+// Unit tests for EffectChain.
+
+#include "effect_chain.h"
+#include "flat_input.h"
+#include "sandbox_effect.h"
+#include "opengl.h"
+#include "gtest/gtest.h"
+
+#include <stdio.h>
+#include <math.h>
+
+#include <algorithm>
+
+class EffectChainTester {
+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);
+ }
+
+ EffectChain *get_chain() { return &chain; }
+
+ void run(float *out_data, ColorSpace color_space, GammaCurve gamma_curve)
+ {
+ 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]);
+ }
+ }
+ }
+
+private:
+ EffectChain chain;
+ unsigned width, height;
+};
+
+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;
+ }
+ }
+
+ const float largest_difference_limit = 1.5 / 255.0;
+ const float rms_limit = 0.5 / 255.0;
+
+ EXPECT_LT(largest_difference, largest_difference_limit);
+
+ float rms = sqrt(squared_difference) / (width * height);
+ EXPECT_LT(rms, rms_limit);
+
+ if (largest_difference >= largest_difference_limit || rms >= rms_limit) {
+ fprintf(stderr, "Dumping matrices for easier debugging, since at least one test failed.\n");
+
+ 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");
+ }
+
+ 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, Identity) {
+ float data[] = {
+ 0.0f, 0.25f, 0.3f,
+ 0.75f, 1.0f, 1.0f,
+ };
+ 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);
+}