+/**
+ * Verify a couple error conditions that will lead to an incomplete FBO and
+ * may cause problems for the driver's RenderTexture path.
+ */
+static bool
+driver_RenderTexture_is_safe(const struct gl_renderbuffer_attachment *att)
+{
+ const struct gl_texture_image *const texImage =
+ att->Texture->Image[att->CubeMapFace][att->TextureLevel];
+
+ if (texImage->Width == 0 || texImage->Height == 0 || texImage->Depth == 0)
+ return false;
+
+ if ((texImage->TexObject->Target == GL_TEXTURE_1D_ARRAY
+ && att->Zoffset >= texImage->Height)
+ || (texImage->TexObject->Target != GL_TEXTURE_1D_ARRAY
+ && att->Zoffset >= texImage->Depth))
+ return false;
+
+ return true;
+}
+
+/**
+ * Create a renderbuffer which will be set up by the driver to wrap the
+ * texture image slice.
+ *
+ * By using a gl_renderbuffer (like user-allocated renderbuffers), drivers get
+ * to share most of their framebuffer rendering code between winsys,
+ * renderbuffer, and texture attachments.
+ *
+ * The allocated renderbuffer uses a non-zero Name so that drivers can check
+ * it for determining vertical orientation, but we use ~0 to make it fairly
+ * unambiguous with actual user (non-texture) renderbuffers.
+ */
+void
+_mesa_update_texture_renderbuffer(struct gl_context *ctx,
+ struct gl_framebuffer *fb,
+ struct gl_renderbuffer_attachment *att)
+{
+ struct gl_texture_image *texImage;
+ struct gl_renderbuffer *rb;
+
+ texImage = att->Texture->Image[att->CubeMapFace][att->TextureLevel];
+
+ rb = att->Renderbuffer;
+ if (!rb) {
+ rb = ctx->Driver.NewRenderbuffer(ctx, ~0);
+ if (!rb) {
+ _mesa_error(ctx, GL_OUT_OF_MEMORY, "glFramebufferTexture()");
+ return;
+ }
+ _mesa_reference_renderbuffer(&att->Renderbuffer, rb);
+
+ /* This can't get called on a texture renderbuffer, so set it to NULL
+ * for clarity compared to user renderbuffers.
+ */
+ rb->AllocStorage = NULL;
+
+ rb->NeedsFinishRenderTexture = ctx->Driver.FinishRenderTexture != NULL;
+ }
+
+ if (!texImage)
+ return;
+
+ rb->_BaseFormat = texImage->_BaseFormat;
+ rb->Format = texImage->TexFormat;
+ rb->InternalFormat = texImage->InternalFormat;
+ rb->Width = texImage->Width2;
+ rb->Height = texImage->Height2;
+ rb->NumSamples = texImage->NumSamples;
+ rb->TexImage = texImage;
+
+ if (driver_RenderTexture_is_safe(att))
+ ctx->Driver.RenderTexture(ctx, fb, att);
+}