2016-04-25 108 views
1

林試圖讀取的紋理我有的RGBA值,但它一直返回下面的錯誤和每一個值出來爲0:WEBGL readPixels()無效操作:無效格式/類型組合

WebGL: INVALID_OPERATION: readPixels: invalid format/type combination 

下面有我在初始化代碼,其中像素是紋理值的數組:

texture = gl.createTexture() 
    gl.activeTexture(gl.TEXTURE0) 
    gl.bindTexture(gl.TEXTURE_2D, texture) 
    gl.pixelStorei(gl.UNPACK_ALIGNMENT, 1) 
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, n, n, 0, 
    gl.RGBA, gl.FLOAT, new Float32Array(pixels)) 

    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST) 
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST) 

    FBO = gl.createFramebuffer() 

    gl.bindFramebuffer(gl.FRAMEBUFFER, FBO) 
    gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, 
     gl.TEXTURE_2D, texture, 0) 

再後來,在點擊事件中,我運行以下命令:

gl.bindFramebuffer(gl.FRAMEBUFFER, FBO); 

var data = new Uint8Array(resolution * resolution * 4); 
gl.readPixels(0, 0, resolution, resolution, gl.RGBA, gl.UNSIGNED_BYTE, data); 

console.log(data) 

數據返回大量的零。 什麼是格式和類型的正確組合,或者我在哪裏出錯了?

回答

1

使用gl.getContext("experimental-webgl")

後我設法使用下面的讀取浮紋的像素:

gl.bindFramebuffer(gl.FRAMEBUFFER, _this.myFrameBufferObject); 
    var data = new Float32Array(resolution * resolution * 4); 
    gl.readPixels(0,0,resolution,resolution,gl.RGBA,gl.FLOAT,data); 

幸得下面的評論this answer