CPU/PGXP: Use GTE MAX_Z for Z normalization

Fixes clipping with depth buffer in some games, e.g. Final Fantasy VII battles.

Author: stenzek

src/core/cpu_pgxp.cpp

@@ -613,7 +613,7 @@ bool CPU::PGXP::GetPreciseVertex(u32 addr, u32 value, int x, int y, int xOffs, i
   {
     *out_x = TruncateVertexPosition(vert->x) + static_cast<float>(xOffs);
     *out_y = TruncateVertexPosition(vert->y) + static_cast<float>(yOffs);
-    *out_w = vert->z / 32768.0f;
+    *out_w = vert->z / static_cast<float>(GTE::MAX_Z);
 
 #ifdef LOG_LOOKUPS
     GL_INS_FMT("0x{:08X} {},{} => {},{} ({},{},{}) ({},{})", addr, x, y, *out_x, *out_y,
@@ -635,7 +635,7 @@ bool CPU::PGXP::GetPreciseVertex(u32 addr, u32 value, int x, int y, int xOffs, i
     {
       *out_x = TruncateVertexPosition(vert->x) + static_cast<float>(xOffs);
       *out_y = TruncateVertexPosition(vert->y) + static_cast<float>(yOffs);
-      *out_w = vert->z / 32768.0f;
+      *out_w = vert->z / static_cast<float>(GTE::MAX_Z);
 
       if (IsWithinTolerance(*out_x, *out_y, x, y))
         return false;

src/core/gte.cpp

@@ -791,9 +791,9 @@ void GTE::RTPS(const s16 V[3], u8 shift, bool lm, bool last)
       }
       else
       {
-        precise_x = static_cast<float>(x) / 4096.0f;
+        precise_x = static_cast<float>(x) / (static_cast<float>(1 << shift));
         precise_y = static_cast<float>(y) / (static_cast<float>(1 << shift));
-        precise_z = static_cast<float>(z) / (static_cast<float>(1 << shift));
+        precise_z = static_cast<float>(z) / 4096.0f;
       }
 
       precise_sz3 = precise_z;

src/core/gte_types.h

@@ -11,7 +11,8 @@ enum : u32
 {
   NUM_DATA_REGS = 32,
   NUM_CONTROL_REGS = 32,
-  NUM_REGS = NUM_DATA_REGS + NUM_CONTROL_REGS
+  NUM_REGS = NUM_DATA_REGS + NUM_CONTROL_REGS,
+  MAX_Z = 65535,
 };
 
 union FLAGS

src/core/settings.cpp

@@ -4,6 +4,7 @@
 #include "settings.h"
 #include "achievements.h"
 #include "controller.h"
+#include "gte.h"
 #include "host.h"
 #include "imgui_overlays.h"
 #include "system.h"
@@ -90,7 +91,20 @@ float SettingInfo::FloatStepValue() const
   return step_value ? StringUtil::FromChars<float>(step_value).value_or(fallback_value) : fallback_value;
 }
 
-GPUSettings::GPUSettings() = default;
+GPUSettings::GPUSettings()
+{
+  SetPGXPDepthClearThreshold(DEFAULT_GPU_PGXP_DEPTH_THRESHOLD);
+}
+
+float GPUSettings::GetPGXPDepthClearThreshold() const
+{
+  return gpu_pgxp_depth_clear_threshold * static_cast<float>(GTE::MAX_Z);
+}
+
+void GPUSettings::SetPGXPDepthClearThreshold(float value)
+{
+  gpu_pgxp_depth_clear_threshold = value / static_cast<float>(GTE::MAX_Z);
+}
 
 #ifdef DYNAMIC_HOST_PAGE_SIZE
 // See note in settings.h - 16K ends up faster with LUT because of nearby code/data.

src/core/settings.h

@@ -150,7 +150,7 @@ struct GPUSettings
   float display_osd_scale = DEFAULT_OSD_SCALE;
   float display_osd_margin = 0.0f;
   float gpu_pgxp_tolerance = -1.0f;
-  float gpu_pgxp_depth_clear_threshold = DEFAULT_GPU_PGXP_DEPTH_THRESHOLD / GPU_PGXP_DEPTH_THRESHOLD_SCALE;
+  float gpu_pgxp_depth_clear_threshold = 0.0f;
 
   // texture replacements
   struct TextureReplacementSettings
@@ -209,6 +209,8 @@ struct GPUSettings
   std::string overlay_image_path;
 
   float GetDisplayAspectRatioValue() const;
+  float GetPGXPDepthClearThreshold() const;
+  void SetPGXPDepthClearThreshold(float value);
 
   ALWAYS_INLINE bool IsUsingSoftwareRenderer() const { return (gpu_renderer == GPURenderer::Software); }
   ALWAYS_INLINE bool IsUsingAccurateBlending() const { return (gpu_accurate_blending && !gpu_true_color); }
@@ -220,14 +222,6 @@ struct GPUSettings
 
   ALWAYS_INLINE bool UsingPGXPCPUMode() const { return gpu_pgxp_enable && gpu_pgxp_cpu; }
   ALWAYS_INLINE bool UsingPGXPDepthBuffer() const { return gpu_pgxp_enable && gpu_pgxp_depth_buffer; }
-  ALWAYS_INLINE float GetPGXPDepthClearThreshold() const
-  {
-    return gpu_pgxp_depth_clear_threshold * GPU_PGXP_DEPTH_THRESHOLD_SCALE;
-  }
-  ALWAYS_INLINE void SetPGXPDepthClearThreshold(float value)
-  {
-    gpu_pgxp_depth_clear_threshold = value / GPU_PGXP_DEPTH_THRESHOLD_SCALE;
-  }
 
   static constexpr GPURenderer DEFAULT_GPU_RENDERER = GPURenderer::Automatic;
   static constexpr GPUTextureFilter DEFAULT_GPU_TEXTURE_FILTER = GPUTextureFilter::Nearest;
@@ -236,7 +230,7 @@ struct GPUSettings
   static constexpr GPUWireframeMode DEFAULT_GPU_WIREFRAME_MODE = GPUWireframeMode::Disabled;
   static constexpr GPUDumpCompressionMode DEFAULT_GPU_DUMP_COMPRESSION_MODE = GPUDumpCompressionMode::ZstDefault;
   static constexpr float DEFAULT_GPU_PGXP_DEPTH_THRESHOLD = 300.0f;
-  static constexpr float GPU_PGXP_DEPTH_THRESHOLD_SCALE = 4096.0f;
+  static constexpr float GPU_PGXP_DEPTH_THRESHOLD_SCALE = 65536.0f;
 
   static constexpr DisplayDeinterlacingMode DEFAULT_DISPLAY_DEINTERLACING_MODE = DisplayDeinterlacingMode::Progressive;
   static constexpr DisplayCropMode DEFAULT_DISPLAY_CROP_MODE = DisplayCropMode::Overscan;