GPU: Compute Pipeline.

With the compute pipeline calculation can be offloaded to the GPU.
This patch only adds the framework for compute. So no changes for users at
this moment.

NOTE: As this is an OpenGL4.3 feature it must always have a fallback.

Use `GPU_compute_shader_support` to check if compute pipeline can be used.
Check `gpu_shader_compute*` test cases for usage.

This patch also adds support for shader storage buffer objects and device only
vertex/index buffers.

An alternative that had been discussed was adding this to the `GPUBatch`, this
was eventually not chosen as it would lead to more code when used as part of a
shading group. The idea is that we add an `eDRWCommandType` in the near
future.

Reviewed By: fclem

Differential Revision: https://developer.blender.org/D10913

1 files changed, 15 insertions, 0 deletions

diff --git a/source/blender/gpu/intern/gpu_vertex_buffer.cc b/source/blender/gpu/intern/gpu_vertex_buffer.cc
index 09b9eba9f95..3ecbb740a0c 100644
--- a/source/blender/gpu/intern/gpu_vertex_buffer.cc
+++ b/source/blender/gpu/intern/gpu_vertex_buffer.cc
@@ -149,6 +149,16 @@ GPUVertBuf *GPU_vertbuf_duplicate(GPUVertBuf *verts_)
   return wrap(unwrap(verts_)->duplicate());
 }
 
+const void *GPU_vertbuf_read(GPUVertBuf *verts)
+{
+  return unwrap(verts)->read();
+}
+
+void *GPU_vertbuf_unmap(const GPUVertBuf *verts, const void *mapped_data)
+{
+  return unwrap(verts)->unmap(mapped_data);
+}
+
 /** Same as discard but does not free. */
 void GPU_vertbuf_clear(GPUVertBuf *verts)
 {
@@ -324,6 +334,11 @@ void GPU_vertbuf_use(GPUVertBuf *verts)
   unwrap(verts)->upload();
 }
 
+void GPU_vertbuf_bind_as_ssbo(struct GPUVertBuf *verts, int binding)
+{
+  unwrap(verts)->bind_as_ssbo(binding);
+}
+
 /* XXX this is just a wrapper for the use of the Hair refine workaround.
  * To be used with GPU_vertbuf_use(). */
 void GPU_vertbuf_update_sub(GPUVertBuf *verts, uint start, uint len, void *data)