Hi. I've just started learning gamedev (in particular android EGL based) and have ran over a code from Pro Android Games 2 that looks as follows:
/* * Copyright (C) 2007 Google Inc.
* * Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License. * You
may obtain a copy of the License at *
* http://www.apache.org/licenses/LICENSE-2.0
* * Unless required by applicable law or agreed to in writing, software *
distributed under the License is
distributed on an "AS IS" BASIS, *
WITHOUT WARRANTIES OR CONDITIONS OF
ANY KIND, either express or implied.
* See the License for the specific language governing permissions and *
limitations under the License. */
package opengl.scenes.cubes;
import java.nio.ByteBuffer; import
java.nio.ByteOrder; import
java.nio.IntBuffer;
import javax.microedition.khronos.opengles.GL10;
public class Cube {
public Cube(){
int one = 0x10000;
int vertices[] = {
-one, -one, -one,
one, -one, -one,
one, one, -one,
-one, one, -one,
-one, -one, one,
one, -one, one,
one, one, one,
-one, one, one,
};
int colors[] = {
0, 0, 0, one,
one, 0, 0, one,
one, one, 0, one,
0, one, 0, one,
0, 0, one, one,
one, 0, one, one,
one, one, one, one,
0, one, one, one,
};
byte indices[] = {
0, 4, 5, 0, 5, 1,
1, 5, 6, 1, 6, 2,
2, 6, 7, 2, 7, 3,
3, 7, 4, 3, 4, 0,
4, 7, 6, 4, 6, 5,
3, 0, 1, 3, 1, 2
};
// Buffers to be passed to gl*Pointer() functions
// must be direct, i.e., they must be placed on the
// native heap where the garbage collector cannot vbb.asIntBuffer()
// move them.
//
// Buffers with multi-byte datatypes (e.g., short, int, float)
// must have their byte order set to native order
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length*4);
vbb.order(ByteOrder.nativeOrder());
mVertexBuffer = vbb.asIntBuffer();
mVertexBuffer.put(vertices);
mVertexBuffer.position(0);
ByteBuffer cbb = ByteBuffer.allocateDirect(colors.length*4);
cbb.order(ByteOrder.nativeOrder());
mColorBuffer = cbb.asIntBuffer();
mColorBuffer.put(colors);
mColorBuffer.position(0);
mIndexBuffer = ByteBuffer.allocateDirect(indices.length);
mIndexBuffer.put(indices);
mIndexBuffer.position(0);
}
public void draw(GL10 gl)
{
gl.glFrontFace(GL10.GL_CW);
gl.glVertexPointer(3, GL10.GL_FIXED, 0, mVertexBuffer);
gl.glColorPointer(4, GL10.GL_FIXED, 0, mColorBuffer);
gl.glDrawElements(GL10.GL_TRIANGLES, 36, GL10.GL_UNSIGNED_BYTE, mIndexBuffer);
}
private IntBuffer mVertexBuffer;
private IntBuffer mColorBuffer;
private ByteBuffer mIndexBuffer;}
So it suggests to draw a cube using triangles. My question is: can I draw the same cube using GL_TPOLYGON? If so, isn't that an easier/more understandable way to do things?
