Sprite

Todo: This page is for sprites in general, as they apply to all Valve games.

• Move Source engine-specific shader stuff to Sprite (shader) and $spriteorientation. See also Shaders in Sprites\.
• GoldSrc-specific engine stuff likely belongs in SPR.

In GoldSrc and Source, a sprite is a rendered world object with some very special geometrickery. The sprite itself is a (static or animated) 2D image that looks 3D when viewed Normally (ie perpendicular to its surface). The trick is to make sure the player always views the sprite normally; which usually means rotating the sprite about its origin so it is always facing the Player. Obviously in multiplayer this rotation in World would not work, so the sprite is rotated only in the Player View.

Although their usefulness is severely limited, sprites are significantly cheaper to render than models or brushwork, and can also achieve convincing effects that would be impractical to model in 3D.

• Lighting: Sprites cannot cast or receive any kind of shadows, nor reflect cubemaps.
• Physics: Sprites cannot be Solid to anything
  Note:In GoldSrc, cycler_sprite entities can have collision (simple bounding box), but this entity is buggy and not meant for final distributables. Use a CLIP brush and/or an MDL instead.

Bug:In Source, reloading the game materials has no effect on sprite textures loaded in a game session. If a sprite material is changed after the game has already loaded the VMT on a sprite, the game must be restarted.  [todo tested in?]

Sprite entities

GoldSrc	Source
env_sprite env_glow env_laser env_beam env_shooter cycler_sprite env_spritetrain(only in and )	env_sprite env_sprite_clientside env_sprite_oriented prop_detail_sprite

Placement

Todo: ... general usage guidelines ... configuring sprite entities in Hammer.

• See Render Modes.
• See Attachments and Movement hierarchy.

Creation

Todo: guidelines/checklist for designing & implementing sprites.

• Design guidelines.
  • the image inside the sprite already depicts a three dimensional object;
  • the animation is constantly changing or depicts rotation;
  • the depicted object has a similar appearance from many common viewing angles (such as something spherical);
  • the viewer accepts that the depicted object only has one perspective (such as small plants or leaves).
  • the sprite exists only briefly, is NotSolid, ... player cannot inspect it too closely.
• SPR file format...
• If using a texture that is intended to be transparent, be sure to close Hammer and restart it before compiling. Hammer likes to only half-load new sprite textures and won't display them as transparent.
• Sprite textures may also have any shade of gray (red, green, and blue values identical) interpreted as being transparent. Have not extensively tested, but it has worked in at least two cases (light_glow01 and a custom one).
• VTF: Vtex compile parameters "clamps", "clampt". note: env_sprite_oriented #angles ...
• VMT: Shaders_in_Sprites\

$spriteorientation Parameters for VMT

The number next to these types MUST be used instead for $spriteorientation when used in any shader other than Sprite^[Clarify].

parallel_upright (0) ! fire1, fire2, fire, fireburst, flame01, flame03, flame04, floorfire4_, floorflame2, parallel_upright, physbeam

facing_upright (1)

• Invalid (?) Unused (?)

vp_parallel (2)

• This always faces the player.

! Most popular.

oriented (3)

• Oriented to the world (does not face player)

! flatframe, lamphalo1, lamphalo

vp_parallel_oriented (4)

• If the sprite entity is rotated, the sprite will match the rotation.

! plasma, smoke, steam1

E.G. of Stock HL2 Sprite

"Sprite"
{
	"$spriteorientation" "vp_parallel"
	"$spriteorigin" "[ 0.50 0.50 ]"
	"$basetexture" "sprites/glow_test02"

	"Proxies"
	{
		"lampbeam"
		{
		}
	}
}

Reference: materials/sprites/glow_test02

E.G. of Custom Sprite

"Sprite"
{
	"$basetexture" "sprites/turret_rebel"
	"$spriteorientation" "vp_parallel"
	"$spriteorigin" "[ 0.50 0.50 ]"
	"$translucent" "1"
	"$nocull" "1"
	"$vertexcolor" "1"
	"$vertexalpha" "1"
        "%keywords" "turret .spr"       
}

Download Reference: http://forum.tsgk.com/viewtopic.php?t=4699

• File Name Reference: gtamikes_custom_turrets_V3_Final.rar
  • turret_rebel.vmt, turret_rebel.vtf
  • turret_combine.vmt, turret_combine.vtf

Rebel and Combine Custom Sprite For HL2DM CTF Mode

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