Merge pull request #337 from Subv/used_buffers

GPU: Don't use explicit binding points when uploading the constbuffers to opengl

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -193,6 +193,9 @@ void RasterizerOpenGL::SetupShaders(u8* buffer_ptr, GLintptr buffer_offset, size
     auto& gpu = Core::System().GetInstance().GPU().Maxwell3D();
     ASSERT_MSG(!gpu.regs.shader_config[0].enable, "VertexA is unsupported!");
 
+    // Next available bindpoint to use when uploading the const buffers to the GLSL shaders.
+    u32 current_constbuffer_bindpoint = 0;
+
     for (unsigned index = 1; index < Maxwell::MaxShaderProgram; ++index) {
         ptr_pos += sizeof(GLShader::MaxwellUniformData);
 
@@ -244,9 +247,13 @@ void RasterizerOpenGL::SetupShaders(u8* buffer_ptr, GLintptr buffer_offset, size
             UNREACHABLE();
         }
 
+        GLuint gl_stage_program = shader_program_manager->GetCurrentProgramStage(
+            static_cast<Maxwell::ShaderStage>(stage));
+
         // Configure the const buffers for this shader stage.
-        SetupConstBuffers(static_cast<Maxwell::ShaderStage>(stage),
+        current_constbuffer_bindpoint =
-                          shader_resources.const_buffer_entries);
+            SetupConstBuffers(static_cast<Maxwell::ShaderStage>(stage), gl_stage_program,
+                              current_constbuffer_bindpoint, shader_resources.const_buffer_entries);
     }
 
     shader_program_manager->UseTrivialGeometryShader();
@@ -543,7 +550,8 @@ void RasterizerOpenGL::SamplerInfo::SyncWithConfig(const Tegra::Texture::TSCEntr
     }
 }
 
-void RasterizerOpenGL::SetupConstBuffers(Maxwell::ShaderStage stage,
+u32 RasterizerOpenGL::SetupConstBuffers(Maxwell::ShaderStage stage, GLuint program,
+                                        u32 current_bindpoint,
                                         const std::vector<GLShader::ConstBufferEntry>& entries) {
     auto& gpu = Core::System::GetInstance().GPU();
     auto& maxwell3d = gpu.Get3DEngine();
@@ -568,7 +576,7 @@ void RasterizerOpenGL::SetupConstBuffers(Maxwell::ShaderStage stage,
 
         ASSERT_MSG(buffer.enabled, "Attempted to upload disabled constbuffer");
         buffer_draw_state.enabled = true;
-        buffer_draw_state.bindpoint = bindpoint;
+        buffer_draw_state.bindpoint = current_bindpoint + bindpoint;
 
         VAddr addr = gpu.memory_manager->PhysicalToVirtualAddress(buffer.address);
         std::vector<u8> data(used_buffer.GetSize() * sizeof(float));
@@ -577,9 +585,18 @@ void RasterizerOpenGL::SetupConstBuffers(Maxwell::ShaderStage stage,
         glBindBuffer(GL_SHADER_STORAGE_BUFFER, buffer_draw_state.ssbo);
         glBufferData(GL_SHADER_STORAGE_BUFFER, data.size(), data.data(), GL_DYNAMIC_DRAW);
         glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+
+        // Now configure the bindpoint of the buffer inside the shader
+        std::string buffer_name = used_buffer.GetName();
+        GLuint index =
+            glGetProgramResourceIndex(program, GL_SHADER_STORAGE_BLOCK, buffer_name.c_str());
+        if (index != -1)
+            glShaderStorageBlockBinding(program, index, buffer_draw_state.bindpoint);
     }
 
     state.Apply();
+
+    return current_bindpoint + entries.size();
 }
 
 void RasterizerOpenGL::BindFramebufferSurfaces(const Surface& color_surface,

src/video_core/renderer_opengl/gl_rasterizer.h

@@ -87,8 +87,16 @@ private:
     /// Binds the required textures to OpenGL before drawing a batch.
     void BindTextures();
 
-    /// Configures the current constbuffers to use for the draw command.
+    /*
-    void SetupConstBuffers(Tegra::Engines::Maxwell3D::Regs::ShaderStage stage,
+     * Configures the current constbuffers to use for the draw command.
+     * @param stage The shader stage to configure buffers for.
+     * @param program The OpenGL program object that contains the specified stage.
+     * @param current_bindpoint The offset at which to start counting new buffer bindpoints.
+     * @param entries Vector describing the buffers that are actually used in the guest shader.
+     * @returns The next available bindpoint for use in the next shader stage.
+     */
+    u32 SetupConstBuffers(Tegra::Engines::Maxwell3D::Regs::ShaderStage stage, GLuint program,
+                          u32 current_bindpoint,
                           const std::vector<GLShader::ConstBufferEntry>& entries);
 
     /// Syncs the viewport to match the guest state

src/video_core/renderer_opengl/gl_shader_decompiler.cpp

@@ -192,7 +192,7 @@ private:
 
     /// Generates code representing a uniform (C buffer) register.
     std::string GetUniform(const Uniform& reg) {
-        declr_const_buffers[reg.index].MarkAsUsed(reg.index, reg.offset);
+        declr_const_buffers[reg.index].MarkAsUsed(reg.index, reg.offset, stage);
         return 'c' + std::to_string(reg.index) + '[' + std::to_string(reg.offset) + ']';
     }
 
@@ -478,8 +478,7 @@ private:
 
         unsigned const_buffer_layout = 0;
         for (const auto& entry : GetConstBuffersDeclarations()) {
-            declarations.AddLine("layout(std430, binding = " + std::to_string(const_buffer_layout) +
+            declarations.AddLine("layout(std430) buffer " + entry.GetName());
-                                 ") buffer c" + std::to_string(entry.GetIndex()) + "_buffer");
             declarations.AddLine("{");
             declarations.AddLine("    float c" + std::to_string(entry.GetIndex()) + "[];");
             declarations.AddLine("};");

src/video_core/renderer_opengl/gl_shader_gen.h

@@ -19,10 +19,13 @@ constexpr size_t MAX_PROGRAM_CODE_LENGTH{0x1000};
 using ProgramCode = std::array<u64, MAX_PROGRAM_CODE_LENGTH>;
 
 class ConstBufferEntry {
+    using Maxwell = Tegra::Engines::Maxwell3D::Regs;
+
 public:
-    void MarkAsUsed(unsigned index, unsigned offset) {
+    void MarkAsUsed(unsigned index, unsigned offset, Maxwell::ShaderStage stage) {
         is_used = true;
         this->index = index;
+        this->stage = stage;
         max_offset = std::max(max_offset, offset);
     }
 
@@ -38,10 +41,19 @@ public:
         return max_offset + 1;
     }
 
+    std::string GetName() const {
+        return BufferBaseNames[static_cast<size_t>(stage)] + std::to_string(index);
+    }
+
 private:
+    static constexpr std::array<const char*, Maxwell::MaxShaderStage> BufferBaseNames = {
+        "buffer_vs_c", "buffer_tessc_c", "buffer_tesse_c", "buffer_gs_c", "buffer_fs_c",
+    };
+
     bool is_used{};
     unsigned index{};
     unsigned max_offset{};
+    Maxwell::ShaderStage stage;
 };
 
 struct ShaderEntries {

src/video_core/renderer_opengl/gl_shader_manager.h

@@ -121,6 +121,17 @@ public:
         return result;
     }
 
+    GLuint GetCurrentProgramStage(Maxwell3D::Regs::ShaderStage stage) {
+        switch (stage) {
+        case Maxwell3D::Regs::ShaderStage::Vertex:
+            return current.vs;
+        case Maxwell3D::Regs::ShaderStage::Fragment:
+            return current.fs;
+        }
+
+        UNREACHABLE();
+    }
+
     void UseTrivialGeometryShader() {
         current.gs = 0;
     }