renderer_opengl: Add assembly program code paths

Add code required to use OpenGL assembly programs based on
NV_gpu_program5. Decompilation for ARB programs is intended to be added
in a follow up commit. This does **not** include ARB decompilation and
it's not in an usable state.

The intention behind assembly programs is to reduce shader stutter
significantly on drivers supporting NV_gpu_program5 (and other required
extensions). Currently only Nvidia's proprietary driver supports these
extensions.

Add a UI option hidden for now to avoid people enabling this option
accidentally.

This code path has some limitations that OpenGL compatibility doesn't
have:
- NV_shader_storage_buffer_object is limited to 16 entries for a single
OpenGL context state (I don't know if this is an intended limitation, an
specification issue or I am missing something). Currently causes issues
on The Legend of Zelda: Link's Awakening.
- NV_parameter_buffer_object can't bind buffers using an offset
different to zero. The used workaround is to copy to a temporary buffer
(this doesn't happen often so it's not an issue).

On the other hand, it has the following advantages:
- Shaders build a lot faster.
- We have control over how floating point rounding is done over
individual instructions (SPIR-V on Vulkan can't do this).
- Operations on shared memory can be unsigned and signed.
- Transform feedbacks are dynamic state (not yet implemented).
- Parameter buffers (uniform buffers) are per stage, matching NVN and
hardware's behavior.
- The API to bind and create assembly programs makes sense, unlike
ARB_separate_shader_objects.

1 files changed, 8 insertions, 8 deletions

diff --git a/src/video_core/renderer_opengl/renderer_opengl.cpp b/src/video_core/renderer_opengl/renderer_opengl.cpp
index b2a179746..6b489e6db 100644
--- a/src/video_core/renderer_opengl/renderer_opengl.cpp
+++ b/src/video_core/renderer_opengl/renderer_opengl.cpp
@@ -316,7 +316,7 @@ public:
 RendererOpenGL::RendererOpenGL(Core::Frontend::EmuWindow& emu_window, Core::System& system,
                                Core::Frontend::GraphicsContext& context)
     : RendererBase{emu_window}, emu_window{emu_window}, system{system}, context{context},
-      has_debug_tool{HasDebugTool()} {}
+      program_manager{device}, has_debug_tool{HasDebugTool()} {}
 
 RendererOpenGL::~RendererOpenGL() = default;
 
@@ -468,8 +468,9 @@ void RendererOpenGL::InitOpenGLObjects() {
     vertex_program.Create(true, false, vertex_shader.handle);
     fragment_program.Create(true, false, fragment_shader.handle);
 
-    // Create program pipeline
-    program_manager.Create();
+    pipeline.Create();
+    glUseProgramStages(pipeline.handle, GL_VERTEX_SHADER_BIT, vertex_program.handle);
+    glUseProgramStages(pipeline.handle, GL_FRAGMENT_SHADER_BIT, fragment_program.handle);
 
     // Generate VBO handle for drawing
     vertex_buffer.Create();
@@ -508,7 +509,7 @@ void RendererOpenGL::CreateRasterizer() {
     if (rasterizer) {
         return;
     }
-    rasterizer = std::make_unique<RasterizerOpenGL>(system, emu_window, screen_info,
+    rasterizer = std::make_unique<RasterizerOpenGL>(system, emu_window, device, screen_info,
                                                     program_manager, state_tracker);
 }
 
@@ -620,10 +621,7 @@ void RendererOpenGL::DrawScreen(const Layout::FramebufferLayout& layout) {
     state_tracker.NotifyClipControl();
     state_tracker.NotifyAlphaTest();
 
-    program_manager.UseVertexShader(vertex_program.handle);
-    program_manager.UseGeometryShader(0);
-    program_manager.UseFragmentShader(fragment_program.handle);
-    program_manager.BindGraphicsPipeline();
+    program_manager.BindHostPipeline(pipeline.handle);
 
     glEnable(GL_CULL_FACE);
     if (screen_info.display_srgb) {
@@ -665,6 +663,8 @@ void RendererOpenGL::DrawScreen(const Layout::FramebufferLayout& layout) {
 
     glClear(GL_COLOR_BUFFER_BIT);
     glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+    program_manager.RestoreGuestPipeline();
 }
 
 bool RendererOpenGL::TryPresent(int timeout_ms) {