javascript - findAttribLocation 在 WebGL 中返回 -1

Question

我知道如果在我的顶点着色器中找不到该属性可能会发生这种情况，但我确信它存在。我将尝试提供大型代码主体中最相关的片段:

  vertices = new Float32Array(dataArrays.verts)
  normals = new Float32Array(dataArrays.norms)
  uvs = new Float32Array(dataArrays.txtcos)

我的片段着色器:

precision highp float;
attribute vec3 aPosition;
attribute vec3 vnorm;
attribute vec2 aTexCoord;
varying vec2 vTexCoord;
uniform mat4 pMatrix;
uniform mat4 vMatrix;
uniform mat4 mMatrix;
void main(void) {
  gl_Position = pMatrix * vMatrix * mMatrix * vec4(aPosition, 1.0);
  vTexCoord = aTexCoord;
}

属性查找器:

findAttribLocations = (gl, program, attributes) ->
    out = {}
    i = 0
    while i < attributes.length
      attrib = attributes[i]
      console.log attrib
      out[attrib] = gl.getAttribLocation(program, attrib)
      console.log out[attrib]
      i++
    out

初始化器:

 TObject::init = (drawingState) ->
    gl = drawingState.gl
    @program = createGLProgram(gl, vertexSource, fragmentSource)
    gl.useProgram @program
    @attributes = findAttribLocations(gl, @program, [
      'aPosition'
      'vnorm'
      'aTexCoord'
    ])
    @uniforms = findUniformLocations(gl, @program, [
      'pMatrix'
      'vMatrix'
      'mMatrix'
      'uTexture'
      'bTexture'
      'lightdir'
    ])
    @texture = createGLTexture(gl, image, true)
    @bumpTexture = createGLTexture(gl, bumpImage, true)
    @buffers[0] = createGLBuffer(gl, vertices, gl.STATIC_DRAW)
    @buffers[1] = createGLBuffer(gl, normals, gl.STATIC_DRAW)
    @buffers[2] = createGLBuffer(gl, uvs, gl.STATIC_DRAW)
    return

程序创建者:

createGLProgram = (gl, vSrc, fSrc) ->
    program = gl.createProgram()
    vShader = createGLShader(gl, gl.VERTEX_SHADER, vSrc)
    fShader = createGLShader(gl, gl.FRAGMENT_SHADER, fSrc)
    gl.attachShader program, vShader
    gl.attachShader program, fShader
    gl.linkProgram program
    if !gl.getProgramParameter(program, gl.LINK_STATUS)
      console.log 'warning: program failed to link'
      return null
    console.log "program"
    console.log program
    program

除了着色器中缺少变量之外，还有其他原因可能导致此错误吗？我正在该程序的其他地方切换着色器，但我相信这里使用的是正确的着色器。我该如何进一步调查？

Answer 1

着色器未使用的属性称为非事件属性，并且没有绑定(bind)。

由于您没有在顶点着色器中使用 vnorm，它会在 glGetAttribLocation 查询时变为非事件状态并返回 -1。激活它的唯一方法是在着色器中以有助于输出的方式使用它。

另见 the answer here