Output the graph in dot form at finalize time.

blur_effect.h

@@ -17,6 +17,8 @@ class BlurEffect : public Effect {
 public:
 	BlurEffect();
 
+	virtual std::string effect_type_id() const { return "BlurEffect"; }
+
 	// We want this for the same reason as ResizeEffect; we could end up scaling
 	// down quite a lot.
 	virtual bool needs_texture_bounce() const { return true; }
@@ -43,6 +45,8 @@ class BlurEffect : public Effect {
 class SingleBlurPassEffect : public Effect {
 public:
 	SingleBlurPassEffect();
+	virtual std::string effect_type_id() const { return "SingleBlurPassEffect"; }
+
 	std::string output_fragment_shader();
 
 	virtual bool needs_texture_bounce() const { return true; }

colorspace_conversion_effect.h

@@ -14,6 +14,7 @@
 class ColorSpaceConversionEffect : public Effect {
 public:
 	ColorSpaceConversionEffect();
+	virtual std::string effect_type_id() const { return "ColorSpaceConversionEffect"; }
 	std::string output_fragment_shader();
 
 	virtual bool needs_srgb_primaries() const { return false; }

diffusion_effect.h

@@ -20,6 +20,7 @@ class OverlayMatteEffect;
 class DiffusionEffect : public Effect {
 public:
 	DiffusionEffect();
+	virtual std::string effect_type_id() const { return "DiffusionEffect"; }
 
 	virtual void add_self_to_effect_chain(EffectChain *chain, const std::vector<Effect *> &input);
 	virtual bool set_float(const std::string &key, float value);
@@ -41,6 +42,7 @@ class DiffusionEffect : public Effect {
 class OverlayMatteEffect : public Effect {
 public:
 	OverlayMatteEffect();
+	virtual std::string effect_type_id() const { return "OverlayMatteEffect"; }
 	std::string output_fragment_shader();
 
 	unsigned num_inputs() const { return 2; }

effect.h

@@ -46,7 +46,12 @@ void set_uniform_vec3(GLuint glsl_program_num, const std::string &prefix, const
 void set_uniform_vec4_array(GLuint glsl_program_num, const std::string &prefix, const std::string &key, const float *values, size_t num_values);
 
 class Effect {
-public: 
+public:
+	// An identifier for this type of effect, mostly used for debug output
+	// (but some special names, like "ColorSpaceConversionEffect", holds special
+	// meaning). Same as the class name is fine.
+	virtual std::string effect_type_id() const = 0;
+
 	// Whether this effects expects its input (and output) to be in
 	// linear gamma, ie. without an applied gamma curve. Most effects
 	// will want this, although the ones that never actually look at

effect_chain.cpp

@@ -414,6 +414,26 @@ void EffectChain::construct_glsl_programs(Node *output)
 	std::reverse(phases.begin(), phases.end());
 }
 
+void EffectChain::output_dot(const char *filename)
+{
+	FILE *fp = fopen(filename, "w");
+	if (fp == NULL) {
+		perror(filename);
+		exit(1);
+	}
+
+	fprintf(fp, "digraph G {\n");
+	for (unsigned i = 0; i < nodes.size(); ++i) {
+		fprintf(fp, "  n%ld [label=\"%s\"];\n", (long)nodes[i], nodes[i]->effect->effect_type_id().c_str());
+		for (unsigned j = 0; j < nodes[i]->outgoing_links.size(); ++j) {
+			fprintf(fp, "  n%ld -> n%ld;\n", (long)nodes[i], (long)nodes[i]->outgoing_links[j]);
+		}
+	}
+	fprintf(fp, "}\n");
+
+	fclose(fp);
+}
+
 void EffectChain::find_output_size(Phase *phase)
 {
 	Node *output_node = phase->effects.back();
@@ -453,6 +473,8 @@ void EffectChain::find_output_size(Phase *phase)
 
 void EffectChain::finalize()
 {
+	output_dot("final.dot");
+
 	// Find the output effect. This is, simply, one that has no outgoing links.
 	// If there are multiple ones, the graph is malformed (we do not support
 	// multiple outputs right now).

effect_chain.h

@@ -123,6 +123,10 @@ class EffectChain {
 	// that depends on it (whenever possible).
 	void construct_glsl_programs(Node *output);
 
+	// Output the current graph to the given file in a Graphviz-compatible format;
+	// only useful for debugging.
+	void output_dot(const char *filename);
+
 	unsigned width, height;
 	ImageFormat output_format;
 

flat_input.h

@@ -9,6 +9,8 @@ class FlatInput : public Input {
 public:
 	FlatInput(ImageFormat format, MovitPixelFormat pixel_format, unsigned width, unsigned height);
 
+	virtual std::string effect_type_id() const { return "FlatInput"; }
+
 	// Create the texture itself. We cannot do this in the constructor,
 	// because we don't necessarily know all the settings (sRGB texture,
 	// mipmap generation) at that point.

gamma_compression_effect.h

@@ -15,6 +15,7 @@
 class GammaCompressionEffect : public Effect {
 public:
 	GammaCompressionEffect();
+	virtual std::string effect_type_id() const { return "GammaCompressionEffect"; }
 	std::string output_fragment_shader();
 
 	virtual bool needs_srgb_primaries() const { return false; }

gamma_expansion_effect.h

@@ -15,6 +15,7 @@
 class GammaExpansionEffect : public Effect {
 public:
 	GammaExpansionEffect();
+	virtual std::string effect_type_id() const { return "GammaExpansionEffect"; }
 	std::string output_fragment_shader();
 
 	virtual bool needs_linear_light() const { return false; }

glow_effect.h

@@ -11,6 +11,7 @@ class MixEffect;
 class GlowEffect : public Effect {
 public:
 	GlowEffect();
+	virtual std::string effect_type_id() const { return "GlowEffect"; }
 
 	virtual bool needs_srgb_primaries() const { return false; }
 

lift_gamma_gain_effect.h

@@ -22,6 +22,7 @@
 class LiftGammaGainEffect : public Effect {
 public:
 	LiftGammaGainEffect();
+	virtual std::string effect_type_id() const { return "LiftGammaGainEffect"; }
 	std::string output_fragment_shader();
 
 	void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);

mirror_effect.h

@@ -8,6 +8,7 @@
 class MirrorEffect : public Effect {
 public:
 	MirrorEffect();
+	virtual std::string effect_type_id() const { return "MirrorEffect"; }
 	std::string output_fragment_shader();
 
 	virtual bool needs_linear_light() const { return false; }

mix_effect.h

@@ -8,6 +8,7 @@
 class MixEffect : public Effect {
 public:
 	MixEffect();
+	virtual std::string effect_type_id() const { return "MixEffect"; }
 	std::string output_fragment_shader();
 
 	virtual bool needs_srgb_primaries() const { return false; }

resize_effect.h

@@ -10,6 +10,7 @@
 class ResizeEffect : public Effect {
 public:
 	ResizeEffect();
+	virtual std::string effect_type_id() const { return "ResizeEffect"; }
 	std::string output_fragment_shader();
 
 	// We want processing done pre-filtering and mipmapped,

sandbox_effect.h

@@ -13,6 +13,7 @@
 class SandboxEffect : public Effect {
 public:
 	SandboxEffect();
+	virtual std::string effect_type_id() const { return "SandboxEffect"; }
 	std::string output_fragment_shader();
 
 	void set_gl_state(GLuint glsl_program_num, const std::string &prefix, unsigned *sampler_num);

saturation_effect.h

@@ -12,6 +12,7 @@
 class SaturationEffect : public Effect {
 public:
 	SaturationEffect();
+	virtual std::string effect_type_id() const { return "SaturationEffect"; }
 	std::string output_fragment_shader();
 
 private:

vignette_effect.h

@@ -9,6 +9,7 @@
 class VignetteEffect : public Effect {
 public:
 	VignetteEffect();
+	virtual std::string effect_type_id() const { return "VignetteEffect"; }
 	std::string output_fragment_shader();
 
 	virtual bool needs_srgb_primaries() const { return false; }

ycbcr_input.h

@@ -31,6 +31,8 @@ class YCbCrInput : public Input {
 	           const YCbCrFormat &ycbcr_format,
 	           unsigned width, unsigned height);
 
+	virtual std::string effect_type_id() const { return "YCbCrInput"; }
+
 	// Create the texture itself. We cannot do this in the constructor,
 	// because we don't necessarily know all the settings (sRGB texture,
 	// mipmap generation) at that point.