开始学习OpenGL ES。绘制四边形

我尝试绘制一个开放GL ES 1.0的四边形。但我有一个例外，说我试图绘制比我更多的顶点。开始学习OpenGL ES。绘制四边形

代码渲染的：

package com.example.MyGLTest; 

import android.opengl.GLES20; 
import android.opengl.GLSurfaceView; 

import javax.microedition.khronos.egl.EGLConfig; 
import javax.microedition.khronos.opengles.GL10; 
import java.nio.ByteBuffer; 
import java.nio.ByteOrder; 
import java.nio.FloatBuffer; 

public class OpenGLRenderer implements GLSurfaceView.Renderer{ 

    FloatBuffer plaineVerticesBuffer; 
    FloatBuffer plaineIndicesBuffer; 

    private float[] plaineVertices = { 
      -1, -1, 0, //bottom left corner 
      -1, 1, 0, //top left corner 
      1, 1, 0, //top right corner 
      1, -1, 0 // bottom right rocner 
    }; 
    private float plaine_indices[] = { 
      0,1,2, // first triangle (bottom left - top left - top right) 
      0,2,3 // second triangle (bottom left - top right - bottom right); 
    }; 

    @Override 
    public void onSurfaceCreated(GL10 gl, EGLConfig config) { 


     ByteBuffer bb = ByteBuffer.allocateDirect(plaineVertices.length * 4); 
     bb.order(ByteOrder.nativeOrder()); 
     plaineVerticesBuffer = bb.asFloatBuffer(); 
     plaineVerticesBuffer.put(plaineVertices); 

     ByteBuffer bb1 = ByteBuffer.allocateDirect(plaine_indices.length * 4); 
     bb1.order(ByteOrder.nativeOrder()); 
     plaineIndicesBuffer = bb1.asFloatBuffer(); 
     plaineIndicesBuffer.put(plaine_indices); 
    } 

    @Override 
    public void onSurfaceChanged(GL10 gl, int width, int height) { 

    } 

    @Override 
    public void onDrawFrame(GL10 gl) { 
     //GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT); 
     gl.glColor4f(0.0f, 1.0f, 0.0f, 0.5f); 
     gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); 

     gl.glVertexPointer(4,GL10.GL_FLOAT,0, plaineVerticesBuffer); 
     gl.glDrawElements(GL10.GL_TRIANGLE_STRIP, 6 ,GL10.GL_FLOAT, plaineIndicesBuffer); 
    } 
}

logcat中的错误：

java.lang.ArrayIndexOutOfBoundsException: remaining() < count < needed 
     at com.google.android.gles_jni.GLImpl.glDrawElements(Native Method) 
     at com.example.MyGLTest.OpenGLRenderer.onDrawFrame(OpenGLRenderer.java:60) 
     at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1531) 
     at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1248)

任何人都可以解释我为什么收到此错误？

来源

2013-11-28 Sergey Shustikov

您正在追踪一条2个三角形，并且您正在传递6个顶点。您应该绘制GL_TRIANGLES或修复索引。

来源

2013-11-28 14:02:11

开始学习OpenGL ES。绘制四边形

回答

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