Opengl ES glGetAttribLocation问题！ 0x0502错误

Question

glGetAttribLocation被执行时发生错误。而且我不知道为什么。我试图检查程序，着色器和逻辑。但是我无法解决这个问题...我认为创建程序或通过程序时发生了问题。但我不知道问题出在哪里。下面是执行日志和代码。

Log

Shader has loaded : 1, 2
D/Debug: Program has linked
E/Error: vPosition attribute: GL_INVALID_OPERATION
E/AndroidRuntime: FATAL EXCEPTION: GLThread 401
    Process: com.sholgames.projd, PID: 11352
    java.lang.RuntimeException: Cannot find value 'vPosition'.
        at com.sholgames.projd.CModel.<init>(CModel.java:114)
        at com.sholgames.projd.CGLRenderer.onSurfaceCreated(CGLRenderer.java:18)
        at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1539)
        at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1270)
D/EGL_emulation: eglMakeCurrent: 0x9f76b320: ver 3 1 (tinfo 0xefaf4a40)
Process 11352 terminated.

CModel.java

public CModel(float[] verticeCoords_, short[] drawOrder_, float[] color_, int vertexShaderId_, int fragmentShaderId_) {
    LogManager.LOG_DEBUG_MESSAGE("Start creating model class");

    //Input factor data to member variable
    mVertexCoords = verticeCoords_;
    mDrawOrder = drawOrder_;
    mColor = color_;

    //Shader Load
    mVertexShader = IOManager.LoadShaderCode(GL_VERTEX_SHADER, vertexShaderId_);
    mFragmentShader = IOManager.LoadShaderCode(GL_FRAGMENT_SHADER, fragmentShaderId_);
    LogManager.LOG_DEBUG_MESSAGE("Shader has loaded : " + mVertexShader + ", " + mFragmentShader);

    //Create program
    mProgramObject = glCreateProgram();

    //Attach shader
    glAttachShader(mProgramObject, mVertexShader);
    LogManager.CHECK_ERROR("Attach vertex shader");
    glAttachShader(mProgramObject, mFragmentShader);
    LogManager.CHECK_ERROR("Attach fragment shader");

    //Bind shader
    glBindAttribLocation(mProgramObject, 0, "vPosition");
    LogManager.CHECK_ERROR("Bind position attrib");
    glBindAttribLocation(mProgramObject, 1, "vColor");
    LogManager.CHECK_ERROR("Bind color attrib");

    //Link program
    glLinkProgram(mProgramObject);
    LogManager.CHECK_ERROR("Linking program");
    LogManager.LOG_DEBUG_MESSAGE("Program has linked");
    int[] result = new int[1];
    glGetProgramiv(mProgramObject, GL_LINK_STATUS, result, 0);
    if(result[0] == -1) throw new RuntimeException("ERROR : shader program link failed.");

    //active data
    glUseProgram(mProgramObject);
    LogManager.CHECK_ERROR("Check using program");
    LogManager.LOG_DEBUG_MESSAGE("Program has actived");

    //Generate buffer id
    mBuffersID = new int[10];

    //Vertex buffer
    mVertexBuffer = ByteBuffer.allocateDirect(mVertexCoords.length * 4)
    .order(ByteOrder.nativeOrder()).asFloatBuffer();
    mVertexBuffer.put(mVertexCoords);
    mVertexBuffer.position(0);

    //Draw order buffer
    mDrawOrderBuffer = ByteBuffer.allocateDirect(mDrawOrder.length * 2)
    .order(ByteOrder.nativeOrder()).asShortBuffer();
    mDrawOrderBuffer.put(mDrawOrder);
    mDrawOrderBuffer.position(0);

    //Color Buffer
    mColorBuffer = ByteBuffer.allocateDirect(mColor.length * 4)
    .order(ByteOrder.nativeOrder()).asFloatBuffer();
    mColorBuffer.put(mColor);
    mColorBuffer.position(0);

    //VBO
    glGenBuffers(3, mBuffersID, 0);
    glBindBuffer(GL_ARRAY_BUFFER, mBuffersID[0]);
    glBufferData(GL_ARRAY_BUFFER, mVertexCoords.length, mVertexBuffer, GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, mBuffersID[1]);
    glBufferData(GL_ARRAY_BUFFER, mColor.length, mColorBuffer, GL_STATIC_DRAW);

    //EBO
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mBuffersID[2]);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, mDrawOrder.length, mDrawOrderBuffer, GL_STATIC_DRAW);

    //VAO
    int[] vaoIDs = new int[1];
    glGenVertexArrays(1, vaoIDs, 0);
    glBindVertexArray(vaoIDs[0]);

    //Pointing vertex attribute
    int vertexCoordAttrib = glGetAttribLocation(mProgramObject, "vPosition");
    LogManager.CHECK_ERROR("vPosition attribute");
    if(vertexCoordAttrib == -1) throw new RuntimeException("Cannot find value 'vPosition'.");
    int colorAttrib = glGetAttribLocation(mProgramObject, "vColor");
    LogManager.CHECK_ERROR("vColor attribute");
    if(colorAttrib == -1) throw new RuntimeException("Cannot find value 'vColor'.");
    glBindBuffer(GL_ARRAY_BUFFER, mBuffersID[0]);
    glVertexAttribPointer(vertexCoordAttrib, 3, GL_FLOAT, false, 0, 0);
    glEnableVertexAttribArray(vertexCoordAttrib);
    glBindBuffer(GL_ARRAY_BUFFER, mBuffersID[1]);
    glVertexAttribPointer(colorAttrib, 4, GL_FLOAT, false, 0, 0);
    glEnableVertexAttribArray(colorAttrib);

    LogManager.LOG_DEBUG_MESSAGE("Create model class done");
}

vertexshader.glsl

#version 300 es
attribute vec3 vPosition;
attribute vec4 vColor;
varying vec4 vPassColor;
void main() {
    gl_Position = vec4(vPosition, 1.0);
    vPassColor = vColor;
}

fragmentshader.glsl

#version 300 es
precision mediump float;
varying vec4 vPassColor;
void main() {
    gl_FragColor = vPassColor;
}

Answer 1

着色器无法编译。 attribute中不推荐使用关键字varying和gl_FragColor，例如内置片段着色器输出OpenGL ES Shading Language 3.00。

使用关键字in，out并为片段着色器输出指定out变量：

顶点着色器：

#version 300 es

in  vec3 vPosition;
in  vec4 vColor;
out vec4 vPassColor;

void main() {
    gl_Position = vec4(vPosition, 1.0);
    vPassColor  = vColor;
}
片段着色器：

#version 300 es
precision mediump float;

in  vec4 vPassColor;
out vec4 fragColor;

void main() {
    fragColor = vPassColor;
}
注意，在OpenGL ES 3.0中仍然可以使用OpenGL ES Shading Language 1.00 着色器。 （在这种情况下，版本指令必须仍为#version 100 es）