Implement framebuffer vertical flip flag (#699)

* Implement framebuffer vertical flip flag

* Make VerticalMirror const

src/common/math_util.h

@@ -1,4 +1,8 @@
-// Copyright 2013 Dolphin Emulator Project / 2014 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+// Copyright 2013 Dolphin Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -23,6 +27,12 @@ struct Rectangle {
     constexpr Rectangle(T left, T top, T right, T bottom)
         : left(left), top(top), right(right), bottom(bottom) {}
 
+    template <typename U>
+    operator Rectangle<U>() const {
+        return Rectangle<U>{static_cast<U>(left), static_cast<U>(top), static_cast<U>(right),
+                            static_cast<U>(bottom)};
+    }
+
     [[nodiscard]] constexpr bool operator==(const Rectangle<T>& rhs) const {
         return (left == rhs.left) && (top == rhs.top) && (right == rhs.right) &&
                (bottom == rhs.bottom);
@@ -55,6 +65,9 @@ struct Rectangle {
         return Rectangle{left, top, static_cast<T>(left + GetWidth() * s),
                          static_cast<T>(top + GetHeight() * s)};
     }
+    [[nodiscard]] Rectangle<T> VerticalMirror(T ref_height) const {
+        return Rectangle{left, ref_height - bottom, right, ref_height - top};
+    }
 };
 
 template <typename T>

src/video_core/pica/regs_framebuffer.h

@@ -1,4 +1,4 @@
-// Copyright 2017 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -233,6 +233,7 @@ struct FramebufferRegs {
             // GetWidth() and GetHeight() instead.
             BitField<0, 11, u32> width;
             BitField<12, 10, u32> height;
+            BitField<24, 1, u32> flip;
         };
 
         INSERT_PADDING_WORDS(0x1);
@@ -251,6 +252,10 @@ struct FramebufferRegs {
         inline u32 GetHeight() const {
             return height + 1;
         }
+
+        inline bool IsFlipped() const {
+            return !flip.Value();
+        }
     } framebuffer;
 
     // Returns the number of bytes in the specified depth format

src/video_core/pica/regs_rasterizer.h

@@ -1,4 +1,4 @@
-// Copyright 2017 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -29,11 +29,13 @@ struct RasterizerRegs {
 
     BitField<0, 24, u32> viewport_size_x;
 
-    INSERT_PADDING_WORDS(0x1);
+    BitField<1, 31, u32> viewport_size_x_inv;
 
     BitField<0, 24, u32> viewport_size_y;
 
-    INSERT_PADDING_WORDS(0x3);
+    BitField<1, 31, u32> viewport_size_y_inv;
+
+    INSERT_PADDING_WORDS(0x2);
 
     BitField<0, 1, u32> clip_enable;
     BitField<0, 24, u32> clip_coef[4]; // float24

src/video_core/pica_types.h

@@ -1,4 +1,4 @@
-// Copyright 2015 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -138,7 +138,7 @@ public:
     }
 
 private:
-    static constexpr u32 MASK = (1 << (M + E + 1)) - 1;
+    static constexpr u32 MASK = static_cast<u32>(1 << (M + E + 1)) - 1;
     static constexpr u32 MANTISSA_MASK = (1 << M) - 1;
     static constexpr u32 EXPONENT_MASK = (1 << E) - 1;
 
@@ -153,6 +153,7 @@ private:
     }
 };
 
+using f31 = Pica::Float<23, 7>;
 using f24 = Pica::Float<16, 7>;
 using f20 = Pica::Float<12, 7>;
 using f16 = Pica::Float<10, 5>;

src/video_core/rasterizer_accelerated.cpp

@@ -1,4 +1,4 @@
-// Copyright 2023 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -846,7 +846,7 @@ void RasterizerAccelerated::SyncTextureBorderColor(int tex_index) {
 }
 
 void RasterizerAccelerated::SyncClipPlane() {
-    const u32 enable_clip1 = regs.rasterizer.clip_enable != 0;
+    const bool enable_clip1 = regs.rasterizer.clip_enable != 0;
     const auto raw_clip_coef = regs.rasterizer.GetClipCoef();
     const Common::Vec4f new_clip_coef = {raw_clip_coef.x.ToFloat32(), raw_clip_coef.y.ToFloat32(),
                                          raw_clip_coef.z.ToFloat32(), raw_clip_coef.w.ToFloat32()};

src/video_core/rasterizer_cache/framebuffer_base.h

@@ -1,4 +1,4 @@
-// Copyright 2023 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -65,13 +65,18 @@ template <class T>
 class FramebufferHelper {
 public:
     explicit FramebufferHelper(RasterizerCache<T>* res_cache_, typename T::Framebuffer* fb_,
-                               const Pica::RasterizerRegs& regs,
+                               bool flip_rect, const Pica::RasterizerRegs& regs,
                                Common::Rectangle<u32> surfaces_rect)
         : res_cache{res_cache_}, fb{fb_} {
         const u32 res_scale = fb->Scale();
+        const u32 height = surfaces_rect.GetHeight() / res_scale;
 
         // Determine the draw rectangle (render area + scissor)
-        const Common::Rectangle viewport_rect = regs.GetViewportRect();
+        Common::Rectangle viewport_rect = regs.GetViewportRect();
+        if (flip_rect) {
+            viewport_rect = viewport_rect.VerticalMirror(height);
+        }
+
         draw_rect.left =
             std::clamp<s32>(static_cast<s32>(surfaces_rect.left) + viewport_rect.left * res_scale,
                             surfaces_rect.left, surfaces_rect.right);
@@ -103,6 +108,10 @@ public:
             static_cast<s32>(surfaces_rect.left + (regs.scissor_test.x2 + 1) * res_scale);
         scissor_rect.top =
             static_cast<s32>(surfaces_rect.bottom + (regs.scissor_test.y2 + 1) * res_scale);
+
+        if (flip_rect) {
+            scissor_rect = scissor_rect.VerticalMirror(height);
+        }
     }
 
     ~FramebufferHelper() {

src/video_core/rasterizer_cache/rasterizer_cache.h

@@ -1,4 +1,4 @@
-// Copyright Citra Emulator Project / Lime3DS Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -765,7 +765,8 @@ FramebufferHelper<T> RasterizerCache<T>::GetFramebufferSurfaces(bool using_color
         it->second = slot_framebuffers.insert(runtime, fb_params, color_surface, depth_surface);
     }
 
-    return FramebufferHelper<T>{this, &slot_framebuffers[it->second], regs.rasterizer, fb_rect};
+    return FramebufferHelper<T>{this, &slot_framebuffers[it->second],
+                                regs.framebuffer.framebuffer.IsFlipped(), regs.rasterizer, fb_rect};
 }
 
 template <class T>

src/video_core/renderer_opengl/gl_rasterizer.cpp

@@ -1,4 +1,4 @@
-// Copyright 2022 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -409,6 +409,12 @@ bool RasterizerOpenGL::Draw(bool accelerate, bool is_indexed) {
     state.viewport.width = static_cast<GLsizei>(viewport.width);
     state.viewport.height = static_cast<GLsizei>(viewport.height);
 
+    // If the framebuffer is flipped, request vertex shader to flip vertex y
+    const bool is_flipped = regs.framebuffer.framebuffer.IsFlipped();
+    vs_uniform_block_data.dirty |= vs_uniform_block_data.data.flip_viewport != is_flipped;
+    vs_uniform_block_data.data.flip_viewport = is_flipped;
+    state.cull.mode = is_flipped && state.cull.enabled ? GL_FRONT : GL_BACK;
+
     // Viewport can have negative offsets or larger dimensions than our framebuffer sub-rect.
     // Enable scissor test to prevent drawing outside of the framebuffer region
     const auto draw_rect = fb_helper.DrawRect();

src/video_core/renderer_vulkan/pica_to_vk.h

@@ -1,4 +1,4 @@
-// Copyright 2023 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -177,13 +177,13 @@ inline vk::PrimitiveTopology PrimitiveTopology(Pica::PipelineRegs::TriangleTopol
     return vk::PrimitiveTopology::eTriangleList;
 }
 
-inline vk::CullModeFlags CullMode(Pica::RasterizerRegs::CullMode mode) {
+inline vk::CullModeFlags CullMode(Pica::RasterizerRegs::CullMode mode, bool flip_viewport) {
     switch (mode) {
     case Pica::RasterizerRegs::CullMode::KeepAll:
         return vk::CullModeFlagBits::eNone;
     case Pica::RasterizerRegs::CullMode::KeepClockWise:
     case Pica::RasterizerRegs::CullMode::KeepCounterClockWise:
-        return vk::CullModeFlagBits::eBack;
+        return flip_viewport ? vk::CullModeFlagBits::eFront : vk::CullModeFlagBits::eBack;
     default:
         UNREACHABLE_MSG("Unknown cull mode {}", mode);
     }

src/video_core/renderer_vulkan/vk_graphics_pipeline.cpp

@@ -1,4 +1,4 @@
-// Copyright 2023 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -147,7 +147,8 @@ bool GraphicsPipeline::Build(bool fail_on_compile_required) {
     const vk::PipelineRasterizationStateCreateInfo raster_state = {
         .depthClampEnable = false,
         .rasterizerDiscardEnable = false,
-        .cullMode = PicaToVK::CullMode(info.rasterization.cull_mode),
+        .cullMode =
+            PicaToVK::CullMode(info.rasterization.cull_mode, info.rasterization.flip_viewport),
         .frontFace = PicaToVK::FrontFace(info.rasterization.cull_mode),
         .depthBiasEnable = false,
         .lineWidth = 1.0f,

src/video_core/renderer_vulkan/vk_graphics_pipeline.h

@@ -1,4 +1,4 @@
-// Copyright 2023 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -54,6 +54,7 @@ union RasterizationState {
     u8 value = 0;
     BitField<0, 2, Pica::PipelineRegs::TriangleTopology> topology;
     BitField<4, 2, Pica::RasterizerRegs::CullMode> cull_mode;
+    BitField<6, 1, u8> flip_viewport;
 };
 
 union DepthStencilState {

src/video_core/renderer_vulkan/vk_pipeline_cache.cpp

@@ -1,4 +1,4 @@
-// Copyright 2023 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -271,8 +271,12 @@ bool PipelineCache::BindPipeline(const PipelineInfo& info, bool wait_built) {
         }
 
         if (instance.IsExtendedDynamicStateSupported()) {
-            if (rasterization.cull_mode != current_rasterization.cull_mode || is_dirty) {
-                cmdbuf.setCullModeEXT(PicaToVK::CullMode(rasterization.cull_mode));
+            const bool needs_flip =
+                rasterization.flip_viewport != current_rasterization.flip_viewport;
+            if (rasterization.cull_mode != current_rasterization.cull_mode || needs_flip ||
+                is_dirty) {
+                cmdbuf.setCullModeEXT(
+                    PicaToVK::CullMode(rasterization.cull_mode, rasterization.flip_viewport));
                 cmdbuf.setFrontFaceEXT(PicaToVK::FrontFace(rasterization.cull_mode));
             }
 

src/video_core/renderer_vulkan/vk_rasterizer.cpp

@@ -1,4 +1,4 @@
-// Copyright 2023 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -509,6 +509,12 @@ bool RasterizerVulkan::Draw(bool accelerate, bool is_indexed) {
         shader_dirty = false;
     }
 
+    // If the framebuffer is flipped, request to also flip vulkan viewport
+    const bool is_flipped = regs.framebuffer.framebuffer.IsFlipped();
+    vs_uniform_block_data.dirty |= vs_uniform_block_data.data.flip_viewport != is_flipped;
+    vs_uniform_block_data.data.flip_viewport = is_flipped;
+    pipeline_info.rasterization.flip_viewport.Assign(is_flipped);
+
     // Sync the LUTs within the texture buffer
     SyncAndUploadLUTs();
     SyncAndUploadLUTsLF();

src/video_core/shader/generator/glsl_shader_gen.cpp

@@ -1,4 +1,4 @@
-// Copyright 2023 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -37,6 +37,7 @@ layout (set = 0, binding = 1, std140) uniform vs_data {
 layout (binding = 1, std140) uniform vs_data {
 #endif
     bool enable_clip1;
+    bool flip_viewport;
     vec4 clip_coef;
 };
 
@@ -123,6 +124,9 @@ void main() {
     normquat = vert_normquat;
     view = vert_view;
     vec4 vtx_pos = SanitizeVertex(vert_position);
+    if (flip_viewport) {
+        vtx_pos.y = -vtx_pos.y;
+    }
     gl_Position = vec4(vtx_pos.x, vtx_pos.y, -vtx_pos.z, vtx_pos.w);
 )";
     if (use_clip_planes) {
@@ -238,6 +242,9 @@ std::string GenerateVertexShader(const ShaderSetup& setup, const PicaVSConfig& c
                semantic(VSOutputAttributes::POSITION_Z) + ", " +
                semantic(VSOutputAttributes::POSITION_W) + ");\n";
         out += "    vtx_pos = SanitizeVertex(vtx_pos);\n";
+        out += "    if (flip_viewport) {\n";
+        out += "        vtx_pos.y = -vtx_pos.y;\n";
+        out += "    }\n";
         out += "    gl_Position = vec4(vtx_pos.x, vtx_pos.y, -vtx_pos.z, vtx_pos.w);\n";
         if (config.state.use_clip_planes) {
             out += "    gl_ClipDistance[0] = -vtx_pos.z;\n"; // fixed PICA clipping plane z <= 0
@@ -332,6 +339,9 @@ struct Vertex {
            semantic(VSOutputAttributes::POSITION_Z) + ", " +
            semantic(VSOutputAttributes::POSITION_W) + ");\n";
     out += "    vtx_pos = SanitizeVertex(vtx_pos);\n";
+    out += "    if (flip_viewport) {\n";
+    out += "        vtx_pos.y = -vtx_pos.y;\n";
+    out += "    }\n";
     out += "    gl_Position = vec4(vtx_pos.x, vtx_pos.y, -vtx_pos.z, vtx_pos.w);\n";
     if (state.use_clip_planes) {
         out += "    gl_ClipDistance[0] = -vtx_pos.z;\n"; // fixed PICA clipping plane z <= 0

src/video_core/shader/generator/shader_uniforms.h

@@ -1,4 +1,4 @@
-// Copyright 2023 Citra Emulator Project
+// Copyright Citra Emulator Project / Azahar Emulator Project
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
@@ -86,7 +86,8 @@ struct PicaUniformsData {
 };
 
 struct VSUniformData {
-    u32 enable_clip1;
+    alignas(4) bool enable_clip1;
+    alignas(4) bool flip_viewport;
     alignas(16) Common::Vec4f clip_coef;
 };
 static_assert(sizeof(VSUniformData) == 32,