ir_constant_expression: Add support for the "distance" builtin.
diff --git a/src/glsl/ir_constant_expression.cpp b/src/glsl/ir_constant_expression.cpp
index e68a7b1..52f53d9 100644
--- a/src/glsl/ir_constant_expression.cpp
+++ b/src/glsl/ir_constant_expression.cpp
@@ -854,7 +854,13 @@
for (unsigned c = 0; c < op[0]->type->components(); c++)
data.f[c] = 180.0/M_PI * op[0]->value.f[c];
} else if (strcmp(callee, "distance") == 0) {
- return NULL; /* FINISHME: implement this */
+ assert(op[0]->type->is_float() && op[1]->type->is_float());
+ float length_squared = 0.0;
+ for (unsigned c = 0; c < op[0]->type->components(); c++) {
+ float t = op[0]->value.f[c] - op[1]->value.f[c];
+ length_squared += t * t;
+ }
+ return new(mem_ctx) ir_constant(sqrtf(length_squared));
} else if (strcmp(callee, "dot") == 0) {
expr = new(mem_ctx) ir_expression(ir_binop_dot, type, op[0], op[1]);
} else if (strcmp(callee, "equal") == 0) {