diff --git a/cocos/renderer/backend/metal/CommandBufferMTL.mm b/cocos/renderer/backend/metal/CommandBufferMTL.mm
index 460df5b1cd..2ac3dadde6 100644
--- a/cocos/renderer/backend/metal/CommandBufferMTL.mm
+++ b/cocos/renderer/backend/metal/CommandBufferMTL.mm
@@ -423,8 +423,8 @@ void CommandBufferMTL::doSetTextures(bool isVertex) const
     for(const auto& iter : bindTextureInfos)
     {
         /* About mutli textures support
-        *  a. sampler2DArray, not implemented in Metal Renderer
-        *  b. texture slot, one BackendTexture, multi GPU texture handlers, used by etc1
+        *  a. TODO: sampler2DArray, not implemented in Metal Renderer currently
+        *  b. texture slot, one BackendTexture, multi GPU texture handlers, used by etc1, restrict: textures must have same size
         *  c. Bind multi BackendTexture to 1 Shader Program, see the ShaderTest
         *  d. iter.second.slots not used for Metal Renderer
         */
@@ -432,24 +432,22 @@ void CommandBufferMTL::doSetTextures(bool isVertex) const
         auto& textures = iter.second.textures;
         auto& indexs = iter.second.indexs;
         
-        int i = 0;
-        for (const auto& texture : textures)
+        auto texture = textures[0];
+        auto index = indexs[0];
+
+        if (isVertex)
         {
-            if (isVertex)
-            {
-                [_mtlRenderEncoder setVertexTexture:getMTLTexture(texture, indexs[i])
-                                        atIndex:location];
-                [_mtlRenderEncoder setVertexSamplerState:getMTLSamplerState(texture)
-                                             atIndex:location];
-            }
-            else
-            {
-                [_mtlRenderEncoder setFragmentTexture:getMTLTexture(texture, indexs[i])
-                                          atIndex:location];
-                [_mtlRenderEncoder setFragmentSamplerState:getMTLSamplerState(texture)
-                                               atIndex:location];
-            }
-            ++i;
+            [_mtlRenderEncoder setVertexTexture:getMTLTexture(texture, index)
+                                    atIndex:location];
+            [_mtlRenderEncoder setVertexSamplerState:getMTLSamplerState(texture)
+                                         atIndex:location];
+        }
+        else
+        {
+            [_mtlRenderEncoder setFragmentTexture:getMTLTexture(texture, index)
+                                      atIndex:location];
+            [_mtlRenderEncoder setFragmentSamplerState:getMTLSamplerState(texture)
+                                           atIndex:location];
         }
     }
 }
diff --git a/cocos/renderer/backend/opengl/CommandBufferGL.cpp b/cocos/renderer/backend/opengl/CommandBufferGL.cpp
index 907ba069a3..e5cf0ec226 100644
--- a/cocos/renderer/backend/opengl/CommandBufferGL.cpp
+++ b/cocos/renderer/backend/opengl/CommandBufferGL.cpp
@@ -480,7 +480,7 @@ void CommandBufferGL::setUniforms(ProgramGL* program) const
         {
             /* About mutli textures support
             *  a. sampler2DArray, sampler2D[2], bind BackendTexture one by one, not use GL_TEXTURE_2D_ARRAY, not used at all engine interanl
-            *  b. texture slot, one BackendTexture, multi GPU texture handlers, used by etc1
+            *  b. texture slot, one BackendTexture, multi GPU texture handlers, used by etc1, restrict: textures must have same size
             *  c. Bind multi BackendTexture to 1 Shader Program, see the ShaderTest
             */
             auto& textures = iter.second.textures;
@@ -498,7 +498,7 @@ void CommandBufferGL::setUniforms(ProgramGL* program) const
             }
             
             auto arrayCount = slots.size();
-            if (arrayCount == 1) // If not use sampler2DArray, always 1
+            if (arrayCount == 1) // Most of the time， not use sampler2DArray, should be 1
                 glUniform1i(location, slots[0]);
             else
                 glUniform1iv(location, (uint32_t)arrayCount, (GLint*)slots.data());
diff --git a/cocos/renderer/backend/opengl/TextureGL.h b/cocos/renderer/backend/opengl/TextureGL.h
index 6bcf28aaa5..3b521537e4 100644
--- a/cocos/renderer/backend/opengl/TextureGL.h
+++ b/cocos/renderer/backend/opengl/TextureGL.h
@@ -63,7 +63,7 @@ struct TextureInfoGL
     }
 
     /// <summary>
-    /// update shader texture
+    /// Apply shader texture
     /// </summary>
     /// <param name="slot">the slot in shader</param>
     /// <param name="index">the index in meta textrues</param>