OpenGL backend: updated AttachToFramebuffer method to control which f…

…ramebuffer targets the texture is attached to

Graphics/GraphicsEngineOpenGL/include/Texture1DArray_GL.hpp

@@ -63,7 +63,8 @@ class Texture1DArray_GL final : public TextureBaseGL
 
     /// Implementation of TextureBaseGL::AttachToFramebuffer() for 1D texture array.
     virtual void AttachToFramebuffer(const struct TextureViewDesc& ViewDesc,
-                                     GLenum                        AttachmentPoint) override final;
+                                     GLenum                        AttachmentPoint,
+                                     FRAMEBUFFER_TARGET_FLAGS      Targets) override final;
 
     /// Implementation of TextureBaseGL::CopyTexSubimage() for 1D texture array.
     virtual void CopyTexSubimage(GLContextState& GLState, const CopyTexSubimageAttribs& Attribs) override final;

Graphics/GraphicsEngineOpenGL/include/Texture1D_GL.hpp

@@ -63,7 +63,8 @@ class Texture1D_GL final : public TextureBaseGL
 
     /// Implementation of TextureBaseGL::AttachToFramebuffer() for 1D texture.
     virtual void AttachToFramebuffer(const struct TextureViewDesc& ViewDesc,
-                                     GLenum                        AttachmentPoint) override final;
+                                     GLenum                        AttachmentPoint,
+                                     FRAMEBUFFER_TARGET_FLAGS      Targets) override final;
 
     /// Implementation of TextureBaseGL::CopyTexSubimage() for 1D texture.
     virtual void CopyTexSubimage(GLContextState& GLState, const CopyTexSubimageAttribs& Attribs) override final;

Graphics/GraphicsEngineOpenGL/include/Texture2DArray_GL.hpp

@@ -63,7 +63,8 @@ class Texture2DArray_GL final : public TextureBaseGL
 
     /// Implementation of TextureBaseGL::AttachToFramebuffer() for 2D texture array.
     virtual void AttachToFramebuffer(const struct TextureViewDesc& ViewDesc,
-                                     GLenum                        AttachmentPoint) override final;
+                                     GLenum                        AttachmentPoint,
+                                     FRAMEBUFFER_TARGET_FLAGS      Targets) override final;
 
     /// Implementation of TextureBaseGL::CopyTexSubimage() for 2D texture array.
     virtual void CopyTexSubimage(GLContextState& GLState, const CopyTexSubimageAttribs& Attribs) override final;

Graphics/GraphicsEngineOpenGL/include/Texture2D_GL.hpp

@@ -71,7 +71,8 @@ class Texture2D_GL final : public TextureBaseGL
 
     /// Implementation of TextureBaseGL::AttachToFramebuffer() for 2D texture.
     virtual void AttachToFramebuffer(const struct TextureViewDesc& ViewDesc,
-                                     GLenum                        AttachmentPoint) override final;
+                                     GLenum                        AttachmentPoint,
+                                     FRAMEBUFFER_TARGET_FLAGS      Targets) override final;
 
     /// Implementation of TextureBaseGL::CopyTexSubimage() for 2D texture.
     virtual void CopyTexSubimage(GLContextState& GLState, const CopyTexSubimageAttribs& Attribs) override final;

Graphics/GraphicsEngineOpenGL/include/Texture3D_GL.hpp

@@ -63,7 +63,8 @@ class Texture3D_GL final : public TextureBaseGL
 
     /// Implementation of TextureBaseGL::AttachToFramebuffer() for 3D texture.
     virtual void AttachToFramebuffer(const struct TextureViewDesc& ViewDesc,
-                                     GLenum                        AttachmentPoint) override final;
+                                     GLenum                        AttachmentPoint,
+                                     FRAMEBUFFER_TARGET_FLAGS      Targets) override final;
 
     /// Implementation of TextureBaseGL::CopyTexSubimage() for 3D texture.
     virtual void CopyTexSubimage(GLContextState& GLState, const CopyTexSubimageAttribs& Attribs) override final;

Graphics/GraphicsEngineOpenGL/include/TextureBaseGL.hpp

@@ -82,7 +82,14 @@ class TextureBaseGL : public TextureBase<EngineGLImplTraits>, public AsyncWritab
 
     __forceinline void TextureMemoryBarrier(MEMORY_BARRIER RequiredBarriers, class GLContextState& GLContextState);
 
-    virtual void AttachToFramebuffer(const struct TextureViewDesc& ViewDesc, GLenum AttachmentPoint) = 0;
+    enum FRAMEBUFFER_TARGET_FLAGS : Uint32
+    {
+        FRAMEBUFFER_TARGET_FLAG_NONE      = 0u,
+        FRAMEBUFFER_TARGET_FLAG_READ      = 1u << 0u,
+        FRAMEBUFFER_TARGET_FLAG_DRAW      = 1u << 1u,
+        FRAMEBUFFER_TARGET_FLAG_READ_DRAW = FRAMEBUFFER_TARGET_FLAG_READ | FRAMEBUFFER_TARGET_FLAG_DRAW
+    };
+    virtual void AttachToFramebuffer(const struct TextureViewDesc& ViewDesc, GLenum AttachmentPoint, FRAMEBUFFER_TARGET_FLAGS Targets) = 0;
 
     void CopyData(DeviceContextGLImpl* pDeviceCtxGL,
                   TextureBaseGL*       pSrcTextureGL,
@@ -141,6 +148,8 @@ class TextureBaseGL : public TextureBase<EngineGLImplTraits>, public AsyncWritab
     //Uint32 m_uiMapTarget;
 };
 
+DEFINE_FLAG_ENUM_OPERATORS(TextureBaseGL::FRAMEBUFFER_TARGET_FLAGS);
+
 void TextureBaseGL::TextureMemoryBarrier(MEMORY_BARRIER RequiredBarriers, GLContextState& GLContextState)
 {
 #if GL_ARB_shader_image_load_store

Graphics/GraphicsEngineOpenGL/include/TextureCubeArray_GL.hpp

@@ -63,7 +63,8 @@ class TextureCubeArray_GL final : public TextureBaseGL
 
     /// Implementation of TextureBaseGL::AttachToFramebuffer() for cube texture array.
     virtual void AttachToFramebuffer(const struct TextureViewDesc& ViewDesc,
-                                     GLenum                        AttachmentPoint) override final;
+                                     GLenum                        AttachmentPoint,
+                                     FRAMEBUFFER_TARGET_FLAGS      Targets) override final;
 
     /// Implementation of TextureBaseGL::CopyTexSubimage() for cube texture array.
     virtual void CopyTexSubimage(GLContextState& GLState, const CopyTexSubimageAttribs& Attribs) override final;

Graphics/GraphicsEngineOpenGL/include/TextureCube_GL.hpp

@@ -63,7 +63,8 @@ class TextureCube_GL final : public TextureBaseGL
 
     /// Implementation of TextureBaseGL::AttachToFramebuffer() for cube texture.
     virtual void AttachToFramebuffer(const struct TextureViewDesc& ViewDesc,
-                                     GLenum                        AttachmentPoint) override final;
+                                     GLenum                        AttachmentPoint,
+                                     FRAMEBUFFER_TARGET_FLAGS      Targets) override final;
 
     /// Implementation of TextureBaseGL::CopyTexSubimage() for cube texture.
     virtual void CopyTexSubimage(GLContextState& GLState, const CopyTexSubimageAttribs& Attribs) override final;

Graphics/GraphicsEngineOpenGL/src/FBOCache.cpp

@@ -133,7 +133,7 @@ GLObjectWrappers::GLFrameBufferObj FBOCache::CreateFBO(GLContextState&    Contex
         {
             const auto& RTVDesc     = pRTView->GetDesc();
             auto*       pColorTexGL = pRTView->GetTexture<TextureBaseGL>();
-            pColorTexGL->AttachToFramebuffer(RTVDesc, GL_COLOR_ATTACHMENT0 + rt);
+            pColorTexGL->AttachToFramebuffer(RTVDesc, GL_COLOR_ATTACHMENT0 + rt, TextureBaseGL::FRAMEBUFFER_TARGET_FLAG_READ_DRAW);
         }
     }
 
@@ -172,7 +172,11 @@ GLObjectWrappers::GLFrameBufferObj FBOCache::CreateFBO(GLContextState&    Contex
         {
             UNEXPECTED(GetTextureFormatAttribs(DSVDesc.Format).Name, " is not valid depth-stencil view format");
         }
-        pDepthTexGL->AttachToFramebuffer(DSVDesc, AttachmentPoint);
+        VERIFY_EXPR(DSVDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL || DSVDesc.ViewType == TEXTURE_VIEW_READ_ONLY_DEPTH_STENCIL);
+        pDepthTexGL->AttachToFramebuffer(DSVDesc, AttachmentPoint,
+                                         DSVDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL ?
+                                             TextureBaseGL::FRAMEBUFFER_TARGET_FLAG_READ_DRAW :
+                                             TextureBaseGL::FRAMEBUFFER_TARGET_FLAG_READ);
     }
 
     if (NumRenderTargets > 0)
@@ -372,7 +376,7 @@ const GLObjectWrappers::GLFrameBufferObj& FBOCache::GetReadFBO(TextureBaseGL* pT
         glBindFramebuffer(GL_READ_FRAMEBUFFER, NewFBO);
         DEV_CHECK_GL_ERROR("Failed to bind new FBO as read framebuffer");
 
-        pTex->AttachToFramebuffer(RTV0, GetFramebufferAttachmentPoint(TexDesc.Format));
+        pTex->AttachToFramebuffer(RTV0, GetFramebufferAttachmentPoint(TexDesc.Format), TextureBaseGL::FRAMEBUFFER_TARGET_FLAG_READ);
 
         GLenum Status = glCheckFramebufferStatus(GL_READ_FRAMEBUFFER);
         if (Status != GL_FRAMEBUFFER_COMPLETE)

Graphics/GraphicsEngineOpenGL/src/Texture1DArray_GL.cpp

@@ -182,29 +182,37 @@ void Texture1DArray_GL::UpdateData(GLContextState&          ContextState,
     ContextState.BindTexture(-1, m_BindTarget, GLObjectWrappers::GLTextureObj::Null());
 }
 
-void Texture1DArray_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint)
+void Texture1DArray_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint, FRAMEBUFFER_TARGET_FLAGS Targets)
 {
     if (ViewDesc.NumArraySlices == m_Desc.ArraySize)
     {
-        if (ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL)
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_DRAW)
         {
+            VERIFY_EXPR(ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL);
             glFramebufferTexture(GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
             CHECK_GL_ERROR("Failed to attach texture 1D array to draw framebuffer");
         }
-        glFramebufferTexture(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
-        CHECK_GL_ERROR("Failed to attach texture 1D array to read framebuffer");
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_READ)
+        {
+            glFramebufferTexture(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
+            CHECK_GL_ERROR("Failed to attach texture 1D array to read framebuffer");
+        }
     }
     else if (ViewDesc.NumArraySlices == 1)
     {
         // Texture name must either be zero or the name of an existing 3D texture, 1D or 2D array texture,
         // cube map array texture, or multisample array texture.
-        if (ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL)
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_DRAW)
         {
+            VERIFY_EXPR(ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL);
             glFramebufferTextureLayer(GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstArraySlice);
             CHECK_GL_ERROR("Failed to attach texture 1D array to draw framebuffer");
         }
-        glFramebufferTextureLayer(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstArraySlice);
-        CHECK_GL_ERROR("Failed to attach texture 1D array to read framebuffer");
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_READ)
+        {
+            glFramebufferTextureLayer(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstArraySlice);
+            CHECK_GL_ERROR("Failed to attach texture 1D array to read framebuffer");
+        }
     }
     else
     {

Graphics/GraphicsEngineOpenGL/src/Texture1D_GL.cpp

@@ -176,16 +176,20 @@ void Texture1D_GL::UpdateData(GLContextState&          ContextState,
     ContextState.BindTexture(-1, m_BindTarget, GLObjectWrappers::GLTextureObj::Null());
 }
 
-void Texture1D_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint)
+void Texture1D_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint, FRAMEBUFFER_TARGET_FLAGS Targets)
 {
     // For glFramebufferTexture1D(), if texture name is not zero, then texture target must be GL_TEXTURE_1D
-    if (ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL)
+    if (Targets & FRAMEBUFFER_TARGET_FLAG_DRAW)
     {
+        VERIFY_EXPR(ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL);
         glFramebufferTexture1D(GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_BindTarget, m_GlTexture, ViewDesc.MostDetailedMip);
         CHECK_GL_ERROR("Failed to attach texture 1D to draw framebuffer");
     }
-    glFramebufferTexture1D(GL_READ_FRAMEBUFFER, AttachmentPoint, m_BindTarget, m_GlTexture, ViewDesc.MostDetailedMip);
-    CHECK_GL_ERROR("Failed to attach texture 1D to read framebuffer");
+    if (Targets & FRAMEBUFFER_TARGET_FLAG_READ)
+    {
+        glFramebufferTexture1D(GL_READ_FRAMEBUFFER, AttachmentPoint, m_BindTarget, m_GlTexture, ViewDesc.MostDetailedMip);
+        CHECK_GL_ERROR("Failed to attach texture 1D to read framebuffer");
+    }
 }
 
 void Texture1D_GL::CopyTexSubimage(GLContextState& GLState, const CopyTexSubimageAttribs& Attribs)

Graphics/GraphicsEngineOpenGL/src/Texture2DArray_GL.cpp

@@ -256,30 +256,38 @@ void Texture2DArray_GL::UpdateData(GLContextState&          ContextState,
     ContextState.BindTexture(-1, m_BindTarget, GLObjectWrappers::GLTextureObj::Null());
 }
 
-void Texture2DArray_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint)
+void Texture2DArray_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint, FRAMEBUFFER_TARGET_FLAGS Targets)
 {
 
     if (ViewDesc.NumArraySlices == m_Desc.ArraySize)
     {
-        if (ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL)
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_DRAW)
         {
+            VERIFY_EXPR(ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL);
             glFramebufferTexture(GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
             CHECK_GL_ERROR("Failed to attach texture 2D array to draw framebuffer");
         }
-        glFramebufferTexture(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
-        CHECK_GL_ERROR("Failed to attach texture 2D array to read framebuffer");
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_READ)
+        {
+            glFramebufferTexture(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
+            CHECK_GL_ERROR("Failed to attach texture 2D array to read framebuffer");
+        }
     }
     else if (ViewDesc.NumArraySlices == 1)
     {
         // Texture name must either be zero or the name of an existing 3D texture, 1D or 2D array texture,
         // cube map array texture, or multisample array texture.
-        if (ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL)
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_DRAW)
         {
+            VERIFY_EXPR(ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL);
             glFramebufferTextureLayer(GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstArraySlice);
             CHECK_GL_ERROR("Failed to attach texture 2D array to draw framebuffer");
         }
-        glFramebufferTextureLayer(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstArraySlice);
-        CHECK_GL_ERROR("Failed to attach texture 2D array to read framebuffer");
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_READ)
+        {
+            glFramebufferTextureLayer(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstArraySlice);
+            CHECK_GL_ERROR("Failed to attach texture 2D array to read framebuffer");
+        }
     }
     else
     {

Graphics/GraphicsEngineOpenGL/src/Texture2D_GL.cpp

@@ -275,17 +275,21 @@ void Texture2D_GL::UpdateData(GLContextState&          ContextState,
     ContextState.BindTexture(-1, m_BindTarget, GLObjectWrappers::GLTextureObj::Null());
 }
 
-void Texture2D_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint)
+void Texture2D_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint, FRAMEBUFFER_TARGET_FLAGS Targets)
 {
     // For glFramebufferTexture2D(), if texture name is not zero, then texture target must be GL_TEXTURE_2D,
     // GL_TEXTURE_RECTANGLE or one of the 6 cubemap face targets GL_TEXTURE_CUBE_MAP_POSITIVE_X, ...
-    if (ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL)
+    if (Targets & FRAMEBUFFER_TARGET_FLAG_DRAW)
     {
+        VERIFY_EXPR(ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL);
         glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_BindTarget, m_GlTexture, ViewDesc.MostDetailedMip);
         CHECK_GL_ERROR("Failed to attach texture 2D to draw framebuffer");
     }
-    glFramebufferTexture2D(GL_READ_FRAMEBUFFER, AttachmentPoint, m_BindTarget, m_GlTexture, ViewDesc.MostDetailedMip);
-    CHECK_GL_ERROR("Failed to attach texture 2D to read framebuffer");
+    if (Targets & FRAMEBUFFER_TARGET_FLAG_READ)
+    {
+        glFramebufferTexture2D(GL_READ_FRAMEBUFFER, AttachmentPoint, m_BindTarget, m_GlTexture, ViewDesc.MostDetailedMip);
+        CHECK_GL_ERROR("Failed to attach texture 2D to read framebuffer");
+    }
 }
 
 void Texture2D_GL::CopyTexSubimage(GLContextState& GLState, const CopyTexSubimageAttribs& Attribs)

Graphics/GraphicsEngineOpenGL/src/Texture3D_GL.cpp

@@ -194,18 +194,22 @@ void Texture3D_GL::UpdateData(GLContextState&          ContextState,
     ContextState.BindTexture(-1, m_BindTarget, GLObjectWrappers::GLTextureObj::Null());
 }
 
-void Texture3D_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint)
+void Texture3D_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum AttachmentPoint, FRAMEBUFFER_TARGET_FLAGS Targets)
 {
     auto NumDepthSlicesInMip = m_Desc.Depth >> ViewDesc.MostDetailedMip;
     if (ViewDesc.NumDepthSlices == NumDepthSlicesInMip)
     {
-        if (ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL)
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_DRAW)
         {
+            VERIFY_EXPR(ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL);
             glFramebufferTexture(GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
             CHECK_GL_ERROR("Failed to attach texture 3D to draw framebuffer");
         }
-        glFramebufferTexture(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
-        CHECK_GL_ERROR("Failed to attach texture 3D to read framebuffer");
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_READ)
+        {
+            glFramebufferTexture(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip);
+            CHECK_GL_ERROR("Failed to attach texture 3D to read framebuffer");
+        }
     }
     else if (ViewDesc.NumDepthSlices == 1)
     {
@@ -215,13 +219,17 @@ void Texture3D_GL::AttachToFramebuffer(const TextureViewDesc& ViewDesc, GLenum A
 
         // On Android (at least on Intel HW), glFramebufferTexture3D() runs without errors, but the
         // FBO turns out to be incomplete. glFramebufferTextureLayer() seems to work fine.
-        if (ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL)
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_DRAW)
         {
+            VERIFY_EXPR(ViewDesc.ViewType == TEXTURE_VIEW_RENDER_TARGET || ViewDesc.ViewType == TEXTURE_VIEW_DEPTH_STENCIL);
             glFramebufferTextureLayer(GL_DRAW_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstDepthSlice);
             CHECK_GL_ERROR("Failed to attach texture 3D to draw framebuffer");
         }
-        glFramebufferTextureLayer(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstDepthSlice);
-        CHECK_GL_ERROR("Failed to attach texture 3D to read framebuffer");
+        if (Targets & FRAMEBUFFER_TARGET_FLAG_READ)
+        {
+            glFramebufferTextureLayer(GL_READ_FRAMEBUFFER, AttachmentPoint, m_GlTexture, ViewDesc.MostDetailedMip, ViewDesc.FirstDepthSlice);
+            CHECK_GL_ERROR("Failed to attach texture 3D to read framebuffer");
+        }
     }
     else
     {