Pica: Write depth value even when depth test is disabled

This has been confirmed on hardware. Fixes Etrian Odyssey IV.

src/video_core/rasterizer.cpp

@@ -858,12 +858,12 @@ static void ProcessTriangleInternal(const Shader::OutputVertex& v0,
                 }
             }
 
-            // TODO: Does depth indeed only get written even if depth testing is enabled?
+            unsigned num_bits = Regs::DepthBitsPerPixel(regs.framebuffer.depth_format);
+            u32 z = (u32)((v0.screenpos[2].ToFloat32() * w0 +
+                           v1.screenpos[2].ToFloat32() * w1 +
+                           v2.screenpos[2].ToFloat32() * w2) * ((1 << num_bits) - 1) / wsum);
+
             if (output_merger.depth_test_enable) {
-                unsigned num_bits = Regs::DepthBitsPerPixel(regs.framebuffer.depth_format);
-                u32 z = (u32)((v0.screenpos[2].ToFloat32() * w0 +
-                               v1.screenpos[2].ToFloat32() * w1 +
-                               v2.screenpos[2].ToFloat32() * w2) * ((1 << num_bits) - 1) / wsum);
                 u32 ref_z = GetDepth(x >> 4, y >> 4);
 
                 bool pass = false;
@@ -907,11 +907,11 @@ static void ProcessTriangleInternal(const Shader::OutputVertex& v0,
                         UpdateStencil(stencil_test.action_depth_fail);
                     continue;
                 }
-
-                if (output_merger.depth_write_enable)
-                    SetDepth(x >> 4, y >> 4, z);
             }
 
+            if (output_merger.depth_write_enable)
+                SetDepth(x >> 4, y >> 4, z);
+
             // The stencil depth_pass action is executed even if depth testing is disabled
             if (stencil_action_enable)
                 UpdateStencil(stencil_test.action_depth_pass);

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -887,8 +887,10 @@ void RasterizerOpenGL::SyncStencilTest() {
 
 void RasterizerOpenGL::SyncDepthTest() {
     const auto& regs = Pica::g_state.regs;
-    state.depth.test_enabled = (regs.output_merger.depth_test_enable == 1);
-    state.depth.test_func = PicaToGL::CompareFunc(regs.output_merger.depth_test_func);
+    state.depth.test_enabled = regs.output_merger.depth_test_enable  == 1 ||
+                               regs.output_merger.depth_write_enable == 1;
+    state.depth.test_func = regs.output_merger.depth_test_enable == 1 ?
+                            PicaToGL::CompareFunc(regs.output_merger.depth_test_func) : GL_ALWAYS;
     state.color_mask.red_enabled = regs.output_merger.red_enable;
     state.color_mask.green_enabled = regs.output_merger.green_enable;
     state.color_mask.blue_enabled = regs.output_merger.blue_enable;