OpenGLES只是第一行对象被绘制 [英] OpenGLES only first Line object gets drawn

问题描述

我是新来的OpenGLES一个我想画几行每帧，但只有前行对象被绘制。这是为什么呢？

这是该行：

 包的形状;

进口java.nio.ByteBuffer中;
进口java.nio.ByteOrder中;
进口java.nio.FloatBuffer中;

进口toimplement.Colored;
进口drawing.DrawingRenderer;
进口android.opengl.GLES20;

公共类线延伸有色
{
    私人最终静态字符串vertexShader code =统一mat4 uMVPMatrix; +
            属性vec4 vPosition; +无效的主要（）{+
            GL_POSITION = uMVPMatrix * vPosition; +};

    私人最终静态字符串fragmentShader code =precision mediump浮动;
            +制服vec4 vColor; +无效的主要（）{
            +gl_FragColor = vColor; +};

    私人最终FloatBuffer vertexBuffer;
    私人最终诠释mProgram;
    私人诠释mPositionHandle;
    私人诠释mColorHandle;
    私人诠释mMVPMatrixHandle;

    //此数组中每个顶点的坐标数量
    静态最终诠释COORDS_PER_VERTEX = 3;
    静浮lineCoords [] = {
            0.0，0.0，0.0，
            0.0，0.0，0.0，
    };

    私人最终诠释vertexCount = lineCoords.length / COORDS_PER_VERTEX;
    私人最终诠释vertexStride = COORDS_PER_VERTEX * 4;每个顶点// 4字节

    公共线（）
    {
        //初始化为形状坐标顶点字节的缓冲区
        ByteBuffer的BB = ByteBuffer.allocateDirect（lineCoords.length * Float.SIZE / 8）;
        //使用设备硬件的本机字节顺序
        bb.order（ByteOrder.nativeOrder（））;
        //创建一个从ByteBuffer的浮点缓冲区
        vertexBuffer = bb.asFloatBuffer（）;
        //添加坐标的FloatBuffer
        vertexBuffer.put（lineCoords）;
        //设置缓冲区读取第一个坐标
        vertexBuffer.position（0）;

        // prepare着​​色引擎和OpenGL程序
        INT vertexShader = DrawingRenderer.loadShader（GLES20.GL_VERTEX_SHADER，vertexShader code）;
        INT fragmentShader = DrawingRenderer.loadShader（GLES20.GL_FRAGMENT_SHADER，fragmentShader code）;

        mProgram = GLES20.glCreateProgram（）; //创建空的OpenGL程序
        GLES20.glAttachShader（mProgram，vertexShader）; //添加顶点着色器程序
        GLES20.glAttachShader（mProgram，fragmentShader）; //添加片段着色器进行编程
        GLES20.glLinkProgram（mProgram）; //创建OpenGL的可执行程序
    }

    公共无效setCoords（最终浮动[] coords）使用
    {
        的for（int i = 0; I＆LT; lineCoords.length;我++）
        {
            lineCoords [i] = COORDS [I]
        }

        //添加坐标的FloatBuffer
        vertexBuffer.put（lineCoords）;
        //设置缓冲区读取第一个坐标
        vertexBuffer.position（0）;
    }

    公共无效setWidth（最终浮动幅度）
    {
        GLES20.glLineWidth（宽）;
    }

    公共无效画（最终浮动[] mMVPMatrix）
    {
        //添加程序的OpenGL环境
        GLES20.glUseProgram（mProgram）;

        //得到处理到顶点着色器的vPosition成员
        mPositionHandle = GLES20.glGetAttribLocation（mProgramvPosition）;

        //启用句柄线顶点
        GLES20.glEnableVertexAttribArray（mPositionHandle）;

        // prepare行坐标数据
        GLES20.glVertexAttribPointer（mPositionHandle，COORDS_PER_VERTEX，GLES20.GL_FLOAT，假的，vertexStride，vertexBuffer）;

        //得到处理，以片段着色器的vColor成员
        mColorHandle = GLES20.glGetUniformLocation（mProgramvColor）;

        //设置颜色绘制线
        GLES20.glUniform4fv（mColorHandle，1，颜色，0）;

        //获取手柄形状的变换矩阵
        mMVPMatrixHandle = GLES20.glGetUniformLocation（mProgramuMVPMatrix）;

        //应用投影和视图变换
        GLES20.glUniformMatrix4fv（mMVPMatrixHandle，1，假的，mMVPMatrix，0）;

        // 划清界线
        GLES20.glDrawArrays（GLES20.GL_LINES，0，vertexCount）;

        //禁用顶点数组
        GLES20.glDisableVertexAttribArray（mPositionHandle）;
    }
}
 

这里是onDrawFrame：

  @覆盖
公共无效onDrawFrame（GL10未使用）
{
    //绘制背景颜色
    GLES20.glClear（GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT）;

    //设置相机位置（视图矩阵）
    Matrix.setLookAtM（mViewMatrix，0，0，0，-3，0F，0F，0F，0F，1.0F，0.0）;

    //计算投影和视图变换
    Matrix.multiplyMM（mMVPMatrix，0，mProjectionMatrix，0，mViewMatrix，0）;

    //画的东西在这里
    一行行=新线（）;
    浮COORDS [] = {-1.0F，-1.0F，0.0，1.0F，1.0F，0.0};
    line.setCoords（COORDS）;
    line.draw（mMVPMatrix）;

    线2号线=新线（）;
    浮coords2 [] = {-1.0F，1.0F，0.0，-1.0F，1.0F，0.0};
    line2.setCoords（coords2）;
    line2.draw（mMVPMatrix）;
}
 

解决方案

原来的问题是，lineCoords被宣布为静态的事实。如果没有在声明中静态的关键字，一切都运行得很好。

I'm new to OpenGLES an I'm trying to draw several line on each frame, but only the first line object gets drawn. Why is that?

This is the Line:

package shapes;

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

import toimplement.Colored;
import drawing.DrawingRenderer;
import android.opengl.GLES20;

public class Line extends Colored
{
    private final static String vertexShaderCode = "uniform mat4 uMVPMatrix;" +
            "attribute vec4 vPosition;" + "void main() {" +
            "  gl_Position = uMVPMatrix * vPosition;" + "}";

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

    private final FloatBuffer vertexBuffer;
    private final int mProgram;
    private int mPositionHandle;
    private int mColorHandle;
    private int mMVPMatrixHandle;

    // number of coordinates per vertex in this array
    static final int COORDS_PER_VERTEX = 3;
    static float lineCoords[] = {
            0.0f, 0.0f, 0.0f, 
            0.0f, 0.0f, 0.0f,
    };

    private final int vertexCount = lineCoords.length / COORDS_PER_VERTEX;
    private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex

    public Line()
    {
        // initialize vertex byte buffer for shape coordinates
        ByteBuffer bb = ByteBuffer.allocateDirect(lineCoords.length * Float.SIZE / 8);
        // use the device hardware's native byte order
        bb.order(ByteOrder.nativeOrder());
        // create a floating point buffer from the ByteBuffer
        vertexBuffer = bb.asFloatBuffer();
        // add the coordinates to the FloatBuffer
        vertexBuffer.put(lineCoords);
        // set the buffer to read the first coordinate
        vertexBuffer.position(0);

        // prepare shaders and OpenGL program
        int vertexShader = DrawingRenderer.loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
        int fragmentShader = DrawingRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);

        mProgram = GLES20.glCreateProgram(); // create empty OpenGL Program
        GLES20.glAttachShader(mProgram, vertexShader); // add the vertex shader to program
        GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
        GLES20.glLinkProgram(mProgram); // create OpenGL program executables
    }

    public void setCoords(final float[] coords)
    {
        for (int i = 0; i < lineCoords.length; i++)
        {
            lineCoords[i] = coords[i];
        }

        // add the coordinates to the FloatBuffer
        vertexBuffer.put(lineCoords);
        // set the buffer to read the first coordinate
        vertexBuffer.position(0);
    }

    public void setWidth(final float width)
    {
        GLES20.glLineWidth(width);
    }

    public void draw(final float[] mMVPMatrix)
    {
        // Add program to OpenGL environment
        GLES20.glUseProgram(mProgram);

        // get handle to vertex shader's vPosition member
        mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");

        // Enable a handle to the line vertices
        GLES20.glEnableVertexAttribArray(mPositionHandle);

        // Prepare the line 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 line
        GLES20.glUniform4fv(mColorHandle, 1, color, 0);

        // get handle to shape's transformation matrix
        mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");

        // Apply the projection and view transformation
        GLES20.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mMVPMatrix, 0);

        // Draw the line
        GLES20.glDrawArrays(GLES20.GL_LINES, 0, vertexCount);

        // Disable vertex array
        GLES20.glDisableVertexAttribArray(mPositionHandle);
    }
}

And here is the onDrawFrame:

@Override
public void onDrawFrame(GL10 unused)
{
    // Draw background color
    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT);

    // Set the camera position (View matrix)
    Matrix.setLookAtM(mViewMatrix, 0, 0, 0, -3, 0f, 0f, 0f, 0f, 1.0f, 0.0f);

    // Calculate the projection and view transformation
    Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mViewMatrix, 0);

    // Draw things here
    Line line = new Line();
    float coords[] = {-1.0f, -1.0f, 0.0f, 1.0f, 1.0f, 0.0f};
    line.setCoords(coords);
    line.draw(mMVPMatrix);

    Line line2 = new Line();
    float coords2[] = {-1.0f, 1.0f, 0.0f, -1.0f, 1.0f, 0.0f};
    line2.setCoords(coords2);
    line2.draw(mMVPMatrix);
}

解决方案

It turns out the problem was the fact that the lineCoords were declared as "static". Without the "static" keyword in the declaration, everything works just fine.

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