update particle grass

[Xtarsia]

Updates particle grass to match ground level region blending when background mode is flat or noise.

[TokisanGames]

Great that it respects the region blend. However it continues outside of the region boundary which is only good for Flat and odd for None/Noise.

[TokisanGames]

Adjusted the texture filter to be a uniform with a positive selection rather than negative filter.

[TokisanGames]

Are these unnecessary?

// Defined Constants
#define SKIP_PASS 0
#define VERTEX_PASS 1
#define FRAGMENT_PASS 2

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The items in the gdscript info group and shadow mode should be moved up above the process & particle material. The last items should be:

• process material
• mesh
• mesh material

I see info is read only, fine, it can go at the very top and marked read only like Terrain3D version so it greys out. Though setting distance by meters is much more intuitive than instance_spacing * cell_width*grid_width or whatever.
Maybe renaming min_draw_distance is in order. It looks more like max draw distance. But if it's read only, maybe calculated_distance or draw distance or calculated_radius.

[pl4ttenbau]

how does it look, any progress towards merge?

[TokisanGames]

All updates will be listed here.

[TokisanGames]

Are these unnecessary?
// Defined Constants
#define SKIP_PASS 0
#define VERTEX_PASS 1
#define FRAGMENT_PASS 2

These were removed from the main shader in #899, but were left in process_material and displacement_buffer.glsl, both removed now.

[TokisanGames]

Ok looks good, thanks @Xtarsia.