Curves: Split curve EEVEE/workbench functions from particle hair

The GPU evaluation for curves will have to change significantly from the
current particle hair drawing code, due to its more general use cases
and support for more curve types. To simplify that process and avoid
introducing regressions for the rendering of hair particle systems,
this commit splits drawing functions for the curves object and
particle hair.

The changes are just inlining of functions and copying code
where necessary.

Differential Revision: https://developer.blender.org/D14576

9 files changed, 237 insertions, 69 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_data.c b/source/blender/draw/engines/eevee/eevee_data.c
index ee70cebcfd2..b846480182b 100644
--- a/source/blender/draw/engines/eevee/eevee_data.c
+++ b/source/blender/draw/engines/eevee/eevee_data.c
@@ -160,7 +160,7 @@ EEVEE_HairMotionData *EEVEE_motion_blur_hair_data_get(EEVEE_ObjectMotionData *mb
 {
   if (mb_data->hair_data == NULL) {
     /* Ugly, we allocate for each modifiers and just fill based on modifier index in the list. */
-    int psys_len = (ob->type != OB_CURVES) ? BLI_listbase_count(&ob->modifiers) : 1;
+    int psys_len = BLI_listbase_count(&ob->modifiers);
     EEVEE_HairMotionData *hair_step = MEM_callocN(
         sizeof(EEVEE_HairMotionData) + sizeof(hair_step->psys[0]) * psys_len, __func__);
     hair_step->psys_len = psys_len;
@@ -170,6 +170,19 @@ EEVEE_HairMotionData *EEVEE_motion_blur_hair_data_get(EEVEE_ObjectMotionData *mb
   return mb_data->hair_data;
 }
 
+EEVEE_HairMotionData *EEVEE_motion_blur_curves_data_get(EEVEE_ObjectMotionData *mb_data,
+                                                        Object *ob)
+{
+  if (mb_data->hair_data == NULL) {
+    EEVEE_HairMotionData *hair_step = MEM_callocN(
+        sizeof(EEVEE_HairMotionData) + sizeof(hair_step->psys[0]), __func__);
+    hair_step->psys_len = 1;
+    hair_step->type = EEVEE_MOTION_DATA_HAIR;
+    mb_data->hair_data = hair_step;
+  }
+  return mb_data->hair_data;
+}
+
 /* View Layer data. */
 
 void EEVEE_view_layer_data_free(void *storage)
diff --git a/source/blender/draw/engines/eevee/eevee_engine.c b/source/blender/draw/engines/eevee/eevee_engine.c
index 6cd1a31085f..0729b2078a8 100644
--- a/source/blender/draw/engines/eevee/eevee_engine.c
+++ b/source/blender/draw/engines/eevee/eevee_engine.c
@@ -111,7 +111,7 @@ void EEVEE_cache_populate(void *vedata, Object *ob)
       EEVEE_materials_cache_populate(vedata, sldata, ob, &cast_shadow);
     }
     else if (ob->type == OB_CURVES) {
-      EEVEE_object_hair_cache_populate(vedata, sldata, ob, &cast_shadow);
+      EEVEE_object_curves_cache_populate(vedata, sldata, ob, &cast_shadow);
     }
     else if (ob->type == OB_VOLUME) {
       EEVEE_volumes_cache_object_add(sldata, vedata, draw_ctx->scene, ob);
diff --git a/source/blender/draw/engines/eevee/eevee_materials.c b/source/blender/draw/engines/eevee/eevee_materials.c
index 4b9ad693971..c3f9a606dd0 100644
--- a/source/blender/draw/engines/eevee/eevee_materials.c
+++ b/source/blender/draw/engines/eevee/eevee_materials.c
@@ -740,34 +740,6 @@ BLI_INLINE EeveeMaterialCache eevee_material_cache_get(
   return matcache;
 }
 
-static void eevee_hair_cache_populate(EEVEE_Data *vedata,
-                                      EEVEE_ViewLayerData *sldata,
-                                      Object *ob,
-                                      ParticleSystem *psys,
-                                      ModifierData *md,
-                                      int matnr,
-                                      bool *cast_shadow)
-{
-  EeveeMaterialCache matcache = eevee_material_cache_get(vedata, sldata, ob, matnr - 1, true);
-
-  if (matcache.depth_grp) {
-    *matcache.depth_grp_p = DRW_shgroup_hair_create_sub(ob, psys, md, matcache.depth_grp, NULL);
-    DRW_shgroup_add_material_resources(*matcache.depth_grp_p, matcache.shading_gpumat);
-  }
-  if (matcache.shading_grp) {
-    *matcache.shading_grp_p = DRW_shgroup_hair_create_sub(
-        ob, psys, md, matcache.shading_grp, matcache.shading_gpumat);
-    DRW_shgroup_add_material_resources(*matcache.shading_grp_p, matcache.shading_gpumat);
-  }
-  if (matcache.shadow_grp) {
-    *matcache.shadow_grp_p = DRW_shgroup_hair_create_sub(ob, psys, md, matcache.shadow_grp, NULL);
-    DRW_shgroup_add_material_resources(*matcache.shadow_grp_p, matcache.shading_gpumat);
-    *cast_shadow = true;
-  }
-
-  EEVEE_motion_blur_hair_cache_populate(sldata, vedata, ob, psys, md);
-}
-
 #define ADD_SHGROUP_CALL(shgrp, ob, geom, oedata) \
   do { \
     if (oedata) { \
@@ -899,18 +871,56 @@ void EEVEE_particle_hair_cache_populate(EEVEE_Data *vedata,
         if (draw_as != PART_DRAW_PATH) {
           continue;
         }
-        eevee_hair_cache_populate(vedata, sldata, ob, psys, md, part->omat, cast_shadow);
+        EeveeMaterialCache matcache = eevee_material_cache_get(
+            vedata, sldata, ob, part->omat - 1, true);
+
+        if (matcache.depth_grp) {
+          *matcache.depth_grp_p = DRW_shgroup_hair_create_sub(
+              ob, psys, md, matcache.depth_grp, NULL);
+          DRW_shgroup_add_material_resources(*matcache.depth_grp_p, matcache.shading_gpumat);
+        }
+        if (matcache.shading_grp) {
+          *matcache.shading_grp_p = DRW_shgroup_hair_create_sub(
+              ob, psys, md, matcache.shading_grp, matcache.shading_gpumat);
+          DRW_shgroup_add_material_resources(*matcache.shading_grp_p, matcache.shading_gpumat);
+        }
+        if (matcache.shadow_grp) {
+          *matcache.shadow_grp_p = DRW_shgroup_hair_create_sub(
+              ob, psys, md, matcache.shadow_grp, NULL);
+          DRW_shgroup_add_material_resources(*matcache.shadow_grp_p, matcache.shading_gpumat);
+          *cast_shadow = true;
+        }
+
+        EEVEE_motion_blur_hair_cache_populate(sldata, vedata, ob, psys, md);
       }
     }
   }
 }
 
-void EEVEE_object_hair_cache_populate(EEVEE_Data *vedata,
-                                      EEVEE_ViewLayerData *sldata,
-                                      Object *ob,
-                                      bool *cast_shadow)
+void EEVEE_object_curves_cache_populate(EEVEE_Data *vedata,
+                                        EEVEE_ViewLayerData *sldata,
+                                        Object *ob,
+                                        bool *cast_shadow)
 {
-  eevee_hair_cache_populate(vedata, sldata, ob, NULL, NULL, CURVES_MATERIAL_NR, cast_shadow);
+  EeveeMaterialCache matcache = eevee_material_cache_get(
+      vedata, sldata, ob, CURVES_MATERIAL_NR - 1, true);
+
+  if (matcache.depth_grp) {
+    *matcache.depth_grp_p = DRW_shgroup_curves_create_sub(ob, matcache.depth_grp, NULL);
+    DRW_shgroup_add_material_resources(*matcache.depth_grp_p, matcache.shading_gpumat);
+  }
+  if (matcache.shading_grp) {
+    *matcache.shading_grp_p = DRW_shgroup_curves_create_sub(
+        ob, matcache.shading_grp, matcache.shading_gpumat);
+    DRW_shgroup_add_material_resources(*matcache.shading_grp_p, matcache.shading_gpumat);
+  }
+  if (matcache.shadow_grp) {
+    *matcache.shadow_grp_p = DRW_shgroup_curves_create_sub(ob, matcache.shadow_grp, NULL);
+    DRW_shgroup_add_material_resources(*matcache.shadow_grp_p, matcache.shading_gpumat);
+    *cast_shadow = true;
+  }
+
+  EEVEE_motion_blur_curves_cache_populate(sldata, vedata, ob);
 }
 
 void EEVEE_materials_cache_finish(EEVEE_ViewLayerData *UNUSED(sldata), EEVEE_Data *vedata)
diff --git a/source/blender/draw/engines/eevee/eevee_motion_blur.c b/source/blender/draw/engines/eevee/eevee_motion_blur.c
index fbc19a01a8b..0ef2e11131e 100644
--- a/source/blender/draw/engines/eevee/eevee_motion_blur.c
+++ b/source/blender/draw/engines/eevee/eevee_motion_blur.c
@@ -270,6 +270,57 @@ void EEVEE_motion_blur_hair_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
   }
 }
 
+void EEVEE_motion_blur_curves_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
+                                             EEVEE_Data *vedata,
+                                             Object *ob)
+{
+  EEVEE_PassList *psl = vedata->psl;
+  EEVEE_StorageList *stl = vedata->stl;
+  EEVEE_EffectsInfo *effects = stl->effects;
+
+  if (!DRW_state_is_scene_render() || psl->velocity_hair == NULL) {
+    return;
+  }
+
+  /* For now we assume curves objects are always moving. */
+  EEVEE_ObjectMotionData *mb_data = EEVEE_motion_blur_object_data_get(&effects->motion_blur, ob);
+  if (mb_data == NULL) {
+    return;
+  }
+
+  int mb_step = effects->motion_blur_step;
+  /* Store transform. */
+  copy_m4_m4(mb_data->obmat[mb_step], ob->obmat);
+
+  EEVEE_HairMotionData *mb_curves = EEVEE_motion_blur_curves_data_get(mb_data, ob);
+
+  if (mb_step == MB_CURR) {
+    /* Fill missing matrices if the object was hidden in previous or next frame. */
+    if (is_zero_m4(mb_data->obmat[MB_PREV])) {
+      copy_m4_m4(mb_data->obmat[MB_PREV], mb_data->obmat[MB_CURR]);
+    }
+    if (is_zero_m4(mb_data->obmat[MB_NEXT])) {
+      copy_m4_m4(mb_data->obmat[MB_NEXT], mb_data->obmat[MB_CURR]);
+    }
+
+    GPUTexture *tex_prev = mb_curves->psys[0].step_data[MB_PREV].hair_pos_tx;
+    GPUTexture *tex_next = mb_curves->psys[0].step_data[MB_NEXT].hair_pos_tx;
+
+    DRWShadingGroup *grp = DRW_shgroup_curves_create_sub(ob, effects->motion_blur.hair_grp, NULL);
+    DRW_shgroup_uniform_mat4(grp, "prevModelMatrix", mb_data->obmat[MB_PREV]);
+    DRW_shgroup_uniform_mat4(grp, "currModelMatrix", mb_data->obmat[MB_CURR]);
+    DRW_shgroup_uniform_mat4(grp, "nextModelMatrix", mb_data->obmat[MB_NEXT]);
+    DRW_shgroup_uniform_texture(grp, "prvBuffer", tex_prev);
+    DRW_shgroup_uniform_texture(grp, "nxtBuffer", tex_next);
+    DRW_shgroup_uniform_bool(grp, "useDeform", &mb_curves->use_deform, 1);
+  }
+  else {
+    /* Store vertex position buffer. */
+    mb_curves->psys[0].step_data[mb_step].hair_pos = DRW_curves_pos_buffer_get(ob);
+    mb_curves->use_deform = true;
+  }
+}
+
 void EEVEE_motion_blur_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
                                       EEVEE_Data *vedata,
                                       Object *ob)
diff --git a/source/blender/draw/engines/eevee/eevee_private.h b/source/blender/draw/engines/eevee/eevee_private.h
index 5220bac4e3f..f58c2339c82 100644
--- a/source/blender/draw/engines/eevee/eevee_private.h
+++ b/source/blender/draw/engines/eevee/eevee_private.h
@@ -1095,6 +1095,8 @@ EEVEE_ObjectEngineData *EEVEE_object_data_ensure(Object *ob);
 EEVEE_ObjectMotionData *EEVEE_motion_blur_object_data_get(EEVEE_MotionBlurData *mb, Object *ob);
 EEVEE_GeometryMotionData *EEVEE_motion_blur_geometry_data_get(EEVEE_ObjectMotionData *mb_data);
 EEVEE_HairMotionData *EEVEE_motion_blur_hair_data_get(EEVEE_ObjectMotionData *mb_data, Object *ob);
+EEVEE_HairMotionData *EEVEE_motion_blur_curves_data_get(EEVEE_ObjectMotionData *mb_data,
+                                                        Object *ob);
 EEVEE_LightProbeEngineData *EEVEE_lightprobe_data_get(Object *ob);
 EEVEE_LightProbeEngineData *EEVEE_lightprobe_data_ensure(Object *ob);
 EEVEE_LightEngineData *EEVEE_light_data_get(Object *ob);
@@ -1120,10 +1122,10 @@ void EEVEE_particle_hair_cache_populate(EEVEE_Data *vedata,
                                         EEVEE_ViewLayerData *sldata,
                                         Object *ob,
                                         bool *cast_shadow);
-void EEVEE_object_hair_cache_populate(EEVEE_Data *vedata,
-                                      EEVEE_ViewLayerData *sldata,
-                                      Object *ob,
-                                      bool *cast_shadow);
+void EEVEE_object_curves_cache_populate(EEVEE_Data *vedata,
+                                        EEVEE_ViewLayerData *sldata,
+                                        Object *ob,
+                                        bool *cast_shadow);
 void EEVEE_materials_cache_finish(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata);
 void EEVEE_materials_free(void);
 void EEVEE_update_noise(EEVEE_PassList *psl, EEVEE_FramebufferList *fbl, const double offsets[3]);
@@ -1463,6 +1465,9 @@ void EEVEE_motion_blur_hair_cache_populate(EEVEE_ViewLayerData *sldata,
                                            Object *ob,
                                            struct ParticleSystem *psys,
                                            struct ModifierData *md);
+void EEVEE_motion_blur_curves_cache_populate(EEVEE_ViewLayerData *sldata,
+                                             EEVEE_Data *vedata,
+                                             Object *ob);
 void EEVEE_motion_blur_swap_data(EEVEE_Data *vedata);
 void EEVEE_motion_blur_cache_finish(EEVEE_Data *vedata);
 void EEVEE_motion_blur_draw(EEVEE_Data *vedata);
diff --git a/source/blender/draw/engines/eevee/eevee_render.c b/source/blender/draw/engines/eevee/eevee_render.c
index e971edbaa44..47e2b95f367 100644
--- a/source/blender/draw/engines/eevee/eevee_render.c
+++ b/source/blender/draw/engines/eevee/eevee_render.c
@@ -230,7 +230,7 @@ void EEVEE_render_cache(void *vedata,
       }
     }
     else if (ob->type == OB_CURVES) {
-      EEVEE_object_hair_cache_populate(vedata, sldata, ob, &cast_shadow);
+      EEVEE_object_curves_cache_populate(vedata, sldata, ob, &cast_shadow);
       if (do_cryptomatte) {
         EEVEE_cryptomatte_object_curves_cache_populate(data, sldata, ob);
       }
diff --git a/source/blender/draw/engines/workbench/workbench_engine.c b/source/blender/draw/engines/workbench/workbench_engine.c
index 85c8f9c420a..566fd30096d 100644
--- a/source/blender/draw/engines/workbench/workbench_engine.c
+++ b/source/blender/draw/engines/workbench/workbench_engine.c
@@ -425,7 +425,8 @@ void workbench_cache_populate(void *ved, Object *ob)
   }
   else if (ob->type == OB_CURVES) {
     int color_type = workbench_color_type_get(wpd, ob, NULL, NULL, NULL);
-    workbench_cache_hair_populate(wpd, ob, NULL, NULL, color_type, false, CURVES_MATERIAL_NR);
+    DRWShadingGroup *grp = workbench_material_hair_setup(wpd, ob, CURVES_MATERIAL_NR, color_type);
+    DRW_shgroup_curves_create_sub(ob, grp, NULL);
   }
   else if (ob->type == OB_VOLUME) {
     if (wpd->shading.type != OB_WIRE) {
diff --git a/source/blender/draw/intern/draw_common.h b/source/blender/draw/intern/draw_common.h
index 34b930ae9c8..d302140d9ac 100644
--- a/source/blender/draw/intern/draw_common.h
+++ b/source/blender/draw/intern/draw_common.h
@@ -53,12 +53,17 @@ struct DRWShadingGroup *DRW_shgroup_hair_create_sub(struct Object *object,
                                                     struct ModifierData *md,
                                                     struct DRWShadingGroup *shgrp,
                                                     struct GPUMaterial *gpu_material);
+
+struct DRWShadingGroup *DRW_shgroup_curves_create_sub(struct Object *object,
+                                                      struct DRWShadingGroup *shgrp,
+                                                      struct GPUMaterial *gpu_material);
 /**
  * \note Only valid after #DRW_hair_update().
  */
 struct GPUVertBuf *DRW_hair_pos_buffer_get(struct Object *object,
                                            struct ParticleSystem *psys,
                                            struct ModifierData *md);
+struct GPUVertBuf *DRW_curves_pos_buffer_get(struct Object *object);
 void DRW_hair_duplimat_get(struct Object *object,
                            struct ParticleSystem *psys,
                            struct ModifierData *md,
diff --git a/source/blender/draw/intern/draw_hair.c b/source/blender/draw/intern/draw_hair.c
index e06df334d23..0a447bf7041 100644
--- a/source/blender/draw/intern/draw_hair.c
+++ b/source/blender/draw/intern/draw_hair.c
@@ -164,17 +164,28 @@ static ParticleHairCache *drw_hair_particle_cache_get(Object *object,
                                                       int subdiv,
                                                       int thickness_res)
 {
-  bool update;
   ParticleHairCache *cache;
-  if (psys) {
-    /* Old particle hair. */
-    update = particles_ensure_procedural_data(
-        object, psys, md, &cache, gpu_material, subdiv, thickness_res);
-  }
-  else {
-    /* New curves object. */
-    update = curves_ensure_procedural_data(object, &cache, gpu_material, subdiv, thickness_res);
+  bool update = particles_ensure_procedural_data(
+      object, psys, md, &cache, gpu_material, subdiv, thickness_res);
+
+  if (update) {
+    if (drw_hair_shader_type_get() == PART_REFINE_SHADER_COMPUTE) {
+      drw_hair_particle_cache_update_compute(cache, subdiv);
+    }
+    else {
+      drw_hair_particle_cache_update_transform_feedback(cache, subdiv);
+    }
   }
+  return cache;
+}
+
+static ParticleHairCache *drw_curves_cache_get(Object *object,
+                                               GPUMaterial *gpu_material,
+                                               int subdiv,
+                                               int thickness_res)
+{
+  ParticleHairCache *cache;
+  bool update = curves_ensure_procedural_data(object, &cache, gpu_material, subdiv, thickness_res);
 
   if (update) {
     if (drw_hair_shader_type_get() == PART_REFINE_SHADER_COMPUTE) {
@@ -201,37 +212,44 @@ GPUVertBuf *DRW_hair_pos_buffer_get(Object *object, ParticleSystem *psys, Modifi
   return cache->final[subdiv].proc_buf;
 }
 
+GPUVertBuf *DRW_curves_pos_buffer_get(Object *object)
+{
+  const DRWContextState *draw_ctx = DRW_context_state_get();
+  Scene *scene = draw_ctx->scene;
+
+  int subdiv = scene->r.hair_subdiv;
+  int thickness_res = (scene->r.hair_type == SCE_HAIR_SHAPE_STRAND) ? 1 : 2;
+
+  ParticleHairCache *cache = drw_curves_cache_get(object, NULL, subdiv, thickness_res);
+
+  return cache->final[subdiv].proc_buf;
+}
+
 void DRW_hair_duplimat_get(Object *object,
-                           ParticleSystem *psys,
+                           ParticleSystem *UNUSED(psys),
                            ModifierData *UNUSED(md),
                            float (*dupli_mat)[4])
 {
   Object *dupli_parent = DRW_object_get_dupli_parent(object);
   DupliObject *dupli_object = DRW_object_get_dupli(object);
 
-  if (psys) {
-    if ((dupli_parent != NULL) && (dupli_object != NULL)) {
-      if (dupli_object->type & OB_DUPLICOLLECTION) {
-        unit_m4(dupli_mat);
-        Collection *collection = dupli_parent->instance_collection;
-        if (collection != NULL) {
-          sub_v3_v3(dupli_mat[3], collection->instance_offset);
-        }
-        mul_m4_m4m4(dupli_mat, dupli_parent->obmat, dupli_mat);
-      }
-      else {
-        copy_m4_m4(dupli_mat, dupli_object->ob->obmat);
-        invert_m4(dupli_mat);
-        mul_m4_m4m4(dupli_mat, object->obmat, dupli_mat);
+  if ((dupli_parent != NULL) && (dupli_object != NULL)) {
+    if (dupli_object->type & OB_DUPLICOLLECTION) {
+      unit_m4(dupli_mat);
+      Collection *collection = dupli_parent->instance_collection;
+      if (collection != NULL) {
+        sub_v3_v3(dupli_mat[3], collection->instance_offset);
       }
+      mul_m4_m4m4(dupli_mat, dupli_parent->obmat, dupli_mat);
     }
     else {
-      unit_m4(dupli_mat);
+      copy_m4_m4(dupli_mat, dupli_object->ob->obmat);
+      invert_m4(dupli_mat);
+      mul_m4_m4m4(dupli_mat, object->obmat, dupli_mat);
     }
   }
   else {
-    /* New curves object. */
-    copy_m4_m4(dupli_mat, object->obmat);
+    unit_m4(dupli_mat);
   }
 }
 
@@ -317,6 +335,71 @@ DRWShadingGroup *DRW_shgroup_hair_create_sub(Object *object,
   return shgrp;
 }
 
+DRWShadingGroup *DRW_shgroup_curves_create_sub(Object *object,
+                                               DRWShadingGroup *shgrp_parent,
+                                               GPUMaterial *gpu_material)
+{
+  const DRWContextState *draw_ctx = DRW_context_state_get();
+  Scene *scene = draw_ctx->scene;
+
+  int subdiv = scene->r.hair_subdiv;
+  int thickness_res = (scene->r.hair_type == SCE_HAIR_SHAPE_STRAND) ? 1 : 2;
+
+  ParticleHairCache *curves_cache = drw_curves_cache_get(
+      object, gpu_material, subdiv, thickness_res);
+
+  DRWShadingGroup *shgrp = DRW_shgroup_create_sub(shgrp_parent);
+
+  /* TODO: optimize this. Only bind the ones GPUMaterial needs. */
+  for (int i = 0; i < curves_cache->num_uv_layers; i++) {
+    for (int n = 0; n < MAX_LAYER_NAME_CT && curves_cache->uv_layer_names[i][n][0] != '\0'; n++) {
+      DRW_shgroup_uniform_texture(
+          shgrp, curves_cache->uv_layer_names[i][n], curves_cache->uv_tex[i]);
+    }
+  }
+  for (int i = 0; i < curves_cache->num_col_layers; i++) {
+    for (int n = 0; n < MAX_LAYER_NAME_CT && curves_cache->col_layer_names[i][n][0] != '\0'; n++) {
+      DRW_shgroup_uniform_texture(
+          shgrp, curves_cache->col_layer_names[i][n], curves_cache->col_tex[i]);
+    }
+  }
+
+  /* Fix issue with certain driver not drawing anything if there is no texture bound to
+   * "ac", "au", "u" or "c". */
+  if (curves_cache->num_uv_layers == 0) {
+    DRW_shgroup_uniform_texture(shgrp, "u", g_dummy_texture);
+    DRW_shgroup_uniform_texture(shgrp, "au", g_dummy_texture);
+  }
+  if (curves_cache->num_col_layers == 0) {
+    DRW_shgroup_uniform_texture(shgrp, "c", g_dummy_texture);
+    DRW_shgroup_uniform_texture(shgrp, "ac", g_dummy_texture);
+  }
+
+  /* TODO: Generalize radius implementation for curves data type. */
+  float hair_rad_shape = 1.0f;
+  float hair_rad_root = 0.005f;
+  float hair_rad_tip = 0.0f;
+  bool hair_close_tip = true;
+
+  DRW_shgroup_uniform_texture(shgrp, "hairPointBuffer", curves_cache->final[subdiv].proc_tex);
+  if (curves_cache->length_tex) {
+    DRW_shgroup_uniform_texture(shgrp, "hairLen", curves_cache->length_tex);
+  }
+  DRW_shgroup_uniform_int(shgrp, "hairStrandsRes", &curves_cache->final[subdiv].strands_res, 1);
+  DRW_shgroup_uniform_int_copy(shgrp, "hairThicknessRes", thickness_res);
+  DRW_shgroup_uniform_float_copy(shgrp, "hairRadShape", hair_rad_shape);
+  DRW_shgroup_uniform_mat4_copy(shgrp, "hairDupliMatrix", object->obmat);
+  DRW_shgroup_uniform_float_copy(shgrp, "hairRadRoot", hair_rad_root);
+  DRW_shgroup_uniform_float_copy(shgrp, "hairRadTip", hair_rad_tip);
+  DRW_shgroup_uniform_bool_copy(shgrp, "hairCloseTip", hair_close_tip);
+  /* TODO(fclem): Until we have a better way to cull the curves and render with orco, bypass
+   * culling test. */
+  GPUBatch *geom = curves_cache->final[subdiv].proc_hairs[thickness_res - 1];
+  DRW_shgroup_call_no_cull(shgrp, geom, object);
+
+  return shgrp;
+}
+
 void DRW_hair_update(void)
 {
 #ifndef USE_TRANSFORM_FEEDBACK