CEG Classes - beyond-all-reason/springrts_engine_wiki_mirror GitHub Wiki

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Common Properties

All classes have the following properties, although not all of them use them:

  • pos (float3): The initial position of the spawner.
  • useAirLos (bool): Whether the spawner uses air LoS to determine if it is visible. This may allow the spawner to be seen from a further distance than normal.
  • alwaysVisible (bool): If true, the spawner is always visible, ignoring LoS.
  • speed (float3): The initial speed of the spawner.

CExpGenSpawner

This is the closest thing CEG has to a function call. Instead of creating a graphical effect on its own, it creates another CEG.

Properties:

  • delay (int): How long to wait before spawning the CEG.
  • dir (float3): The CEG will be called with this direction.
  • damage (float): The CEG will be called with this damage. The CEG doesn't actually deal any damage, but you can use this as a parameter and read it using the 'd' operator.
  • explosionGenerator (string): The name of the CEG you want to spawn.

Suggested Use:

  • If you use a spawner a lot of times, you may want to make it a separate CEG to avoid having to copy-paste many times.
  • This is the only way to truly delay a graphical effect.
  • The spawned CEG still checks conditions, so if you want to, say, spawn an effect only if it is in water and doesn't hit a unit, you can give the CExpGenSpawner nounit = 1; and the spawned CEG water = 1;.
  • This allows you to give a set of spawners the same (and possibly random) direction.
  • You can animate an explosion flip-book style using delays and several bitmaps.

CBitmapMuzzleFlame

This creates three rectangular textures at right angles to each other. The frontTexture has dir as its normal.

Properties:

  • sideTexture (string)
  • frontTexture (string)
  • dir (float3)
  • colorMap (string)
  • size (float): The initial width of the muzzle flame.
  • length (float): The initial length of the muzzle flame.
  • sizeGrowth (float): By the end of its life, the muzzle flame grows to 1 + sizeGrowth times its initial size and length. The flame grows quickly at first and more slowly toward the end.
  • ttl (int): How long the muzzle flame lasts.
  • frontOffset (float): Where the frontTexture is along the length of the muzzle flame. 0 means it is in the back, 1 is in the front.

Suggested Use:

  • Muzzle flames, obviously.
  • You can use an upward-pointing CBitmapMuzzleFlame as a simple splash of water or dirt.
  • Railgun trails.
  • This is the only class that both obeys perspective and allows for a custom texture.

CExploSpikeProjectile

This creates a glowy spike. Note that the spike is two sided, i.e., symmetric about the position of the spawner.

  • length (float): The initial length of (half) of the spike (multiplied by dir).
  • width (float): Half the initial width of of the spike. This is an absolute value.
  • alpha (float): The starting alpha of the spike.
  • alphaDecay (float): How quickly the alpha of the spike decreases.
  • dir (float3): The direction of the spike. Not normalized.
  • color (float3): The color of the spike.

Suggested Use:

  • Anything glowy.
  • For large, slow missiles, you can try using this as an extended engine flame. Set the width to something fairly large.
  • Long and thin spikes will look spiky; meanwhile, shorter and wider spikes look more blobby.
  • The colors of spikes add together, so if you have several spikes and all three color channels are non-zero, it will be white in the center.
  • The length growth of the spike depends on the norm of the dir vector. The spike does not grow in width.

CHeatCloudProjectile

Creates an expanding sprite. Simple but effective.

  • heat (float)
  • maxheat (float)
  • heatFalloff (float)

This is really confusing way of representing alpha and alphaDecay. Basically alpha = heat/maxheat, and alphaDecay = heatFalloff/maxHeat.

  • size (float): The initial radius of the heatcloud.
  • sizeGrowth (float): The heatcloud grows by this amount every frame.
  • sizemod (float): The size of the heatcloud is multiplied by 1 - sizemod.
  • sizemodmod (float): Each frame, sizemod is multiplied by sizemodmod.
  • texture (string): The texture used for the heatcloud.

Suggested Use:

  • As the main background to an explosion.

CSimpleParticleSystem

Creates a sprite that can undergo complex motion. Probably the most versatile class. Since there are a lot of properties, I'll group them:

Initial Velocity Properties

  • emitVector (float3): The basic direction in which the particle is emitted.

Protip: When spawning CEGs via EmitSfx you can make the particles go into the direction of the emiting piece with: emitvector = dir, This is usefull for eg fire coming out of a gun barrel.

  • emitRot (float): At what angle to emit the particle relative to emitVector. 0 means that the particle will be emitted in emitVector's direction; 180 will emit the particle in the opposite direction. 90 will emit the particle in a random direction perpendicular to emitVector, which is good for creating rings.
  • emitRotSpread (float): For each particle, a random number between 0 and emitRotSpread is added to the emitRot.
  • emitMul (float3): Scales the initial particle velocity; for this property, +y is considered to be in the direction of emitVector. Good if you want to create an egg-shaped explosion.
  • particleSpeed (float): The particle's initial speed.
  • particleSpeedSpread (float): For each particle, a random number between 0 and particleSpeedSpread is added to the particleSpeed .

Movement Properties

  • gravity (float3): This will be added to the particle's velocity every frame.
  • airdrag (float): The particle's velocity is multiplied by this every frame.

Size Properties

  • particleSize (float): The initial size of the particle.
  • particleSizeSpread (float): For each particle, a random number between 0 and particleSizeSpread is added to the particleSize.
  • sizeGrowth (float): How much the particle grows each frame.
  • sizeMod (float): The size of the particle is multiplied by this each frame.

Visual Properties

  • directional (bool): If true, the particle will point in the direction it is moving.
  • texture (string): The texture to use for the particle.
  • colorMap (string): The colormap to use for the particle.

Life Properties

  • numParticles (int): How many particles to create. This is not the same as count; if you spawn multiple particles using count, any CEG-Operators will be reevaluated for each particle, whereas if you use numParticles they will not be. However, the spread properties are evaluated separately for each particle regardless of which one you use.
  • particleLife (float): How long each particle lasts.
  • particleLifeSpread (float); For each particle, a random number between 0 and particleLifeSpread is added to the particleLife .

Suggested Use:

  • This is probably the most versatile class.
  • Anything moving that is not doing so at constant velocity.
  • If you want something that expands (or shrinks) to some size then stops, set sizeMod to something less than 1, and sizeGrowth to something positive. The particle will grow to a size equal to sizeGrowth/ (1 - sizeMod) and stop. The smaller sizeMod is, the faster it will reach this size.

CSpherePartSpawner

Draws an expanding sphere.

Properties:

  • alpha (float): The alpha of the sphere.
  • ttl (int): How long the sphere lasts.
  • expansionSpeed (float): How quickly the sphere expands.
  • color (float3): The color of the sphere.

Suggested Use:

  • Looks like a shockwave.

CSimpleGroundFlash

Draws an expanding ground texture.

Properties:

  • size (float): The radius of the particle.
  • sizeGrowth (float): How much the particle grows each frame.
  • ttl (int): How long the particle lasts.
  • texture (string): The texture to use for the particle.
  • colorMap (string): The colormap to use for the particle.

Suggested Use:

  • A short groundflash (~8 frames) is good for any explosion that gives off light. You can also use a longer groundflash to suggest the ground is glowing from heat.

CEG Textures

  • Textures on CEG definitions are referenced by name.
  • The list of available textures and their names should be on a "resources.tdf" or "resources.lua" file that's usually placed on the "gamedata" subfolder.
  • Texture definitions to be used in projectile classes should be placed within the "projectiletextures" category and textures to be used with "CSimpleGroundFlash" class should be placed within the "groundfx" category.
  • Texture images are usually placed in the "bitmaps" subfolder.