Android Open Source - androidOpenGLShapes Circle

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License

The source code is released under:

MIT License

Java Source Code

package com.example.opengl;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
//from   w w  w  . j a v  a2 s . c  o  m
import android.opengl.GLES20;
import android.util.Log;

public class Circle {

  
    static final int COORDS_PER_VERTEX = 3;

  
  private  int mProgram, mPositionHandle, mColorHandle, mMVPMatrixHandle ;
  private FloatBuffer vertexBuffer;
  private float vertices[] = new float[364 * 3];
  
  float color[] = { 0.00f, 0.76953125f, 0.22265625f, 1.0f };
  private final int vertexCount = 364 * 3 / COORDS_PER_VERTEX;
  private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex

  private final String vertexShaderCode =
  "attribute vec4 vPosition;" +
  "void main() {" +
  "  gl_Position = vPosition;" +
  "}";
  
  private final String fragmentShaderCode =
  "precision mediump float;" +
  "uniform vec4 vColor;" +
  "void main() {" +
  "  gl_FragColor = vColor;" +
  "}";

  Circle(){
    
    
      int vertexShader = MyGLRenderer.loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
      int fragmentShader = MyGLRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);
    
      vertices[0] = 0;
      vertices[1] = 0;
      vertices[2] = 0;
  
      for(int i =0; i <363; i++){
          vertices[(i * 3)+ 0] = (float) (0.5 * Math.cos((3.14/180) * (float)i ));
          vertices[(i * 3)+ 1] = (float) (0.5 * Math.sin((3.14/180) * (float)i ));
          vertices[(i * 3)+ 2] = 0;
  
          //Log.v("Thread",""+vertices[(i*3)+0]+", "+vertices[(i*3)+1]+", "+vertices[(i*3)+2]);
      }
  
  
      Log.v("Thread",""+vertices[0]+","+vertices[1]+","+vertices[2]);
      ByteBuffer vertexByteBuffer = ByteBuffer.allocateDirect(vertices.length * 4);
      vertexByteBuffer.order(ByteOrder.nativeOrder());
      vertexBuffer = vertexByteBuffer.asFloatBuffer();
      vertexBuffer.put(vertices);
      vertexBuffer.position(0);
  
  
      mProgram = GLES20.glCreateProgram();             // create empty OpenGL ES Program
      GLES20.glAttachShader(mProgram, vertexShader);   // add the vertex shader to program
      GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
      GLES20.glLinkProgram(mProgram);  
  
   }


  public void draw (float[] mvpMatrix){
      // Add program to OpenGL ES environment
      GLES20.glUseProgram(mProgram);
  
      // get handle to vertex shader's vPosition member
      mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
  
      // Enable a handle to the triangle vertices
      GLES20.glEnableVertexAttribArray(mPositionHandle);
  
      // Prepare the triangle coordinate data
      GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,
                                   GLES20.GL_FLOAT, false,
                                   vertexStride, vertexBuffer);
  
      // get handle to fragment shader's vColor member
      mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");
  
      // Set color for drawing the triangle
      GLES20.glUniform4fv(mColorHandle, 1, color, 0);
      
      
      mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
      // Apply the projection and view transformation
      GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mvpMatrix, 0);
      
  
      // Draw the circle
      GLES20.glDrawArrays(GLES20.GL_TRIANGLE_FAN, 0, vertexCount);
  
      // Disable vertex array
      GLES20.glDisableVertexAttribArray(mPositionHandle);
      
      
  
  
  
  
  
  
  
  }

}

Java Source Code List

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