X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=effect_chain.cpp;h=23156cb2db604422a7b3ecf66f24f345cac36a8c;hb=f909bfe0621e8c844695ef327b71457893633cae;hp=a83a952dfaae331bb5431000823cecefd6b82e7f;hpb=5e771df1523ea3f7926c0b5a115c29d134c53f11;p=movit

diff --git a/effect_chain.cpp b/effect_chain.cpp
index a83a952..23156cb 100644
--- a/effect_chain.cpp
+++ b/effect_chain.cpp
@@ -38,8 +38,8 @@ namespace {
 class IdentityEffect : public Effect {
 public:
 	IdentityEffect() {}
-	virtual string effect_type_id() const { return "IdentityEffect"; }
-	string output_fragment_shader() { return read_file("identity.frag"); }
+	string effect_type_id() const override { return "IdentityEffect"; }
+	string output_fragment_shader() override { return read_file("identity.frag"); }
 };
 
 }  // namespace
@@ -1882,9 +1882,18 @@ void EffectChain::render(GLuint dest_fbo, const vector<DestinationTexture> &dest
 
 	set<Phase *> generated_mipmaps;
 
-	// We choose the simplest option of having one texture per output,
-	// since otherwise this turns into an (albeit simple) register allocation problem.
+	// We keep one texture per output, but only for as long as we actually have any
+	// phases that need it as an input. (We don't make any effort to reorder phases
+	// to minimize the number of textures in play, as register allocation can be
+	// complicated and we rarely have much to gain, since our graphs are typically
+	// pretty linear.)
 	map<Phase *, GLuint> output_textures;
+	map<Phase *, int> ref_counts;
+	for (Phase *phase : phases) {
+		for (Phase *input : phase->inputs) {
+			++ref_counts[input];
+		}
+	}
 
 	size_t num_phases = phases.size();
 	if (destinations.empty()) {
@@ -1972,6 +1981,15 @@ void EffectChain::render(GLuint dest_fbo, const vector<DestinationTexture> &dest
 		if (do_phase_timing) {
 			glEndQuery(GL_TIME_ELAPSED);
 		}
+
+		// Drop any input textures we don't need anymore.
+		for (Phase *input : phase->inputs) {
+			assert(ref_counts[input] > 0);
+			if (--ref_counts[input] == 0) {
+				resource_pool->release_2d_texture(output_textures[input]);
+				output_textures.erase(input);
+			}
+		}
 	}
 
 	for (const auto &phase_and_texnum : output_textures) {