Question

我对OpenGL编程非常陌生，所以如果我忽略了明显的内容，请原谅我。我使用VBO创建了一个多维数据集，并加载了顶点，绘制顺序和颜色信息。渲染多维数据集时，它是完全黑色的。谁能建议为什么不显示颜色信息？我正在创建4个缓冲对象，但仅使用3个（法线将是第四个）。

1）创建VBO

GLES31.glGenBuffers ( 4, mVBOIds, 0 );

    // Bind the first buffer to put vertices info in
    GLES31.glBindBuffer ( GLES31.GL_ARRAY_BUFFER, mVBOIds[0] );

    //Transfer data to buffer
    GLES31.glBufferData(GLES31.GL_ARRAY_BUFFER, mCubePositions.capacity() * mBytesPerFloat,
            mCubePositions, GLES31.GL_STATIC_DRAW);

    // Unbind buffer
    GLES31.glBindBuffer(GLES31.GL_ARRAY_BUFFER, 0);

    // Bind the second buffer to put draw order info in
    GLES31.glBindBuffer ( GLES31.GL_ELEMENT_ARRAY_BUFFER, mVBOIds[1] );

    // Transfer data to the buffer
    GLES31.glBufferData(GLES31.GL_ELEMENT_ARRAY_BUFFER, mDrawOrder.capacity() * mBytesPerShort,
            mDrawOrder, GLES31.GL_STATIC_DRAW);
    // Unbind buffer
    GLES31.glBindBuffer(GLES31.GL_ELEMENT_ARRAY_BUFFER, 0);

    // Bind the third buffer to put the colour data in
    GLES31.glBindBuffer ( GLES31.GL_ELEMENT_ARRAY_BUFFER, mVBOIds[2] );

    // Transfer the colour data to the buffer
    GLES31.glBufferData(GLES31.GL_ARRAY_BUFFER, mCubeColors.capacity() * mBytesPerFloat,
            mCubeColors, GLES31.GL_STATIC_DRAW);
    // Unbind buffer
    GLES31.glBindBuffer(GLES31.GL_ARRAY_BUFFER, 0);

现在，我创建VAO并将其绑定到VBO：

// Generate VAO Id
    GLES31.glGenVertexArrays ( 1, mVAOId, 0 );

    // Bind the VAO and then setup the vertex
    // attributes
    GLES31.glBindVertexArray ( mVAOId[0] );

    // Bind the vertex buffer
    GLES31.glBindBuffer ( GLES31.GL_ARRAY_BUFFER, mVBOIds[0] );

    // Bind the draw order buffer
    GLES31.glBindBuffer ( GLES31.GL_ELEMENT_ARRAY_BUFFER, mVBOIds[1] );

    GLES31.glEnableVertexAttribArray ( VERTEX_POS_INDEX );

    GLES31.glEnableVertexAttribArray ( VERTEX_DRAW_ORDER_INDEX );

    GLES31.glVertexAttribPointer ( VERTEX_POS_INDEX, VERTEX_POS_SIZE, GLES31.GL_FLOAT, false, VERTEX_STRIDE, 0 );

    GLES31.glVertexAttribPointer ( VERTEX_DRAW_ORDER_INDEX, VERTEX_DRAW_ORDER_SIZE, GLES31.GL_SHORT, false, VERTEX_STRIDE, 0 );

    // Now bind the colour buffer

    GLES31.glBindBuffer ( GLES31.GL_ARRAY_BUFFER, mVBOIds[2] );
    GLES31.glEnableVertexAttribArray(VERTEX_COLOUR_INDEX);
    GLES31.glVertexAttribPointer(VERTEX_COLOUR_INDEX, VERTEX_COLOUR_SIZE, GLES31.GL_FLOAT, false, VERTEX_STRIDE, 0 );

    // Reset to the default VAO
    GLES31.glBindVertexArray ( 0 );

我的顶点和片段着色器看起来像：

private final String vertexShaderCode =
        // This matrix member variable provides a hook to manipulate
        // the coordinates of the objects that use this vertex shader
        // have now added uMVP projection matrix for making square stuff square
        "uniform mat4 uMVPMatrix;" +
                "attribute vec4 vPosition;" +
                "void main() {" +
                "  gl_Position = uMVPMatrix * vPosition;" +
                "}";

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

我在另一个堆栈溢出问题中看到，您可能需要将VBO的属性号绑定到着色器变量，因此尝试了下面的行，但没有成功（VERTEX_COLOUR_INDEX设置为“ 2”- glVertexAtttribPointer绑定颜色缓冲区时。

GLES31.glBindAttribLocation(mProgram, 2, "vColor");

我已尽力做到这一点，但现在已经用尽了很多想法。

谢谢

OpenGL ES VBO-无法显示颜色信息

0 个答案: