Alexander Gavrilov
f61ff22967
The attribute node already allows accessing attributes associated with objects and meshes, which allows changing the behavior of the same material between different objects or instances. The same idea can be extended to an even more global level of layers and scenes. Currently view layers provide an option to replace all materials with a different one. However, since the same material will be applied to all objects in the layer, varying the behavior between layers while preserving distinct materials requires duplicating objects. Providing access to properties of layers and scenes via the attribute node enables making materials with built-in switches or settings that can be controlled globally at the view layer level. This is probably most useful for complex NPR shading and compositing. Like with objects, the node can also access built-in scene properties, like render resolution or FOV of the active camera. Lookup is also attempted in World, similar to how the Object mode checks the Mesh datablock. In Cycles this mode is implemented by replacing the attribute node with the attribute value during sync, allowing constant folding to take the values into account. This means however that materials that use this feature have to be re-synced upon any changes to scene, world or camera. The Eevee version uses a new uniform buffer containing a sorted array mapping name hashes to values, with binary search lookup. The array is limited to 512 entries, which is effectively limitless even considering it is shared by all materials in the scene; it is also just 16KB of memory so no point trying to optimize further. The buffer has to be rebuilt when new attributes are detected in a material, so the draw engine keeps a table of recently seen attribute names to minimize the chance of extra rebuilds mid-draw. Differential Revision: https://developer.blender.org/D15941
52 lines
1.5 KiB
C++
52 lines
1.5 KiB
C++
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright 2005 Blender Foundation. All rights reserved. */
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/** \file
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* \ingroup gpu
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*
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* Uniform buffers API. Used to handle many uniforms update at once.
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* Make sure that the data structure is compatible with what the implementation expect.
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* (see "7.6.2.2 Standard Uniform Block Layout" from the OpenGL spec for more info about std140
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* layout)
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* Rule of thumb: Padding to 16bytes, don't use vec3, don't use arrays of anything that is not vec4
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* aligned .
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*/
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#pragma once
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct ListBase;
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/** Opaque type hiding blender::gpu::UniformBuf. */
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typedef struct GPUUniformBuf GPUUniformBuf;
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GPUUniformBuf *GPU_uniformbuf_create_ex(size_t size, const void *data, const char *name);
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/**
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* Create UBO from inputs list.
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* Return NULL if failed to create or if \param inputs: is empty.
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*
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* \param inputs: ListBase of #BLI_genericNodeN(#GPUInput).
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*/
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GPUUniformBuf *GPU_uniformbuf_create_from_list(struct ListBase *inputs, const char *name);
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#define GPU_uniformbuf_create(size) GPU_uniformbuf_create_ex(size, NULL, __func__);
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void GPU_uniformbuf_free(GPUUniformBuf *ubo);
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void GPU_uniformbuf_update(GPUUniformBuf *ubo, const void *data);
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void GPU_uniformbuf_bind(GPUUniformBuf *ubo, int slot);
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void GPU_uniformbuf_unbind(GPUUniformBuf *ubo);
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void GPU_uniformbuf_unbind_all(void);
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#define GPU_UBO_BLOCK_NAME "node_tree"
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#define GPU_ATTRIBUTE_UBO_BLOCK_NAME "unf_attrs"
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#define GPU_LAYER_ATTRIBUTE_UBO_BLOCK_NAME "drw_layer_attrs"
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#ifdef __cplusplus
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}
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#endif
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