From c9b511da084bcf1655a7e844ee0d80e46ce681c9 Mon Sep 17 00:00:00 2001
From: Subv <subv2112@gmail.com>
Date: Sat, 14 Apr 2018 11:50:15 -0500
Subject: GPU: Upload the entirety of each constbuffer for each shader stage as
 SSBOs.

We're going to need the shader generator to give us a mapping of the actual used const buffers to properly bind them to the shader.
---
 src/video_core/renderer_opengl/gl_rasterizer.cpp | 39 +++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

(limited to 'src/video_core/renderer_opengl/gl_rasterizer.cpp')

diff --git a/src/video_core/renderer_opengl/gl_rasterizer.cpp b/src/video_core/renderer_opengl/gl_rasterizer.cpp
index 71b862114..2a2268c20 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.cpp
+++ b/src/video_core/renderer_opengl/gl_rasterizer.cpp
@@ -306,6 +306,8 @@ void RasterizerOpenGL::DrawArrays() {
 
     // Sync and bind the texture surfaces
     BindTextures();
+    // Configure the constant buffer objects
+    SetupConstBuffers();
 
     // Viewport can have negative offsets or larger dimensions than our framebuffer sub-rect. Enable
     // scissor test to prevent drawing outside of the framebuffer region
@@ -388,7 +390,7 @@ void RasterizerOpenGL::DrawArrays() {
 
 void RasterizerOpenGL::BindTextures() {
     using Regs = Tegra::Engines::Maxwell3D::Regs;
-    auto maxwell3d = Core::System::GetInstance().GPU().Get3DEngine();
+    auto& maxwell3d = Core::System::GetInstance().GPU().Get3DEngine();
 
     // Each Maxwell shader stage can have an arbitrary number of textures, but we're limited to a
     // certain number in OpenGL. We try to only use the minimum amount of host textures by not
@@ -535,6 +537,41 @@ void RasterizerOpenGL::SamplerInfo::SyncWithConfig(const Tegra::Texture::TSCEntr
     }
 }
 
+void RasterizerOpenGL::SetupConstBuffers() {
+    using Regs = Tegra::Engines::Maxwell3D::Regs;
+    auto& gpu = Core::System::GetInstance().GPU();
+    auto& maxwell3d = gpu.Get3DEngine();
+
+    // Upload only the enabled buffers from the 16 constbuffers of each shader stage
+    u32 current_bindpoint = 0;
+    for (u32 stage = 0; stage < Regs::MaxShaderStage; ++stage) {
+        auto& shader_stage = maxwell3d.state.shader_stages[stage];
+        bool stage_enabled = maxwell3d.IsShaderStageEnabled(static_cast<Regs::ShaderStage>(stage));
+
+        for (u32 buffer_id = 0; buffer_id < Regs::MaxConstBuffers; ++buffer_id) {
+            const auto& buffer = shader_stage.const_buffers[buffer_id];
+
+            state.draw.const_buffers[stage][buffer_id].enabled = buffer.enabled && stage_enabled;
+
+            if (buffer.enabled && stage_enabled) {
+                state.draw.const_buffers[stage][buffer_id].bindpoint = current_bindpoint;
+                current_bindpoint++;
+
+                VAddr addr = gpu.memory_manager->PhysicalToVirtualAddress(buffer.address);
+                const u8* data = Memory::GetPointer(addr);
+                glBindBuffer(GL_SHADER_STORAGE_BUFFER,
+                             state.draw.const_buffers[stage][buffer_id].ssbo);
+                glBufferData(GL_SHADER_STORAGE_BUFFER, buffer.size, data, GL_DYNAMIC_DRAW);
+                glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+            } else {
+                state.draw.const_buffers[stage][buffer_id].bindpoint = -1;
+            }
+        }
+    }
+
+    state.Apply();
+}
+
 void RasterizerOpenGL::BindFramebufferSurfaces(const Surface& color_surface,
                                                const Surface& depth_surface, bool has_stencil) {
     state.draw.draw_framebuffer = framebuffer.handle;
-- 
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