| // Copyright (c) 2018-2020 NVIDIA Corporation |
| // |
| // SPDX-License-Identifier: CC-BY-4.0 |
| |
| [[drawing-mesh-shading]] |
| == Programmable Mesh Shading |
| |
| In this drawing approach, primitives are assembled by the mesh shader stage. |
| <<mesh, Mesh shading>> operates similarly to <<dispatch, dispatching |
| compute>> as the shaders make use of workgroups. |
| |
| |
| [open,refpage='vkCmdDrawMeshTasksNV',desc='Draw mesh task work items',type='protos'] |
| -- |
| :refpage: vkCmdDrawMeshTasksNV |
| |
| To record a draw that uses the mesh pipeline, call: |
| |
| include::{generated}/api/protos/vkCmdDrawMeshTasksNV.txt[] |
| |
| * pname:commandBuffer is the command buffer into which the command will be |
| recorded. |
| * pname:taskCount is the number of local workgroups to dispatch in the X |
| dimension. |
| Y and Z dimension are implicitly set to one. |
| * pname:firstTask is the X component of the first workgroup ID. |
| |
| When the command is executed, a global workgroup consisting of |
| pname:taskCount local workgroups is assembled. |
| |
| .Valid Usage |
| **** |
| include::{chapters}/commonvalidity/draw_common.txt[] |
| * [[VUID-vkCmdDrawMeshTasksNV-taskCount-02119]] |
| pname:taskCount must: be less than or equal to |
| sname:VkPhysicalDeviceMeshShaderPropertiesNV::pname:maxDrawMeshTasksCount |
| **** |
| |
| include::{generated}/validity/protos/vkCmdDrawMeshTasksNV.txt[] |
| -- |
| |
| [open,refpage='vkCmdDrawMeshTasksIndirectNV',desc='Issue an indirect mesh tasks draw into a command buffer',type='protos'] |
| -- |
| :refpage: vkCmdDrawMeshTasksIndirectNV |
| |
| To record an indirect mesh tasks draw, call: |
| |
| include::{generated}/api/protos/vkCmdDrawMeshTasksIndirectNV.txt[] |
| |
| * pname:commandBuffer is the command buffer into which the command is |
| recorded. |
| * pname:buffer is the buffer containing draw parameters. |
| * pname:offset is the byte offset into pname:buffer where parameters |
| begin. |
| * pname:drawCount is the number of draws to execute, and can: be zero. |
| * pname:stride is the byte stride between successive sets of draw |
| parameters. |
| |
| fname:vkCmdDrawMeshTasksIndirectNV behaves similarly to |
| flink:vkCmdDrawMeshTasksNV except that the parameters are read by the device |
| from a buffer during execution. |
| pname:drawCount draws are executed by the command, with parameters taken |
| from pname:buffer starting at pname:offset and increasing by pname:stride |
| bytes for each successive draw. |
| The parameters of each draw are encoded in an array of |
| slink:VkDrawMeshTasksIndirectCommandNV structures. |
| If pname:drawCount is less than or equal to one, pname:stride is ignored. |
| |
| .Valid Usage |
| **** |
| include::{chapters}/commonvalidity/draw_common.txt[] |
| include::{chapters}/commonvalidity/draw_dispatch_indirect_common.txt[] |
| include::{chapters}/commonvalidity/draw_indirect_drawcount.txt[] |
| * [[VUID-vkCmdDrawMeshTasksIndirectNV-drawCount-02146]] |
| If pname:drawCount is greater than `1`, pname:stride must: be a multiple |
| of `4` and must: be greater than or equal to |
| code:sizeof(sname:VkDrawMeshTasksIndirectCommandNV) |
| * [[VUID-vkCmdDrawMeshTasksIndirectNV-drawCount-02156]] |
| If pname:drawCount is equal to `1`, [eq]#(pname:offset {plus} |
| code:sizeof(slink:VkDrawMeshTasksIndirectCommandNV))# must: be less than |
| or equal to the size of pname:buffer |
| * [[VUID-vkCmdDrawMeshTasksIndirectNV-drawCount-02157]] |
| If pname:drawCount is greater than `1`, [eq]#(pname:stride {times} |
| (pname:drawCount - 1) {plus} pname:offset {plus} |
| code:sizeof(slink:VkDrawMeshTasksIndirectCommandNV))# must: be less than |
| or equal to the size of pname:buffer |
| **** |
| |
| include::{generated}/validity/protos/vkCmdDrawMeshTasksIndirectNV.txt[] |
| -- |
| |
| [open,refpage='VkDrawMeshTasksIndirectCommandNV',desc='Structure specifying a mesh tasks draw indirect command',type='structs',xrefs='vkCmdDrawMeshTasksIndirectNV'] |
| -- |
| The sname:VkDrawMeshTasksIndirectCommandNV structure is defined as: |
| |
| include::{generated}/api/structs/VkDrawMeshTasksIndirectCommandNV.txt[] |
| |
| * pname:taskCount is the number of local workgroups to dispatch in the X |
| dimension. |
| Y and Z dimension are implicitly set to one. |
| * pname:firstTask is the X component of the first workgroup ID. |
| |
| The members of sname:VkDrawMeshTasksIndirectCommandNV have the same meaning |
| as the similarly named parameters of flink:vkCmdDrawMeshTasksNV. |
| |
| .Valid Usage |
| **** |
| * [[VUID-VkDrawMeshTasksIndirectCommandNV-taskCount-02175]] |
| pname:taskCount must: be less than or equal to |
| sname:VkPhysicalDeviceMeshShaderPropertiesNV::pname:maxDrawMeshTasksCount |
| **** |
| |
| include::{generated}/validity/structs/VkDrawMeshTasksIndirectCommandNV.txt[] |
| -- |
| |
| [open,refpage='vkCmdDrawMeshTasksIndirectCountNV',desc='Perform an indirect mesh tasks draw with the draw count sourced from a buffer',type='protos'] |
| -- |
| :refpage: vkCmdDrawMeshTasksIndirectCountNV |
| |
| To record an indirect mesh tasks draw with the draw count sourced from a |
| buffer, call: |
| |
| include::{generated}/api/protos/vkCmdDrawMeshTasksIndirectCountNV.txt[] |
| |
| * pname:commandBuffer is the command buffer into which the command is |
| recorded. |
| * pname:buffer is the buffer containing draw parameters. |
| * pname:offset is the byte offset into pname:buffer where parameters |
| begin. |
| * pname:countBuffer is the buffer containing the draw count. |
| * pname:countBufferOffset is the byte offset into pname:countBuffer where |
| the draw count begins. |
| * pname:maxDrawCount specifies the maximum number of draws that will be |
| executed. |
| The actual number of executed draw calls is the minimum of the count |
| specified in pname:countBuffer and pname:maxDrawCount. |
| * pname:stride is the byte stride between successive sets of draw |
| parameters. |
| |
| fname:vkCmdDrawMeshTasksIndirectCountNV behaves similarly to |
| flink:vkCmdDrawMeshTasksIndirectNV except that the draw count is read by the |
| device from a buffer during execution. |
| The command will read an unsigned 32-bit integer from pname:countBuffer |
| located at pname:countBufferOffset and use this as the draw count. |
| |
| .Valid Usage |
| **** |
| include::{chapters}/commonvalidity/draw_common.txt[] |
| include::{chapters}/commonvalidity/draw_dispatch_indirect_common.txt[] |
| include::{chapters}/commonvalidity/draw_indirect_count_common.txt[] |
| * [[VUID-vkCmdDrawMeshTasksIndirectCountNV-stride-02182]] |
| pname:stride must: be a multiple of `4` and must: be greater than or |
| equal to code:sizeof(sname:VkDrawMeshTasksIndirectCommandNV) |
| * [[VUID-vkCmdDrawMeshTasksIndirectCountNV-maxDrawCount-02183]] |
| If pname:maxDrawCount is greater than or equal to `1`, |
| [eq]#(pname:stride {times} (pname:maxDrawCount - 1) {plus} pname:offset |
| {plus} code:sizeof(sname:VkDrawMeshTasksIndirectCommandNV))# must: be |
| less than or equal to the size of pname:buffer |
| * [[VUID-vkCmdDrawMeshTasksIndirectCountNV-countBuffer-02191]] |
| If the count stored in pname:countBuffer is equal to `1`, |
| [eq]#(pname:offset {plus} |
| code:sizeof(sname:VkDrawMeshTasksIndirectCommandNV))# must: be less than |
| or equal to the size of pname:buffer |
| * [[VUID-vkCmdDrawMeshTasksIndirectCountNV-countBuffer-02192]] |
| If the count stored in pname:countBuffer is greater than `1`, |
| [eq]#(pname:stride {times} (pname:drawCount - 1) {plus} pname:offset |
| {plus} code:sizeof(sname:VkDrawMeshTasksIndirectCommandNV))# must: be |
| less than or equal to the size of pname:buffer |
| **** |
| |
| include::{generated}/validity/protos/vkCmdDrawMeshTasksIndirectCountNV.txt[] |
| |
| -- |
