RED Portals and Rooms - Revision history

Goober at 14:24, 28 January 2024

2024-01-28T14:24:22Z

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			This page describes the portal-based rendering system used in [[Red Faction]].
	==Portal Rendering Basics==		==Portal Rendering Basics==
	[[Red Faction]] uses portal rendering to determine what geometry and objects will be visible at any given time and therefore avoid instances where level assets that can't be seen by the player are still being rendered. By determining which geometry and objects are not currently visible, and not rendering those assets, significant performance improvements are achieved.		Red Faction uses portal rendering to determine what geometry and objects will be visible at any given time and therefore avoid instances where level assets that can't be seen by the player are still being rendered. By determining which geometry and objects are not currently visible, and not rendering those assets, significant performance improvements are achieved.

	As a concept, this approach involves separating levels into zones/sectors (referred to as rooms in Red Faction), which are connected to one another by small openings that the engine has been instructed to consider as portals. When the engine determines that a room behind a portal needs to be rendered (based on the player's current camera position and view direction), only the parts of that room that are visible through the portal are rendered, rather than the entire space. As a general practice, portals should be configured in any confined areas (doors, tunnels, windows, etc.) that connect two otherwise separate areas of a level. The use of portals in this way greatly simplifies the engine's task of determining visible areas and objects from any given point of view. At a technical level, portals allow the engine to use each portal as a [https://en.wikipedia.org/wiki/Viewing_frustum viewing frustrum] for the area behind the portal.		As a concept, this approach involves separating levels into zones/sectors (referred to as rooms in Red Faction), which are connected to one another by small openings that the engine has been instructed to consider as portals. When the engine determines that a room behind a portal needs to be rendered (based on the player's current camera position and view direction), only the parts of that room that are visible through the portal are rendered, rather than the entire space. As a general practice, portals should be configured in any confined areas (doors, tunnels, windows, etc.) that connect two otherwise separate areas of a level. The use of portals in this way greatly simplifies the engine's task of determining visible areas and objects from any given point of view. At a technical level, portals allow the engine to use each portal as a [https://en.wikipedia.org/wiki/Viewing_frustum viewing frustrum] for the area behind the portal.

Goober at 14:23, 28 January 2024

2024-01-28T14:23:10Z

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	==Portal Rendering Basics==		==Portal Rendering Basics==
	[[Red Faction]] uses portal rendering to determine what geometry and objects will be visible at any given time and therefore avoid instances where level assets that can't be seen by the player are still being rendered. By determining which geometry and objects are not currently visible, and not rendering those assets, significant performance improvements are achieved.		[[Red Faction]] uses portal rendering to determine what geometry and objects will be visible at any given time and therefore avoid instances where level assets that can't be seen by the player are still being rendered. By determining which geometry and objects are not currently visible, and not rendering those assets, significant performance improvements are achieved.

Goober at 19:37, 16 November 2020

2020-11-16T19:37:33Z

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	Skyboxes provide level designers with a method to create the illusion of a sky in a level. When present, a sky room is rendered as if the level is physically within the sky room, with the player camera position always located at the center of the room. Players will see the skybox projected whenever [[RED Brushes#Invisible Geometry\|invisible textures]] or surfaces configured as '''Show Sky''' are used to allow the player to look outside of the level.		Skyboxes provide level designers with a method to create the illusion of a sky in a level. When present, a sky room is rendered as if the level is physically within the sky room, with the player camera position always located at the center of the room. Players will see the skybox projected whenever [[RED Brushes#Invisible Geometry\|invisible textures]] or surfaces configured as '''Show Sky''' are used to allow the player to look outside of the level.

			[[Basic Skyboxes\|Basic Skyboxes Tutorial]]

	===Liquid Rooms===		===Liquid Rooms===
	A Liquid Room, designated via a [[RED Objects#Room Effect\|Room Effect]] object with effect type '''Liquid Room''', contains liquid of the specified type, and at the specified depth, as configured in the [[RED Objects#Room Effect\|Room Effect]] properties. The depth is calculated from the lowermost point in the Liquid Room.		A Liquid Room, designated via a [[RED Objects#Room Effect\|Room Effect]] object with effect type '''Liquid Room''', contains liquid of the specified type, and at the specified depth, as configured in the [[RED Objects#Room Effect\|Room Effect]] properties. The depth is calculated from the lowermost point in the Liquid Room.

			[[Basic Liquids\|Basic Liquids Tutorial]]

	===Ambient Light Rooms===		===Ambient Light Rooms===

Goober at 19:25, 16 November 2020

2020-11-16T19:25:01Z

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	===Liquid Rooms===		===Liquid Rooms===
			A Liquid Room, designated via a [[RED Objects#Room Effect\|Room Effect]] object with effect type '''Liquid Room''', contains liquid of the specified type, and at the specified depth, as configured in the [[RED Objects#Room Effect\|Room Effect]] properties. The depth is calculated from the lowermost point in the Liquid Room.

	===Ambient Light Rooms===		===Ambient Light Rooms===

Goober: /* Ambient Light Rooms */

2020-11-16T18:49:45Z

Ambient Light Rooms

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	===Ambient Light Rooms===		===Ambient Light Rooms===
	An Ambient Light room has its own specific ambient light color value which takes precedence over the [[RED User Guide#Level Properties\|Level Properties]] ambient light value. The ambient light color is the base light color applied to all normal and [[RED Brushes#Detail Brushes\|detail]] brush surfaces when lighting is calculated.		An Ambient Light room has its own specific ambient light color value which takes precedence over the [[RED User Guide#Level Properties\|Level Properties]] ambient light value in that room. The ambient light color is the base light color applied to all normal and [[RED Brushes#Detail Brushes\|detail]] brush surfaces when lighting is calculated.

	An Ambient Light Room is designated via the presence of a [[RED Objects#Room Effect\|Room Effect]] object with effect type '''Ambient Light'''. The ambient light color is also configured in [[RED Objects#Room Effect\|Room Effect]] properties.		An Ambient Light Room is designated via the presence of a [[RED Objects#Room Effect\|Room Effect]] object with effect type '''Ambient Light'''. The ambient light color is also configured in [[RED Objects#Room Effect\|Room Effect]] properties.

Goober at 18:49, 16 November 2020

2020-11-16T18:49:05Z

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	===Ambient Light Rooms===		===Ambient Light Rooms===
			An Ambient Light room has its own specific ambient light color value which takes precedence over the [[RED User Guide#Level Properties\|Level Properties]] ambient light value. The ambient light color is the base light color applied to all normal and [[RED Brushes#Detail Brushes\|detail]] brush surfaces when lighting is calculated.

			An Ambient Light Room is designated via the presence of a [[RED Objects#Room Effect\|Room Effect]] object with effect type '''Ambient Light'''. The ambient light color is also configured in [[RED Objects#Room Effect\|Room Effect]] properties.

	{{CreditWikipedia\|Portal rendering}}		{{CreditWikipedia\|Portal rendering}}

Goober: /* Portals */

2020-11-16T13:25:17Z

Portals

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 In theory, placing as many portals throughout your level as possible until frame rate starts going down instead of up is ideal. In practice, you should try to place as many as it takes to separate the areas of your level from each other, always considering visibility at different angles throughout your level and how portal placement will affect rendering in those areas. Try to take special care to subdivide areas that contain a large number of visible objects or complex geometry. Portals should never intersect other portals.
 ===Air Brush Portals===
 Functionally, air brush portals are the same as placing solid brush portals at each intersection point between the air brush portal and other air brushes - for this reason, solid brush portals often offer more flexibility and versatility. The most common use for air brush portals are doorways and windows. When creating doorways, you should take special care to ensure the door is tightly constrained by the air brush portal and the player is never able to look through the [[RED Portals and Rooms#Door Rooms|Door Room]] you've created into another adjacent room while the door is closed. Simple [[RED Portals and Rooms#Liquid Room|Liquid Rooms]] (such as small puddles or craters filled with water) may also use air brush portals.

Goober: /* Rooms */

2020-11-16T02:47:27Z

Rooms

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	If the engine determines that a room is visible to the player, and that visibility is through a portal, only the geometry and objects within that room that are visible through that portal are rendered. In addition, room definition also determines the boundaries of [[RED Objects#Room Effect\|Room Effects]], [[RED Objects#EAX Effect\|EAX Effects]], and airlocks.		If the engine determines that a room is visible to the player, and that visibility is through a portal, only the geometry and objects within that room that are visible through that portal are rendered. In addition, room definition also determines the boundaries of [[RED Objects#Room Effect\|Room Effects]], [[RED Objects#EAX Effect\|EAX Effects]], and airlocks.

	The [[GeoMod]] engine renders each room separately, so if you have a large amount of objects or complex geometry in a single room, subdividing that room into multiple rooms may help improve performance and/or resolve rendering issues caused by limits being exceeded. Furthermore, there is a specific limit of '''2048''' objects per room (this includes [[RED Brushes#Detail Brushes\|detail brushes]] with alpha textures).		The [[GeoMod]] engine renders each room separately, so if you have a large amount of objects or complex geometry in a single room, subdividing that room into multiple rooms may help improve performance and/or resolve rendering issues caused by limits being exceeded. Furthermore, there is a specific limit of '''2048''' rendered objects per room at any given time (this includes [[RED Brushes#Detail Brushes\|detail brushes]] with alpha textures). If this limit is exceeded, some objects that normally would be rendered will be skipped.
	===Door Rooms===		===Door Rooms===
	Any room that contains a gold [[RED Objects#Keyframe\|keyframe]] object with the '''Is Door''' flag set is considered a Door Room. Door Rooms have the status "Blocked" whenever the door [[RED Groups#Moving Groups\|mover]] is closed. When looking through the Door Room into an adjacent room, the adjacent room will only be rendered if the Door Room is not currently "Blocked". The theory behind this concept makes a lot of sense - adjacent rooms will not be visible when the door is closed (since the door is blocking visibility), so they don't need to be rendered. In practice, this can cause visibility issues if the boundaries of the Door Room are not tightly constrained to just the door/doorframe by the level designer. The images below illustrate this concept. In each, the camera is in Room 1.		Any room that contains a gold [[RED Objects#Keyframe\|keyframe]] object with the '''Is Door''' flag set is considered a Door Room. Door Rooms have the status "Blocked" whenever the door [[RED Groups#Moving Groups\|mover]] is closed. When looking through the Door Room into an adjacent room, the adjacent room will only be rendered if the Door Room is not currently "Blocked". The theory behind this concept makes a lot of sense - adjacent rooms will not be visible when the door is closed (since the door is blocking visibility), so they don't need to be rendered. In practice, this can cause visibility issues if the boundaries of the Door Room are not tightly constrained to just the door/doorframe by the level designer. The images below illustrate this concept. In each, the camera is in Room 1.

Goober: /* Rooms */

2020-11-16T00:33:13Z

Rooms

← Older revision		Revision as of 00:33, 16 November 2020
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	If the engine determines that a room is visible to the player, and that visibility is through a portal, only the geometry and objects within that room that are visible through that portal are rendered. In addition, room definition also determines the boundaries of [[RED Objects#Room Effect\|Room Effects]], [[RED Objects#EAX Effect\|EAX Effects]], and airlocks.		If the engine determines that a room is visible to the player, and that visibility is through a portal, only the geometry and objects within that room that are visible through that portal are rendered. In addition, room definition also determines the boundaries of [[RED Objects#Room Effect\|Room Effects]], [[RED Objects#EAX Effect\|EAX Effects]], and airlocks.

	The [[GeoMod]] engine renders each room separately, so if you have a large amount of objects or complex geometry in a single room, subdividing that room into multiple rooms may help improve performance and/or resolve rendering issues caused by limits being ~~hit~~. Furthermore, there is a specific limit of '''2048''' objects per room (this includes [[RED Brushes#Detail Brushes\|detail brushes]] with alpha textures).		The [[GeoMod]] engine renders each room separately, so if you have a large amount of objects or complex geometry in a single room, subdividing that room into multiple rooms may help improve performance and/or resolve rendering issues caused by limits being exceeded. Furthermore, there is a specific limit of '''2048''' objects per room (this includes [[RED Brushes#Detail Brushes\|detail brushes]] with alpha textures).
	===Door Rooms===		===Door Rooms===
	Any room that contains a gold [[RED Objects#Keyframe\|keyframe]] object with the '''Is Door''' flag set is considered a Door Room. Door Rooms have the status "Blocked" whenever the door [[RED Groups#Moving Groups\|mover]] is closed. When looking through the Door Room into an adjacent room, the adjacent room will only be rendered if the Door Room is not currently "Blocked". The theory behind this concept makes a lot of sense - adjacent rooms will not be visible when the door is closed (since the door is blocking visibility), so they don't need to be rendered. In practice, this can cause visibility issues if the boundaries of the Door Room are not tightly constrained to just the door/doorframe by the level designer. The images below illustrate this concept. In each, the camera is in Room 1.		Any room that contains a gold [[RED Objects#Keyframe\|keyframe]] object with the '''Is Door''' flag set is considered a Door Room. Door Rooms have the status "Blocked" whenever the door [[RED Groups#Moving Groups\|mover]] is closed. When looking through the Door Room into an adjacent room, the adjacent room will only be rendered if the Door Room is not currently "Blocked". The theory behind this concept makes a lot of sense - adjacent rooms will not be visible when the door is closed (since the door is blocking visibility), so they don't need to be rendered. In practice, this can cause visibility issues if the boundaries of the Door Room are not tightly constrained to just the door/doorframe by the level designer. The images below illustrate this concept. In each, the camera is in Room 1.

Goober: /* Rooms */

2020-11-16T00:32:48Z

Rooms

← Older revision		Revision as of 00:32, 16 November 2020
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	If the engine determines that a room is visible to the player, and that visibility is through a portal, only the geometry and objects within that room that are visible through that portal are rendered. In addition, room definition also determines the boundaries of [[RED Objects#Room Effect\|Room Effects]], [[RED Objects#EAX Effect\|EAX Effects]], and airlocks.		If the engine determines that a room is visible to the player, and that visibility is through a portal, only the geometry and objects within that room that are visible through that portal are rendered. In addition, room definition also determines the boundaries of [[RED Objects#Room Effect\|Room Effects]], [[RED Objects#EAX Effect\|EAX Effects]], and airlocks.

	The [[GeoMod]] engine renders each room separately, so if you have a large amount of objects or complex geometry in a single room, subdividing that room into multiple rooms may help improve performance and/or resolve rendering issues. Furthermore, there is a specific limit of '''2048''' objects per room (this includes [[RED Brushes#Detail Brushes\|detail brushes]] with alpha textures).		The [[GeoMod]] engine renders each room separately, so if you have a large amount of objects or complex geometry in a single room, subdividing that room into multiple rooms may help improve performance and/or resolve rendering issues caused by limits being hit. Furthermore, there is a specific limit of '''2048''' objects per room (this includes [[RED Brushes#Detail Brushes\|detail brushes]] with alpha textures).
	===Door Rooms===		===Door Rooms===
	Any room that contains a gold [[RED Objects#Keyframe\|keyframe]] object with the '''Is Door''' flag set is considered a Door Room. Door Rooms have the status "Blocked" whenever the door [[RED Groups#Moving Groups\|mover]] is closed. When looking through the Door Room into an adjacent room, the adjacent room will only be rendered if the Door Room is not currently "Blocked". The theory behind this concept makes a lot of sense - adjacent rooms will not be visible when the door is closed (since the door is blocking visibility), so they don't need to be rendered. In practice, this can cause visibility issues if the boundaries of the Door Room are not tightly constrained to just the door/doorframe by the level designer. The images below illustrate this concept. In each, the camera is in Room 1.		Any room that contains a gold [[RED Objects#Keyframe\|keyframe]] object with the '''Is Door''' flag set is considered a Door Room. Door Rooms have the status "Blocked" whenever the door [[RED Groups#Moving Groups\|mover]] is closed. When looking through the Door Room into an adjacent room, the adjacent room will only be rendered if the Door Room is not currently "Blocked". The theory behind this concept makes a lot of sense - adjacent rooms will not be visible when the door is closed (since the door is blocking visibility), so they don't need to be rendered. In practice, this can cause visibility issues if the boundaries of the Door Room are not tightly constrained to just the door/doorframe by the level designer. The images below illustrate this concept. In each, the camera is in Room 1.