ir_constant_visitor: Handle array access of constant vectors and matrices
diff --git a/ir_constant_expression.cpp b/ir_constant_expression.cpp
index 8e9e74b..a7c4fe6 100644
--- a/ir_constant_expression.cpp
+++ b/ir_constant_expression.cpp
@@ -557,9 +557,57 @@
void
ir_constant_visitor::visit(ir_dereference_array *ir)
{
- (void) ir;
- value = NULL;
- /* FINISHME: Other dereference modes. */
+ ir_constant *array = ir->array->constant_expression_value();
+ ir_constant *idx = ir->array_index->constant_expression_value();
+
+ this->value = NULL;
+
+ if ((array != NULL) && (idx != NULL)) {
+ if (array->type->is_matrix()) {
+ /* Array access of a matrix results in a vector.
+ */
+ const unsigned column = idx->value.u[0];
+
+ const glsl_type *const column_type = array->type->column_type();
+
+ /* Offset in the constant matrix to the first element of the column
+ * to be extracted.
+ */
+ const unsigned mat_idx = column * column_type->vector_elements;
+
+ union {
+ unsigned u[4];
+ float f[4];
+ } data;
+
+ switch (column_type->base_type) {
+ case GLSL_TYPE_UINT:
+ case GLSL_TYPE_INT:
+ for (unsigned i = 0; i < column_type->vector_elements; i++)
+ data.u[i] = array->value.u[mat_idx + i];
+
+ break;
+
+ case GLSL_TYPE_FLOAT:
+ for (unsigned i = 0; i < column_type->vector_elements; i++)
+ data.f[i] = array->value.f[mat_idx + i];
+
+ break;
+
+ default:
+ assert(!"Should not get here.");
+ break;
+ }
+
+ this->value = new ir_constant(column_type, &data);
+ } else if (array->type->is_vector()) {
+ const unsigned component = idx->value.u[0];
+
+ this->value = new ir_constant(array, component);
+ } else {
+ /* FINISHME: Handle access of constant arrays. */
+ }
+ }
}