CNA-GAP-023: On DIRECTX9 a Texture2D can only be created with SurfaceFormat::Color

CNA snapshot 009d40f5  ·  Known Issues › Functional gaps  ·  source links pinned to 009d40f5

DIRECTX9 leaves ClassifySurfaceFormatEXT at its Defer default, so Texture2D creation falls back to a Color-only check although the renderer maps D3D formats internally; DXT XNB textures still load because the reader converts them to RGBA, but XNB textures stored in any other non-Color format do not.

Identifier

CNA-GAP-023

Category

Functional gap

Subsystem

Graphics & renderers

Status

Open

Verified against

CNA 009d40f5 (009d40f5dd085c4e674d3479675fac84b12b3e0a)

Evidence basis

Source-verified: read at TARGET, not executed

Tests touching this area

Yes: see Current tests

Affected contract

Texture2D constructors with a SurfaceFormat other than Color on DIRECTX9

Expected behaviour

XNA HiDef on Direct3D 9 creates textures in the DXT, Bgr565, Bgra5551, Bgra4444, Alpha8, floating-point and other formats the device supports.

Actual behaviour at TARGET

The default ClassifySurfaceFormatEXT returns Defer; DIRECTX9 does not override it (the renderers that do are DIRECTX11/12, EasyGL, OPENGL4, SDL_GPU, SOFTWARE, VULKAN and WEBGPU). Texture2D.cpp then calls Texture.cpp, which throws std::runtime_error ("Texture: SurfaceFormat N is not implemented by the selected graphics renderer") for anything but Color, and D3D9TextureRenderer allocates D3DFMT_A8B8G8R8 only. The XNB Texture2D reader (CreateTexture2DFromXnbData) converts DXT1/3/5 data to RGBA when the renderer does not keep it compressed, so DXT content loads. Every other non-Color format the XNB reader accepts (Bgr565, Bgra5551, Bgra4444, Alpha8, NormalizedByte, Rgba1010102, Rg32, Rgba64, Single, Vector2/4, Half*, HdrBlendable, ColorBgraEXT) is passed through unchanged as the Texture2D format, so such an asset also fails to load on DIRECTX9 with the same std::runtime_error, as does programmatic creation.

Source locations

• modules/graphics/src/Xna/Texture2D.cpp — format admission: RendererFormatVerdict::Defer -> Texture::ValidateFormat
• modules/graphics/src/Xna/Texture.cpp — Texture::ValidateFormat
• modules/graphics/include/CNA/Internal/Renderers/Common/IGraphicsRenderer.hpp — ClassifySurfaceFormatEXT default Defer

Evidence

Checked by reading the named sources at 009d40f5; nothing was built or executed for this entry.

Independent re-verification: Checked by reading the named sources at 009d40f5; nothing was built or executed for this entry. The XNB consequence is inferred from the reader's format handling (only compressed formats are converted); no non-DXT, non-Color asset was loaded on DIRECTX9.

Focused reproduction

No focused reproduction is known. Nothing has been invented here; the evidence above is what exists.

Current tests

DIRECTX9 texture fixtures use Color.

Regression test

A DIRECTX9 ClassifySurfaceFormatEXT backed by CheckDeviceFormat, with a creation test per supported format.

Blast radius

DIRECTX9 games that create non-Color textures at run time (procedural DXT, 565 lightmaps, float data textures).

Workaround

Create Color textures and convert the data.