Implement zcomploc on OpenGL4.2+

This commit is contained in:
degasus
2013-07-22 12:02:16 +02:00
parent f693488c8a
commit 15b8ac64ef
9 changed files with 45 additions and 16 deletions

View File

@ -258,7 +258,8 @@ static void GeneratePixelShader(T& out, DSTALPHA_MODE dstAlphaMode, API_TYPE Api
unsigned int numStages = bpmem.genMode.numtevstages + 1;
unsigned int numTexgen = bpmem.genMode.numtexgens;
const bool per_pixel_depth = (bpmem.ztex2.op != ZTEXTURE_DISABLE && !bpmem.zcontrol.early_ztest && bpmem.zmode.testenable) || !g_ActiveConfig.bFastDepthCalc;
const bool forced_early_z = g_ActiveConfig.backend_info.bSupportsEarlyZ && bpmem.zcontrol.early_ztest && (g_ActiveConfig.bFastDepthCalc || bpmem.alpha_test.TestResult() == AlphaTest::UNDETERMINED);
const bool per_pixel_depth = (bpmem.ztex2.op != ZTEXTURE_DISABLE && !bpmem.zcontrol.early_ztest && bpmem.zmode.testenable) || (!g_ActiveConfig.bFastDepthCalc && !forced_early_z);
out.Write("//Pixel Shader for TEV stages\n");
out.Write("//%i TEV stages, %i texgens, %i IND stages\n",
@ -372,6 +373,14 @@ static void GeneratePixelShader(T& out, DSTALPHA_MODE dstAlphaMode, API_TYPE Api
}
out.Write("float4 clipPos;\n");
}
if (forced_early_z)
{
// HACK: This doesn't force the driver to write to depth buffer if alpha test fails.
// It just allows it, but it seems that all drivers do.
out.Write("layout(early_fragment_tests) in;\n");
}
out.Write("void main()\n{\n");
}
else
@ -584,6 +593,7 @@ static void GeneratePixelShader(T& out, DSTALPHA_MODE dstAlphaMode, API_TYPE Api
uid_data.ztex_op = bpmem.ztex2.op;
uid_data.per_pixel_depth = per_pixel_depth;
uid_data.forced_early_z = forced_early_z;
uid_data.fast_depth_calc = g_ActiveConfig.bFastDepthCalc;
uid_data.early_ztest = bpmem.zcontrol.early_ztest;
uid_data.fog_fsel = bpmem.fog.c_proj_fsel.fsel;
@ -1129,17 +1139,20 @@ static void WriteAlphaTest(T& out, pixel_shader_uid_data& uid_data, API_TYPE Api
out.Write("\t\tdepth = 1.f;\n");
// HAXX: zcomploc (aka early_ztest) is a way to control whether depth test is done before
// or after texturing and alpha test. PC GPUs have no way to support this
// feature properly as of 2012: depth buffer and depth test are not
// or after texturing and alpha test. PC graphics APIs have no way to support this
// feature properly as of 2012: Depth buffer and depth test are not
// programmable and the depth test is always done after texturing.
// Most importantly, PC GPUs do not allow writing to the z-buffer without
// Most importantly, they do not allow writing to the z-buffer without
// writing a color value (unless color writing is disabled altogether).
// We implement "depth test before texturing" by discarding the fragment
// when the alpha test fail. This is not a correct implementation because
// even if the depth test fails the fragment could be alpha blended, but
// we don't have a choice.
uid_data.alpha_test_use_zcomploc_hack = bpmem.zcontrol.early_ztest && bpmem.zmode.updateenable;
if (!(bpmem.zcontrol.early_ztest && bpmem.zmode.updateenable))
// We implement "depth test before texturing" by disabling alpha test when early-z is in use.
// It seems to be less buggy than not to update the depth buffer if alpha test fails,
// but both ways wouldn't be accurate.
// OpenGL 4.2 has a flag which allows the driver to still update the depth buffer
// if alpha test fails. The driver doesn't have to, but I assume they all do because
// it's the much faster code path for the GPU.
uid_data.alpha_test_use_zcomploc_hack = bpmem.zcontrol.early_ztest && bpmem.zmode.updateenable && !g_ActiveConfig.backend_info.bSupportsEarlyZ;
if (!uid_data.alpha_test_use_zcomploc_hack)
{
out.Write("\t\tdiscard;\n");
if (ApiType != API_D3D11)