+
+ return (node->effect->needs_linear_light() && node->output_gamma_curve != GAMMA_LINEAR);
+}
+
+// Very similar to fix_internal_color_spaces(), but for gamma.
+// There is one difference, though; before we start adding conversion nodes,
+// we see if we can get anything out of asking the sources to deliver
+// linear gamma directly. fix_internal_gamma_by_asking_inputs()
+// does that part, while fix_internal_gamma_by_inserting_nodes()
+// inserts nodes as needed afterwards.
+void EffectChain::fix_internal_gamma_by_asking_inputs(unsigned step)
+{
+ unsigned gamma_propagation_pass = 0;
+ bool found_any;
+ do {
+ found_any = false;
+ for (unsigned i = 0; i < nodes.size(); ++i) {
+ Node *node = nodes[i];
+ if (!node_needs_gamma_fix(node)) {
+ continue;
+ }
+
+ // See if all inputs can give us linear gamma. If not, leave it.
+ std::vector<Node *> nonlinear_inputs;
+ find_all_nonlinear_inputs(node, &nonlinear_inputs);
+ assert(!nonlinear_inputs.empty());
+
+ bool all_ok = true;
+ for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
+ Input *input = static_cast<Input *>(nonlinear_inputs[i]->effect);
+ all_ok &= input->can_output_linear_gamma();
+ }
+
+ if (!all_ok) {
+ continue;
+ }
+
+ for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
+ nonlinear_inputs[i]->effect->set_int("output_linear_gamma", 1);
+ nonlinear_inputs[i]->output_gamma_curve = GAMMA_LINEAR;
+ }
+
+ // Re-sort topologically, and propagate the new information.
+ propagate_gamma_and_color_space();
+
+ found_any = true;
+ break;
+ }
+
+ char filename[256];
+ sprintf(filename, "step%u-gammafix-iter%u.dot", step, ++gamma_propagation_pass);
+ output_dot(filename);
+ assert(gamma_propagation_pass < 100);
+ } while (found_any);
+}
+
+void EffectChain::fix_internal_gamma_by_inserting_nodes(unsigned step)
+{
+ unsigned gamma_propagation_pass = 0;
+ bool found_any;
+ do {
+ found_any = false;
+ for (unsigned i = 0; i < nodes.size(); ++i) {
+ Node *node = nodes[i];
+ if (!node_needs_gamma_fix(node)) {
+ continue;
+ }
+
+ // Special case: We could be an input and still be asked to
+ // fix our gamma; if so, we should be the only node
+ // (as node_needs_gamma_fix() would only return true in
+ // for an input in that case). That means we should insert
+ // a conversion node _after_ ourselves.
+ if (node->incoming_links.empty()) {
+ assert(node->outgoing_links.empty());
+ Node *conversion = add_node(new GammaExpansionEffect());
+ conversion->effect->set_int("source_curve", node->output_gamma_curve);
+ conversion->output_gamma_curve = GAMMA_LINEAR;
+ connect_nodes(node, conversion);
+ }
+
+ // If not, go through each input that is not linear gamma,
+ // and insert a gamma conversion before it.
+ for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
+ Node *input = node->incoming_links[j];
+ assert(input->output_gamma_curve != GAMMA_INVALID);
+ if (input->output_gamma_curve == GAMMA_LINEAR) {
+ continue;
+ }
+ Node *conversion = add_node(new GammaExpansionEffect());
+ conversion->effect->set_int("source_curve", input->output_gamma_curve);
+ conversion->output_gamma_curve = GAMMA_LINEAR;
+ insert_node_between(input, conversion, node);
+ }
+
+ // Re-sort topologically, and propagate the new information.
+ propagate_gamma_and_color_space();
+
+ found_any = true;
+ break;