maxwell3d: Implement Conditional Rendering

Conditional Rendering takes care of conditionaly clearing or drawing
depending on a set of queries. This PR implements the query checks to
stablish if things can be rendered or not.

src/video_core/engines/maxwell_3d.cpp

@@ -249,6 +249,10 @@ void Maxwell3D::CallMethod(const GPU::MethodCall& method_call) {
         ProcessQueryGet();
         break;
     }
+    case MAXWELL3D_REG_INDEX(condition.mode): {
+        ProcessQueryCondition();
+        break;
+    }
     case MAXWELL3D_REG_INDEX(sync_info): {
         ProcessSyncPoint();
         break;
@@ -302,6 +306,7 @@ void Maxwell3D::ProcessQueryGet() {
         result = regs.query.query_sequence;
         break;
     default:
+        result = 1;
         UNIMPLEMENTED_MSG("Unimplemented query select type {}",
                           static_cast<u32>(regs.query.query_get.select.Value()));
     }
@@ -342,6 +347,45 @@ void Maxwell3D::ProcessQueryGet() {
     }
 }
 
+void Maxwell3D::ProcessQueryCondition() {
+    const GPUVAddr condition_address{regs.condition.Address()};
+    switch (regs.condition.mode) {
+    case Regs::ConditionMode::Always: {
+        execute_on = true;
+        break;
+    }
+    case Regs::ConditionMode::Never: {
+        execute_on = false;
+        break;
+    }
+    case Regs::ConditionMode::ResNonZero: {
+        Regs::QueryCompare cmp;
+        memory_manager.ReadBlockUnsafe(condition_address, &cmp, sizeof(cmp));
+        execute_on = cmp.initial_sequence != 0U && cmp.initial_mode != 0U;
+        break;
+    }
+    case Regs::ConditionMode::Equal: {
+        Regs::QueryCompare cmp;
+        memory_manager.ReadBlockUnsafe(condition_address, &cmp, sizeof(cmp));
+        execute_on =
+            cmp.initial_sequence == cmp.current_sequence && cmp.initial_mode == cmp.current_mode;
+        break;
+    }
+    case Regs::ConditionMode::NotEqual: {
+        Regs::QueryCompare cmp;
+        memory_manager.ReadBlockUnsafe(condition_address, &cmp, sizeof(cmp));
+        execute_on =
+            cmp.initial_sequence != cmp.current_sequence || cmp.initial_mode != cmp.current_mode;
+        break;
+    }
+    default: {
+        UNIMPLEMENTED_MSG("Uninplemented Condition Mode!");
+        execute_on = true;
+        break;
+    }
+    }
+}
+
 void Maxwell3D::ProcessSyncPoint() {
     const u32 sync_point = regs.sync_info.sync_point.Value();
     const u32 increment = regs.sync_info.increment.Value();

src/video_core/engines/maxwell_3d.h

@@ -90,6 +90,20 @@ public:
 
         enum class QuerySelect : u32 {
             Zero = 0,
+            TimeElapsed = 2,
+            TransformFeedbackPrimitivesGenerated = 11,
+            PrimitivesGenerated = 18,
+            SamplesPassed = 21,
+            TransformFeedbackUnknown = 26,
+        };
+
+        struct QueryCompare {
+            u32 initial_sequence;
+            u32 initial_mode;
+            u32 unknown1;
+            u32 unknown2;
+            u32 current_sequence;
+            u32 current_mode;
         };
 
         enum class QuerySyncCondition : u32 {
@@ -97,6 +111,14 @@ public:
             GreaterThan = 1,
         };
 
+        enum class ConditionMode : u32 {
+            Never = 0,
+            Always = 1,
+            ResNonZero = 2,
+            Equal = 3,
+            NotEqual = 4,
+        };
+
         enum class ShaderProgram : u32 {
             VertexA = 0,
             VertexB = 1,
@@ -815,7 +837,18 @@ public:
                     BitField<4, 1, u32> alpha_to_one;
                 } multisample_control;
 
-                INSERT_PADDING_WORDS(0x7);
+                INSERT_PADDING_WORDS(0x4);
+
+                struct {
+                    u32 address_high;
+                    u32 address_low;
+                    ConditionMode mode;
+
+                    GPUVAddr Address() const {
+                        return static_cast<GPUVAddr>((static_cast<GPUVAddr>(address_high) << 32) |
+                                                     address_low);
+                    }
+                } condition;
 
                 struct {
                     u32 tsc_address_high;
@@ -1169,6 +1202,10 @@ public:
         return macro_memory;
     }
 
+    bool ShouldExecute() const {
+        return execute_on;
+    }
+
 private:
     void InitializeRegisterDefaults();
 
@@ -1194,6 +1231,8 @@ private:
 
     Upload::State upload_state;
 
+    bool execute_on{true};
+
     /// Retrieves information about a specific TIC entry from the TIC buffer.
     Texture::TICEntry GetTICEntry(u32 tic_index) const;
 
@@ -1219,6 +1258,9 @@ private:
     /// Handles a write to the QUERY_GET register.
     void ProcessQueryGet();
 
+    // Handles Conditional Rendering
+    void ProcessQueryCondition();
+
     /// Handles writes to syncing register.
     void ProcessSyncPoint();
 
@@ -1290,6 +1332,7 @@ ASSERT_REG_POSITION(clip_distance_enabled, 0x544);
 ASSERT_REG_POSITION(point_size, 0x546);
 ASSERT_REG_POSITION(zeta_enable, 0x54E);
 ASSERT_REG_POSITION(multisample_control, 0x54F);
+ASSERT_REG_POSITION(condition, 0x554);
 ASSERT_REG_POSITION(tsc, 0x557);
 ASSERT_REG_POSITION(polygon_offset_factor, 0x55b);
 ASSERT_REG_POSITION(tic, 0x55D);

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -520,7 +520,13 @@ std::pair<bool, bool> RasterizerOpenGL::ConfigureFramebuffers(
 }
 
 void RasterizerOpenGL::Clear() {
-    const auto& regs = system.GPU().Maxwell3D().regs;
+    const auto& maxwell3d = system.GPU().Maxwell3D();
+
+    if (!maxwell3d.ShouldExecute()) {
+        return;
+    }
+
+    const auto& regs = maxwell3d.regs;
     bool use_color{};
     bool use_depth{};
     bool use_stencil{};
@@ -616,6 +622,11 @@ void RasterizerOpenGL::DrawArrays() {
 
     MICROPROFILE_SCOPE(OpenGL_Drawing);
     auto& gpu = system.GPU().Maxwell3D();
+
+    if (!gpu.ShouldExecute()) {
+        return;
+    }
+
     const auto& regs = gpu.regs;
 
     SyncColorMask();