Merge pull request #619 from Subv/flip_cull

GPU: Flip the triangle front face winding if the GPU is configured to not flip the triangles.

src/video_core/engines/maxwell_3d.h

@@ -478,7 +478,9 @@ public:
 
                 u32 depth_write_enabled;
 
-                INSERT_PADDING_WORDS(0x8);
+                INSERT_PADDING_WORDS(0x7);
+
+                u32 d3d_cull_mode;
 
                 BitField<0, 3, ComparisonOp> depth_test_func;
 
@@ -498,7 +500,13 @@ public:
                     u32 enable[NumRenderTargets];
                 } blend;
 
-                INSERT_PADDING_WORDS(0x2D);
+                INSERT_PADDING_WORDS(0xB);
+
+                union {
+                    BitField<4, 1, u32> triangle_rast_flip;
+                } screen_y_control;
+
+                INSERT_PADDING_WORDS(0x21);
 
                 u32 vb_element_base;
 
@@ -528,7 +536,12 @@ public:
                     }
                 } tic;
 
-                INSERT_PADDING_WORDS(0x22);
+                INSERT_PADDING_WORDS(0x21);
+
+                union {
+                    BitField<2, 1, u32> coord_origin;
+                    BitField<3, 10, u32> enable;
+                } point_coord_replace;
 
                 struct {
                     u32 code_address_high;
@@ -818,11 +831,14 @@ ASSERT_REG_POSITION(rt_control, 0x487);
 ASSERT_REG_POSITION(depth_test_enable, 0x4B3);
 ASSERT_REG_POSITION(independent_blend_enable, 0x4B9);
 ASSERT_REG_POSITION(depth_write_enabled, 0x4BA);
+ASSERT_REG_POSITION(d3d_cull_mode, 0x4C2);
 ASSERT_REG_POSITION(depth_test_func, 0x4C3);
 ASSERT_REG_POSITION(blend, 0x4CF);
+ASSERT_REG_POSITION(screen_y_control, 0x4EB);
 ASSERT_REG_POSITION(vb_element_base, 0x50D);
 ASSERT_REG_POSITION(tsc, 0x557);
 ASSERT_REG_POSITION(tic, 0x55D);
+ASSERT_REG_POSITION(point_coord_replace, 0x581);
 ASSERT_REG_POSITION(code_address, 0x582);
 ASSERT_REG_POSITION(draw, 0x585);
 ASSERT_REG_POSITION(index_array, 0x5F2);

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -771,6 +771,16 @@ void RasterizerOpenGL::SyncCullMode() {
     if (state.cull.enabled) {
         state.cull.front_face = MaxwellToGL::FrontFace(regs.cull.front_face);
         state.cull.mode = MaxwellToGL::CullFace(regs.cull.cull_face);
+
+        // If the GPU is configured to flip the rasterized triangles, then we need to flip the
+        // notion of front and back. Note: We flip the triangles when the value of the register is 0
+        // because OpenGL already does it for us.
+        if (regs.screen_y_control.triangle_rast_flip == 0) {
+            if (state.cull.front_face == GL_CCW)
+                state.cull.front_face = GL_CW;
+            else if (state.cull.front_face == GL_CW)
+                state.cull.front_face = GL_CCW;
+        }
     }
 }