Change Details

This adds generic attribute rendering support for meshes for Eevee and Workbench. Each attribute is stored inside of the `MeshBufferList` as a separate VBO, with a maximum of `GPU_MAX_ATTR` VBOs for consistency with the GPU shader compilation code. Since `DRW_MeshCDMask` is not general enough, attribute requests are stored in new `DRW_AttributeRequest` structures inside of a convenient `DRW_MeshAttributes` structure. The latter is used in a similar manner as `DRW_MeshCDMask`, with the `MeshBatchCache` keeping track of needed, used, and used-over-time attributes. Again, `GPU_MAX_ATTR` is used in `DRW_MeshAttributes` to prevent too many attributes being used. To ensure thread-safety when updating the used attributes list, a mutex is added to the Mesh runtime. This mutex will also be used in the future for other things when other part of the rendre pre-processing are multi-threaded. `GPU_BATCH_VBO_MAX_LEN` was increased to 16 in order to accommodate for this design. Since `CD_PROP_COLOR` are a valid attribute type, sculpt vertex colors are now handled using this system to avoid to complicate things. In the future regular vertex colors will also use this. From this change, bit operations for DRW_MeshCDMask are now using uint32_t (to match the representation now used by the compiler). Users should be warned that when using the color or vector output of the Attribute node with a scalar attribute, it will be read as `vec4(v, 0, 0, 1)` (i.e. a red-ish color), instead of the usual conversion to `vec4(v, v, v, 1)` (i.e. a white-ish color) which we are all accustomed to. This is a limitation of the current shading system, and will be resolved during or after the EEVEE rewrite. Ref T85075

This adds generic attribute rendering support for meshes for Eevee and Workbench. Each attribute is stored inside of the `MeshBufferList` as a separate VBO, with a maximum of `GPU_MAX_ATTR` VBOs for consistency with the GPU shader compilation code. Since `DRW_MeshCDMask` is not general enough, attribute requests are stored in new `DRW_AttributeRequest` structures inside of a convenient `DRW_MeshAttributes` structure. The latter is used in a similar manner as `DRW_MeshCDMask`, with the `MeshBatchCache` keeping track of needed, used, and used-over-time attributes. Again, `GPU_MAX_ATTR` is used in `DRW_MeshAttributes` to prevent too many attributes being used. To ensure thread-safety when updating the used attributes list, a mutex is added to the Mesh runtime. This mutex will also be used in the future for other things when other part of the rendre pre-processing are multi-threaded. `GPU_BATCH_VBO_MAX_LEN` was increased to 16 in order to accommodate for this design. Since `CD_PROP_COLOR` are a valid attribute type, sculpt vertex colors are now handled using this system to avoid to complicate things. In the future regular vertex colors will also use this. From this change, bit operations for DRW_MeshCDMask are now using uint32_t (to match the representation now used by the compiler). Due to the difference in behavior for implicit type conversion for scalar types between OpenGL and what users expect (a scalar `s` is converted to `vec4(s, 0, 0, 1)` by OpenGL, vs. `vec4(s, s, s, 1)` in Blender's various node graphs) , all scalar types are using a float3 internally for now, which increases memory usage. This will be resolved during or after the EEVEE rewrite as properly handling this involves much deeper changes. Ref T85075

This adds generic attribute rendering support for meshes for Eevee and Workbench. Each attribute is stored inside of the `MeshBufferList` as a separate VBO, with a maximum of `GPU_MAX_ATTR` VBOs for consistency with the GPU shader compilation code. Since `DRW_MeshCDMask` is not general enough, attribute requests are stored in new `DRW_AttributeRequest` structures inside of a convenient `DRW_MeshAttributes` structure. The latter is used in a similar manner as `DRW_MeshCDMask`, with the `MeshBatchCache` keeping track of needed, used, and used-over-time attributes. Again, `GPU_MAX_ATTR` is used in `DRW_MeshAttributes` to prevent too many attributes being used. To ensure thread-safety when updating the used attributes list, a mutex is added to the Mesh runtime. This mutex will also be used in the future for other things when other part of the rendre pre-processing are multi-threaded. `GPU_BATCH_VBO_MAX_LEN` was increased to 16 in order to accommodate for this design. Since `CD_PROP_COLOR` are a valid attribute type, sculpt vertex colors are now handled using this system to avoid to complicate things. In the future regular vertex colors will also use this. From this change, bit operations for DRW_MeshCDMask are now using uint32_t (to match the representation now used by the compiler). Users should be warned that when using the color or vector output of the AttributeDue to the difference in behavior for implicit type conversion for scalar types node with a scalar attribute, it will be read as `vec4(v, 0, 0, 1)` (i.e. a red-ish color),between OpenGL and what users expect (a scalar `s` is converted to instead of the usual conversion to `vec4(v`vec4(s, 0, 0, 1)` by OpenGL, v,vs. v`vec4(s, 1)` (i.e.s, s, a white-ish color) which we are1)` in Blender's various node graphs) , all accustomed to. This is a limitation of the current shading systemscalar types are using a float3 internally for now, and will bewhich increases memory usage. This will be resolved during or after the EEVEE rewrite as properly handling this involves much deeper changes. Ref T85075