# Eevee-next world shader

**Issue**: [105649](https://projects.blender.org/blender/blender/issues/105649)

classDiagram
    class World {
        DefaultWorldNodeTree default_world_get()
        sync()
    }
    
    class DefaultWorldNodeTree {
    
    }
    
    class Instance {
        +World world
        +PipelineModule pipelines
    }
    
    class PipelineModule {
    
    }
    
    class WorldPipeline {
        PassSimple world_ps_
        
        void sync()
        coid render()
    }
    Instance --> World: world
    Instance --> PipelineModule: pipelines
    PipelineModule --> WorldPipeline: world

## Current state

### High level

* [x] The world background is drawn
* [x] A default node-tree is used when use_nodes is not checked
* [x] The world node-tree is used when use_nodes is checked
* [x] Resources are attached for custom node trees
* [ ] An internal Node tree is generated when viewport `Scene World` is not checked
* [ ] Render world cube map.
* [ ] Coordinates are incorrect when using an environment texture node.
* [x] Is that because matrices in `_drw_view_` are all 0 (no)
* [ ] P (world position is 0,0,0, but legacy eevee contains the actual viewport position)
* Eevee-legacy uses (x,y,0), Eevee-next uses (x,y,1) `interp.P = project_point(ProjectionMatrixInverse, gl_Position.xyz);``
* When setting the camera to the origin the environment texture is rendered correctly. So assuming that this is failing.
* [ ] Legacy Eevee contains viewPosition, not sure to which component that translate to in Eevee-next.
* **Although this is an issue, we postpone it for now and place the camera at the origin**
*

### Med level

* [ ]

## Approach

* Add a CubemapModule that will record the cubemap from the world shader.
* The cubemap module keeps track of multiple cubemaps. The first slot is always the world
*
* Use a compute shader
* Incorporate the cubemap module with the deferred lighting pass
* Incorporate the cubemap module with the forward lighting pass
* Assume that the world is always rendered from scene origin.

classDiagram
    class World {
        sync()
        GPUMaterial* get_world_material()
    }
    
    class Instance {
        +World world
        +PipelineModule pipelines
    }
    
    class PipelineModule {
    
    }
    
    class ReflectionProbeModule {
        +set_world_dirty()
    }
    
    class WorldProbePipeline {
        PassSimple world_ps_
        
        void sync()
        coid render()
    }
    Instance --> ReflectionProbeModule: reflection_probes
    Instance --> World: world
    Instance --> PipelineModule: pipelines
    PipelineModule --> WorldProbePipeline: world_probe

sequenceDiagram
    participant Instance
    participant World
    participant ReflectionProbeModule
    participant WorldProbePipeline
    
    Note over Instance: sync
    activate Instance
    
    Instance ->>+ World: sync
    World ->>+ ReflectionProbeModule: set_world_dirty
    deactivate ReflectionProbeModule
    deactivate World
    
    Instance ->>+ ReflectionProbeModule: sync
    ReflectionProbeModule ->>+ World: get_world_material()
    World -->>- ReflectionProbeModule: GPUMaterial*
    ReflectionProbeModule ->>+ WorldProbePipeline: sync(world_material)
    deactivate WorldProbePipeline
    deactivate ReflectionProbeModule
    
    deactivate Instance
    
    Note over Instance: render
    activate Instance
    Instance ->>+ WorldProbePipeline: render
    deactivate WorldProbePipeline
    deactivate Instance