c/render: Refactor gfx mesh shader allocation and dispatch

src/xrt/compositor/main/comp_renderer.c

@@ -810,11 +810,12 @@ do_gfx_mesh(struct comp_renderer *r,
 	VkResult ret;
 
 	/*
-	 * Reserve UBOs and fill in any data a head of time, if we ever want to
+	 * Reserve UBOs, create descriptor sets, and fill in any data a head of
-	 * copy UBO data this lets us do that easily write a copy command before
+	 * time, if we ever want to copy UBO data this lets us do that easily
-	 * the other gfx commands.
+	 * write a copy command before the other gfx commands.
 	 */
-	struct render_sub_alloc ubos[2];
+
+	VkDescriptorSet descriptor_sets[2] = XRT_STRUCT_INIT;
 	for (uint32_t i = 0; i < 2; i++) {
 
 		struct render_gfx_mesh_ubo_data data = {
@@ -822,13 +823,13 @@ do_gfx_mesh(struct comp_renderer *r,
 		    .post_transform = src_norm_rects[i],
 		};
 
-		ret = render_sub_alloc_ubo_alloc_and_write( //
+		ret = render_gfx_mesh_alloc_and_write( //
-		    vk,                                     // vk_bundle
+		    rr,                                //
-		    &rr->ubo_tracker,                       // rsat
+		    &data,                             //
-		    &data,                                  // ptr
+		    src_samplers[i],                   //
-		    sizeof(data),                           // size
+		    src_image_views[i],                //
-		    &ubos[i]);                              // out_rsa
+		    &descriptor_sets[i]);              //
-		VK_CHK_WITH_GOTO(ret, "render_sub_alloc_ubo_alloc_and_write", err_no_memory);
+		VK_CHK_WITH_GOTO(ret, "render_gfx_mesh_alloc", err_no_memory);
 	}
 
 
@@ -846,12 +847,10 @@ do_gfx_mesh(struct comp_renderer *r,
 		    i,                   // view_index
 		    &viewport_datas[i]); // viewport_data
 
-		render_gfx_distortion(   //
+		render_gfx_mesh_draw(    //
-		    rr,                  //
+		    rr,                  // rr
-		    i,                   //
+		    i,                   // mesh_index
-		    &ubos[i],            //
+		    descriptor_sets[i]); // descriptor_set
-		    src_samplers[i],     //
-		    src_image_views[i]); //
 
 		render_gfx_end_view(rr);
 	}

src/xrt/compositor/render/render_gfx.c

@@ -714,35 +714,71 @@ render_gfx_end_view(struct render_gfx *rr)
 	assert(rr->rtr != NULL);
 }
 
+XRT_CHECK_RESULT VkResult
+render_gfx_mesh_alloc_and_write(struct render_gfx *rr,
+                                const struct render_gfx_mesh_ubo_data *data,
+                                VkSampler src_sampler,
+                                VkImageView src_image_view,
+                                VkDescriptorSet *out_descriptor_set)
+{
+	VkDescriptorSet descriptor_set = VK_NULL_HANDLE;
+	struct render_sub_alloc ubo = XRT_STRUCT_INIT;
+	struct vk_bundle *vk = vk_from_rr(rr);
+	struct render_resources *r = rr->r;
+	VkResult ret;
+
+
+	/*
+	 * Allocate and upload data.
+	 */
+
+	ret = render_sub_alloc_ubo_alloc_and_write( //
+	    vk,                                     // vk_bundle
+	    &rr->ubo_tracker,                       // rsat
+	    data,                                   // ptr
+	    sizeof(*data),                          // size
+	    &ubo);                                  // out_rsa
+	VK_CHK_AND_RET(ret, "render_sub_alloc_ubo_alloc_and_write");
+
+
+	/*
+	 * Create and fill out destriptor.
+	 */
+
+	ret = vk_create_descriptor_set(    //
+	    vk,                            // vk_bundle
+	    r->mesh.descriptor_pool,       // descriptor_pool
+	    r->mesh.descriptor_set_layout, // descriptor_set_layout
+	    &descriptor_set);              // descriptor_set
+	VK_CHK_AND_RET(ret, "vk_create_descriptor_set");
+
+	update_mesh_discriptor_set( //
+	    vk,                     // vk_bundle
+	    r->mesh.src_binding,    // src_binding
+	    src_sampler,            // sampler
+	    src_image_view,         // image_view
+	    r->mesh.ubo_binding,    // ubo_binding
+	    ubo.buffer,             // buffer
+	    ubo.offset,             // offset
+	    ubo.size,               // size
+	    descriptor_set);        // descriptor_set
+
+	*out_descriptor_set = descriptor_set;
+
+	return VK_SUCCESS;
+}
+
 void
-render_gfx_distortion(
+render_gfx_mesh_draw(struct render_gfx *rr, uint32_t mesh_index, VkDescriptorSet descriptor_set)
-    struct render_gfx *rr, uint32_t view_index, struct render_sub_alloc *ubo, VkSampler sampler, VkImageView image_view)
 {
 	struct vk_bundle *vk = vk_from_rr(rr);
 	struct render_resources *r = rr->r;
 
-	assert(view_index == rr->current_view);
-
-	struct render_gfx_view *v = &rr->views[view_index];
-
-	VkDescriptorSet descriptor_set = v->mesh.descriptor_set;
-
 
 	/*
 	 * Descriptors and pipeline.
 	 */
 
-	update_mesh_discriptor_set( //
-	    vk,                     // vk_bundle
-	    r->mesh.src_binding,    // src_binding
-	    sampler,                // sampler
-	    image_view,             // image_view
-	    r->mesh.ubo_binding,    // ubo_binding
-	    ubo->buffer,            // buffer
-	    ubo->offset,            // offset
-	    ubo->size,              // size
-	    descriptor_set);        // descriptor_set
-
 	VkDescriptorSet descriptor_sets[1] = {descriptor_set};
 	vk->vkCmdBindDescriptorSets(         //
 	    r->cmd,                          // commandBuffer
@@ -789,9 +825,9 @@ render_gfx_distortion(
 
 		vk->vkCmdDrawIndexed(                  //
 		    r->cmd,                            // commandBuffer
-		    r->mesh.index_counts[view_index],  // indexCount
+		    r->mesh.index_counts[mesh_index],  // indexCount
 		    1,                                 // instanceCount
-		    r->mesh.index_offsets[view_index], // firstIndex
+		    r->mesh.index_offsets[mesh_index], // firstIndex
 		    0,                                 // vertexOffset
 		    0);                                // firstInstance
 	} else {

src/xrt/compositor/render/render_interface.h

@@ -891,16 +891,31 @@ void
 render_gfx_end_view(struct render_gfx *rr);
 
 /*!
- * Dispatch one mesh shader instance into the current view.
+ * Allocate needed resources for one mesh shader dispatch, will also update the
+ * descriptor set, ubo will be filled out with the given @p data argument.
+ *
+ * Uses the @ref render_sub_alloc_tracker of the @ref render_gfx and the
+ * descriptor pool of @ref render_resources, both of which will be reset once
+ * closed, so don't save any reference to these objects beyond the frame.
+ *
+ * @public @memberof render_gfx
+ */
+XRT_CHECK_RESULT VkResult
+render_gfx_mesh_alloc_and_write(struct render_gfx *rr,
+                                const struct render_gfx_mesh_ubo_data *data,
+                                VkSampler src_sampler,
+                                VkImageView src_image_view,
+                                VkDescriptorSet *out_descriptor_set);
+
+/*!
+ * Dispatch one mesh shader instance, using the give @p mesh_index as source for
+ * mesh geometry.
  *
  * @public @memberof render_gfx
  */
 void
-render_gfx_distortion(struct render_gfx *rr,
+render_gfx_mesh_draw(struct render_gfx *rr, uint32_t mesh_index, VkDescriptorSet descriptor_set);
-                      uint32_t view_index,
+
-                      struct render_sub_alloc *ubo,
-                      VkSampler sampler,
-                      VkImageView image_view);
 
 /*!
  * @}