They're both implemented the same in GLSL IR (since round() has
undefined behavior for n + 0.5). The specification of the C function
in use here is a bit unclear: rint(3) says that nearbyint() is like
rint() in that it uses the current rounding direction from
fesetround(3). fesetround(3) says behavior is according to
FLT_ROUNDS, which on this system is 1 ("Rounding is toward nearest
number"), but doesn't specify behavior for n + 0.5 in that case.
However, round(3) says that rint(3) has roundEven()'s behavior for n +
0.5.
The testcases we have that do test roundEven()'s behavior for n + 0.5
pass with this change.
Fixes glsl-1.30/compiler/built-in-functions/round*
---
src/glsl/ir_constant_expression.cpp | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/src/glsl/ir_constant_expression.cpp
b/src/glsl/ir_constant_expression.cpp
index b3fe6cf..0d7fae7 100644
--- a/src/glsl/ir_constant_expression.cpp
+++ b/src/glsl/ir_constant_expression.cpp
@@ -196,6 +196,13 @@ ir_expression::constant_expression_value()
}
break;
+ case ir_unop_round_even:
+ assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
+ for (unsigned c = 0; c < op[0]->type->components(); c++) {
+ data.f[c] = nearbyint(op[0]->value.f[c]);
+ }
+ break;
+
case ir_unop_ceil:
assert(op[0]->type->base_type == GLSL_TYPE_FLOAT);
for (unsigned c = 0; c < op[0]->type->components(); c++) {
@@ -1324,6 +1331,9 @@ ir_call::constant_expression_value()
* op[1]->value.f[c];
}
}
+ } else if (strcmp(callee, "round") == 0 ||
+ strcmp(callee, "roundEven") == 0) {
+ expr = new(mem_ctx) ir_expression(ir_unop_round_even, op[0]);
} else if (strcmp(callee, "sign") == 0) {
expr = new(mem_ctx) ir_expression(ir_unop_sign, type, op[0], NULL);
} else if (strcmp(callee, "sin") == 0) {
--
1.7.6.3
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