[D3D12] Truncate depth to float24 in EDRAM range ownership transfers and resolves by default

Doesn't ruin the "greater or equal" depth test in subsequent rendering passes if precision is lost, unlike rounding to the nearest

src/xenia/gpu/render_target_cache.h

@@ -29,6 +29,8 @@
 #include "xenia/gpu/xenos.h"
 
 DECLARE_bool(depth_transfer_not_equal_test);
+DECLARE_bool(depth_float24_round);
+DECLARE_bool(depth_float24_convert_in_pixel_shader);
 DECLARE_bool(draw_resolution_scaled_texture_offsets);
 DECLARE_bool(gamma_render_target_as_srgb);
 DECLARE_bool(native_2x_msaa);
@@ -89,60 +91,6 @@ class RenderTargetCache {
     kPixelShaderInterlock,
   };
 
-  enum class DepthFloat24Conversion {
-    // Doing depth test at the host precision, converting to 20e4 to support
-    // reinterpretation, but keeping track of both the last color (or non-20e4
-    // depth) value (let's call it stored_f24) and the last host depth value
-    // (stored_host) for each EDRAM pixel, reloading the last host depth value
-    // if stored_f24 == to_f24(stored_host) (otherwise it was overwritten by
-    // something else, like clearing, or an actually used color buffer; this is
-    // inexact though, and will incorrectly load pixels that were overwritten by
-    // something else in the EDRAM, but turned out to have the same value on the
-    // guest as before - an outdated host-precision value will be loaded in
-    // these cases instead).
-    //
-    // EDRAM > RAM, then reusing the EDRAM region for something else > EDRAM
-    // round trip destroys precision beyond repair.
-    //
-    // Full host early Z and MSAA with pixel-rate shading are supported.
-    kOnCopy,
-    // Converting the depth to the closest host value representable exactly as a
-    // 20e4 float in pixel shaders, to support invariance in cases when the
-    // guest reuploads a previously resolved depth buffer to the EDRAM, rounding
-    // towards zero (which contradicts the rounding used by the Direct3D 9
-    // reference rasterizer, but allows less-than-or-equal pixel shader depth
-    // output to be used to preserve most of early Z culling when the game is
-    // using reversed depth, which is the usual way of doing depth testing on
-    // the Xbox 360 and of utilizing the advantages of a floating-point
-    // encoding).
-    //
-    // With MSAA, pixel shaders must run at sample frequency - otherwise, if the
-    // depth is the same for the entire pixel, intersections of polygons cannot
-    // be antialiased.
-    //
-    // Important usage note: When using this mode, bounds of the fixed-function
-    // viewport must be converted to and back from float24 too (preferably using
-    // correct rounding to the nearest even, to reduce the error already caused
-    // by truncation rather than to amplify it). This ensures that clamping to
-    // the viewport bounds, which happens after the pixel shader even if it
-    // overwrites the resulting depth, is never done to a value not
-    // representable as float24 (for example, if the minimum Z is a number too
-    // small to be represented as float24, but not zero, it won't be possible to
-    // write what should become 0x000000 to the depth buffer). Note that this
-    // may add some error to the depth values from the rasterizer; however,
-    // modifying Z in the vertex shader to make interpolated depth values would
-    // cause clipping to be done to different bounds, which may be more
-    // undesirable, especially in cases when Z is explicitly set to a value like
-    // 0 or W (in such cases, the adjusted polygon may go outside 0...W in clip
-    // space and disappear).
-    kOnOutputTruncating,
-    // Similar to kOnOutputTruncating, but rounding to the nearest even, more
-    // correctly, however, because the resulting depth can be bigger than the
-    // original host value, early depth testing can't be used at all. Same
-    // viewport usage rules apply.
-    kOnOutputRounding,
-  };
-
   // Useful host-specific values.
   // sRGB conversion from the Direct3D 11.3 functional specification.
   static constexpr float kSrgbToLinearDenominator1 = 12.92f;
@@ -512,8 +460,6 @@ class RenderTargetCache {
     }
   };
 
-  static DepthFloat24Conversion GetConfigDepthFloat24Conversion();
-
   virtual uint32_t GetMaxRenderTargetWidth() const = 0;
   virtual uint32_t GetMaxRenderTargetHeight() const = 0;