From f3d387867f74ae758b41168f23992671f7dce254 Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Tue, 1 Nov 2016 11:56:13 -0700 Subject: [PATCH] nir: Flip gl_SamplePosition in nir_lower_wpos_ytransform(). Assuming the hardware is set up to use a screen coordinate system flipped vertically with respect to the GL's window coordinate system, the SYSTEM_VALUE_SAMPLE_POS vector will also be flipped vertically with respect to the value expected by the GL, so we need to give it the same treatment as gl_FragCoord. Fixes the following CTS tests on i965: ES31-CTS.functional.shaders.multisample_interpolation.interpolate_at_offset.at_sample_position.default_framebuffer ES31-CTS.functional.shaders.sample_variables.sample_pos.correctness.default_framebuffer when run with any multisample configuration, e.g. rgba8888d24s8ms4. Cc: Reviewed-by: Kenneth Graunke Reviewed-by: Anuj Phogat --- src/compiler/nir/nir_lower_wpos_ytransform.c | 24 ++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/src/compiler/nir/nir_lower_wpos_ytransform.c b/src/compiler/nir/nir_lower_wpos_ytransform.c index 173f0585729..f211c733d0d 100644 --- a/src/compiler/nir/nir_lower_wpos_ytransform.c +++ b/src/compiler/nir/nir_lower_wpos_ytransform.c @@ -272,6 +272,26 @@ lower_interp_var_at_offset(lower_wpos_ytransform_state *state, flip_y))); } +static void +lower_load_sample_pos(lower_wpos_ytransform_state *state, + nir_intrinsic_instr *intr) +{ + nir_builder *b = &state->b; + b->cursor = nir_after_instr(&intr->instr); + + nir_ssa_def *pos = &intr->dest.ssa; + nir_ssa_def *scale = nir_channel(b, get_transform(state), 0); + nir_ssa_def *neg_scale = nir_channel(b, get_transform(state), 2); + /* Either y or 1-y for scale equal to 1 or -1 respectively. */ + nir_ssa_def *flipped_y = + nir_fadd(b, nir_fmax(b, neg_scale, nir_imm_float(b, 0.0)), + nir_fmul(b, nir_channel(b, pos, 1), scale)); + nir_ssa_def *flipped_pos = nir_vec2(b, nir_channel(b, pos, 0), flipped_y); + + nir_ssa_def_rewrite_uses_after(&intr->dest.ssa, nir_src_for_ssa(flipped_pos), + flipped_pos->parent_instr); +} + static void lower_wpos_ytransform_block(lower_wpos_ytransform_state *state, nir_block *block) { @@ -287,6 +307,10 @@ lower_wpos_ytransform_block(lower_wpos_ytransform_state *state, nir_block *block /* gl_FragCoord should not have array/struct deref's: */ assert(dvar->deref.child == NULL); lower_fragcoord(state, intr); + } else if (var->data.mode == nir_var_system_value && + var->data.location == SYSTEM_VALUE_SAMPLE_POS) { + assert(dvar->deref.child == NULL); + lower_load_sample_pos(state, intr); } } else if (intr->intrinsic == nir_intrinsic_interp_var_at_offset) { lower_interp_var_at_offset(state, intr); -- 2.30.2