1 files changed, 127 insertions, 22 deletions

diff --git a/Source/Core/VideoBackends/OGL/BoundingBox.cpp b/Source/Core/VideoBackends/OGL/BoundingBox.cpp
index 0ee4bd2afe..ebf8433d92 100644
--- a/Source/Core/VideoBackends/OGL/BoundingBox.cpp
+++ b/Source/Core/VideoBackends/OGL/BoundingBox.cpp
@@ -2,22 +2,47 @@
 // Licensed under GPLv2+
 // Refer to the license.txt file included.
 
+#include <algorithm>
+#include <array>
 #include <cstring>
 
 #include "Common/GL/GLUtil.h"
 
 #include "VideoBackends/OGL/BoundingBox.h"
+#include "VideoBackends/OGL/FramebufferManager.h"
 
 #include "VideoCommon/DriverDetails.h"
 #include "VideoCommon/VideoConfig.h"
 
 static GLuint s_bbox_buffer_id;
+static GLuint s_pbo;
+
+static std::array<int, 4> s_stencil_bounds;
+static bool s_stencil_updated;
+static bool s_stencil_cleared;
+
+static int s_target_width;
+static int s_target_height;
 
 namespace OGL
 {
-void BoundingBox::Init()
+void BoundingBox::SetTargetSizeChanged(int target_width, int target_height)
 {
-  if (g_ActiveConfig.backend_info.bSupportsBBox)
+  if (g_ActiveConfig.BBoxUseFragmentShaderImplementation())
+    return;
+
+  s_target_width = target_width;
+  s_target_height = target_height;
+  s_stencil_updated = false;
+
+  glBindBuffer(GL_PIXEL_PACK_BUFFER, s_pbo);
+  glBufferData(GL_PIXEL_PACK_BUFFER, s_target_width * s_target_height, nullptr, GL_STREAM_READ);
+  glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
+}
+
+void BoundingBox::Init(int target_width, int target_height)
+{
+  if (g_ActiveConfig.BBoxUseFragmentShaderImplementation())
   {
     int initial_values[4] = {0, 0, 0, 0};
     glGenBuffers(1, &s_bbox_buffer_id);
@@ -25,46 +50,126 @@ void BoundingBox::Init()
     glBufferData(GL_SHADER_STORAGE_BUFFER, 4 * sizeof(s32), initial_values, GL_DYNAMIC_DRAW);
     glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, s_bbox_buffer_id);
   }
+  else
+  {
+    s_stencil_bounds = {{0, 0, 0, 0}};
+    glGenBuffers(1, &s_pbo);
+    SetTargetSizeChanged(target_width, target_height);
+  }
 }
 
 void BoundingBox::Shutdown()
 {
-  if (g_ActiveConfig.backend_info.bSupportsBBox)
+  if (g_ActiveConfig.BBoxUseFragmentShaderImplementation())
+  {
     glDeleteBuffers(1, &s_bbox_buffer_id);
+  }
+  else
+  {
+    glDeleteBuffers(1, &s_pbo);
+  }
 }
 
 void BoundingBox::Set(int index, int value)
 {
-  glBindBuffer(GL_SHADER_STORAGE_BUFFER, s_bbox_buffer_id);
-  glBufferSubData(GL_SHADER_STORAGE_BUFFER, index * sizeof(int), sizeof(int), &value);
-  glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+  if (g_ActiveConfig.BBoxUseFragmentShaderImplementation())
+  {
+    glBindBuffer(GL_SHADER_STORAGE_BUFFER, s_bbox_buffer_id);
+    glBufferSubData(GL_SHADER_STORAGE_BUFFER, index * sizeof(int), sizeof(int), &value);
+    glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+  }
+  else
+  {
+    s_stencil_bounds[index] = value;
+
+    if (!s_stencil_cleared)
+    {
+      // Assumes that the EFB framebuffer is currently bound
+      glClearStencil(0);
+      glClear(GL_STENCIL_BUFFER_BIT);
+      s_stencil_updated = false;
+      s_stencil_cleared = true;
+    }
+  }
 }
 
 int BoundingBox::Get(int index)
 {
-  int data = 0;
-  glBindBuffer(GL_SHADER_STORAGE_BUFFER, s_bbox_buffer_id);
-
-  if (!DriverDetails::HasBug(DriverDetails::BUG_SLOW_GETBUFFERSUBDATA))
+  if (g_ActiveConfig.BBoxUseFragmentShaderImplementation())
   {
-    // Using glMapBufferRange to read back the contents of the SSBO is extremely slow
-    // on nVidia drivers. This is more noticeable at higher internal resolutions.
-    // Using glGetBufferSubData instead does not seem to exhibit this slowdown.
-    glGetBufferSubData(GL_SHADER_STORAGE_BUFFER, index * sizeof(int), sizeof(int), &data);
+    int data = 0;
+    glBindBuffer(GL_SHADER_STORAGE_BUFFER, s_bbox_buffer_id);
+    if (!DriverDetails::HasBug(DriverDetails::BUG_SLOW_GETBUFFERSUBDATA))
+    {
+      // Using glMapBufferRange to read back the contents of the SSBO is extremely slow
+      // on nVidia drivers. This is more noticeable at higher internal resolutions.
+      // Using glGetBufferSubData instead does not seem to exhibit this slowdown.
+      glGetBufferSubData(GL_SHADER_STORAGE_BUFFER, index * sizeof(int), sizeof(int), &data);
+    }
+    else
+    {
+      // Using glMapBufferRange is faster on AMD cards by a measurable margin.
+      void* ptr = glMapBufferRange(GL_SHADER_STORAGE_BUFFER, index * sizeof(int), sizeof(int),
+                                   GL_MAP_READ_BIT);
+      if (ptr)
+      {
+        memcpy(&data, ptr, sizeof(int));
+        glUnmapBuffer(GL_SHADER_STORAGE_BUFFER);
+      }
+    }
+    glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
+    return data;
   }
   else
   {
-    // Using glMapBufferRange is faster on AMD cards by a measurable margin.
-    void* ptr = glMapBufferRange(GL_SHADER_STORAGE_BUFFER, index * sizeof(int), sizeof(int),
-                                 GL_MAP_READ_BIT);
-    if (ptr)
+    if (s_stencil_updated)
     {
-      memcpy(&data, ptr, sizeof(int));
-      glUnmapBuffer(GL_SHADER_STORAGE_BUFFER);
+      s_stencil_updated = false;
+
+      FramebufferManager::ResolveEFBStencilTexture();
+      glBindFramebuffer(GL_READ_FRAMEBUFFER, FramebufferManager::GetResolvedFramebuffer());
+      glBindBuffer(GL_PIXEL_PACK_BUFFER, s_pbo);
+      glPixelStorei(GL_PACK_ALIGNMENT, 1);
+      glReadPixels(0, 0, s_target_width, s_target_height, GL_STENCIL_INDEX, GL_UNSIGNED_BYTE, 0);
+      glBindFramebuffer(GL_READ_FRAMEBUFFER, FramebufferManager::GetEFBFramebuffer());
+
+      // Eke every bit of performance out of the compiler that we can
+      std::array<int, 4> bounds = s_stencil_bounds;
+
+      u8* data = static_cast<u8*>(glMapBufferRange(
+          GL_PIXEL_PACK_BUFFER, 0, s_target_height * s_target_width, GL_MAP_READ_BIT));
+
+      for (int row = 0; row < s_target_height; row++)
+      {
+        for (int col = 0; col < s_target_width; col++)
+        {
+          if (data[row * s_target_width + col] == 0)
+            continue;
+          bounds[0] = std::min(bounds[0], col);
+          bounds[1] = std::max(bounds[1], col);
+          bounds[2] = std::min(bounds[2], row);
+          bounds[3] = std::max(bounds[3], row);
+        }
+      }
+
+      s_stencil_bounds = bounds;
+
+      glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
+      glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
     }
+
+    return s_stencil_bounds[index];
   }
+}
 
-  glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
-  return data;
+void BoundingBox::StencilWasUpdated()
+{
+  s_stencil_updated = true;
+  s_stencil_cleared = false;
+}
+
+bool BoundingBox::NeedsStencilBuffer()
+{
+  return g_ActiveConfig.bBBoxEnable && !g_ActiveConfig.BBoxUseFragmentShaderImplementation();
 }
 };