Merge pull request #4085 from Armada651/vertex-depth

VideoCommon: Implement depth range equation in vertex shader.

1 files changed, 35 insertions, 3 deletions

diff --git a/Source/Core/VideoBackends/OGL/Render.cpp b/Source/Core/VideoBackends/OGL/Render.cpp
index bde616deac..d637c308ca 100644
--- a/Source/Core/VideoBackends/OGL/Render.cpp
+++ b/Source/Core/VideoBackends/OGL/Render.cpp
@@ -481,6 +481,9 @@ Renderer::Renderer()
   g_Config.backend_info.bSupportsBindingLayout =
       GLExtensions::Supports("GL_ARB_shading_language_420pack");
 
+  // Clip distance support is useless without a method to clamp the depth range
+  g_Config.backend_info.bSupportsDepthClamp = GLExtensions::Supports("GL_ARB_depth_clamp");
+
   g_ogl_config.bSupportsGLSLCache = GLExtensions::Supports("GL_ARB_get_program_binary");
   g_ogl_config.bSupportsGLPinnedMemory = GLExtensions::Supports("GL_AMD_pinned_memory");
   g_ogl_config.bSupportsGLSync = GLExtensions::Supports("GL_ARB_sync");
@@ -520,6 +523,10 @@ Renderer::Renderer()
     g_ogl_config.bSupportsGLSLCache = true;
     g_ogl_config.bSupportsGLSync = true;
 
+    // TODO: Implement support for GL_EXT_clip_cull_distance when there is an extension for
+    // depth clamping.
+    g_Config.backend_info.bSupportsDepthClamp = false;
+
     if (strstr(g_ogl_config.glsl_version, "3.0"))
     {
       g_ogl_config.eSupportedGLSLVersion = GLSLES_300;
@@ -669,7 +676,7 @@ Renderer::Renderer()
                                    g_ogl_config.gl_renderer, g_ogl_config.gl_version),
                   5000);
 
-  WARN_LOG(VIDEO, "Missing OGL Extensions: %s%s%s%s%s%s%s%s%s%s%s%s%s",
+  WARN_LOG(VIDEO, "Missing OGL Extensions: %s%s%s%s%s%s%s%s%s%s%s%s%s%s",
            g_ActiveConfig.backend_info.bSupportsDualSourceBlend ? "" : "DualSourceBlend ",
            g_ActiveConfig.backend_info.bSupportsPrimitiveRestart ? "" : "PrimitiveRestart ",
            g_ActiveConfig.backend_info.bSupportsEarlyZ ? "" : "EarlyZ ",
@@ -681,7 +688,8 @@ Renderer::Renderer()
            g_ActiveConfig.backend_info.bSupportsSSAA ? "" : "SSAA ",
            g_ActiveConfig.backend_info.bSupportsGSInstancing ? "" : "GSInstancing ",
            g_ActiveConfig.backend_info.bSupportsClipControl ? "" : "ClipControl ",
-           g_ogl_config.bSupportsCopySubImage ? "" : "CopyImageSubData ");
+           g_ogl_config.bSupportsCopySubImage ? "" : "CopyImageSubData ",
+           g_ActiveConfig.backend_info.bSupportsDepthClamp ? "" : "DepthClamp ");
 
   s_last_multisamples = g_ActiveConfig.iMultisamples;
   s_MSAASamples = s_last_multisamples;
@@ -724,6 +732,12 @@ Renderer::Renderer()
   glClearDepthf(1.0f);
   glEnable(GL_DEPTH_TEST);
   glDepthFunc(GL_LEQUAL);
+  if (g_ActiveConfig.backend_info.bSupportsDepthClamp)
+  {
+    glEnable(GL_CLIP_DISTANCE0);
+    glEnable(GL_CLIP_DISTANCE1);
+    glEnable(GL_DEPTH_CLAMP);
+  }
 
   glPixelStorei(GL_UNPACK_ALIGNMENT, 4);  // 4-byte pixel alignment
 
@@ -1142,7 +1156,15 @@ void Renderer::SetViewport()
     auto iceilf = [](float f) { return static_cast<GLint>(ceilf(f)); };
     glViewport(iceilf(X), iceilf(Y), iceilf(Width), iceilf(Height));
   }
-  glDepthRangef(GLFar, GLNear);
+
+  // Set the reversed depth range. If we do depth clipping and depth range in the
+  // vertex shader we only need to ensure depth values don't exceed the maximum
+  // value supported by the console GPU. If not, we simply clamp the near/far values
+  // themselves to the maximum value as done above.
+  if (g_ActiveConfig.backend_info.bSupportsDepthClamp)
+    glDepthRangef(GX_MAX_DEPTH, 0.0f);
+  else
+    glDepthRangef(GLFar, GLNear);
 }
 
 void Renderer::ClearScreen(const EFBRectangle& rc, bool colorEnable, bool alphaEnable, bool zEnable,
@@ -1647,6 +1669,11 @@ void Renderer::ResetAPIState()
   glDisable(GL_BLEND);
   if (GLInterface->GetMode() == GLInterfaceMode::MODE_OPENGL)
     glDisable(GL_COLOR_LOGIC_OP);
+  if (g_ActiveConfig.backend_info.bSupportsDepthClamp)
+  {
+    glDisable(GL_CLIP_DISTANCE0);
+    glDisable(GL_CLIP_DISTANCE1);
+  }
   glDepthMask(GL_FALSE);
   glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
 }
@@ -1655,6 +1682,11 @@ void Renderer::RestoreAPIState()
 {
   // Gets us back into a more game-like state.
   glEnable(GL_SCISSOR_TEST);
+  if (g_ActiveConfig.backend_info.bSupportsDepthClamp)
+  {
+    glEnable(GL_CLIP_DISTANCE0);
+    glEnable(GL_CLIP_DISTANCE1);
+  }
   SetGenerationMode();
   BPFunctions::SetScissor();
   SetColorMask();