In "Far Cry" there were parameters you could use, but I don't know of anything for HL2.
From Firingsquad's article:
I'm running a GeForce FX 5900xt overclocked to 5950 Ultra speeds for the time being, which, according to this list, will be using the DX8.1 path.
Errr....I'd rather not? What can you do to force the DX9 path? What kind of performance penalty would be involved?
From Firingsquad's article:
DirectX 7 path
Half-Life 2s DirectX 7 path includes NVIDIAs GeForce 256, GeForce 2 series, GeForce2/4 MX, and nForce, and the RADEON 7xxx series (with RADEON 9100 IGP and MOBILITY RADEON 9000/9100 defaulting to the DirectX 7 path as well).
- Screen space effects are really simple.
- No model decals
- No detail props
- No refractive water
- Reduced decal visibility distance
- No bumpmaps
- Reduced model LODs
- Reduced material mip level
DirectX 8 path
Among the cards included in the DirectX 8 path are GeForce4 Titanium series (including GeForce4 Go), GeForce FX 5200/5600/5700, and GeForce FX Go 5600/5700 series.
- On some cards with poor fillrate, bumpmaps may be turned off in some scenes that use a lot of bumpmaps. At the moment, this is true for the GeForce4 Ti 4200 but we've worked with Nvidia to come up with a solution to reactivate bumpmaps on the 4200.
- Water by default is refractive but does not have local specular.
- Water has a hard edge when it meets the shore, volumetric fog is used for this. Its per vertex screen space effects are better than DirectX 7, but still simple.
- Shadows are render-to-texture but are not supersampled to make them
look softer.
DirectX 8.1 path
Cards that use the DirectX 8.1 path include RADEON 8500/9100, RADEON 9000/9200, GeForce FX 5800/5900.
- Water by default is refractive but does not have local reflections. If you activate local reflections on this card, it will occur in one pass as opposed to happening in 2 passes on DX8.0, which will make it cheaper from a fillrate perspective.
- As in DX8.0, water has a hard edge when it meets the shore, volumetric fog is used for water. Its per vertex screen space effects are better than DX7, but still simple.
- Shadows are render-to-texture and are supersampled to make them look
softer.
DirectX 9 path
Graphics cards that use the DX9 path include GeForce 6800 series, GeForce 6600 series, RADEON 9500/9600, RADEON X300/X600 series, RADEON X800 series, RADEON 9700/9800, MOBILITY RADEON 9600/9700, and MOBILITY RADEON 9800
- Water by default is refractive with local reflections from world geometry.
- Water refraction realistically refracts the geometry beneath the water (when looking into the water) based on the depth of the geometry in DX9.
- There is a special water rendering feature which smooths out the shorelines which reduces water refraction in areas with shallow water.
- There is a gradual blend from water to shore volumetric fog (for water) its per pixel screen space effects (post effects) are more complex.
- Shadows are render-to-texture and are supersampled to make them look
softer.- Certain displacements use blended bumpmaps instead of a single bumpmaps (for example, displacements that blend between sand and rocks).
I'm running a GeForce FX 5900xt overclocked to 5950 Ultra speeds for the time being, which, according to this list, will be using the DX8.1 path.
Errr....I'd rather not? What can you do to force the DX9 path? What kind of performance penalty would be involved?