OpenGL 4.2+和shader_image_load_store不适用于3D纹理？

Question

我想弄清楚为什么我无法使用（现在内置的）shader_image_load_store扩展名写入3D纹理。

我创建了两个简单的例子（在python，使其更容易）：一个写入到一个2D纹理，这样的作品，和一个写入到3D纹理不起作用

的（工作）2D版本如下：

#! /usr/bin/env python 

from PyQt4 import QtGui, QtCore 
from PyQt4.QtOpenGL import * 
from OpenGL.GL import * 
from OpenGL.GLU import * 
import sys 

iTexSize = 256 


_vsClearSource = """ 
    #version 440 compatibility 
    void main() { 
     gl_Position = ftransform(); 
     gl_FrontColor = gl_Color; 
    } 
    """  

_fsClearSource = """ 
#version 440 compatibility 
uniform int   iPrimitiveCount; 
uniform int   iSliceIndex; 

layout(size4x32, binding=0) coherent uniform image2D volColorVolume; 
const int iMaxTexSize = 255; 

void main() { 
    ivec2 ivecVolumeCoordinate = ivec2(gl_FragCoord.x, gl_FragCoord.y); //, iSliceIndex); 

    vec4 vecVolumeValue = vec4(0,1,0,1); // vec4(  float(iSlabIndex)/float(iPrimitiveCount)); //,0.0,0.0,0.0); 

    imageStore(volColorVolume, ivecVolumeCoordinate, vecVolumeValue);     
    gl_FragData[0] = vec4(1,0,1,1); 
}  
    """  

_fsFillSource = """ 
#version 440 compatibility 
uniform int   iPrimitiveCount; 
uniform int   iSliceIndex; 

layout(size4x32, binding=0) coherent uniform image2D volColorVolume; 
const int iMaxTexSize = 255; 

void main() { 
    ivec2 ivecVolumeCoordinate = ivec2(gl_FragCoord.x, gl_FragCoord.y); 

    vec4 vecVolumeValue = vec4(float(gl_FragCoord.x)/float(iMaxTexSize) , float(gl_FragCoord.y)/float(iMaxTexSize) , 0 , 1 ); 

    imageStore(volColorVolume, ivecVolumeCoordinate, vecVolumeValue);     
    gl_FragData[0] = vec4(1,0,1,1); 
}  
"""  



class Viewer3DWidget(QGLWidget): 

    def __init__(self, parent): 
     QGLWidget.__init__(self, parent) 

     self.uWidth = 0 
     self.uHeight = 0 

     self.texColorTexture = None 
     self.fboRendering = None 
     self.texColorVolume = None 

     self.vecBackgroundColor = (1.,1.,1.) 

     self.vecDrawBuffers = [ GL_COLOR_ATTACHMENT0 , GL_COLOR_ATTACHMENT1 , GL_COLOR_ATTACHMENT2, GL_COLOR_ATTACHMENT3, GL_COLOR_ATTACHMENT4, GL_COLOR_ATTACHMENT5 ] 


     self.fSurfacesSpacing = 1.0 
     self.fSurfacesTransparency = 1.0 






    def initializeGL(self): 
     self.shaShaderFill = QGLShaderProgram(self.context()) 
     self.shaShaderFill.addShaderFromSourceCode(QGLShader.Vertex, _vsClearSource) 
     self.shaShaderFill.addShaderFromSourceCode(QGLShader.Fragment, _fsFillSource) 
     self.shaShaderFill.link()  

     self.shaShaderClear = QGLShaderProgram(self.context()) 
     self.shaShaderClear.addShaderFromSourceCode(QGLShader.Vertex, _vsClearSource) 
     self.shaShaderClear.addShaderFromSourceCode(QGLShader.Fragment, _fsClearSource) 
     self.shaShaderClear.link()  



     glClearColor(1.0, 1.0, 1.0, 1.0) 
     glClearDepth(1.0) 


    def initRenderTargets(self): 
     global iTexSize 
     if (self.texColorTexture is None): 
      self.texColorTexture = glGenTextures(1) 
     if (self.fboRendering is None): 
      self.fboRendering = glGenFramebuffers(1)    

     glBindTexture(GL_TEXTURE_RECTANGLE, self.texColorTexture) 
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_S, GL_CLAMP) 
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_T, GL_CLAMP) 
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MIN_FILTER, GL_NEAREST) 
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MAG_FILTER, GL_NEAREST) 
     glTexImage2D(GL_TEXTURE_RECTANGLE, 0, GL_RGBA32F, iTexSize, iTexSize, 0, GL_RGBA, GL_FLOAT, None) 


     glBindTexture(GL_TEXTURE_RECTANGLE, 0); 

     glBindFramebuffer(GL_FRAMEBUFFER, self.fboRendering) 
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_RECTANGLE, self.texColorTexture, 0) 
     glBindFramebuffer(GL_FRAMEBUFFER, 0)  


    def deleteRenderTargets(self): 
     if (self.fboAccumulation is not None): 
      glDeleteFramebuffers(1,self.fboRendering)   
      self.fboAccumulation = None 
     if (self.texColorTexture is not None): 
      glDeleteTextures(self.texColorTexture) 
      self.texColorTexture = None 


    def initColorVolume(self): 
     if (self.texColorVolume is None): 
      self.texColorVolume = glGenTextures(1) 


     glBindTexture(GL_TEXTURE_2D, self.texColorVolume) 
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP) 
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP) 
     #glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP) 
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST) 
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST) 
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, iTexSize, iTexSize, 0, GL_RGBA, GL_FLOAT, None); 


     glBindTexture(GL_TEXTURE_2D, 0);  



    def fillVolume(self, bClear): 
     global iTexSize 

     shaShader = self.shaShaderClear 
     if(not bClear): 
      shaShader = self.shaShaderFill 

     if (not self.fboRendering): 
      self.initRenderTargets() 

     if (not self.texColorVolume): 
      self.initColorVolume() 

     glMatrixMode(GL_PROJECTION) 
     glLoadIdentity() 

     glMatrixMode(GL_MODELVIEW); 
     glLoadIdentity();    



     glBindImageTexture(0,self.texColorVolume,0,GL_FALSE,0,GL_READ_WRITE,GL_RGBA32F); 

     glBindFramebuffer(GL_FRAMEBUFFER, self.fboRendering); 
     glDrawBuffers(1, self.vecDrawBuffers); 

     glClearColor(0, 0, 0, 0); 
     glClear(GL_COLOR_BUFFER_BIT);    

     shaShader.bind() 

     shaShader.setUniformValue("iPrimitiveCount", iTexSize) 
     shaShader.setUniformValue("volColorVolume", 0) 

     for i in range(iTexSize): 


      shaShader.setUniformValue("iSliceIndex", i) 




      glBegin(GL_QUADS); 
      glVertex2f(-1.0, -1.0); 
      glVertex2f(1.0, -1.0); 
      glVertex2f(1.0, 1.0); 
      glVertex2f(-1.0, 1.0); 
      glEnd(); 


      #sync 
      glMemoryBarrier(GL_ALL_BARRIER_BITS); 


     glBindImageTexture(0,0,0,GL_FALSE,0,GL_READ_WRITE,GL_RGBA32F); 
     shaShader.release() 

     glBindFramebuffer(GL_FRAMEBUFFER, 0); 


    def paintGL(self): 
     if (self.uWidth is 0): 
      return   
     if (not self.fboRendering): 
      self.initRenderTargets() 
      self.initColorVolume() 

     glMatrixMode(GL_PROJECTION) 
     glLoadIdentity() 

     glMatrixMode(GL_MODELVIEW); 
     glLoadIdentity(); 

     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) 


     self.fillVolume(True) 
     #draw into the volume 
     self.fillVolume(False) 

     #slice the volume 
     self.displayTexture() 



     glFlush() 




    def displayTexture(self): #essentially not useable here 
     glMatrixMode(GL_PROJECTION) 
     glLoadIdentity() 
     glMatrixMode(GL_MODELVIEW); 
     glLoadIdentity(); 
     glDisable(GL_BLEND) 
     glDisable(GL_DEPTH_TEST); 
     glDisable(GL_LIGHTING) 

     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) 
     glColor(1.0, 1.0,1.0) 

     glEnable(GL_TEXTURE_2D); 
     glBindTexture(GL_TEXTURE_2D, self.texColorVolume) 

     glBegin(GL_QUADS); 
     glTexCoord2f(0,0) #,0.5) 
     glVertex2f(-1.0, -1.0); 
     glTexCoord2f(1,0) #,0.5) 
     glVertex2f(1.0, -1.0); 
     glTexCoord2f(1,1) #,0.5) 
     glVertex2f(1.0, 1.0); 
     glTexCoord2f(0,1) #,0.5) 
     glVertex2f(-1.0, 1.0); 
     glEnd(); 
     glBindTexture(GL_TEXTURE_2D, 0) 



    def resizeGL(self, widthInPixels, heightInPixels): 
     if ((widthInPixels is not self.uWidth) or (heightInPixels is not self.uHeight)):   
      self.uWidth = widthInPixels 
      self.uHeight = heightInPixels 

      glViewport(0, 0, widthInPixels, heightInPixels) 
      self.update() 


class TestImageLoadStore2D(QtGui.QMainWindow): 
    def __init__(self): 
     QtGui.QMainWindow.__init__(self) 
     self.setWindowTitle('TestImageLoadStore2D') 
     self.statusBar().showMessage("Hello there") 

     exit = QtGui.QAction("Exit", self) 
     exit.setShortcut("Ctrl+Q") 
     exit.setStatusTip('Exit application') 
     self.connect(exit, QtCore.SIGNAL('triggered()'), QtCore.SLOT('close()')) 


     self.viewer3D = Viewer3DWidget(self) 

     self.setCentralWidget(self.viewer3D) 

     self.resize(500,500) 

    def closeEvent(self, event): 
     event.accept() 


if __name__ == '__main__': 
    # app = QtGui.QApplication(['Python Qt OpenGL Demo']) 
    app = QtGui.QApplication(sys.argv) 
    window = TestImageLoadStore2D() 
    window.show() 
    sys.exit(app.exec_()) 

而对非工作的3D版本如下：

#! /usr/bin/env python 

from PyQt4 import QtGui, QtCore 
from PyQt4.QtOpenGL import * 
from OpenGL.GL import * 
from OpenGL.GLU import * 
import sys 
iTexSize = 256 


_vsClearSource = """ 
    #version 440 compatibility 
    void main() { 
     gl_Position = ftransform(); 
     gl_FrontColor = gl_Color; 
    } 
    """  

_fsClearSource = """ 
#version 440 compatibility 
uniform int   iPrimitiveCount; 
uniform int   iSliceIndex; 

layout(size4x32, binding=0) writeonly uniform image3D volColorVolume; 
//layout(rgba32f, binding=0) writeonly uniform image3D volColorVolume; 
const int iMaxTexSize = 255; 

void main() { 
    ivec3 ivecVolumeCoordinate = ivec3(gl_FragCoord.x, gl_FragCoord.y, 0); //iSliceIndex); 

    vec4 vecVolumeValue = vec4(0,1,0,1); // vec4(  float(iSlabIndex)/float(iPrimitiveCount)); //,0.0,0.0,0.0); 

    imageStore(volColorVolume, ivecVolumeCoordinate, vecVolumeValue); 
    memoryBarrier();     
    gl_FragData[0] = vec4(1,0,1,1); 
}  
    """  

_fsFillSource = """ 
#version 440 compatibility 
uniform int   iPrimitiveCount; 
uniform int   iSliceIndex; 

layout(size4x32, binding=0) writeonly uniform image3D volColorVolume; 
const int iMaxTexSize = 255; 

void main() { 
    ivec3 ivecVolumeCoordinate = ivec3(gl_FragCoord.x, gl_FragCoord.y, 0); //iSliceIndex); 

    vec4 vecVolumeValue = vec4(float(gl_FragCoord.x)/float(iMaxTexSize) , float(gl_FragCoord.y)/float(iMaxTexSize) , float(iSliceIndex)/float(iPrimitiveCount) , 1 ); 

    imageStore(volColorVolume, ivecVolumeCoordinate, vecVolumeValue); 
    memoryBarrier();    
    gl_FragData[0] = vec4(1,0,1,1); 
}  
"""  



class Viewer3DWidget(QGLWidget): 

    def __init__(self, parent): 
     QGLWidget.__init__(self, parent) 

     self.uWidth = 0 
     self.uHeight = 0 

     self.texColorTexture = None 
     self.fboRendering = None 
     self.texColorVolume = None 

     self.vecBackgroundColor = (1.,1.,1.) 

     self.vecDrawBuffers = [ GL_COLOR_ATTACHMENT0 , GL_COLOR_ATTACHMENT1 , GL_COLOR_ATTACHMENT2, GL_COLOR_ATTACHMENT3, GL_COLOR_ATTACHMENT4, GL_COLOR_ATTACHMENT5 ] 


     self.fSurfacesSpacing = 1.0 
     self.fSurfacesTransparency = 1.0 
     self.fZCoord = 0.0 


    def setZCoordinate(self, fZCoordinate): 
     self.fZCoord = fZCoordinate 
     self.update() 



    def initializeGL(self): 
     self.shaShaderFill = QGLShaderProgram(self.context()) 
     self.shaShaderFill.addShaderFromSourceCode(QGLShader.Vertex, _vsClearSource) 
     self.shaShaderFill.addShaderFromSourceCode(QGLShader.Fragment, _fsFillSource) 
     self.shaShaderFill.link()  

     self.shaShaderClear = QGLShaderProgram(self.context()) 
     self.shaShaderClear.addShaderFromSourceCode(QGLShader.Vertex, _vsClearSource) 
     self.shaShaderClear.addShaderFromSourceCode(QGLShader.Fragment, _fsClearSource) 
     self.shaShaderClear.link()  



     glClearColor(1.0, 1.0, 1.0, 1.0) 
     glClearDepth(1.0) 


    def initRenderTargets(self): 
     global iTexSize 
     if (self.texColorTexture is None): 
      self.texColorTexture = glGenTextures(1) 
     if (self.fboRendering is None): 
      self.fboRendering = glGenFramebuffers(1)    

     glBindTexture(GL_TEXTURE_RECTANGLE, self.texColorTexture) 
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_S, GL_CLAMP) 
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_T, GL_CLAMP) 
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MIN_FILTER, GL_NEAREST) 
     glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MAG_FILTER, GL_NEAREST) 
     glTexImage2D(GL_TEXTURE_RECTANGLE, 0, GL_RGBA32F, iTexSize, iTexSize, 0, GL_RGBA, GL_FLOAT, None) 


     glBindTexture(GL_TEXTURE_RECTANGLE, 0); 

     glBindFramebuffer(GL_FRAMEBUFFER, self.fboRendering) 
     glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_RECTANGLE, self.texColorTexture, 0) 
     glBindFramebuffer(GL_FRAMEBUFFER, 0)  


    def deleteRenderTargets(self): 
     if (self.fboAccumulation is not None): 
      glDeleteFramebuffers(1,self.fboRendering)   
      self.fboAccumulation = None 
     if (self.texColorTexture is not None): 
      glDeleteTextures(self.texColorTexture) 
      self.texColorTexture = None 


    def initColorVolume(self): 
     if (self.texColorVolume is None): 
      self.texColorVolume = glGenTextures(1) 


     glBindTexture(GL_TEXTURE_3D, self.texColorVolume) 
     glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP) 
     glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP) 
     glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP) 
     glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_NEAREST) 
     glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_NEAREST) 
     glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA32F, iTexSize, iTexSize, iTexSize, 0, GL_RGBA, GL_FLOAT, None); 


     glBindTexture(GL_TEXTURE_3D, 0);  



    def fillVolume(self, bClear): 
     global iTexSize 

     shaShader = self.shaShaderClear 
     if(not bClear): 
      shaShader = self.shaShaderFill 

     if (not self.fboRendering): 
      self.initRenderTargets() 

     if (not self.texColorVolume): 
      self.initColorVolume() 

     glMatrixMode(GL_PROJECTION) 
     glLoadIdentity() 

     glMatrixMode(GL_MODELVIEW); 
     glLoadIdentity();    



     glBindImageTexture(0,self.texColorVolume,0,GL_FALSE,0,GL_WRITE_ONLY,GL_RGBA32F); 

     glBindFramebuffer(GL_FRAMEBUFFER, self.fboRendering); 
     glDrawBuffers(1, self.vecDrawBuffers); 

     glClearColor(0, 0, 0, 0); 
     glClear(GL_COLOR_BUFFER_BIT);    

     shaShader.bind() 

     shaShader.setUniformValue("iPrimitiveCount", iTexSize) 
     shaShader.setUniformValue("volColorVolume", 0) 

     for i in range(iTexSize): 


      shaShader.setUniformValue("iSliceIndex", i) 




      glBegin(GL_QUADS); 
      glVertex2f(-1.0, -1.0); 
      glVertex2f(1.0, -1.0); 
      glVertex2f(1.0, 1.0); 
      glVertex2f(-1.0, 1.0); 
      glEnd(); 


      #sync 
      glMemoryBarrier(GL_ALL_BARRIER_BITS); 
     glMemoryBarrier(GL_ALL_BARRIER_BITS); 

     glBindImageTexture(0,0,0,GL_FALSE,0,GL_WRITE_ONLY,GL_RGBA32F); 
     shaShader.release() 

     glBindFramebuffer(GL_FRAMEBUFFER, 0); 


    def paintGL(self): 
     if (self.uWidth is 0): 
      return   
     if (not self.fboRendering): 
      self.initRenderTargets() 
      self.initColorVolume() 

     glMatrixMode(GL_PROJECTION) 
     glLoadIdentity() 

     glMatrixMode(GL_MODELVIEW); 
     glLoadIdentity(); 

     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) 


     self.fillVolume(True) 
     #draw into the volume 
     #self.fillVolume(False) 

     #slice the volume 
     self.displayTexture() 



     glFlush() 




    def displayTexture(self): #essentially not useable here 
     glMatrixMode(GL_PROJECTION) 
     glLoadIdentity() 
     glMatrixMode(GL_MODELVIEW); 
     glLoadIdentity(); 
     glDisable(GL_BLEND) 
     glDisable(GL_DEPTH_TEST); 
     glDisable(GL_LIGHTING) 

     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT) 
     glColor(1.0, 1.0,1.0) 

     glEnable(GL_TEXTURE_3D); 
     glBindTexture(GL_TEXTURE_3D, self.texColorVolume) 

     fZCoord = self.fZCoord   

     glBegin(GL_QUADS); 
     glTexCoord3f(0,0,fZCoord) 
     glVertex2f(-1.0, -1.0); 
     glTexCoord3f(1,0,fZCoord) 
     glVertex2f(1.0, -1.0); 
     glTexCoord3f(1,1,fZCoord) 
     glVertex2f(1.0, 1.0); 
     glTexCoord3f(0,1,fZCoord) 
     glVertex2f(-1.0, 1.0); 
     glEnd(); 
     glBindTexture(GL_TEXTURE_3D, 0) 



    def resizeGL(self, widthInPixels, heightInPixels): 
     if ((widthInPixels is not self.uWidth) or (heightInPixels is not self.uHeight)):   
      self.uWidth = widthInPixels 
      self.uHeight = heightInPixels 

      glViewport(0, 0, widthInPixels, heightInPixels) 
      self.update() 





class TestImageLoadStore3D(QtGui.QMainWindow): 
    def __init__(self): 
     QtGui.QMainWindow.__init__(self) 
     self.setWindowTitle('TestImageLoadStore3D') 
     self.statusBar().showMessage("Hello there") 

     exit = QtGui.QAction("Exit", self) 
     exit.setShortcut("Ctrl+Q") 
     exit.setStatusTip('Exit application') 
     self.connect(exit, QtCore.SIGNAL('triggered()'), QtCore.SLOT('close()')) 


     self.setToolTip('This is a window, or <b>something</b>') 

     self.viewer3D = Viewer3DWidget(self) 

     parentWidget = QtGui.QWidget() 
     slider1 = QtGui.QSlider(QtCore.Qt.Horizontal, None) 
     slider1.setRange(0,10000) 
     slider1.setValue(5000) 
     slider1.setMaximumWidth(120) 
     slider1.valueChanged.connect(self.slider1Handler) 
     vbox = QtGui.QVBoxLayout() 
     vbox.addWidget(slider1) 
     vbox.addStretch(1) 
     self.viewer3D.setSizePolicy(QtGui.QSizePolicy.Expanding, QtGui.QSizePolicy.Expanding) 
     hbox = QtGui.QHBoxLayout() 
     hbox.addLayout(vbox) 
     hbox.addWidget(self.viewer3D) 

     parentWidget.setLayout(hbox)   
     self.setCentralWidget(parentWidget) 


     self.resize(500,500) 

    def closeEvent(self, event): 
     event.accept() 
    def slider1Handler(self, iVal):  
     fVal = iVal/10000.0 
     #print "zcoord: ",fVal 
     self.viewer3D.setZCoordinate(fVal)   

if __name__ == '__main__': 
    # app = QtGui.QApplication(['Python Qt OpenGL Demo']) 
    app = QtGui.QApplication(sys.argv) 
    window = TestImageLoadStore3D() 
    window.show() 
    sys.exit(app.exec_()) 

代码没有多余的整洁，还因为我复制/粘贴/修改的一些老pyopengl代码我有。 问题是，写在3D纹理中的值绝对没有意义。 我使用最新版本的PyOpenGL（实验版本），Quadro K5000和最新的驱动程序（332.76）来运行它，它们也提供了对OpenGL 4.4的支持。

我不知道我可能是做错了，也因为我还没有发现写入3D纹理的例子很多（实际上没有，我也看了红皮书的最新版本）

有人可以启发我吗？

Answer 1

你的问题是在你这里断枝着色器：

layout(size4x32, binding=0) writeonly uniform image3D volColorVolume; 

您具有约束力的3D纹理通过

glBindImageTexture(0,self.texColorVolume,0,GL_FALSE,0,GL_WRITE_ONLY,GL_RGBA32F); 

让我从了OpenGL 4.4规格报价，节8.26“纹理图像加载和商店“（重点是我的）：

如果由纹理标识的纹理是一维数组， tw o维阵列，三维立方体贴图，立方体贴图阵列或二维多重采样阵列纹理，可以将 绑定到整个纹理级别或纹理级别的单个图层或面。如果分层为TRUE，则整个层次都是绑定的。如果 分层为FALSE，则只有由图层标识的单层将为 界限。 当层状为FALSE，则单个界层被当作图像的 不同纹理目标访问：

• 一维阵列的纹理层被作为一维纹理处理;
• 二维阵列三维立方体贴图立方体贴图阵列纹理层被视为二维纹理;和
• 二维多采样阵列纹理被视为二维多采样纹理。

所以，如果你只是绑定3D纹理的一层与layered参数设置为GL_FALSE（因为你正在做的），它将作为，如果它仅仅是一个2D纹理，所以无论是刚使用image2D并使用2D坐标访问它，或者将其与layered设置为GL_TRUE并将其绑定到GL_TRUE，并使用image3D和三维图像坐标，可以将其写入特定的图层/切片纹理。