GPUVertBuf: Add support for binding as buffer texture

This is often needed and somehow cumbersome to set up. This will allow some
code simplifications.

5 files changed, 26 insertions, 0 deletions

diff --git a/source/blender/gpu/GPU_vertex_buffer.h b/source/blender/gpu/GPU_vertex_buffer.h
index fe6ed7eaf87..722ef878271 100644
--- a/source/blender/gpu/GPU_vertex_buffer.h
+++ b/source/blender/gpu/GPU_vertex_buffer.h
@@ -165,6 +165,7 @@ void GPU_vertbuf_tag_dirty(GPUVertBuf *verts);
  */
 void GPU_vertbuf_use(GPUVertBuf *);
 void GPU_vertbuf_bind_as_ssbo(struct GPUVertBuf *verts, int binding);
+void GPU_vertbuf_bind_as_texture(struct GPUVertBuf *verts, int binding);
 
 void GPU_vertbuf_wrap_handle(GPUVertBuf *verts, uint64_t handle);
 
diff --git a/source/blender/gpu/intern/gpu_vertex_buffer.cc b/source/blender/gpu/intern/gpu_vertex_buffer.cc
index 13f409cfba5..f47970d48d1 100644
--- a/source/blender/gpu/intern/gpu_vertex_buffer.cc
+++ b/source/blender/gpu/intern/gpu_vertex_buffer.cc
@@ -328,6 +328,11 @@ void GPU_vertbuf_bind_as_ssbo(struct GPUVertBuf *verts, int binding)
   unwrap(verts)->bind_as_ssbo(binding);
 }
 
+void GPU_vertbuf_bind_as_texture(struct GPUVertBuf *verts, int binding)
+{
+  unwrap(verts)->bind_as_texture(binding);
+}
+
 void GPU_vertbuf_update_sub(GPUVertBuf *verts, uint start, uint len, const void *data)
 {
   unwrap(verts)->update_sub(start, len, data);
diff --git a/source/blender/gpu/intern/gpu_vertex_buffer_private.hh b/source/blender/gpu/intern/gpu_vertex_buffer_private.hh
index e5b70de9dfa..7a0b53cf958 100644
--- a/source/blender/gpu/intern/gpu_vertex_buffer_private.hh
+++ b/source/blender/gpu/intern/gpu_vertex_buffer_private.hh
@@ -51,6 +51,7 @@ class VertBuf {
   void resize(uint vert_len);
   void upload();
   virtual void bind_as_ssbo(uint binding) = 0;
+  virtual void bind_as_texture(uint binding) = 0;
 
   virtual void wrap_handle(uint64_t handle) = 0;
 
diff --git a/source/blender/gpu/opengl/gl_vertex_buffer.cc b/source/blender/gpu/opengl/gl_vertex_buffer.cc
index a7a0c92431f..6942a220892 100644
--- a/source/blender/gpu/opengl/gl_vertex_buffer.cc
+++ b/source/blender/gpu/opengl/gl_vertex_buffer.cc
@@ -5,6 +5,8 @@
  * \ingroup gpu
  */
 
+#include "GPU_texture.h"
+
 #include "gl_context.hh"
 
 #include "gl_vertex_buffer.hh"
@@ -38,6 +40,7 @@ void GLVertBuf::release_data()
   }
 
   if (vbo_id_ != 0) {
+    GPU_TEXTURE_FREE_SAFE(buffer_texture_);
     GLContext::buf_free(vbo_id_);
     vbo_id_ = 0;
     memory_usage -= vbo_size_;
@@ -51,6 +54,7 @@ void GLVertBuf::duplicate_data(VertBuf *dst_)
   BLI_assert(GLContext::get() != nullptr);
   GLVertBuf *src = this;
   GLVertBuf *dst = static_cast<GLVertBuf *>(dst_);
+  dst->buffer_texture_ = nullptr;
 
   if (src->vbo_id_ != 0) {
     dst->vbo_size_ = src->size_used_get();
@@ -111,6 +115,16 @@ void GLVertBuf::bind_as_ssbo(uint binding)
   glBindBufferBase(GL_SHADER_STORAGE_BUFFER, binding, vbo_id_);
 }
 
+void GLVertBuf::bind_as_texture(uint binding)
+{
+  bind();
+  BLI_assert(vbo_id_ != 0);
+  if (buffer_texture_ == nullptr) {
+    buffer_texture_ = GPU_texture_create_from_vertbuf("vertbuf_as_texture", wrap(this));
+  }
+  GPU_texture_bind(buffer_texture_, binding);
+}
+
 const void *GLVertBuf::read() const
 {
   BLI_assert(is_active());
diff --git a/source/blender/gpu/opengl/gl_vertex_buffer.hh b/source/blender/gpu/opengl/gl_vertex_buffer.hh
index 4c29c17dcf7..88d2a455778 100644
--- a/source/blender/gpu/opengl/gl_vertex_buffer.hh
+++ b/source/blender/gpu/opengl/gl_vertex_buffer.hh
@@ -11,6 +11,8 @@
 
 #include "glew-mx.h"
 
+#include "GPU_texture.h"
+
 #include "gpu_vertex_buffer_private.hh"
 
 namespace blender {
@@ -23,6 +25,8 @@ class GLVertBuf : public VertBuf {
  private:
   /** OpenGL buffer handle. Init on first upload. Immutable after that. */
   GLuint vbo_id_ = 0;
+  /** Texture used if the buffer is bound as buffer texture. Init on first use. */
+  struct ::GPUTexture *buffer_texture_ = nullptr;
   /** Defines whether the buffer handle is wrapped by this GLVertBuf, i.e. we do not own it and
    * should not free it. */
   bool is_wrapper_ = false;
@@ -46,6 +50,7 @@ class GLVertBuf : public VertBuf {
   void upload_data() override;
   void duplicate_data(VertBuf *dst) override;
   void bind_as_ssbo(uint binding) override;
+  void bind_as_texture(uint binding) override;
 
  private:
   bool is_active() const;