- unsigned location = this->location;
- unsigned location_frac = this->location_frac;
- unsigned num_components = this->num_components();
- while (num_components > 0) {
- unsigned output_size = MIN2(num_components, 4 - location_frac);
- assert((info->NumOutputs == 0 && max_outputs == 0) ||
- info->NumOutputs < max_outputs);
+ {
+ unsigned location = this->location;
+ unsigned location_frac = this->location_frac;
+ unsigned num_components = this->num_components();
+ while (num_components > 0) {
+ unsigned output_size = MIN2(num_components, 4 - location_frac);
+ assert((info->NumOutputs == 0 && max_outputs == 0) ||
+ info->NumOutputs < max_outputs);
+
+ /* From the ARB_enhanced_layouts spec:
+ *
+ * "If such a block member or variable is not written during a shader
+ * invocation, the buffer contents at the assigned offset will be
+ * undefined. Even if there are no static writes to a variable or
+ * member that is assigned a transform feedback offset, the space is
+ * still allocated in the buffer and still affects the stride."
+ */
+ if (this->is_varying_written()) {
+ info->Outputs[info->NumOutputs].ComponentOffset = location_frac;
+ info->Outputs[info->NumOutputs].OutputRegister = location;
+ info->Outputs[info->NumOutputs].NumComponents = output_size;
+ info->Outputs[info->NumOutputs].StreamId = stream_id;
+ info->Outputs[info->NumOutputs].OutputBuffer = buffer;
+ info->Outputs[info->NumOutputs].DstOffset = xfb_offset;
+ ++info->NumOutputs;
+ }
+ info->Buffers[buffer].Stream = this->stream_id;
+ xfb_offset += output_size;