PointCloud: Initial rendering support for Workbench

Also includes outline overlays. Removes the temp overlay drawing

We make the geometry follow camera like billboards this uses less
geometry. Currently we use half octahedron for now. Goal would be
to use icospheres.

This patch also optimize the case when pointcloud has uniform radius.
However we should premultiply the radius prop by the default radius
beforehand to avoid a multiplication on CPU.

Using geometry instead of pseudo raytraced spheres is more scalable as
we can render as low as 1 or 2 triangle to a full half sphere and can
integrate easily in the render pipeline using a low amount of code.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D8301

1 files changed, 136 insertions, 24 deletions

diff --git a/source/blender/draw/intern/draw_cache_impl_pointcloud.c b/source/blender/draw/intern/draw_cache_impl_pointcloud.c
index 53939b35285..91baf9fa15e 100644
--- a/source/blender/draw/intern/draw_cache_impl_pointcloud.c
+++ b/source/blender/draw/intern/draw_cache_impl_pointcloud.c
@@ -28,6 +28,7 @@
 #include "MEM_guardedalloc.h"
 
 #include "BLI_math_base.h"
+#include "BLI_math_vector.h"
 #include "BLI_utildefines.h"
 
 #include "DNA_object_types.h"
@@ -45,11 +46,18 @@ static void pointcloud_batch_cache_clear(PointCloud *pointcloud);
 /* PointCloud GPUBatch Cache */
 
 typedef struct PointCloudBatchCache {
-  GPUVertBuf *pos;
-  GPUBatch *batch;
+  GPUVertBuf *pos;  /* Position and radius. */
+  GPUVertBuf *geom; /* Instanced geometry for each point in the cloud (small sphere). */
+  GPUIndexBuf *geom_indices;
+
+  GPUBatch *dots;
+  GPUBatch *surface;
+  GPUBatch **surface_per_mat;
 
   /* settings to determine if cache is invalid */
   bool is_dirty;
+
+  int mat_len;
 } PointCloudBatchCache;
 
 /* GPUBatch cache management. */
@@ -57,7 +65,14 @@ typedef struct PointCloudBatchCache {
 static bool pointcloud_batch_cache_valid(PointCloud *pointcloud)
 {
   PointCloudBatchCache *cache = pointcloud->batch_cache;
-  return (cache && cache->is_dirty == false);
+
+  if (cache == NULL) {
+    return false;
+  }
+  if (cache->mat_len != DRW_pointcloud_material_count_get(pointcloud)) {
+    return false;
+  }
+  return cache->is_dirty == false;
 }
 
 static void pointcloud_batch_cache_init(PointCloud *pointcloud)
@@ -71,6 +86,10 @@ static void pointcloud_batch_cache_init(PointCloud *pointcloud)
     memset(cache, 0, sizeof(*cache));
   }
 
+  cache->mat_len = DRW_pointcloud_material_count_get(pointcloud);
+  cache->surface_per_mat = MEM_callocN(sizeof(GPUBatch *) * cache->mat_len,
+                                       "pointcloud suface_per_mat");
+
   cache->is_dirty = false;
 }
 
@@ -109,8 +128,18 @@ static void pointcloud_batch_cache_clear(PointCloud *pointcloud)
     return;
   }
 
-  GPU_BATCH_DISCARD_SAFE(cache->batch);
+  GPU_BATCH_DISCARD_SAFE(cache->dots);
+  GPU_BATCH_DISCARD_SAFE(cache->surface);
   GPU_VERTBUF_DISCARD_SAFE(cache->pos);
+  GPU_VERTBUF_DISCARD_SAFE(cache->geom);
+  GPU_INDEXBUF_DISCARD_SAFE(cache->geom_indices);
+
+  if (cache->surface_per_mat) {
+    for (int i = 0; i < cache->mat_len; i++) {
+      GPU_BATCH_DISCARD_SAFE(cache->surface_per_mat[i]);
+    }
+  }
+  MEM_SAFE_FREE(cache->surface_per_mat);
 }
 
 void DRW_pointcloud_batch_cache_free(PointCloud *pointcloud)
@@ -126,35 +155,83 @@ static void pointcloud_batch_cache_ensure_pos(Object *ob, PointCloudBatchCache *
   }
 
   PointCloud *pointcloud = ob->data;
+  const bool has_radius = pointcloud->radius != NULL;
 
   static GPUVertFormat format = {0};
-  static uint pos_id;
-  static uint radius_id;
+  static uint pos;
   if (format.attr_len == 0) {
     /* initialize vertex format */
-    pos_id = GPU_vertformat_attr_add(&format, "pointcloud_pos", GPU_COMP_F32, 3, GPU_FETCH_FLOAT);
-    radius_id = GPU_vertformat_attr_add(
-        &format, "pointcloud_radius", GPU_COMP_F32, 1, GPU_FETCH_FLOAT);
+    /* From the opengl wiki:
+     * Note that size​ does not have to exactly match the size used by the vertex shader. If the
+     * vertex shader has fewer components than the attribute provides, then the extras are ignored.
+     * If the vertex shader has more components than the array provides, the extras are given
+     * values from the vector (0, 0, 0, 1) for the missing XYZW components.
+     */
+    int comp_len = has_radius ? 4 : 3;
+    pos = GPU_vertformat_attr_add(&format, "pos", GPU_COMP_F32, comp_len, GPU_FETCH_FLOAT);
   }
 
-  GPU_VERTBUF_DISCARD_SAFE(cache->pos);
   cache->pos = GPU_vertbuf_create_with_format(&format);
   GPU_vertbuf_data_alloc(cache->pos, pointcloud->totpoint);
-  GPU_vertbuf_attr_fill(cache->pos, pos_id, pointcloud->co);
 
-  if (pointcloud->radius) {
-    GPU_vertbuf_attr_fill(cache->pos, radius_id, pointcloud->radius);
-  }
-  else if (pointcloud->totpoint) {
-    /* TODO: optimize for constant radius by not including in vertex buffer at all? */
-    float *radius = MEM_malloc_arrayN(pointcloud->totpoint, sizeof(float), __func__);
+  if (has_radius) {
+    float(*vbo_data)[4] = (float(*)[4])cache->pos->data;
     for (int i = 0; i < pointcloud->totpoint; i++) {
-      /* TODO: add default radius to PointCloud data structure. */
-      radius[i] = 0.01f;
+      copy_v3_v3(vbo_data[i], pointcloud->co[i]);
+      /* TODO(fclem) remove multiplication here. Here only for keeping the size correct for now. */
+      vbo_data[i][3] = pointcloud->radius[i] * 100.0f;
     }
-    GPU_vertbuf_attr_fill(cache->pos, radius_id, radius);
-    MEM_freeN(radius);
   }
+  else {
+    GPU_vertbuf_attr_fill(cache->pos, pos, pointcloud->co);
+  }
+}
+
+static const float half_octahedron_normals[5][3] = {
+    {0.0f, 0.0f, 1.0f},
+    {1.0f, 0.0f, 0.0f},
+    {0.0f, 1.0f, 0.0f},
+    {-1.0f, 0.0f, 0.0f},
+    {0.0f, -1.0f, 0.0f},
+};
+
+static const uint half_octahedron_tris[4][3] = {
+    {0, 1, 2},
+    {0, 2, 3},
+    {0, 3, 4},
+    {0, 4, 1},
+};
+
+static void pointcloud_batch_cache_ensure_geom(Object *UNUSED(ob), PointCloudBatchCache *cache)
+{
+  if (cache->geom != NULL) {
+    return;
+  }
+
+  static GPUVertFormat format = {0};
+  static uint pos;
+  if (format.attr_len == 0) {
+    /* initialize vertex format */
+    pos = GPU_vertformat_attr_add(&format, "pos_inst", GPU_COMP_F32, 3, GPU_FETCH_FLOAT);
+    GPU_vertformat_alias_add(&format, "nor");
+  }
+
+  cache->geom = GPU_vertbuf_create_with_format(&format);
+  GPU_vertbuf_data_alloc(cache->geom, ARRAY_SIZE(half_octahedron_normals));
+
+  GPU_vertbuf_attr_fill(cache->geom, pos, half_octahedron_normals);
+
+  GPUIndexBufBuilder builder;
+  GPU_indexbuf_init(&builder,
+                    GPU_PRIM_TRIS,
+                    ARRAY_SIZE(half_octahedron_tris),
+                    ARRAY_SIZE(half_octahedron_normals));
+
+  for (int i = 0; i < ARRAY_SIZE(half_octahedron_tris); i++) {
+    GPU_indexbuf_add_tri_verts(&builder, UNPACK3(half_octahedron_tris[i]));
+  }
+
+  cache->geom_indices = GPU_indexbuf_build(&builder);
 }
 
 GPUBatch *DRW_pointcloud_batch_cache_get_dots(Object *ob)
@@ -162,12 +239,47 @@ GPUBatch *DRW_pointcloud_batch_cache_get_dots(Object *ob)
   PointCloud *pointcloud = ob->data;
   PointCloudBatchCache *cache = pointcloud_batch_cache_get(pointcloud);
 
-  if (cache->batch == NULL) {
+  if (cache->dots == NULL) {
     pointcloud_batch_cache_ensure_pos(ob, cache);
-    cache->batch = GPU_batch_create(GPU_PRIM_POINTS, cache->pos, NULL);
+    cache->dots = GPU_batch_create(GPU_PRIM_POINTS, cache->pos, NULL);
+  }
+
+  return cache->dots;
+}
+
+GPUBatch *DRW_pointcloud_batch_cache_get_surface(Object *ob)
+{
+  PointCloud *pointcloud = ob->data;
+  PointCloudBatchCache *cache = pointcloud_batch_cache_get(pointcloud);
+
+  if (cache->surface == NULL) {
+    pointcloud_batch_cache_ensure_pos(ob, cache);
+    pointcloud_batch_cache_ensure_geom(ob, cache);
+
+    cache->surface = GPU_batch_create(GPU_PRIM_TRIS, cache->geom, cache->geom_indices);
+    GPU_batch_instbuf_add_ex(cache->surface, cache->pos, false);
+  }
+
+  return cache->surface;
+}
+
+GPUBatch **DRW_cache_pointcloud_surface_shaded_get(Object *ob,
+                                                   struct GPUMaterial **UNUSED(gpumat_array),
+                                                   uint gpumat_array_len)
+{
+  PointCloud *pointcloud = ob->data;
+  PointCloudBatchCache *cache = pointcloud_batch_cache_get(pointcloud);
+  BLI_assert(cache->mat_len == gpumat_array_len);
+
+  if (cache->surface_per_mat[0] == NULL) {
+    pointcloud_batch_cache_ensure_pos(ob, cache);
+    pointcloud_batch_cache_ensure_geom(ob, cache);
+
+    cache->surface_per_mat[0] = GPU_batch_create(GPU_PRIM_TRIS, cache->geom, cache->geom_indices);
+    GPU_batch_instbuf_add_ex(cache->surface_per_mat[0], cache->pos, false);
   }
 
-  return cache->batch;
+  return cache->surface_per_mat;
 }
 
 int DRW_pointcloud_material_count_get(PointCloud *pointcloud)