bevy/pipelined
Carter Anderson 85487707ef Sprite Batching (#3060)
This implements the following:

* **Sprite Batching**: Collects sprites in a vertex buffer to draw many sprites with a single draw call. Sprites are batched by their `Handle<Image>` within a specific z-level. When possible, sprites are opportunistically batched _across_ z-levels (when no sprites with a different texture exist between two sprites with the same texture on different z levels). With these changes, I can now get ~130,000 sprites at 60fps on the `bevymark_pipelined` example.
* **Sprite Color Tints**: The `Sprite` type now has a `color` field. Non-white color tints result in a specialized render pipeline that passes the color in as a vertex attribute. I chose to specialize this because passing vertex colors has a measurable price (without colors I get ~130,000 sprites on bevymark, with colors I get ~100,000 sprites). "Colored" sprites cannot be batched with "uncolored" sprites, but I think this is fine because the chance of a "colored" sprite needing to batch with other "colored" sprites is generally probably way higher than an "uncolored" sprite needing to batch with a "colored" sprite.
* **Sprite Flipping**: Sprites can be flipped on their x or y axis using `Sprite::flip_x` and `Sprite::flip_y`. This is also true for `TextureAtlasSprite`.
* **Simpler BufferVec/UniformVec/DynamicUniformVec Clearing**:  improved the clearing interface by removing the need to know the size of the final buffer at the initial clear.

![image](https://user-images.githubusercontent.com/2694663/140001821-99be0d96-025d-489e-9bfa-ba19c1dc9548.png)


Note that this moves sprites away from entity-driven rendering and back to extracted lists. We _could_ use entities here, but it necessitates that an intermediate list is allocated / populated to collect and sort extracted sprites. This redundant copy, combined with the normal overhead of spawning extracted sprite entities, brings bevymark down to ~80,000 sprites at 60fps. I think making sprites a bit more fixed (by default) is worth it. I view this as acceptable because batching makes normal entity-driven rendering pretty useless anyway (and we would want to batch most custom materials too). We can still support custom shaders with custom bindings, we'll just need to define a specific interface for it.
2021-11-04 20:28:53 +00:00
..
bevy_core_pipeline Sprite Batching (#3060) 2021-11-04 20:28:53 +00:00
bevy_gltf2 Update for edition 2021 (#2997) 2021-10-25 18:00:13 +00:00
bevy_pbr2 Sprite Batching (#3060) 2021-11-04 20:28:53 +00:00
bevy_render2 Sprite Batching (#3060) 2021-11-04 20:28:53 +00:00
bevy_sprite2 Sprite Batching (#3060) 2021-11-04 20:28:53 +00:00