Adding the ability to access MODULATE in the shader breaks when final_modulate is baked into vertex colors (this is a technique used to batch together different colored items). This PR prevents baking vertex colors when MODULATE is detected in the shader.
It also prevents baking when COLOR is read in canvas shaders, which could currently produce the wrong result in the shader if colors were baked. It does not prevent baking if COLOR is only written, which happens in most shaders, and will operate correctly without baking.
Although 2D draws in painters order with strict ordering, in certain circumstances items can be reordered to increase batching / decrease state changes, without affecting the end result. This can be determined by an overlap test.
In situation with item:
A-B-A
providing the third item does not overlap the second, they can be reordered:
A-A-B
Items already contain an AABB which can be used for this overlap test.
1)
To utilise this, I have implemented item reordering (only for single rects for now), with the lookahead adjustable in project settings. This can increase performance in situations where items may not be grouped in the scene tree by texture. It can also be switched off (by setting lookahead to 0).
2)
This same trick can be used to help join items that are lit. Lit items previously would prevent joining completely, thus missing out on performance gains other than multi-command items such as tilemaps.
In this PR, lights are assigned as bits in a bitfield (up to 64, the optimization is disabled above this), and on each try_item (for joining), the bitfield for lights and shadows is constructed and compared with the previous items. If these match the 2 items can potentially be joined. However, this can only be done without changing the rendered result if an overlap test is successful.
This overlap test can be adjusted to join items up to a specific number of item references, selectable in project settings, or turned off.
3)
The legacy uniform single rect drawing routine seems to have been identified as the source of flicker, particularly on nvidia. However, it can also be up to 2x as fast. Because of the speed the batching contains a fallback where it can use the legacy single rect method, but I have now added a project setting to make this switchable. In most cases with batching it should not be necessary (as single rects are drawn less frequently) and thus the flickering can be totally avoided.
4)
This PR also fixes a color modulate bug when drawing light passes, in certain situations (particularly custom _draw routines with multiple rects).
5)
This PR also fixes#38291, a bug in the legacy renderer where light passes could draw rects in wrong position.
- Resurrect it for GL ES 2
- Apply roll over with `fmod()` instead of resetting it to 0
- Expose the setting from the `VisualServer`, since it does not belong in any specific rasterizer
When reading SCREEN_TEXTURE in a shader, this previously only worked succesfully for the first read of the screen, because state.canvas_texscreen_used was never getting reset. This PR resets state.canvas_texscreen_used at the beginning of each joined item, so that further screen reads can happen.
Joining items across z_indices can interfere with light culling for lights which only affect certain z ranges. This PR disables joining across z_indices when lights are present, except specifically for lights with both z_min set to the global minimum (-4096) and z_max set to the global maximum (4096).
In addition, the z_index is now stored on the joined_item for accurate light culling. The z_index is also displayed in frame diagnostics.
In rare circumstances default batches were being joined incorrectly, causing visual regressions. This logic has been fixed.
In addition slightly more output information has been added to frame diagnosis mode.
Batching across z_index layers was not preserving the batch_break flag, which determines whether to not join the previous item. This is fixed by storing the flag in RenderItemState and preserving it across canvas_render_items calls.
Added project setting to enable / disable print frame diagnostics every 10 seconds. This prints out a list of batches and info, which is useful to optimize games and identify performance problems.
This adds 2 new values (items and draw calls) to the performance monitor in a '2d' section, rather than reusing the 3d values in the 'raster' section.
This makes it far easier to optimize games to minimize drawcalls.
Defers sending 'transform' commands within a RasterizerCanvas::Item until they are needed for default batches. Instead locally caches the extra matrix and applies it using software transform, preventing unnecessary batch breaks.
The logic is relatively complex, and the whole 'extra matrix' of the legacy renderer in addition to the final_transform is not ideal. However this is required to accelerate some user drawing techniques, and later the lines in the IDE.
Extra functions canvas_render_items_begin and canvas_render_items_end are added to RasterizerCanvas, with noop stubs for non-GLES2 renderers. This enables batching to be spready over multiple z_indices, and multiple calls to canvas_render_items.
It does this by only performing item joining within canvas_render_items, and deferring rendering until canvas_render_items_end().
Determined that a large reason for the decrease in performance in unbatchable scenes was due to the new routine being analogous to the 'nvidia workaround' code, that is about half the speed. So this simply uses the old routine in the case of single unbatchable rects. Hopefully we will be able to remove the old path at a later stage.
Where the final_modulate color varies between render_items this can prevent batching. This PR solves this by baking final_modulate into the vertex colors, and setting the uniform 'final_modulate' to white, and allowing the joining of items that have different final_modulate values. The previous batching system can then cope with vertex color changes as normal.
2d rendering is currently bottlenecked by drawing primitives one at a time, limiting OpenGL efficiency. This PR batches primitives and renders in fewer drawcalls, resulting in significant performance improvements. This also speeds up text rendering.
This PR batches across canvas items as well as within items.
The code dynamically chooses between a vertex format with and without color, depending on the input data for a frame, in order to optimize throughput and maximize batch size. It also adds an option to use glScissor to reduce fillrate in light passes.
Fixes#26637.
Fixes#19900.
The viewport_size returned by get_viewport_size was previously incorrect, being half the correct value. The function is renamed to get_viewport_half_extents, and now returns a Vector2.
Code which called this function has also been modified accordingly.
This PR also fixes shadow culling when using ortho cameras, because the correct input for CameraMatrix::set_orthogonal should be the full HEIGHT from get_viewport_half_extents, and not half the width.
It also fixes state.ubo_data.viewport_size in rasterizer_scene_gles3.cpp to be the width and the height of the viewport in pixels as stated in the documentation, rather than the current value which is half the viewport extents in worldspace, presumed to be a bug.
