[Bf-blender-cvs] [04b7c12af25] temp-gpu-compute-shaders: Added support for device only index buffers.

[Jeroen Bakker]

Commit: 04b7c12af25f6bf87b1b543c61c2c93217670d85
Author: Jeroen Bakker
Date:   Fri May 7 15:08:38 2021 +0200
Branches: temp-gpu-compute-shaders
https://developer.blender.org/rB04b7c12af25f6bf87b1b543c61c2c93217670d85

Added support for device only index buffers.

===================================================================

M	source/blender/gpu/GPU_index_buffer.h
M	source/blender/gpu/intern/gpu_index_buffer.cc
M	source/blender/gpu/intern/gpu_index_buffer_private.hh
M	source/blender/gpu/opengl/gl_index_buffer.cc
M	source/blender/gpu/tests/gpu_shader_test.cc

===================================================================

diff --git a/source/blender/gpu/GPU_index_buffer.h b/source/blender/gpu/GPU_index_buffer.h
index 41861ff6fd5..7746db1092e 100644
--- a/source/blender/gpu/GPU_index_buffer.h
+++ b/source/blender/gpu/GPU_index_buffer.h
@@ -44,8 +44,17 @@ typedef struct GPUIndexBufBuilder {
   uint32_t *data;
 } GPUIndexBufBuilder;
 
+typedef enum {
+  GPU_INDEX_U16,
+  GPU_INDEX_U32,
+} GPUIndexBufType;
+
 /* supports all primitive types. */
 void GPU_indexbuf_init_ex(GPUIndexBufBuilder *, GPUPrimType, uint index_len, uint vertex_len);
+void GPU_indexbuf_init_device_only(GPUIndexBuf *elem,
+                                   GPUIndexBufType type,
+                                   GPUPrimType,
+                                   uint prim_len);
 
 /* supports only GPU_PRIM_POINTS, GPU_PRIM_LINES and GPU_PRIM_TRIS. */
 void GPU_indexbuf_init(GPUIndexBufBuilder *, GPUPrimType, uint prim_len, uint vertex_len);
diff --git a/source/blender/gpu/intern/gpu_index_buffer.cc b/source/blender/gpu/intern/gpu_index_buffer.cc
index c41deb3b3d8..b13aa1a9741 100644
--- a/source/blender/gpu/intern/gpu_index_buffer.cc
+++ b/source/blender/gpu/intern/gpu_index_buffer.cc
@@ -66,6 +66,15 @@ void GPU_indexbuf_init(GPUIndexBufBuilder *builder,
   GPU_indexbuf_init_ex(builder, prim_type, prim_len * (uint)verts_per_prim, vertex_len);
 }
 
+void GPU_indexbuf_init_device_only(GPUIndexBuf *elem_,
+                                   GPUIndexBufType index_type,
+                                   GPUPrimType prim_type,
+                                   uint prim_len)
+{
+  IndexBuf *elem = unwrap(elem_);
+  elem->init_device_only(index_type, prim_type, prim_len);
+}
+
 void GPU_indexbuf_add_generic_vert(GPUIndexBufBuilder *builder, uint v)
 {
 #if TRUST_NO_ONE
@@ -241,6 +250,15 @@ void IndexBuf::init(uint indices_len, uint32_t *indices)
 #endif
 }
 
+void IndexBuf::init_device_only(GPUIndexBufType index_type, GPUPrimType prim_type, uint prim_len)
+{
+  is_init_ = true;
+  index_start_ = 0;
+  index_len_ = prim_len * indices_per_primitive(prim_type);
+  index_type_ = index_type;
+  data_ = nullptr;
+}
+
 void IndexBuf::init_subrange(IndexBuf *elem_src, uint start, uint length)
 {
   /* We don't support nested subranges. */
diff --git a/source/blender/gpu/intern/gpu_index_buffer_private.hh b/source/blender/gpu/intern/gpu_index_buffer_private.hh
index 1916c5a5256..b65d3e8122d 100644
--- a/source/blender/gpu/intern/gpu_index_buffer_private.hh
+++ b/source/blender/gpu/intern/gpu_index_buffer_private.hh
@@ -31,11 +31,6 @@
 
 namespace blender::gpu {
 
-typedef enum {
-  GPU_INDEX_U16,
-  GPU_INDEX_U32,
-} GPUIndexBufType;
-
 static inline size_t to_bytesize(GPUIndexBufType type)
 {
   return (type == GPU_INDEX_U32) ? sizeof(uint32_t) : sizeof(uint16_t);
@@ -75,6 +70,7 @@ class IndexBuf {
 
   void init(uint indices_len, uint32_t *indices);
   void init_subrange(IndexBuf *elem_src, uint start, uint length);
+  void init_device_only(GPUIndexBufType index_type, GPUPrimType prim_type, uint prim_len);
 
   uint32_t index_len_get(void) const
   {
diff --git a/source/blender/gpu/opengl/gl_index_buffer.cc b/source/blender/gpu/opengl/gl_index_buffer.cc
index b607ec8d55a..308fec40038 100644
--- a/source/blender/gpu/opengl/gl_index_buffer.cc
+++ b/source/blender/gpu/opengl/gl_index_buffer.cc
@@ -40,17 +40,14 @@ void GLIndexBuf::bind()
     return;
   }
 
-  if (ibo_id_ == 0) {
+  const bool allocate_on_device = ibo_id_ == 0;
+  if (allocate_on_device) {
     glGenBuffers(1, &ibo_id_);
-
-    if (data_ == nullptr) {
-      debug::raise_gl_error("Trying to use Index Buffer but the buffer contains no data");
-    }
   }
 
   glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo_id_);
 
-  if (data_ != nullptr) {
+  if (data_ != nullptr || allocate_on_device) {
     size_t size = this->size_get();
     /* Sends data to GPU. */
     glBufferData(GL_ELEMENT_ARRAY_BUFFER, size, data_, GL_STATIC_DRAW);
diff --git a/source/blender/gpu/tests/gpu_shader_test.cc b/source/blender/gpu/tests/gpu_shader_test.cc
index 5a50a4c8b0e..c3bbb8a72b3 100644
--- a/source/blender/gpu/tests/gpu_shader_test.cc
+++ b/source/blender/gpu/tests/gpu_shader_test.cc
@@ -244,14 +244,8 @@ void main() {
   GPU_shader_bind(shader);
 
   /* Construct IBO. */
-  GPUIndexBufBuilder ibo_builder;
-  const int max_vertex_index = 65536;
-  GPU_indexbuf_init(&ibo_builder, GPU_PRIM_POINTS, SIZE, max_vertex_index);
-  for (int index = 0; index < SIZE; index++) {
-    GPU_indexbuf_set_point_vert(&ibo_builder, index, 57005);
-  }
-  GPUIndexBuf *ibo = GPU_indexbuf_build(&ibo_builder);
-
+  GPUIndexBuf *ibo = GPU_indexbuf_calloc();
+  GPU_indexbuf_init_device_only(ibo, GPU_INDEX_U16, GPU_PRIM_POINTS, SIZE);
   GPU_indexbuf_bind_as_ssbo(ibo, GPU_shader_get_ssbo(shader, "outputIboData"));
 
   /* Dispatch compute task. */
@@ -310,13 +304,8 @@ void main() {
   GPU_shader_bind(shader);
 
   /* Construct IBO. */
-  GPUIndexBufBuilder ibo_builder;
-  GPU_indexbuf_init(&ibo_builder, GPU_PRIM_POINTS, SIZE, 0);
-  for (int index = 0; index < SIZE; index++) {
-    GPU_indexbuf_set_point_vert(&ibo_builder, index, 65536 * index);
-  }
-  GPUIndexBuf *ibo = GPU_indexbuf_build(&ibo_builder);
-
+  GPUIndexBuf *ibo = GPU_indexbuf_calloc();
+  GPU_indexbuf_init_device_only(ibo, GPU_INDEX_U32, GPU_PRIM_POINTS, SIZE);
   GPU_indexbuf_bind_as_ssbo(ibo, GPU_shader_get_ssbo(shader, "outputIboData"));
 
   /* Dispatch compute task. */