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-rw-r--r--src/shader_recompiler/backend/spirv/emit_spirv_special.cpp45
1 files changed, 45 insertions, 0 deletions
diff --git a/src/shader_recompiler/backend/spirv/emit_spirv_special.cpp b/src/shader_recompiler/backend/spirv/emit_spirv_special.cpp
index 7af29e4dd..8bb94f546 100644
--- a/src/shader_recompiler/backend/spirv/emit_spirv_special.cpp
+++ b/src/shader_recompiler/backend/spirv/emit_spirv_special.cpp
@@ -37,6 +37,48 @@ Id DefaultVarying(EmitContext& ctx, u32 num_components, u32 element, Id zero, Id
}
throw InvalidArgument("Bad element");
}
+
+Id ComparisonFunction(EmitContext& ctx, CompareFunction comparison, Id operand_1, Id operand_2) {
+ switch (comparison) {
+ case CompareFunction::Never:
+ return ctx.false_value;
+ case CompareFunction::Less:
+ return ctx.OpFOrdLessThan(ctx.U1, operand_1, operand_2);
+ case CompareFunction::Equal:
+ return ctx.OpFOrdEqual(ctx.U1, operand_1, operand_2);
+ case CompareFunction::LessThanEqual:
+ return ctx.OpFOrdLessThanEqual(ctx.U1, operand_1, operand_2);
+ case CompareFunction::Greater:
+ return ctx.OpFOrdGreaterThan(ctx.U1, operand_1, operand_2);
+ case CompareFunction::NotEqual:
+ return ctx.OpFOrdNotEqual(ctx.U1, operand_1, operand_2);
+ case CompareFunction::GreaterThanEqual:
+ return ctx.OpFOrdGreaterThanEqual(ctx.U1, operand_1, operand_2);
+ case CompareFunction::Always:
+ return ctx.true_value;
+ }
+ throw InvalidArgument("Comparison function {}", comparison);
+}
+
+void AlphaTest(EmitContext& ctx) {
+ const auto comparison{*ctx.profile.alpha_test_func};
+ if (comparison == CompareFunction::Always) {
+ return;
+ }
+ const Id type{ctx.F32[1]};
+ const Id rt0_color{ctx.OpLoad(ctx.F32[4], ctx.frag_color[0])};
+ const Id alpha{ctx.OpCompositeExtract(type, rt0_color, 3u)};
+
+ const Id true_label{ctx.OpLabel()};
+ const Id discard_label{ctx.OpLabel()};
+ const Id alpha_reference{ctx.Constant(ctx.F32[1], ctx.profile.alpha_test_reference)};
+ const Id condition{ComparisonFunction(ctx, comparison, alpha, alpha_reference)};
+
+ ctx.OpBranchConditional(condition, true_label, discard_label);
+ ctx.AddLabel(discard_label);
+ ctx.OpKill();
+ ctx.AddLabel(true_label);
+}
} // Anonymous namespace
void EmitPrologue(EmitContext& ctx) {
@@ -68,6 +110,9 @@ void EmitEpilogue(EmitContext& ctx) {
if (ctx.stage == Stage::VertexB && ctx.profile.convert_depth_mode) {
ConvertDepthMode(ctx);
}
+ if (ctx.stage == Stage::Fragment) {
+ AlphaTest(ctx);
+ }
}
void EmitEmitVertex(EmitContext& ctx, const IR::Value& stream) {