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, 3 insertions, 1 deletions

diff --git a/source/blender/gpu/opengl/gl_shader.hh b/source/blender/gpu/opengl/gl_shader.hh
index 152eb2f068a..48aaaf2283d 100644
--- a/source/blender/gpu/opengl/gl_shader.hh
+++ b/source/blender/gpu/opengl/gl_shader.hh
@@ -43,6 +43,7 @@ class GLShader : public Shader {
   GLuint vert_shader_ = 0;
   GLuint geom_shader_ = 0;
   GLuint frag_shader_ = 0;
+  GLuint compute_shader_ = 0;
   /** True if any shader failed to compile. */
   bool compilation_failed_ = false;
 
@@ -56,6 +57,7 @@ class GLShader : public Shader {
   void vertex_shader_from_glsl(MutableSpan<const char *> sources) override;
   void geometry_shader_from_glsl(MutableSpan<const char *> sources) override;
   void fragment_shader_from_glsl(MutableSpan<const char *> sources) override;
+  void compute_shader_from_glsl(MutableSpan<const char *> sources) override;
   bool finalize(void) override;
 
   void transform_feedback_names_set(Span<const char *> name_list,
@@ -75,7 +77,7 @@ class GLShader : public Shader {
   int program_handle_get(void) const override;
 
  private:
-  char *glsl_patch_get(void);
+  char *glsl_patch_get(GLenum gl_stage);
 
   GLuint create_shader_stage(GLenum gl_stage, MutableSpan<const char *> sources);