GPUVertBuf: GL Backend Isolation

Part of the Vulkan port T68990

This makes a few changes in how the data is being handled by the
backend to allow more flexibility in the future.

The overall code logic is left unchanged.

1 files changed, 61 insertions, 8 deletions

diff --git a/source/blender/gpu/opengl/gl_vertex_buffer.cc b/source/blender/gpu/opengl/gl_vertex_buffer.cc
index ee9e0a0b0c9..66ff1f36cef 100644
--- a/source/blender/gpu/opengl/gl_vertex_buffer.cc
+++ b/source/blender/gpu/opengl/gl_vertex_buffer.cc
@@ -27,30 +27,83 @@
 
 namespace blender::gpu {
 
-void GLVertBuf::bind(void)
+void GLVertBuf::acquire_data(void)
 {
+  /* Discard previous data if any. */
+  MEM_SAFE_FREE(data);
+  data = (uchar *)MEM_mallocN(sizeof(uchar) * this->size_alloc_get(), __func__);
 }
 
-void GLVertBuf::upload_data(void)
+void GLVertBuf::resize_data(void)
 {
+  data = (uchar *)MEM_reallocN(data, sizeof(uchar) * this->size_alloc_get());
 }
 
-uchar *GLVertBuf::acquire_data(void)
+void GLVertBuf::release_data(void)
 {
-  return nullptr;
+  if (vbo_id_ != 0) {
+    GLBackend::get()->buf_free(vbo_id_);
+    vbo_id_ = 0;
+    memory_usage -= vbo_size_;
+  }
+
+  MEM_SAFE_FREE(data);
 }
 
-uchar *GLVertBuf::resize_data(void)
+void GLVertBuf::duplicate_data(VertBuf *dst_)
 {
-  return nullptr;
+  BLI_assert(GPU_context_active_get() != NULL);
+  GLVertBuf *src = this;
+  GLVertBuf *dst = static_cast<GLVertBuf *>(dst_);
+
+  if (src->vbo_id_ != 0) {
+    dst->vbo_size_ = src->size_used_get();
+
+    glGenBuffers(1, &dst->vbo_id_);
+    glBindBuffer(GL_COPY_WRITE_BUFFER, dst->vbo_id_);
+    glBufferData(GL_COPY_WRITE_BUFFER, dst->vbo_size_, NULL, to_gl(dst->usage_));
+
+    glBindBuffer(GL_COPY_READ_BUFFER, src->vbo_id_);
+
+    glCopyBufferSubData(GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, 0, 0, dst->vbo_size_);
+
+    memory_usage += dst->vbo_size_;
+  }
+
+  if (data != nullptr) {
+    dst->data = (uchar *)MEM_dupallocN(src->data);
+  }
 }
 
-void GLVertBuf::release_data(void)
+void GLVertBuf::upload_data(void)
 {
+  this->bind();
 }
 
-void GLVertBuf::duplicate_data(VertBuf *)
+void GLVertBuf::bind(void)
 {
+  BLI_assert(GPU_context_active_get() != NULL);
+
+  if (vbo_id_ == 0) {
+    glGenBuffers(1, &vbo_id_);
+  }
+
+  glBindBuffer(GL_ARRAY_BUFFER, vbo_id_);
+
+  if (flag & GPU_VERTBUF_DATA_DIRTY) {
+    vbo_size_ = this->size_used_get();
+    /* Orphan the vbo to avoid sync then upload data. */
+    glBufferData(GL_ARRAY_BUFFER, vbo_size_, NULL, to_gl(usage_));
+    glBufferSubData(GL_ARRAY_BUFFER, 0, vbo_size_, data);
+
+    memory_usage += vbo_size_;
+
+    if (usage_ == GPU_USAGE_STATIC) {
+      MEM_SAFE_FREE(data);
+    }
+    flag &= ~GPU_VERTBUF_DATA_DIRTY;
+    flag |= GPU_VERTBUF_DATA_UPLOADED;
+  }
 }
 
 }  // namespace blender::gpu
\ No newline at end of file