]> git.sesse.net Git - movit/blobdiff - effect_chain_test.cpp
Don't use GL_RGBA32F/GL_RGBA16F with GL_UNSIGNED_BYTE.
[movit] / effect_chain_test.cpp
index c8fd946e6717fdd523048e58005b5f68e73d0d75..70701b35095511d19c45a5bf39a7e14668d004a0 100644 (file)
 // Unit tests for EffectChain.
+//
+// Note that this also contains the tests for some of the simpler effects.
 
+#include <epoxy/gl.h>
+#include <assert.h>
+
+#include "effect.h"
 #include "effect_chain.h"
 #include "flat_input.h"
-#include "sandbox_effect.h"
-#include "opengl.h"
 #include "gtest/gtest.h"
+#include "init.h"
+#include "input.h"
+#include "mirror_effect.h"
+#include "multiply_effect.h"
+#include "resize_effect.h"
+#include "test_util.h"
+#include "util.h"
+
+using namespace std;
+
+namespace movit {
 
-#include <stdio.h>
-#include <math.h>
+TEST(EffectChainTest, EmptyChain) {
+       float data[] = {
+               0.0f, 0.25f, 0.3f,
+               0.75f, 1.0f, 1.0f,
+       };
+       float out_data[6];
+       EffectChainTester tester(data, 3, 2, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
 
-#include <algorithm>
+       expect_equal(data, out_data, 3, 2);
+}
 
-class EffectChainTester {
+// An effect that does nothing.
+class IdentityEffect : public Effect {
 public:
-       EffectChainTester(const float *data, unsigned width, unsigned height, ColorSpace color_space, GammaCurve gamma_curve)
-               : chain(width, height), width(width), height(height)
-       {
-               ImageFormat format;
-               format.color_space = color_space;
-               format.gamma_curve = gamma_curve;
-       
-               FlatInput *input = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, width, height);
-               input->set_pixel_data(data);
-               chain.add_input(input);
+       IdentityEffect() {}
+       virtual string effect_type_id() const { return "IdentityEffect"; }
+       string output_fragment_shader() { return read_file("identity.frag"); }
+};
+
+TEST(EffectChainTest, Identity) {
+       float data[] = {
+               0.0f, 0.25f, 0.3f,
+               0.75f, 1.0f, 1.0f,
+       };
+       float out_data[6];
+       EffectChainTester tester(data, 3, 2, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+       tester.get_chain()->add_effect(new IdentityEffect());
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(data, out_data, 3, 2);
+}
+
+// An effect that does nothing, but requests texture bounce.
+class BouncingIdentityEffect : public Effect {
+public:
+       BouncingIdentityEffect() {}
+       virtual string effect_type_id() const { return "IdentityEffect"; }
+       string output_fragment_shader() { return read_file("identity.frag"); }
+       bool needs_texture_bounce() const { return true; }
+       AlphaHandling alpha_handling() const { return DONT_CARE_ALPHA_TYPE; }
+};
+
+TEST(EffectChainTest, TextureBouncePreservesIdentity) {
+       float data[] = {
+               0.0f, 0.25f, 0.3f,
+               0.75f, 1.0f, 1.0f,
+       };
+       float out_data[6];
+       EffectChainTester tester(data, 3, 2, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+       tester.get_chain()->add_effect(new BouncingIdentityEffect());
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(data, out_data, 3, 2);
+}
+
+TEST(MirrorTest, BasicTest) {
+       float data[] = {
+               0.0f, 0.25f, 0.3f,
+               0.75f, 1.0f, 1.0f,
+       };
+       float expected_data[6] = {
+               0.3f, 0.25f, 0.0f,
+               1.0f, 1.0f, 0.75f,
+       };
+       float out_data[6];
+       EffectChainTester tester(data, 3, 2, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+       tester.get_chain()->add_effect(new MirrorEffect());
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(expected_data, out_data, 3, 2);
+}
+
+// A dummy effect that inverts its input.
+class InvertEffect : public Effect {
+public:
+       InvertEffect() {}
+       virtual string effect_type_id() const { return "InvertEffect"; }
+       string output_fragment_shader() { return read_file("invert_effect.frag"); }
+
+       // A real invert would actually care about its alpha,
+       // but in this unit test, it only complicates things.
+       virtual AlphaHandling alpha_handling() const { return DONT_CARE_ALPHA_TYPE; }
+};
+
+// Like IdentityEffect, but rewrites itself out of the loop,
+// splicing in a different effect instead. Also stores the new node,
+// so we later can check whatever properties we'd like about the graph.
+template<class T>
+class RewritingEffect : public Effect {
+public:
+       RewritingEffect() : effect(new T()), replaced_node(NULL) {}
+       virtual string effect_type_id() const { return "RewritingEffect[" + effect->effect_type_id() + "]"; }
+       string output_fragment_shader() { EXPECT_TRUE(false); return read_file("identity.frag"); }
+       virtual void rewrite_graph(EffectChain *graph, Node *self) {
+               replaced_node = graph->add_node(effect);
+               graph->replace_receiver(self, replaced_node);
+               graph->replace_sender(self, replaced_node);
+               self->disabled = true;
+       }
+
+       T *effect;
+       Node *replaced_node;
+};
+
+TEST(EffectChainTest, RewritingWorksAndGammaConversionsAreInserted) {
+       float data[] = {
+               0.0f, 0.25f, 0.3f,
+               0.75f, 1.0f, 1.0f,
+       };
+       float expected_data[6] = {
+               1.0f, 0.9771f, 0.9673f,
+               0.7192f, 0.0f, 0.0f,
+       };
+       float out_data[6];
+       EffectChainTester tester(data, 3, 2, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_sRGB);
+       RewritingEffect<InvertEffect> *effect = new RewritingEffect<InvertEffect>();
+       tester.get_chain()->add_effect(effect);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_sRGB);
+
+       Node *node = effect->replaced_node;
+       ASSERT_EQ(1, node->incoming_links.size());
+       ASSERT_EQ(1, node->outgoing_links.size());
+       EXPECT_EQ("GammaExpansionEffect", node->incoming_links[0]->effect->effect_type_id());
+       EXPECT_EQ("GammaCompressionEffect", node->outgoing_links[0]->effect->effect_type_id());
+
+       expect_equal(expected_data, out_data, 3, 2);
+}
+
+TEST(EffectChainTest, RewritingWorksAndTexturesAreAskedForsRGB) {
+       unsigned char data[] = {
+               0, 64,
+               128, 255,
+       };
+       float expected_data[4] = {
+               1.0f, 0.9771f,
+               0.8983f, 0.0f,
+       };
+       float out_data[4];
+       EffectChainTester tester(NULL, 2, 2);
+       tester.add_input(data, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_sRGB);
+       RewritingEffect<InvertEffect> *effect = new RewritingEffect<InvertEffect>();
+       tester.get_chain()->add_effect(effect);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_sRGB);
+
+       Node *node = effect->replaced_node;
+       ASSERT_EQ(1, node->incoming_links.size());
+       ASSERT_EQ(1, node->outgoing_links.size());
+       EXPECT_EQ("FlatInput", node->incoming_links[0]->effect->effect_type_id());
+       EXPECT_EQ("GammaCompressionEffect", node->outgoing_links[0]->effect->effect_type_id());
+
+       expect_equal(expected_data, out_data, 2, 2);
+}
+
+TEST(EffectChainTest, RewritingWorksAndColorspaceConversionsAreInserted) {
+       float data[] = {
+               0.0f, 0.25f, 0.3f,
+               0.75f, 1.0f, 1.0f,
+       };
+       float expected_data[6] = {
+               1.0f, 0.75f, 0.7f,
+               0.25f, 0.0f, 0.0f,
+       };
+       float out_data[6];
+       EffectChainTester tester(data, 3, 2, FORMAT_GRAYSCALE, COLORSPACE_REC_601_525, GAMMA_LINEAR);
+       RewritingEffect<InvertEffect> *effect = new RewritingEffect<InvertEffect>();
+       tester.get_chain()->add_effect(effect);
+       tester.run(out_data, GL_RED, COLORSPACE_REC_601_525, GAMMA_LINEAR);
+
+       Node *node = effect->replaced_node;
+       ASSERT_EQ(1, node->incoming_links.size());
+       ASSERT_EQ(1, node->outgoing_links.size());
+       EXPECT_EQ("ColorspaceConversionEffect", node->incoming_links[0]->effect->effect_type_id());
+       EXPECT_EQ("ColorspaceConversionEffect", node->outgoing_links[0]->effect->effect_type_id());
+
+       expect_equal(expected_data, out_data, 3, 2);
+}
+
+// A fake input that can change its output colorspace and gamma between instantiation
+// and finalize.
+class UnknownColorspaceInput : public FlatInput {
+public:
+       UnknownColorspaceInput(ImageFormat format, MovitPixelFormat pixel_format, GLenum type, unsigned width, unsigned height)
+           : FlatInput(format, pixel_format, type, width, height),
+             overridden_color_space(format.color_space),
+             overridden_gamma_curve(format.gamma_curve) {}
+       virtual string effect_type_id() const { return "UnknownColorspaceInput"; }
+
+       void set_color_space(Colorspace colorspace) {
+               overridden_color_space = colorspace;
+       }
+       void set_gamma_curve(GammaCurve gamma_curve) {
+               overridden_gamma_curve = gamma_curve;
+       }
+       Colorspace get_color_space() const { return overridden_color_space; }
+       GammaCurve get_gamma_curve() const { return overridden_gamma_curve; }
+
+private:
+       Colorspace overridden_color_space;
+       GammaCurve overridden_gamma_curve;
+};
+
+TEST(EffectChainTester, HandlesInputChangingColorspace) {
+       const int size = 4;
+
+       float data[size] = {
+               0.0,
+               0.5,
+               0.7,
+               1.0,
+       };
+       float out_data[size];
+
+       EffectChainTester tester(NULL, 4, 1, FORMAT_GRAYSCALE);
+
+       // First say that we have sRGB, linear input.
+       ImageFormat format;
+       format.color_space = COLORSPACE_sRGB;
+       format.gamma_curve = GAMMA_LINEAR;
+
+       UnknownColorspaceInput *input = new UnknownColorspaceInput(format, FORMAT_GRAYSCALE, GL_FLOAT, 4, 1);
+       input->set_pixel_data(data);
+       tester.get_chain()->add_input(input);
+
+       // Now we change to Rec. 601 input.
+       input->set_color_space(COLORSPACE_REC_601_625);
+       input->set_gamma_curve(GAMMA_REC_601);
+
+       // Now ask for Rec. 601 output. Thus, our chain should now be a no-op.
+       tester.run(out_data, GL_RED, COLORSPACE_REC_601_625, GAMMA_REC_601);
+       expect_equal(data, out_data, 4, 1);
+}
+
+TEST(EffectChainTest, NoGammaConversionsWhenLinearLightNotNeeded) {
+       float data[] = {
+               0.0f, 0.25f, 0.3f,
+               0.75f, 1.0f, 1.0f,
+       };
+       float expected_data[6] = {
+               0.3f, 0.25f, 0.0f,
+               1.0f, 1.0f, 0.75f,
+       };
+       float out_data[6];
+       EffectChainTester tester(data, 3, 2, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_sRGB);
+       RewritingEffect<MirrorEffect> *effect = new RewritingEffect<MirrorEffect>();
+       tester.get_chain()->add_effect(effect);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_sRGB);
+
+       Node *node = effect->replaced_node;
+       ASSERT_EQ(1, node->incoming_links.size());
+       EXPECT_EQ(0, node->outgoing_links.size());
+       EXPECT_EQ("FlatInput", node->incoming_links[0]->effect->effect_type_id());
+
+       expect_equal(expected_data, out_data, 3, 2);
+}
+
+TEST(EffectChainTest, NoColorspaceConversionsWhensRGBPrimariesNotNeeded) {
+       float data[] = {
+               0.0f, 0.25f, 0.3f,
+               0.75f, 1.0f, 1.0f,
+       };
+       float expected_data[6] = {
+               0.3f, 0.25f, 0.0f,
+               1.0f, 1.0f, 0.75f,
+       };
+       float out_data[6];
+       EffectChainTester tester(data, 3, 2, FORMAT_GRAYSCALE, COLORSPACE_REC_601_525, GAMMA_LINEAR);
+       RewritingEffect<MirrorEffect> *effect = new RewritingEffect<MirrorEffect>();
+       tester.get_chain()->add_effect(effect);
+       tester.run(out_data, GL_RED, COLORSPACE_REC_601_525, GAMMA_LINEAR);
+
+       Node *node = effect->replaced_node;
+       ASSERT_EQ(1, node->incoming_links.size());
+       EXPECT_EQ(0, node->outgoing_links.size());
+       EXPECT_EQ("FlatInput", node->incoming_links[0]->effect->effect_type_id());
+
+       expect_equal(expected_data, out_data, 3, 2);
+}
+
+// The identity effect needs linear light, and thus will get conversions on both sides.
+// Verify that sRGB data is properly converted to and from linear light for the entire ramp.
+TEST(EffectChainTest, IdentityThroughsRGBConversions) {
+       float data[256];
+       for (unsigned i = 0; i < 256; ++i) {
+               data[i] = i / 255.0;
+       };
+       float out_data[256];
+       EffectChainTester tester(data, 256, 1, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_sRGB);
+       tester.get_chain()->add_effect(new IdentityEffect());
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_sRGB);
+
+       expect_equal(data, out_data, 256, 1);
+}
+
+// Same, but uses the forward sRGB table from the GPU.
+TEST(EffectChainTest, IdentityThroughGPUsRGBConversions) {
+       unsigned char data[256];
+       float expected_data[256];
+       for (unsigned i = 0; i < 256; ++i) {
+               data[i] = i;
+               expected_data[i] = i / 255.0;
+       };
+       float out_data[256];
+       EffectChainTester tester(NULL, 256, 1);
+       tester.add_input(data, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_sRGB);
+       tester.get_chain()->add_effect(new IdentityEffect());
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_sRGB);
+
+       expect_equal(expected_data, out_data, 256, 1);
+}
+
+// Same, for the Rec. 601/709 gamma curve.
+TEST(EffectChainTest, IdentityThroughRec709) {
+       float data[256];
+       for (unsigned i = 0; i < 256; ++i) {
+               data[i] = i / 255.0;
+       };
+       float out_data[256];
+       EffectChainTester tester(data, 256, 1, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_REC_709);
+       tester.get_chain()->add_effect(new IdentityEffect());
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_REC_709);
+
+       expect_equal(data, out_data, 256, 1);
+}
+
+// The identity effect needs premultiplied alpha, and thus will get conversions on both sides.
+TEST(EffectChainTest, IdentityThroughAlphaConversions) {
+       const int size = 3;
+       float data[4 * size] = {
+               0.8f, 0.0f, 0.0f, 0.5f,
+               0.0f, 0.2f, 0.2f, 0.3f,
+               0.1f, 0.0f, 1.0f, 1.0f,
+       };
+       float out_data[4 * size];
+       EffectChainTester tester(data, size, 1, FORMAT_RGBA_POSTMULTIPLIED_ALPHA, COLORSPACE_sRGB, GAMMA_LINEAR);
+       tester.get_chain()->add_effect(new IdentityEffect());
+       tester.run(out_data, GL_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(data, out_data, 4, size);
+}
+
+TEST(EffectChainTest, NoAlphaConversionsWhenPremultipliedAlphaNotNeeded) {
+       const int size = 3;
+       float data[4 * size] = {
+               0.8f, 0.0f, 0.0f, 0.5f,
+               0.0f, 0.2f, 0.2f, 0.3f,
+               0.1f, 0.0f, 1.0f, 1.0f,
+       };
+       float expected_data[4 * size] = {
+               0.1f, 0.0f, 1.0f, 1.0f,
+               0.0f, 0.2f, 0.2f, 0.3f,
+               0.8f, 0.0f, 0.0f, 0.5f,
+       };
+       float out_data[4 * size];
+       EffectChainTester tester(data, size, 1, FORMAT_RGBA_POSTMULTIPLIED_ALPHA, COLORSPACE_sRGB, GAMMA_LINEAR);
+       RewritingEffect<MirrorEffect> *effect = new RewritingEffect<MirrorEffect>();
+       tester.get_chain()->add_effect(effect);
+       tester.run(out_data, GL_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       Node *node = effect->replaced_node;
+       ASSERT_EQ(1, node->incoming_links.size());
+       EXPECT_EQ(0, node->outgoing_links.size());
+       EXPECT_EQ("FlatInput", node->incoming_links[0]->effect->effect_type_id());
+
+       expect_equal(expected_data, out_data, 4, size);
+}
+
+// An input that outputs only blue, which has blank alpha.
+class BlueInput : public Input {
+public:
+       BlueInput() { register_int("needs_mipmaps", &needs_mipmaps); }
+       virtual string effect_type_id() const { return "IdentityEffect"; }
+       string output_fragment_shader() { return read_file("blue.frag"); }
+       virtual AlphaHandling alpha_handling() const { return OUTPUT_BLANK_ALPHA; }
+       virtual void finalize() {}
+       virtual bool can_output_linear_gamma() const { return true; }
+       virtual unsigned get_width() const { return 1; }
+       virtual unsigned get_height() const { return 1; }
+       virtual Colorspace get_color_space() const { return COLORSPACE_sRGB; }
+       virtual GammaCurve get_gamma_curve() const { return GAMMA_LINEAR; }
+
+private:
+       int needs_mipmaps;
+};
+
+// Like RewritingEffect<InvertEffect>, but splicing in a BlueInput instead,
+// which outputs blank alpha.
+class RewritingToBlueInput : public Input {
+public:
+       RewritingToBlueInput() : blue_node(NULL) { register_int("needs_mipmaps", &needs_mipmaps); }
+       virtual string effect_type_id() const { return "RewritingToBlueInput"; }
+       string output_fragment_shader() { EXPECT_TRUE(false); return read_file("identity.frag"); }
+       virtual void rewrite_graph(EffectChain *graph, Node *self) {
+               Node *blue_node = graph->add_node(new BlueInput());
+               graph->replace_receiver(self, blue_node);
+               graph->replace_sender(self, blue_node);
+
+               self->disabled = true;
+               this->blue_node = blue_node;
        }
 
-       EffectChain *get_chain() { return &chain; }
+       // Dummy values that we need to implement because we inherit from Input.
+       // Same as BlueInput.
+       virtual AlphaHandling alpha_handling() const { return OUTPUT_BLANK_ALPHA; }
+       virtual void finalize() {}
+       virtual bool can_output_linear_gamma() const { return true; }
+       virtual unsigned get_width() const { return 1; }
+       virtual unsigned get_height() const { return 1; }
+       virtual Colorspace get_color_space() const { return COLORSPACE_sRGB; }
+       virtual GammaCurve get_gamma_curve() const { return GAMMA_LINEAR; }
 
-       void run(float *out_data, ColorSpace color_space, GammaCurve gamma_curve)
+       Node *blue_node;
+
+private:
+       int needs_mipmaps;
+};
+
+TEST(EffectChainTest, NoAlphaConversionsWithBlankAlpha) {
+       const int size = 3;
+       float data[4 * size] = {
+               0.0f, 0.0f, 1.0f, 1.0f,
+               0.0f, 0.0f, 1.0f, 1.0f,
+               0.0f, 0.0f, 1.0f, 1.0f,
+       };
+       float out_data[4 * size];
+       EffectChainTester tester(NULL, size, 1);
+       RewritingToBlueInput *input = new RewritingToBlueInput();
+       tester.get_chain()->add_input(input);
+       tester.run(out_data, GL_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR, OUTPUT_ALPHA_FORMAT_PREMULTIPLIED);
+
+       Node *node = input->blue_node;
+       EXPECT_EQ(0, node->incoming_links.size());
+       EXPECT_EQ(0, node->outgoing_links.size());
+
+       expect_equal(data, out_data, 4, size);
+}
+
+// An effect that does nothing, and specifies that it preserves blank alpha.
+class BlankAlphaPreservingEffect : public Effect {
+public:
+       BlankAlphaPreservingEffect() {}
+       virtual string effect_type_id() const { return "BlankAlphaPreservingEffect"; }
+       string output_fragment_shader() { return read_file("identity.frag"); }
+       virtual AlphaHandling alpha_handling() const { return INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK; }
+};
+
+TEST(EffectChainTest, NoAlphaConversionsWithBlankAlphaPreservingEffect) {
+       const int size = 3;
+       float data[4 * size] = {
+               0.0f, 0.0f, 1.0f, 1.0f,
+               0.0f, 0.0f, 1.0f, 1.0f,
+               0.0f, 0.0f, 1.0f, 1.0f,
+       };
+       float out_data[4 * size];
+       EffectChainTester tester(NULL, size, 1);
+       tester.get_chain()->add_input(new BlueInput());
+       tester.get_chain()->add_effect(new BlankAlphaPreservingEffect());
+       RewritingEffect<MirrorEffect> *effect = new RewritingEffect<MirrorEffect>();
+       tester.get_chain()->add_effect(effect);
+       tester.run(out_data, GL_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
+
+       Node *node = effect->replaced_node;
+       EXPECT_EQ(1, node->incoming_links.size());
+       EXPECT_EQ(0, node->outgoing_links.size());
+
+       expect_equal(data, out_data, 4, size);
+}
+
+// This is the counter-test to NoAlphaConversionsWithBlankAlphaPreservingEffect;
+// just to be sure that with a normal INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA effect,
+// an alpha conversion _should_ be inserted at the very end. (There is some overlap
+// with other tests.)
+TEST(EffectChainTest, AlphaConversionsWithNonBlankAlphaPreservingEffect) {
+       const int size = 3;
+       float data[4 * size] = {
+               0.0f, 0.0f, 1.0f, 1.0f,
+               0.0f, 0.0f, 1.0f, 1.0f,
+               0.0f, 0.0f, 1.0f, 1.0f,
+       };
+       float out_data[4 * size];
+       EffectChainTester tester(NULL, size, 1);
+       tester.get_chain()->add_input(new BlueInput());
+       tester.get_chain()->add_effect(new IdentityEffect());  // Not BlankAlphaPreservingEffect.
+       RewritingEffect<MirrorEffect> *effect = new RewritingEffect<MirrorEffect>();
+       tester.get_chain()->add_effect(effect);
+       tester.run(out_data, GL_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
+
+       Node *node = effect->replaced_node;
+       EXPECT_EQ(1, node->incoming_links.size());
+       EXPECT_EQ(1, node->outgoing_links.size());
+       EXPECT_EQ("AlphaDivisionEffect", node->outgoing_links[0]->effect->effect_type_id());
+
+       expect_equal(data, out_data, 4, size);
+}
+
+// Effectively scales down its input linearly by 4x (and repeating it),
+// which is not attainable without mipmaps.
+class MipmapNeedingEffect : public Effect {
+public:
+       MipmapNeedingEffect() {}
+       virtual bool needs_mipmaps() const { return true; }
+
+       // To be allowed to mess with the sampler state.
+       virtual bool needs_texture_bounce() const { return true; }
+
+       virtual string effect_type_id() const { return "MipmapNeedingEffect"; }
+       string output_fragment_shader() { return read_file("mipmap_needing_effect.frag"); }
+       virtual void inform_added(EffectChain *chain) { this->chain = chain; }
+
+       void set_gl_state(GLuint glsl_program_num, const string& prefix, unsigned *sampler_num)
        {
-               ImageFormat format;
-               format.color_space = color_space;
-               format.gamma_curve = gamma_curve;
-               chain.add_output(format);
-               chain.finalize();
-
-               glViewport(0, 0, width, height);
-               chain.render_to_screen();
-
-               glReadPixels(0, 0, width, height, GL_RED, GL_FLOAT, out_data);
-
-               // Flip upside-down to compensate for different origin.
-               for (unsigned y = 0; y < height / 2; ++y) {
-                       unsigned flip_y = height - y - 1;
-                       for (unsigned x = 0; x < width; ++x) {
-                               std::swap(out_data[y * width + x], out_data[flip_y * width + x]);
-                       }
-               }
+               Node *self = chain->find_node_for_effect(this);
+               glActiveTexture(chain->get_input_sampler(self, 0));
+               check_error();
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+               check_error();
+               glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+               check_error();
        }
 
 private:
-       EffectChain chain;
-       unsigned width, height;
+       EffectChain *chain;
 };
 
-void expect_equal(const float *ref, const float *result, unsigned width, unsigned height)
-{
-       float largest_difference = -1.0f;
-       float squared_difference = 0.0f;
-
-       for (unsigned y = 0; y < height; ++y) {
-               for (unsigned x = 0; x < width; ++x) {
-                       float diff = ref[y * width + x] - result[y * width + x];
-                       largest_difference = std::max(largest_difference, fabsf(diff));
-                       squared_difference += diff * diff;
-               }
+TEST(EffectChainTest, MipmapGenerationWorks) {
+       float data[] = {  // In 4x4 blocks.
+               1.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 1.0f,
+
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.5f, 0.0f, 0.0f,
+               0.0f, 0.0f, 1.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+
+               1.0f, 1.0f, 1.0f, 1.0f,
+               1.0f, 1.0f, 1.0f, 1.0f,
+               1.0f, 1.0f, 1.0f, 1.0f,
+               1.0f, 1.0f, 1.0f, 1.0f,
+
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 1.0f, 1.0f, 0.0f,
+               0.0f, 1.0f, 1.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+       };
+       float expected_data[] = {  // Repeated four times each way.
+               0.125f,   0.125f,   0.125f,   0.125f,
+               0.09375f, 0.09375f, 0.09375f, 0.09375f,
+               1.0f,     1.0f,     1.0f,     1.0f,
+               0.25f,    0.25f,    0.25f,    0.25f,
+
+               0.125f,   0.125f,   0.125f,   0.125f,
+               0.09375f, 0.09375f, 0.09375f, 0.09375f,
+               1.0f,     1.0f,     1.0f,     1.0f,
+               0.25f,    0.25f,    0.25f,    0.25f,
+
+               0.125f,   0.125f,   0.125f,   0.125f,
+               0.09375f, 0.09375f, 0.09375f, 0.09375f,
+               1.0f,     1.0f,     1.0f,     1.0f,
+               0.25f,    0.25f,    0.25f,    0.25f,
+
+               0.125f,   0.125f,   0.125f,   0.125f,
+               0.09375f, 0.09375f, 0.09375f, 0.09375f,
+               1.0f,     1.0f,     1.0f,     1.0f,
+               0.25f,    0.25f,    0.25f,    0.25f,
+       };
+       float out_data[4 * 16];
+       EffectChainTester tester(data, 4, 16, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+       tester.get_chain()->add_effect(new MipmapNeedingEffect());
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(expected_data, out_data, 4, 16);
+}
+
+TEST(EffectChainTest, ResizeDownByFourThenUpByFour) {
+       float data[] = {  // In 4x4 blocks.
+               1.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 1.0f,
+
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.5f, 0.0f, 0.0f,
+               0.0f, 0.0f, 1.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+
+               1.0f, 1.0f, 1.0f, 1.0f,
+               1.0f, 1.0f, 1.0f, 1.0f,
+               1.0f, 1.0f, 1.0f, 1.0f,
+               1.0f, 1.0f, 1.0f, 1.0f,
+
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 1.0f, 1.0f, 0.0f,
+               0.0f, 1.0f, 1.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+       };
+       float expected_data[] = {  // Repeated four times horizontaly, interpolated vertically.
+               0.1250f, 0.1250f, 0.1250f, 0.1250f,
+               0.1250f, 0.1250f, 0.1250f, 0.1250f,
+               0.1211f, 0.1211f, 0.1211f, 0.1211f,
+               0.1133f, 0.1133f, 0.1133f, 0.1133f,
+               0.1055f, 0.1055f, 0.1055f, 0.1055f,
+               0.0977f, 0.0977f, 0.0977f, 0.0977f,
+               0.2070f, 0.2070f, 0.2070f, 0.2070f,
+               0.4336f, 0.4336f, 0.4336f, 0.4336f,
+               0.6602f, 0.6602f, 0.6602f, 0.6602f,
+               0.8867f, 0.8867f, 0.8867f, 0.8867f,
+               0.9062f, 0.9062f, 0.9062f, 0.9062f,
+               0.7188f, 0.7188f, 0.7188f, 0.7188f,
+               0.5312f, 0.5312f, 0.5312f, 0.5312f,
+               0.3438f, 0.3438f, 0.3438f, 0.3438f,
+               0.2500f, 0.2500f, 0.2500f, 0.2500f,
+               0.2500f, 0.2500f, 0.2500f, 0.2500f,
+       };
+       float out_data[4 * 16];
+
+       ResizeEffect *downscale = new ResizeEffect();
+       ASSERT_TRUE(downscale->set_int("width", 1));
+       ASSERT_TRUE(downscale->set_int("height", 4));
+
+       ResizeEffect *upscale = new ResizeEffect();
+       ASSERT_TRUE(upscale->set_int("width", 4));
+       ASSERT_TRUE(upscale->set_int("height", 16));
+
+       EffectChainTester tester(data, 4, 16, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+       tester.get_chain()->add_effect(downscale);
+       tester.get_chain()->add_effect(upscale);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(expected_data, out_data, 4, 16);
+}
+
+// An effect that adds its two inputs together. Used below.
+class AddEffect : public Effect {
+public:
+       AddEffect() {}
+       virtual string effect_type_id() const { return "AddEffect"; }
+       string output_fragment_shader() { return read_file("add.frag"); }
+       virtual unsigned num_inputs() const { return 2; }
+       virtual AlphaHandling alpha_handling() const { return DONT_CARE_ALPHA_TYPE; }
+};
+
+// Constructs the graph
+//
+//             FlatInput               |
+//            /         \              |
+//  MultiplyEffect  MultiplyEffect     |
+//            \         /              |
+//             AddEffect               |
+//
+// and verifies that it gives the correct output.
+TEST(EffectChainTest, DiamondGraph) {
+       float data[] = {
+               1.0f, 1.0f,
+               1.0f, 0.0f,
+       };
+       float expected_data[] = {
+               2.5f, 2.5f,
+               2.5f, 0.0f,
+       };
+       float out_data[2 * 2];
+
+       const float half[] = { 0.5f, 0.5f, 0.5f, 0.5f };
+       const float two[] = { 2.0f, 2.0f, 2.0f, 0.5f };
+
+       MultiplyEffect *mul_half = new MultiplyEffect();
+       ASSERT_TRUE(mul_half->set_vec4("factor", half));
+       
+       MultiplyEffect *mul_two = new MultiplyEffect();
+       ASSERT_TRUE(mul_two->set_vec4("factor", two));
+
+       EffectChainTester tester(NULL, 2, 2);
+
+       ImageFormat format;
+       format.color_space = COLORSPACE_sRGB;
+       format.gamma_curve = GAMMA_LINEAR;
+
+       FlatInput *input = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, 2, 2);
+       input->set_pixel_data(data);
+
+       tester.get_chain()->add_input(input);
+       tester.get_chain()->add_effect(mul_half, input);
+       tester.get_chain()->add_effect(mul_two, input);
+       tester.get_chain()->add_effect(new AddEffect(), mul_half, mul_two);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(expected_data, out_data, 2, 2);
+}
+
+// Constructs the graph
+//
+//             FlatInput                     |
+//            /         \                    |
+//  MultiplyEffect  MultiplyEffect           |
+//         \             |                   |
+//          \    BouncingIdentityEffect      |  
+//            \         /                    |
+//             AddEffect                     |
+//
+// and verifies that it gives the correct output.
+TEST(EffectChainTest, DiamondGraphWithOneInputUsedInTwoPhases) {
+       float data[] = {
+               1.0f, 1.0f,
+               1.0f, 0.0f,
+       };
+       float expected_data[] = {
+               2.5f, 2.5f,
+               2.5f, 0.0f,
+       };
+       float out_data[2 * 2];
+
+       const float half[] = { 0.5f, 0.5f, 0.5f, 0.5f };
+       const float two[] = { 2.0f, 2.0f, 2.0f, 0.5f };
+
+       MultiplyEffect *mul_half = new MultiplyEffect();
+       ASSERT_TRUE(mul_half->set_vec4("factor", half));
+       
+       MultiplyEffect *mul_two = new MultiplyEffect();
+       ASSERT_TRUE(mul_two->set_vec4("factor", two));
+       
+       BouncingIdentityEffect *bounce = new BouncingIdentityEffect();
+
+       EffectChainTester tester(NULL, 2, 2);
+
+       ImageFormat format;
+       format.color_space = COLORSPACE_sRGB;
+       format.gamma_curve = GAMMA_LINEAR;
+
+       FlatInput *input = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, 2, 2);
+       input->set_pixel_data(data);
+
+       tester.get_chain()->add_input(input);
+       tester.get_chain()->add_effect(mul_half, input);
+       tester.get_chain()->add_effect(mul_two, input);
+       tester.get_chain()->add_effect(bounce, mul_two);
+       tester.get_chain()->add_effect(new AddEffect(), mul_half, bounce);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(expected_data, out_data, 2, 2);
+}
+
+TEST(EffectChainTest, EffectUsedTwiceOnlyGetsOneGammaConversion) {
+       float data[] = {
+               0.735f, 0.0f,
+               0.735f, 0.0f,
+       };
+       float expected_data[] = {
+               0.0f, 0.5f,  // 0.5 and not 1.0, since AddEffect doesn't clamp alpha properly.
+               0.0f, 0.5f,
+       };
+       float out_data[2 * 2];
+       
+       EffectChainTester tester(NULL, 2, 2);
+       tester.add_input(data, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_sRGB);
+
+       // MirrorEffect does not get linear light, so the conversions will be
+       // inserted after it, not before.
+       RewritingEffect<MirrorEffect> *effect = new RewritingEffect<MirrorEffect>();
+       tester.get_chain()->add_effect(effect);
+
+       Effect *identity1 = tester.get_chain()->add_effect(new IdentityEffect(), effect);
+       Effect *identity2 = tester.get_chain()->add_effect(new IdentityEffect(), effect);
+       tester.get_chain()->add_effect(new AddEffect(), identity1, identity2);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(expected_data, out_data, 2, 2);
+
+       Node *node = effect->replaced_node;
+       ASSERT_EQ(1, node->incoming_links.size());
+       ASSERT_EQ(1, node->outgoing_links.size());
+       EXPECT_EQ("FlatInput", node->incoming_links[0]->effect->effect_type_id());
+       EXPECT_EQ("GammaExpansionEffect", node->outgoing_links[0]->effect->effect_type_id());
+}
+
+TEST(EffectChainTest, EffectUsedTwiceOnlyGetsOneColorspaceConversion) {
+       float data[] = {
+               0.5f, 0.0f,
+               0.5f, 0.0f,
+       };
+       float expected_data[] = {
+               0.0f, 0.5f,  // 0.5 and not 1.0, since AddEffect doesn't clamp alpha properly.
+               0.0f, 0.5f,
+       };
+       float out_data[2 * 2];
+       
+       EffectChainTester tester(NULL, 2, 2);
+       tester.add_input(data, FORMAT_GRAYSCALE, COLORSPACE_REC_601_625, GAMMA_LINEAR);
+
+       // MirrorEffect does not get linear light, so the conversions will be
+       // inserted after it, not before.
+       RewritingEffect<MirrorEffect> *effect = new RewritingEffect<MirrorEffect>();
+       tester.get_chain()->add_effect(effect);
+
+       Effect *identity1 = tester.get_chain()->add_effect(new IdentityEffect(), effect);
+       Effect *identity2 = tester.get_chain()->add_effect(new IdentityEffect(), effect);
+       tester.get_chain()->add_effect(new AddEffect(), identity1, identity2);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       expect_equal(expected_data, out_data, 2, 2);
+
+       Node *node = effect->replaced_node;
+       ASSERT_EQ(1, node->incoming_links.size());
+       ASSERT_EQ(1, node->outgoing_links.size());
+       EXPECT_EQ("FlatInput", node->incoming_links[0]->effect->effect_type_id());
+       EXPECT_EQ("ColorspaceConversionEffect", node->outgoing_links[0]->effect->effect_type_id());
+}
+
+// An effect that does nothing, but requests texture bounce and stores
+// its input size.
+class SizeStoringEffect : public BouncingIdentityEffect {
+public:
+       SizeStoringEffect() : input_width(-1), input_height(-1) {}
+       virtual void inform_input_size(unsigned input_num, unsigned width, unsigned height) {
+               assert(input_num == 0);
+               input_width = width;
+               input_height = height;
        }
+       virtual string effect_type_id() const { return "SizeStoringEffect"; }
+
+       int input_width, input_height;
+};
 
-       const float largest_difference_limit = 1.5 / 255.0;
-       const float rms_limit = 0.5 / 255.0;
+TEST(EffectChainTest, SameInputsGiveSameOutputs) {
+       float data[2 * 2] = {
+               0.0f, 0.0f,
+               0.0f, 0.0f,
+       };
+       float out_data[2 * 2];
+       
+       EffectChainTester tester(NULL, 4, 3);  // Note non-square aspect.
 
-       EXPECT_LT(largest_difference, largest_difference_limit);
+       ImageFormat format;
+       format.color_space = COLORSPACE_sRGB;
+       format.gamma_curve = GAMMA_LINEAR;
 
-       float rms = sqrt(squared_difference) / (width * height);
-       EXPECT_LT(rms, rms_limit);
+       FlatInput *input1 = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, 2, 2);
+       input1->set_pixel_data(data);
+       
+       FlatInput *input2 = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, 2, 2);
+       input2->set_pixel_data(data);
 
-       if (largest_difference >= largest_difference_limit || rms >= rms_limit) {
-               fprintf(stderr, "Dumping matrices for easier debugging, since at least one test failed.\n");
+       SizeStoringEffect *input_store = new SizeStoringEffect();
 
-               fprintf(stderr, "Reference:\n");
-               for (unsigned y = 0; y < height; ++y) {
-                       for (unsigned x = 0; x < width; ++x) {
-                               fprintf(stderr, "%7.4f ", ref[y * width + x]);
-                       }
-                       fprintf(stderr, "\n");
-               }
+       tester.get_chain()->add_input(input1);
+       tester.get_chain()->add_input(input2);
+       tester.get_chain()->add_effect(new AddEffect(), input1, input2);
+       tester.get_chain()->add_effect(input_store);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       EXPECT_EQ(2, input_store->input_width);
+       EXPECT_EQ(2, input_store->input_height);
+}
 
-               fprintf(stderr, "\nResult:\n");
-               for (unsigned y = 0; y < height; ++y) {
-                       for (unsigned x = 0; x < width; ++x) {
-                               fprintf(stderr, "%7.4f ", result[y * width + x]);
-                       }
-                       fprintf(stderr, "\n");
-               }
+TEST(EffectChainTest, AspectRatioConversion) {
+       float data1[4 * 3] = {
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f,
+       };
+       float data2[7 * 7] = {
+               0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
+               0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f,
+       };
+
+       // The right conversion here is that the 7x7 image decides the size,
+       // since it is the biggest, so everything is scaled up to 9x7
+       // (keep the height, round the width 9.333 to 9). 
+       float out_data[9 * 7];
+       
+       EffectChainTester tester(NULL, 4, 3);
+
+       ImageFormat format;
+       format.color_space = COLORSPACE_sRGB;
+       format.gamma_curve = GAMMA_LINEAR;
+
+       FlatInput *input1 = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, 4, 3);
+       input1->set_pixel_data(data1);
+       
+       FlatInput *input2 = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, 7, 7);
+       input2->set_pixel_data(data2);
+
+       SizeStoringEffect *input_store = new SizeStoringEffect();
+
+       tester.get_chain()->add_input(input1);
+       tester.get_chain()->add_input(input2);
+       tester.get_chain()->add_effect(new AddEffect(), input1, input2);
+       tester.get_chain()->add_effect(input_store);
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       EXPECT_EQ(9, input_store->input_width);
+       EXPECT_EQ(7, input_store->input_height);
+}
+
+// An effect that does nothing except changing its output sizes.
+class VirtualResizeEffect : public Effect {
+public:
+       VirtualResizeEffect(int width, int height, int virtual_width, int virtual_height)
+               : width(width),
+                 height(height),
+                 virtual_width(virtual_width),
+                 virtual_height(virtual_height) {}
+       virtual string effect_type_id() const { return "VirtualResizeEffect"; }
+       string output_fragment_shader() { return read_file("identity.frag"); }
+
+       virtual bool changes_output_size() const { return true; }
+
+       virtual void get_output_size(unsigned *width, unsigned *height,
+                                    unsigned *virtual_width, unsigned *virtual_height) const {
+               *width = this->width;
+               *height = this->height;
+               *virtual_width = this->virtual_width;
+               *virtual_height = this->virtual_height;
        }
+
+private:
+       int width, height, virtual_width, virtual_height;
+};
+
+TEST(EffectChainTest, VirtualSizeIsSentOnToInputs) {
+       const int size = 2, bigger_size = 3;
+       float data[size * size] = {
+               1.0f, 0.0f,
+               0.0f, 1.0f,
+       };
+       float out_data[size * size];
+       
+       EffectChainTester tester(data, size, size, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       SizeStoringEffect *size_store = new SizeStoringEffect();
+
+       tester.get_chain()->add_effect(new VirtualResizeEffect(size, size, bigger_size, bigger_size));
+       tester.get_chain()->add_effect(size_store);
+       tester.get_chain()->add_effect(new VirtualResizeEffect(size, size, size, size));
+       tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+       EXPECT_EQ(bigger_size, size_store->input_width);
+       EXPECT_EQ(bigger_size, size_store->input_height);
+
+       // If the resize is implemented as non-virtual, we'll fail here,
+       // since bilinear scaling from 2x2 → 3x3 → 2x2 is not very exact.
+       expect_equal(data, out_data, size, size);
 }
 
-TEST(EffectChainTest, Identity) {
+// Does not use EffectChainTest, so that it can construct an EffectChain without
+// a shared ResourcePool (which is also properly destroyed afterwards).
+// Also turns on debugging to test that code path.
+TEST(EffectChainTest, IdentityWithOwnPool) {
+       const int width = 3, height = 2;
        float data[] = {
                0.0f, 0.25f, 0.3f,
                0.75f, 1.0f, 1.0f,
        };
+       const float expected_data[] = {
+               0.75f, 1.0f, 1.0f,
+               0.0f, 0.25f, 0.3f,
+       };
        float out_data[6];
-       EffectChainTester tester(data, 3, 2, COLORSPACE_sRGB, GAMMA_LINEAR);
-       tester.run(out_data, COLORSPACE_sRGB, GAMMA_LINEAR);
 
-       expect_equal(data, out_data, 3, 2);
+       EffectChain chain(width, height);
+       movit_debug_level = MOVIT_DEBUG_ON;
+
+       ImageFormat format;
+       format.color_space = COLORSPACE_sRGB;
+       format.gamma_curve = GAMMA_LINEAR;
+
+       FlatInput *input = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, width, height);
+       input->set_pixel_data(data);
+       chain.add_input(input);
+       chain.add_output(format, OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED);
+
+       GLuint texnum, fbo;
+       glGenTextures(1, &texnum);
+       check_error();
+       glBindTexture(GL_TEXTURE_2D, texnum);
+       check_error();
+       glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, width, height, 0, GL_RGBA, GL_FLOAT, NULL);
+       check_error();
+
+       glGenFramebuffers(1, &fbo);
+       check_error();
+       glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+       check_error();
+       glFramebufferTexture2D(
+               GL_FRAMEBUFFER,
+               GL_COLOR_ATTACHMENT0,
+               GL_TEXTURE_2D,
+               texnum,
+               0);
+       check_error();
+       glBindFramebuffer(GL_FRAMEBUFFER, 0);
+       check_error();
+
+       chain.finalize();
+
+       chain.render_to_fbo(fbo, width, height);
+
+       glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+       glReadPixels(0, 0, width, height, GL_RED, GL_FLOAT, out_data);
+
+       expect_equal(expected_data, out_data, width, height);
+
+       // Reset the debug status again.
+       movit_debug_level = MOVIT_DEBUG_OFF;
 }
+
+}  // namespace movit