Module: Mesa Branch: main Commit: f8eec4c4e3a11de7e4617d9e7d8c9a28105ca645 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=f8eec4c4e3a11de7e4617d9e7d8c9a28105ca645
Author: Friedrich Vock <[email protected]> Date: Thu Jul 13 16:10:12 2023 +0200 radv/rt: Reject hits within 10ULP of previous hits in emulated RT This is an alternative workaround that fixes double hits on shared edges failing some watertightness CTS tests. Fixes: e034ba1c44 ("radv/rt: Miss rays that hit the triangle's v edge") Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24093> --- src/amd/vulkan/radv_rt_common.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/src/amd/vulkan/radv_rt_common.c b/src/amd/vulkan/radv_rt_common.c index 5aab4dc9e9c..22e950a18ef 100644 --- a/src/amd/vulkan/radv_rt_common.c +++ b/src/amd/vulkan/radv_rt_common.c @@ -258,13 +258,6 @@ intersect_ray_amd_software_tri(struct radv_device *device, nir_builder *b, nir_d nir_def *cond = nir_inot(b, nir_iand(b, cond_back, cond_front)); - /* If the ray is exactly on the edge where v is 0, consider it a miss. - * This seems to correspond to what the hardware is doing. - * Also, it avoids invoking hit shaders twice on a shared edge, which is - * discouraged by the spec. - */ - cond = nir_iand(b, cond, nir_fneu(b, v, nir_imm_float(b, 0.0f))); - nir_push_if(b, cond); { nir_def *det = nir_fadd(b, u, nir_fadd(b, v, w)); @@ -373,7 +366,9 @@ insert_traversal_triangle_case(struct radv_device *device, nir_builder *b, const nir_def *div = nir_channel(b, result, 1); intersection.t = nir_fdiv(b, intersection.t, div); - nir_push_if(b, nir_flt(b, intersection.t, nir_load_deref(b, args->vars.tmax))); + nir_def *tmax = nir_load_deref(b, args->vars.tmax); + + nir_push_if(b, nir_flt(b, intersection.t, tmax)); { intersection.frontface = nir_fgt_imm(b, div, 0); nir_def *switch_ccw = @@ -408,6 +403,20 @@ insert_traversal_triangle_case(struct radv_device *device, nir_builder *b, const nir_def *divs[2] = {div, div}; intersection.barycentrics = nir_fdiv(b, nir_channels(b, result, 0xc), nir_vec(b, divs, 2)); + nir_def *hit_t = intersection.t; + /* t values within 10 ULP of the current hit t are most likely duplicate hits along shared edges, which + * might occur with emulated RT. The Vulkan spec discourages double-hits along shared-edges, so reject them + * here by subtracting 10 ULP from t. + */ + if (radv_emulate_rt(device->physical_device)) { + nir_def *abs_t = nir_fabs(b, hit_t); + nir_def *sign_t = nir_fsign(b, hit_t); + + nir_def *tm1 = nir_iadd(b, hit_t, nir_imul_imm(b, nir_f2i32(b, sign_t), -10)); + nir_def *tm2 = nir_fmul(b, nir_isub_imm(b, 10, abs_t), nir_fneg(b, sign_t)); + intersection.t = nir_bcsel(b, nir_ige_imm(b, abs_t, 10), tm1, tm2); + } + args->triangle_cb(b, &intersection, args, ray_flags); } nir_pop_if(b, NULL);
