CNA-GAP-015: Only BasicEffect exposes XNA's parameter graph and technique name; the other stock effects publish partial, hand-built parameter tables

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

AlphaTestEffect lacks Texture, DualTextureEffect lacks Texture/Texture2, EnvironmentMapEffect lacks Texture/EnvironmentMap/DirLight*, SkinnedEffect lacks Texture/DirLight*; these effects carry a 'Default' technique and some parameter shapes differ from XNA's.

Identifier

CNA-GAP-015

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

Effect::getParametersProperty() and CurrentTechnique of AlphaTestEffect, DualTextureEffect, EnvironmentMapEffect, SkinnedEffect

Expected behaviour

XNA 4.0's stock effects cache the parameters of their compiled effect (IL of each CacheEffectParameters): Texture for AlphaTest; Texture and Texture2 for DualTexture; Texture, EnvironmentMap and DirLight0..2 for EnvironmentMap; Texture and DirLight0..2 (with specular) for Skinned. Code can read or set them through Parameters[name].

Actual behaviour at TARGET

CNA's AlphaTestEffect.cpp, DualTextureEffect.cpp, EnvironmentMapEffect.cpp and SkinnedEffect.cpp add only numeric parameters with AddParam; the texture and light parameters above are absent, so Parameters["Texture"] returns null. These effects are built on Effect(GraphicsDevice&), whose single technique is named "Default" (BasicEffect alone passes a stock technique name). The chapter package also recorded shape differences (WorldInverseTranspose declared 4x4 where XNA's .fx uses float3x3; Bones as 72 four-column rows rather than float4x3[72]).

Source locations

• modules/graphics/src/Xna/AlphaTestEffect.cpp — AlphaTestEffect::CacheEffectParameters
• modules/graphics/src/Xna/EnvironmentMapEffect.cpp — EnvironmentMapEffect::CacheEffectParameters
• modules/graphics/src/Xna/SkinnedEffect.cpp — SkinnedEffect::CacheEffectParameters (Bones rows)
• modules/graphics/src/Xna/BasicEffect.cpp — BasicEffect uses the stock-technique constructor

Evidence

Checked by reading the named sources at 009d40f5; nothing was built or executed for this entry. XNA parameter names read from the genuine XNA 4.0 Graphics IL. The typed properties (Texture, EnvironmentMap, lights) work; only the generic parameter surface is incomplete.

Focused reproduction

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

Current tests

Stock-effect tests use the typed properties; none enumerates Parameters against XNA's list.

Regression test

A table-driven test per stock effect comparing parameter names, classes, types and shapes with XNA's (a generated list from the XNA IL).

Blast radius

Code that manipulates stock effects generically through Parameters (editors, material systems, serializers).

Workaround

Use the typed properties.