ir_constant_expression: Add support for the "lessThan" builtin.

1 files changed, 16 insertions, 1 deletions

diff --git a/src/glsl/ir_constant_expression.cpp b/src/glsl/ir_constant_expression.cpp
index 4a5eb7540a4..032214eb3c4 100644
--- a/src/glsl/ir_constant_expression.cpp
+++ b/src/glsl/ir_constant_expression.cpp
@@ -901,7 +901,22 @@ ir_call::constant_expression_value()
    } else if (strcmp(callee, "length") == 0) {
       return NULL; /* FINISHME: implement this */
    } else if (strcmp(callee, "lessThan") == 0) {
-      return NULL; /* FINISHME: implement this */
+      assert(op[0]->type->is_vector() && op[1] && op[1]->type->is_vector());
+      for (unsigned c = 0; c < op[0]->type->components(); c++) {
+	 switch (op[0]->type->base_type) {
+	 case GLSL_TYPE_UINT:
+	    data.b[c] = op[0]->value.u[c] < op[1]->value.u[c];
+	    break;
+	 case GLSL_TYPE_INT:
+	    data.b[c] = op[0]->value.i[c] < op[1]->value.i[c];
+	    break;
+	 case GLSL_TYPE_FLOAT:
+	    data.b[c] = op[0]->value.f[c] < op[1]->value.f[c];
+	    break;
+	 default:
+	    assert(!"Should not get here.");
+	 }
+      }
    } else if (strcmp(callee, "lessThanEqual") == 0) {
       return NULL; /* FINISHME: implement this */
    } else if (strcmp(callee, "log") == 0) {