GPU: Add auto (game native) aspect ratio

src/core/gpu.cpp

@@ -7,6 +7,7 @@
 #include "host_display.h"
 #include "host_interface.h"
 #include "interrupt_controller.h"
+#include "settings.h"
 #include "stb_image_write.h"
 #include "system.h"
 #include "timers.h"
@@ -456,9 +457,41 @@ float GPU::ComputeVerticalFrequency() const
 float GPU::GetDisplayAspectRatio() const
 {
   if (g_settings.display_force_4_3_for_24bit && m_GPUSTAT.display_area_color_depth_24)
+  {
     return 4.0f / 3.0f;
+  }
+  else if (g_settings.display_aspect_ratio == DisplayAspectRatio::Auto)
+  {
+    const CRTCState& cs = m_crtc_state;
+    float relative_width = static_cast<float>(cs.horizontal_visible_end - cs.horizontal_visible_start);
+    float relative_height = static_cast<float>(cs.vertical_visible_end - cs.vertical_visible_start);
+
+    if (relative_width <= 0 || relative_height <= 0)
+      return 4.0f / 3.0f;
+
+    if (m_GPUSTAT.pal_mode)
+    {
+      relative_width /= static_cast<float>(PAL_HORIZONTAL_ACTIVE_END - PAL_HORIZONTAL_ACTIVE_START);
+      relative_height /= static_cast<float>(PAL_VERTICAL_ACTIVE_END - PAL_VERTICAL_ACTIVE_START);
+    }
+    else
+    {
+      relative_width /= static_cast<float>(NTSC_HORIZONTAL_ACTIVE_END - NTSC_HORIZONTAL_ACTIVE_START);
+      relative_height /= static_cast<float>(NTSC_VERTICAL_ACTIVE_END - NTSC_VERTICAL_ACTIVE_START);
+    }
+    return (relative_width / relative_height) * (4.0f / 3.0f);
+  }
+  else if (g_settings.display_aspect_ratio == DisplayAspectRatio::PAR1_1)
+  {
+    if (m_crtc_state.display_width == 0 || m_crtc_state.display_height == 0)
+      return 4.0f / 3.0f;
+
+    return static_cast<float>(m_crtc_state.display_width) / static_cast<float>(m_crtc_state.display_height);
+  }
   else
+  {
     return Settings::GetDisplayAspectRatioValue(g_settings.display_aspect_ratio);
+  }
 }
 
 void GPU::UpdateCRTCConfig()

src/core/gte.cpp

@@ -655,6 +655,7 @@ static void RTPS(const s16 V[3], u8 shift, bool lm, bool last)
         Sx = ((((s64(result) * s64(REGS.IR1)) * s64(7)) / s64(6)) + s64(REGS.OFX));
         break;
 
+      case DisplayAspectRatio::Auto:
       case DisplayAspectRatio::R4_3:
       case DisplayAspectRatio::PAR1_1:
       default:
@@ -747,6 +748,7 @@ static void RTPS(const s16 V[3], u8 shift, bool lm, bool last)
           precise_x = (precise_x * 7.0f) / 6.0f;
           break;
 
+        case DisplayAspectRatio::Auto:
         case DisplayAspectRatio::R4_3:
         case DisplayAspectRatio::PAR1_1:
         default:

src/core/host_display.cpp

@@ -138,7 +138,6 @@ void HostDisplay::CalculateDrawRect(s32 window_width, s32 window_height, s32* ou
                                     s32* out_height, s32* out_left_padding, s32* out_top_padding, float* out_scale,
                                     float* out_y_scale, bool apply_aspect_ratio) const
 {
-  apply_aspect_ratio = (m_display_aspect_ratio > 0) ? apply_aspect_ratio : false;
   const float y_scale =
     apply_aspect_ratio ?
       ((static_cast<float>(m_display_width) / static_cast<float>(m_display_height)) / m_display_aspect_ratio) :

src/core/settings.cpp

@@ -625,10 +625,11 @@ const char* Settings::GetDisplayCropModeDisplayName(DisplayCropMode crop_mode)
   return s_display_crop_mode_display_names[static_cast<int>(crop_mode)];
 }
 
-static std::array<const char*, 11> s_display_aspect_ratio_names = {
-  {"4:3", "16:9", "16:10", "19:9", "21:9", "8:7", "5:4", "3:2", "2:1 (VRAM 1:1)", "1:1", "PAR 1:1"}};
-static constexpr std::array<float, 11> s_display_aspect_ratio_values = {
-  {4.0f / 3.0f, 16.0f / 9.0f, 16.0f / 10.0f, 19.0f / 9.0f, 21.0f / 9.0f, 8.0f / 7.0f, 5.0f / 4.0f, 3.0f / 2.0f,
+static std::array<const char*, 12> s_display_aspect_ratio_names = {{"Auto (Game Native)", "4:3", "16:9", "16:10",
+                                                                    "19:9", "21:9", "8:7", "5:4", "3:2",
+                                                                    "2:1 (VRAM 1:1)", "1:1", "PAR 1:1"}};
+static constexpr std::array<float, 12> s_display_aspect_ratio_values = {
+  {-1.0f, 4.0f / 3.0f, 16.0f / 9.0f, 16.0f / 10.0f, 19.0f / 9.0f, 21.0f / 9.0f, 8.0f / 7.0f, 5.0f / 4.0f, 3.0f / 2.0f,
    2.0f / 1.0f, 1.0f, -1.0f}};
 
 std::optional<DisplayAspectRatio> Settings::ParseDisplayAspectRatio(const char* str)

src/core/settings.h

@@ -111,7 +111,7 @@ struct Settings
   bool gpu_pgxp_cpu = false;
   bool gpu_pgxp_preserve_proj_fp = false;
   DisplayCropMode display_crop_mode = DisplayCropMode::None;
-  DisplayAspectRatio display_aspect_ratio = DisplayAspectRatio::R4_3;
+  DisplayAspectRatio display_aspect_ratio = DisplayAspectRatio::Auto;
   s16 display_active_start_offset = 0;
   s16 display_active_end_offset = 0;
   s8 display_line_start_offset = 0;
@@ -300,7 +300,7 @@ struct Settings
 #endif
 
   static constexpr DisplayCropMode DEFAULT_DISPLAY_CROP_MODE = DisplayCropMode::Overscan;
-  static constexpr DisplayAspectRatio DEFAULT_DISPLAY_ASPECT_RATIO = DisplayAspectRatio::R4_3;
+  static constexpr DisplayAspectRatio DEFAULT_DISPLAY_ASPECT_RATIO = DisplayAspectRatio::Auto;
   static constexpr ControllerType DEFAULT_CONTROLLER_1_TYPE = ControllerType::DigitalController;
   static constexpr ControllerType DEFAULT_CONTROLLER_2_TYPE = ControllerType::None;
   static constexpr MemoryCardType DEFAULT_MEMORY_CARD_1_TYPE = MemoryCardType::PerGameTitle;

src/core/types.h

@@ -85,6 +85,7 @@ enum class DisplayCropMode : u8
 
 enum class DisplayAspectRatio : u8
 {
+  Auto,
   R4_3,
   R16_9,
   R16_10,

src/duckstation-libretro/libretro_host_interface.cpp

@@ -704,7 +704,8 @@ static std::array<retro_core_option_definition, 49> s_option_definitions = {{
   {"duckstation_Display.AspectRatio",
    "Aspect Ratio",
    "Sets the core-provided aspect ratio.",
-   {{"4:3", "4:3"},
+   {{"Auto", "Auto (Game Native)"},
+    {"4:3", "4:3"},
     {"16:9", "16:9"},
     {"16:10", "16:10"},
     {"19:9", "19:9"},
@@ -715,7 +716,7 @@ static std::array<retro_core_option_definition, 49> s_option_definitions = {{
     {"2:1 (VRAM 1:1)", "2:1 (VRAM 1:1)"},
     {"1:1", "1:1"},
     {"PAR 1:1", "PAR 1:1"}},
-   "4:3"},
+   "Auto"},
   {"duckstation_Main.LoadDevicesFromSaveStates",
    "Load Devices From Save States",
    "Sets whether the contents of devices and memory cards will be loaded when a save state is loaded.",

src/duckstation-qt/displaysettingswidget.cpp

@@ -62,9 +62,9 @@ DisplaySettingsWidget::DisplaySettingsWidget(QtHostInterface* host_interface, QW
        "renderers. <br>This option is only supported in Direct3D and Vulkan. OpenGL will always use the default "
        "device."));
   dialog->registerWidgetHelp(
-    m_ui.displayAspectRatio, tr("Aspect Ratio"), QStringLiteral("4:3"),
-    tr("Changes the aspect ratio used to display the console's output to the screen. The default "
-       "is 4:3 which matches a typical TV of the era."));
+    m_ui.displayAspectRatio, tr("Aspect Ratio"), QStringLiteral("Auto (Game Native)"),
+    tr("Changes the aspect ratio used to display the console's output to the screen. The default is Auto (Game Native) "
+       "which automatically adjusts the aspect ratio to match how a game would be shown on a typical TV of the era."));
   dialog->registerWidgetHelp(
     m_ui.displayCropMode, tr("Crop Mode"), tr("Only Overscan Area"),
     tr("Determines how much of the area typically not visible on a consumer TV set to crop/hide. <br>"