()).asCharBuffer();

        /*
         * Initialize triangle list mesh.
         *
         *     [0]-----[  1] ...
         *      |    /   |
         *      |   /    |
         *      |  /     |
         *     [w]-----[w+1] ...
         *      |       |
         *
         */

        {
            int i = 0;
            for (int y = 0; y < quadH; y++) {
                for (int x = 0; x < quadW; x++) {
                    char a = (char) (y * mW + x);
                    char b = (char) (y * mW + x + 1);
                    char c = (char) ((y + 1) * mW + x);
                    char d = (char) ((y + 1) * mW + x + 1);

                    mIndexBuffer.put(i++, a);
                    mIndexBuffer.put(i++, b);
                    mIndexBuffer.put(i++, c);

                    mIndexBuffer.put(i++, b);
                    mIndexBuffer.put(i++, c);
                    mIndexBuffer.put(i++, d);
                }
            }
        }
Methods Summary
public voiddraw(javax.microedition.khronos.opengles.GL10 gl, boolean useTexture)

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, mVertexBuffer);

        if (useTexture) {
            gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
            gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, mTexCoordBuffer);
            gl.glEnable(GL10.GL_TEXTURE_2D);
        } else {
            gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
            gl.glDisable(GL10.GL_TEXTURE_2D);
        }

        gl.glDrawElements(GL10.GL_TRIANGLES, mIndexCount,
                GL10.GL_UNSIGNED_SHORT, mIndexBuffer);
        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
voidset(int i, int j, float x, float y, float z, float u, float v)

        if (i < 0 || i >= mW) {
            throw new IllegalArgumentException("i");
        }
        if (j < 0 || j >= mH) {
            throw new IllegalArgumentException("j");
        }

        int index = mW * j + i;

        int posIndex = index * 3;
        mVertexBuffer.put(posIndex, x);
        mVertexBuffer.put(posIndex + 1, y);
        mVertexBuffer.put(posIndex + 2, z);

        int texIndex = index * 2;
        mTexCoordBuffer.put(texIndex, u);
        mTexCoordBuffer.put(texIndex + 1, v);