3 files changed, 30 insertions, 18 deletions

diff --git a/src/video_core/engines/maxwell_3d.h b/src/video_core/engines/maxwell_3d.h
index 0e1ae5912..3066bc606 100644
--- a/src/video_core/engines/maxwell_3d.h
+++ b/src/video_core/engines/maxwell_3d.h
@@ -11,6 +11,7 @@
 #include "common/bit_field.h"
 #include "common/common_funcs.h"
 #include "common/common_types.h"
+#include "common/math_util.h"
 #include "video_core/gpu.h"
 #include "video_core/memory_manager.h"
 #include "video_core/textures/texture.h"
@@ -281,6 +282,15 @@ public:
                     };
                     float depth_range_near;
                     float depth_range_far;
+
+                    MathUtil::Rectangle<s32> GetRect() const {
+                        return {
+                            static_cast<s32>(x),          // left
+                            static_cast<s32>(y + height), // top
+                            static_cast<s32>(x + width),  // right
+                            static_cast<s32>(y)           // bottom
+                        };
+                    };
                 } viewport[NumViewports];
 
                 INSERT_PADDING_WORDS(0x1D);
diff --git a/src/video_core/renderer_opengl/gl_rasterizer.cpp b/src/video_core/renderer_opengl/gl_rasterizer.cpp
index 487d37a26..d83c38cf8 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.cpp
+++ b/src/video_core/renderer_opengl/gl_rasterizer.cpp
@@ -228,13 +228,7 @@ void RasterizerOpenGL::DrawArrays() {
     const bool has_stencil = false;
     const bool using_color_fb = true;
     const bool using_depth_fb = false;
-
-    MathUtil::Rectangle<s32> viewport_rect_unscaled{
-        static_cast<s32>(regs.viewport[0].x),                           // left
-        static_cast<s32>(regs.viewport[0].y + regs.viewport[0].height), // top
-        static_cast<s32>(regs.viewport[0].x + regs.viewport[0].width),  // right
-        static_cast<s32>(regs.viewport[0].y)                            // bottom
-    };
+    const MathUtil::Rectangle<s32> viewport_rect{regs.viewport[0].GetRect()};
 
     const bool write_color_fb =
         state.color_mask.red_enabled == GL_TRUE || state.color_mask.green_enabled == GL_TRUE ||
@@ -248,7 +242,7 @@ void RasterizerOpenGL::DrawArrays() {
     Surface depth_surface;
     MathUtil::Rectangle<u32> surfaces_rect;
     std::tie(color_surface, depth_surface, surfaces_rect) =
-        res_cache.GetFramebufferSurfaces(using_color_fb, using_depth_fb, viewport_rect_unscaled);
+        res_cache.GetFramebufferSurfaces(using_color_fb, using_depth_fb, viewport_rect);
 
     const u16 res_scale = color_surface != nullptr
                               ? color_surface->res_scale
@@ -256,16 +250,16 @@ void RasterizerOpenGL::DrawArrays() {
 
     MathUtil::Rectangle<u32> draw_rect{
         static_cast<u32>(MathUtil::Clamp<s32>(static_cast<s32>(surfaces_rect.left) +
-                                                  viewport_rect_unscaled.left * res_scale,
+                                                  viewport_rect.left * res_scale,
                                               surfaces_rect.left, surfaces_rect.right)), // Left
         static_cast<u32>(MathUtil::Clamp<s32>(static_cast<s32>(surfaces_rect.bottom) +
-                                                  viewport_rect_unscaled.top * res_scale,
+                                                  viewport_rect.top * res_scale,
                                               surfaces_rect.bottom, surfaces_rect.top)), // Top
         static_cast<u32>(MathUtil::Clamp<s32>(static_cast<s32>(surfaces_rect.left) +
-                                                  viewport_rect_unscaled.right * res_scale,
+                                                  viewport_rect.right * res_scale,
                                               surfaces_rect.left, surfaces_rect.right)), // Right
         static_cast<u32>(MathUtil::Clamp<s32>(static_cast<s32>(surfaces_rect.bottom) +
-                                                  viewport_rect_unscaled.bottom * res_scale,
+                                                  viewport_rect.bottom * res_scale,
                                               surfaces_rect.bottom, surfaces_rect.top))}; // Bottom
 
     // Bind the framebuffer surfaces
@@ -293,12 +287,7 @@ void RasterizerOpenGL::DrawArrays() {
     }
 
     // Sync the viewport
-    state.viewport.x =
-        static_cast<GLint>(surfaces_rect.left) + viewport_rect_unscaled.left * res_scale;
-    state.viewport.y =
-        static_cast<GLint>(surfaces_rect.bottom) + viewport_rect_unscaled.bottom * res_scale;
-    state.viewport.width = static_cast<GLsizei>(viewport_rect_unscaled.GetWidth() * res_scale);
-    state.viewport.height = static_cast<GLsizei>(viewport_rect_unscaled.GetHeight() * res_scale);
+    SyncViewport(surfaces_rect, res_scale);
 
     // TODO(bunnei): Sync framebuffer_scale uniform here
     // TODO(bunnei): Sync scissorbox uniform(s) here
@@ -541,6 +530,16 @@ void main() {
     }
 }
 
+void RasterizerOpenGL::SyncViewport(const MathUtil::Rectangle<u32>& surfaces_rect, u16 res_scale) {
+    const auto& regs = Core::System().GetInstance().GPU().Maxwell3D().regs;
+    const MathUtil::Rectangle<s32> viewport_rect{regs.viewport[0].GetRect()};
+
+    state.viewport.x = static_cast<GLint>(surfaces_rect.left) + viewport_rect.left * res_scale;
+    state.viewport.y = static_cast<GLint>(surfaces_rect.bottom) + viewport_rect.bottom * res_scale;
+    state.viewport.width = static_cast<GLsizei>(viewport_rect.GetWidth() * res_scale);
+    state.viewport.height = static_cast<GLsizei>(viewport_rect.GetHeight() * res_scale);
+}
+
 void RasterizerOpenGL::SyncClipEnabled() {
     UNREACHABLE();
 }
diff --git a/src/video_core/renderer_opengl/gl_rasterizer.h b/src/video_core/renderer_opengl/gl_rasterizer.h
index c889b1aff..1cd46c96a 100644
--- a/src/video_core/renderer_opengl/gl_rasterizer.h
+++ b/src/video_core/renderer_opengl/gl_rasterizer.h
@@ -87,6 +87,9 @@ public:
 private:
     struct SamplerInfo {};
 
+    /// Syncs the viewport to match the guest state
+    void SyncViewport(const MathUtil::Rectangle<u32>& surfaces_rect, u16 res_scale);
+
     /// Syncs the clip enabled status to match the guest state
     void SyncClipEnabled();