By default, the render target precision of Iray Interactive is LDR, i.e., the result is downloaded from the GPU in RGBA format (8 bits per channel). When the scene is rendered with a high framerate, the canvas transfer times may constitute a significant portion of the overall rendering time per frame. For optimal performance it is thus recommended to avoid conversions from one type to another and use the same format for the output canvas too.
However, Iray Interactive does also support the HDR output format, when explicitly enabled via the following key-value pair to be passed to mi::neuraylib::IRender_context::set_option():
- bool hdr_output = false
If enabled, switches the output format used by the renderer to HDR, i.e., supporting full floating point precision output formats as RGBA_FP. Note, that this may degrade performance significantly, especially with network rendering.