[java] Opengl을 이용한 삼각형, 사각형 만들기

오픈GL을 공부하면서 'Beginning Android Games'라는 Mario Zechner공저의 책을 이용했습니다.

삼각형은 소스에서 크기를 변경했고,

사각형은 일부 함수를 바꾸었습니다.

그리고, impliment의 소스파일은 책은 소스를 이용했습니다. ( https://github.com/Apress/beg-android-games-2ed.git)

메인화면에 버튼을 만들고 도형 화면 을 링크했습니다.

삼각형

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;

import javax.microedition.khronos.opengles.GL10;

import korea2canada.com.test2_jiwonkim.framework.Game;
import korea2canada.com.test2_jiwonkim.framework.Screen;
import korea2canada.com.test2_jiwonkim.framework.impl.GLGame;
import korea2canada.com.test2_jiwonkim.framework.impl.GLGraphics;


public class MyTriangle2 extends GLGame {
    public Screen getStartScreen() {
        return new ColoredTriangleScreen(this);
    }

    class ColoredTriangleScreen extends Screen {
        final int VERTEX_SIZE = (2 + 4) * 4;
        GLGraphics glGraphics;
        FloatBuffer vertices;

        public ColoredTriangleScreen(Game game) {
            super(game);
            glGraphics = ((GLGame) game).getGLGraphics();

            ByteBuffer byteBuffer = ByteBuffer.allocateDirect(3 * VERTEX_SIZE);
            byteBuffer.order(ByteOrder.nativeOrder());
            vertices = byteBuffer.asFloatBuffer();
            vertices.put( new float[] {   80.0f,   80.0f, 1, 0, 0, 1,
                    260.0f,   80.0f, 0, 1, 0, 1,
                    160f, 400.0f, 0, 0, 1, 1});
            vertices.flip();
        }

        @Override
        public void present(float deltaTime) {
            GL10 gl = glGraphics.getGL();
            gl.glViewport(0, 0, glGraphics.getWidth(), glGraphics.getHeight());
            gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
            gl.glMatrixMode(GL10.GL_PROJECTION);
            gl.glLoadIdentity();
            gl.glOrthof(0, 320, 0, 480, 1, -1);

            gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
            gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

            vertices.position(0);
            gl.glVertexPointer(2, GL10.GL_FLOAT, VERTEX_SIZE, vertices);
            vertices.position(2);
            gl.glColorPointer(4, GL10.GL_FLOAT, VERTEX_SIZE, vertices);

            gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);
        }

        @Override
        public void update(float deltaTime) {
        }

        @Override
        public void pause() {
        }

        @Override
        public void resume() {
        }

        @Override
        public void dispose() {
        }
    }

}

사각형

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;

import javax.microedition.khronos.opengles.GL10;

import korea2canada.com.test2_jiwonkim.framework.Game;
import korea2canada.com.test2_jiwonkim.framework.Screen;
import korea2canada.com.test2_jiwonkim.framework.impl.GLGame;
import korea2canada.com.test2_jiwonkim.framework.impl.GLGraphics;


public class MySquare2 extends GLGame {
    public Screen getStartScreen() {
        return new ColoredSquareScreen(this);
    }

    class ColoredSquareScreen extends Screen {
        final int VERTEX_SIZE = (2 + 4) * 4;
//        final int VERTEX_SIZE = (2 + 4) * 4;
        GLGraphics glGraphics;
        FloatBuffer vertices;

        public ColoredSquareScreen(Game game) {
            super(game);
            glGraphics = ((GLGame) game).getGLGraphics();

            ByteBuffer byteBuffer = ByteBuffer.allocateDirect(4 * VERTEX_SIZE);
//            ByteBuffer byteBuffer = ByteBuffer.allocateDirect(3 * VERTEX_SIZE);
            byteBuffer.order(ByteOrder.nativeOrder());
            vertices = byteBuffer.asFloatBuffer();


            vertices.put( new float[] {   80.0f,   120.0f, 1, 0, 0, 1,
                    260.0f, 120.0f, 0, 1, 0, 1,
                    260.0f, 300.0f, 0, 1, 0, 1,
                    80.0f,  300.0f, 0, 0, 1, 1});


            vertices.flip();
        }

        @Override
        public void present(float deltaTime) {
            GL10 gl = glGraphics.getGL();
            gl.glViewport(0, 0, glGraphics.getWidth(), glGraphics.getHeight());
            gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
            gl.glMatrixMode(GL10.GL_PROJECTION);
            gl.glLoadIdentity();
            gl.glOrthof(0, 320, 0, 480, 1, -1);

            gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
            gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

            vertices.position(0);
            gl.glVertexPointer(2, GL10.GL_FLOAT, VERTEX_SIZE, vertices);
            vertices.position(2);
            gl.glColorPointer(4, GL10.GL_FLOAT, VERTEX_SIZE, vertices);

//            gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);
            gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, 4);
        }

        @Override
        public void update(float deltaTime) {
        }

        @Override
        public void pause() {
        }

        @Override
        public void resume() {
        }

        @Override
        public void dispose() {
        }
    }

}

//

gl.glDrawArrays(GL10.GL_TRIANGLE_FAN, 0, 4); 

=> 이부분을 사각형으로 바꾸면서 4로 교체하고, 꼭지점 갯수를 4개로 늘렸습니다.

아래는 디렉토리 화면입니다. 맨 위의 링크를 참조하여 framework가 있어야 합니다.

그리고 메인화면을 아래와같이 만들었습니다. 아래의 소스는 제외하였습니다.

삼각형의 화면입니다.

아래는 사각형의 화면입니다.