From bdcedc850602bd375caeb21c053426062b462c99 Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Sun, 22 Mar 2020 03:26:07 -0300
Subject: [PATCH] gl_rasterizer: Use transformed viewport for depth ranges

Implement depth ranges using the transformed viewport instead of the
generic one. This matches the current Vulkan implementation but doesn't
support negative depth ranges. An update to glad is required for this.
---
 src/video_core/renderer_opengl/gl_rasterizer.cpp | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/video_core/renderer_opengl/gl_rasterizer.cpp b/src/video_core/renderer_opengl/gl_rasterizer.cpp
index 063f41327c..826eee7df8 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.cpp
+++ b/src/video_core/renderer_opengl/gl_rasterizer.cpp
@@ -933,13 +933,15 @@ void RasterizerOpenGL::SyncViewport() {
             }
             flags[Dirty::Viewport0 + i] = false;
 
-            const Common::Rectangle<f32> rect{regs.viewport_transform[i].GetRect()};
+            const auto& src = regs.viewport_transform[i];
+            const Common::Rectangle<f32> rect{src.GetRect()};
             glViewportIndexedf(static_cast<GLuint>(i), rect.left, rect.bottom, rect.GetWidth(),
                                rect.GetHeight());
 
-            const auto& src = regs.viewports[i];
-            glDepthRangeIndexed(static_cast<GLuint>(i), static_cast<GLdouble>(src.depth_range_near),
-                                static_cast<GLdouble>(src.depth_range_far));
+            const GLdouble reduce_z = regs.depth_mode == Maxwell::DepthMode::MinusOneToOne;
+            const GLdouble near_depth = src.translate_z - src.scale_z * reduce_z;
+            const GLdouble far_depth = src.translate_z + src.scale_z;
+            glDepthRangeIndexed(static_cast<GLuint>(i), near_depth, far_depth);
         }
     }
 }