Mesh Batch Cache: Refactor + Multithread

For clarity sake, the batch cache now uses exclusively per Loop attributes.
While this is a bit of a waste of VRAM (for the few case where per vert
attribs are enough) it reduces the complexity and amount of overall VBO
to update in general situations.

This patch also makes the VertexBuffers filling multithreaded. This make
the update of dense meshes a bit faster. The main bottleneck is the
IndexBuffers update which cannot be multithreaded efficiently (have to
increment a counter and/or do a final sorting pass).

We introduce the concept of "extract" functions/step.
All extract functions are executed in one thread each and if possible,
using multiple thread for looping over all elements.

Reviewed By: brecht

Differential Revision: http://developer.blender.org/D5424

1 files changed, 38 insertions, 6 deletions

diff --git a/source/blender/gpu/intern/gpu_batch.c b/source/blender/gpu/intern/gpu_batch.c
index 11b487f7be4..583551e3e58 100644
--- a/source/blender/gpu/intern/gpu_batch.c
+++ b/source/blender/gpu/intern/gpu_batch.c
@@ -182,6 +182,25 @@ void GPU_batch_instbuf_set(GPUBatch *batch, GPUVertBuf *inst, bool own_vbo)
   }
 }
 
+void GPU_batch_elembuf_set(GPUBatch *batch, GPUIndexBuf *elem, bool own_ibo)
+{
+  BLI_assert(elem != NULL);
+  /* redo the bindings */
+  GPU_batch_vao_cache_clear(batch);
+
+  if (batch->elem != NULL && (batch->owns_flag & GPU_BATCH_OWNS_INDEX)) {
+    GPU_indexbuf_discard(batch->elem);
+  }
+  batch->elem = elem;
+
+  if (own_ibo) {
+    batch->owns_flag |= GPU_BATCH_OWNS_INDEX;
+  }
+  else {
+    batch->owns_flag &= ~GPU_BATCH_OWNS_INDEX;
+  }
+}
+
 /* Returns the index of verts in the batch. */
 int GPU_batch_vertbuf_add_ex(GPUBatch *batch, GPUVertBuf *verts, bool own_vbo)
 {
@@ -362,13 +381,23 @@ static void create_bindings(GPUVertBuf *verts,
   const GPUVertFormat *format = &verts->format;
 
   const uint attr_len = format->attr_len;
-  const uint stride = format->stride;
+  uint stride = format->stride;
+  uint offset = 0;
 
   GPU_vertbuf_use(verts);
 
   for (uint a_idx = 0; a_idx < attr_len; ++a_idx) {
     const GPUVertAttr *a = &format->attrs[a_idx];
-    const GLvoid *pointer = (const GLubyte *)0 + a->offset + v_first * stride;
+
+    if (format->deinterleaved) {
+      offset += ((a_idx == 0) ? 0 : format->attrs[a_idx - 1].sz) * verts->vertex_len;
+      stride = a->sz;
+    }
+    else {
+      offset = a->offset;
+    }
+
+    const GLvoid *pointer = (const GLubyte *)0 + offset + v_first * stride;
 
     for (uint n_idx = 0; n_idx < a->name_len; ++n_idx) {
       const char *name = GPU_vertformat_attr_name_get(format, a, n_idx);
@@ -419,8 +448,11 @@ static void create_bindings(GPUVertBuf *verts,
 
 static void batch_update_program_bindings(GPUBatch *batch, uint v_first)
 {
-  for (int v = 0; v < GPU_BATCH_VBO_MAX_LEN && batch->verts[v] != NULL; ++v) {
-    create_bindings(batch->verts[v], batch->interface, (batch->inst) ? 0 : v_first, false);
+  /* Reverse order so first vbos have more prevalence (in term of attrib override). */
+  for (int v = GPU_BATCH_VBO_MAX_LEN - 1; v > -1; --v) {
+    if (batch->verts[v] != NULL) {
+      create_bindings(batch->verts[v], batch->interface, (batch->inst) ? 0 : v_first, false);
+    }
   }
   if (batch->inst) {
     create_bindings(batch->inst, batch->interface, v_first, true);
@@ -550,10 +582,10 @@ static void *elem_offset(const GPUIndexBuf *el, int v_first)
 {
 #if GPU_TRACK_INDEX_RANGE
   if (el->index_type == GPU_INDEX_U16) {
-    return (GLushort *)0 + v_first;
+    return (GLushort *)0 + v_first + el->index_start;
   }
 #endif
-  return (GLuint *)0 + v_first;
+  return (GLuint *)0 + v_first + el->index_start;
 }
 
 /* Use when drawing with GPU_batch_draw_advanced */