java – Android的OpenGL ES教程似乎不起作用_app

概述我一直在为 Android上的OpenGL ES在 http://developer.android.com/resources/tutorials/opengl/opengl-es20.html的教程.我已经得到了“应用投影和相机视图”部分,但是我总是似乎得到一个没有三角形的空白屏幕,上一节工作得很好.我也尝试只是复制粘贴整个教程到我的代码,但得到相同的结果.改变行： gl_Position = 我一直在为 Android上的OpenGL ES在 http://developer.android.com/resources/tutorials/opengl/opengl-es20.html的教程.我已经得到了“应用投影和相机视图”部分,但是我总是似乎得到一个没有三角形的空白屏幕,上一节工作得很好.我也尝试只是复制粘贴整个教程到我的代码,但得到相同的结果.改变行：

gl_position = uMVPMatrix * vposition;

至：

gl_position = vposition;

将应用程序放回第一部分(根据屏幕方向,三角形延伸).任何想法是什么问题？这是我到目前为止的代码,以防万一我错过了一些东西：

public class GLTest20Renderer implements Renderer {    private final String vertexshadercode =         // This matrix member variable provIDes a hook to manipulate        // the coordinates of the objects that use this vertex shader        "uniform mat4 uMVPMatrix;   \n" +        "attribute vec4 vposition;  \n" +        "voID main(){               \n" +        // the matrix must be included as a modifIEr of gl_position        " gl_position = uMVPMatrix * vposition; \n" +        "}  \n";    private final String fragmentshadercode =         "precision mediump float;  \n" +        "voID main(){              \n" +        " gl_Fragcolor = vec4 (0.63671875,0.76953125,0.22265625,1.0); \n" +        "}                         \n";    private floatBuffer triangleVB;    private int mProgram;    private int mapositionHandle;    private int muMVPMatrixHandle;    private float[] mMVPMatrix = new float[16];    private float[] mMMatrix = new float[16];    private float[] mVMatrix = new float[16];    private float[] mProjMatrix = new float[16];    public voID onSurfaceCreated(GL10 unused,EGLConfig config) {        GLES20.glClearcolor(0.5f,0.5f,1.0f);        initShapes();        int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER,vertexshadercode);        int fragmentShader = 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);                  // creates OpenGL program executables        // get handle to the vertex shader's vposition member        mapositionHandle = GLES20.glGetAttribLocation(mProgram,"vposition");    }    public voID onDrawFrame(GL10 unused) {        GLES20.glClear( GLES20.GL_color_BUFFER_BIT | GLES20.GL_DEPTH_BUFFER_BIT );        // Add program to OpenGL environment        GLES20.gluseProgram(mProgram);        // Prepare the triangle data        GLES20.glVertexAttribPointer(mapositionHandle,3,GLES20.GL_float,false,12,triangleVB);        GLES20.glEnabLevertexAttribarray(mapositionHandle);        // Apply a ModelVIEw Projection transformation        Matrix.multiplyMM(mMVPMatrix,mProjMatrix,mVMatrix,0);        GLES20.gluniformMatrix4fv(muMVPMatrixHandle,1,mMVPMatrix,0);        // Draw the triangle        GLES20.glDrawArrays(GLES20.GL_TRIANGLES,3);    }    public voID onSurfaceChanged(GL10 unused,int wIDth,int height) {        GLES20.glVIEwport(0,wIDth,height);        float ratio = (float) wIDth / height;        Matrix.frustumM(mProjMatrix,-ratio,ratio,-1,7);        muMVPMatrixHandle = GLES20.glGetUniformlocation(mProgram,"uMVPMatrix");        Matrix.setLookAtM(mVMatrix,-3,0f,1.0f,0.0f);    }    private voID initShapes() {        float triangleCoords[] = {            // X,Y,Z            -0.5f,-0.25f,0.0f,0.559016994f,0        };         // initialize vertex Buffer for triangle          ByteBuffer vbb = ByteBuffer.allocateDirect(                // (# of coordinate values * 4 bytes per float)                triangleCoords.length * 4);         vbb.order(ByteOrder.nativeOrder());// use the device harDWare's native byte order        triangleVB = vbb.asfloatBuffer();  // create a floating point buffer from the ByteBuffer        triangleVB.put(triangleCoords);    // add the coordinates to the floatBuffer        triangleVB.position(0);            // set the buffer to read the first coordinate    }    private int loadShader(int type,String shadercode) {        // create a vertex shader type (GLES20.GL_VERTEX_SHADER)        // or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)        int shader = GLES20.glCreateShader(type);         // add the source code to the shader and compile it        GLES20.glShaderSource(shader,shadercode);        GLES20.glCompileShader(shader);        return shader;    }}

我正在三星galaxy S2上运行所有这些.

解决方法修正了,只是将观察点的近点改为3：