Spread resolution information throughout the effect chain.

[movit] / effect_chain.cpp

diff --git a/effect_chain.cpp b/effect_chain.cpp
index 87d0663e098be1920fe1419144ccaf6f99f0756e..4eda18d7afc166eddb0f126f921b3a98ce215d3e 100644 (file)
--- a/effect_chain.cpp
+++ b/effect_chain.cpp
@@ -450,12 +450,69 @@ unsigned EffectChain::fit_rectangle_to_aspect(unsigned width, unsigned height)
        }
 }
 
+// Propagate input texture sizes throughout, and inform effects downstream.
+// (Like a lot of other code, we depend on effects being in topological order.)
+void EffectChain::inform_input_sizes(Phase *phase)
+{
+       // All effects that have a defined size (inputs and RTT inputs)
+       // get that. Reset all others.
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               Node *node = phase->effects[i];
+               if (node->effect->num_inputs() == 0) {
+                       Input *input = static_cast<Input *>(node->effect);
+                       node->output_width = input->get_width();
+                       node->output_height = input->get_height();
+                       assert(node->output_width != 0);
+                       assert(node->output_height != 0);
+               } else {
+                       node->output_width = node->output_height = 0;
+               }
+       }
+       for (unsigned i = 0; i < phase->inputs.size(); ++i) {
+               Node *input = phase->inputs[i];
+               input->output_width = input->phase->output_width;
+               input->output_height = input->phase->output_height;
+               assert(input->output_width != 0);
+               assert(input->output_height != 0);
+       }
+
+       // Now propagate from the inputs towards the end, and inform as we go.
+       // The rules are simple:
+       //
+       //   1. Don't touch effects that already have given sizes (ie., inputs).
+       //   2. If all of your inputs have the same size, that will be your output size.
+       //   3. Otherwise, your output size is 0x0.
+       for (unsigned i = 0; i < phase->effects.size(); ++i) {
+               Node *node = phase->effects[i];
+               if (node->effect->num_inputs() == 0) {
+                       continue;
+               }
+               unsigned this_output_width = 0;
+               unsigned this_output_height = 0;
+               for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
+                       Node *input = node->incoming_links[j];
+                       node->effect->inform_input_size(j, input->output_width, input->output_height);
+                       if (j == 0) {
+                               this_output_width = input->output_width;
+                               this_output_height = input->output_height;
+                       } else if (input->output_width != this_output_width || input->output_height != this_output_height) {
+                               // Inputs disagree.
+                               this_output_width = 0;
+                               this_output_height = 0;
+                       }
+               }
+               node->output_width = this_output_width;
+               node->output_height = this_output_height;
+       }
+}
+
+// Note: You should call inform_input_sizes() before this, as the last effect's
+// desired output size might change based on the inputs.
 void EffectChain::find_output_size(Phase *phase)
 {
        Node *output_node = phase->effects.back();
 
-       // If the last effect explicitly sets an output size,
-       // use that.
+       // If the last effect explicitly sets an output size, use that.
        if (output_node->effect->changes_output_size()) {
                output_node->effect->get_output_size(&phase->output_width, &phase->output_height);
                return;
@@ -843,6 +900,7 @@ void EffectChain::finalize()
                glGenFramebuffers(1, &fbo);
 
                for (unsigned i = 0; i < phases.size() - 1; ++i) {
+                       inform_input_sizes(phases[i]);
                        find_output_size(phases[i]);
 
                        Node *output_node = phases[i]->effects.back();
@@ -905,6 +963,7 @@ void EffectChain::render_to_screen()
                // See if the requested output size has changed. If so, we need to recreate
                // the texture (and before we start setting up inputs).
                if (phase != phases.size() - 1) {
+                       inform_input_sizes(phases[phase]);
                        find_output_size(phases[phase]);
 
                        Node *output_node = phases[phase]->effects.back();