+// A compute shader to mirror the inputs, in 2x2 blocks.
+class MirrorComputeEffect : public Effect {
+public:
+ MirrorComputeEffect() {}
+ string effect_type_id() const override { return "MirrorComputeEffect"; }
+ bool is_compute_shader() const override { return true; }
+ string output_fragment_shader() override { return read_file("mirror.comp"); }
+ void get_compute_dimensions(unsigned output_width, unsigned output_height,
+ unsigned *x, unsigned *y, unsigned *z) const override {
+ *x = output_width / 2;
+ *y = output_height / 2;
+ *z = 1;
+ }
+};
+
+TEST(ComputeShaderTest, ComputeThenOneToOne) {
+ float data[] = {
+ 0.0f, 0.25f, 0.3f, 0.8f,
+ 0.75f, 1.0f, 1.0f, 0.2f,
+ };
+ float expected_data[] = {
+ 0.8f, 0.3f, 0.25f, 0.0f,
+ 0.2f, 1.0f, 1.0f, 0.75f,
+ };
+ float out_data[8];
+ EffectChainTester tester(data, 4, 2, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+ tester.get_chain()->add_effect(new MirrorComputeEffect());
+ tester.get_chain()->add_effect(new OneToOneEffect());
+ tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ expect_equal(expected_data, out_data, 4, 2);
+}
+
+// A compute shader that also resizes its input, taking the upper-left pixel
+// of every 2x2 group. (The shader is hard-coded to 4x2 input for simplicity.)
+class Downscale2xComputeEffect : public Effect {
+public:
+ Downscale2xComputeEffect() {}
+ string effect_type_id() const override { return "Downscale2xComputeEffect"; }
+ bool is_compute_shader() const override { return true; }
+ string output_fragment_shader() override { return read_file("downscale2x.comp"); }
+ bool changes_output_size() const override { return true; }
+ void inform_input_size(unsigned input_num, unsigned width, unsigned height) override
+ {
+ this->width = width;
+ this->height = height;
+ }
+ void get_output_size(unsigned *width, unsigned *height,
+ unsigned *virtual_width, unsigned *virtual_height) const override {
+ *width = *virtual_width = this->width / 2;
+ *height = *virtual_height = this->height / 2;
+ }
+
+private:
+ unsigned width, height;
+};
+
+// Even if the compute shader is not the last effect, it's the one that should decide
+// the output size of the phase.
+TEST(ComputeShaderTest, ResizingComputeThenOneToOne) {
+ float data[] = {
+ 0.0f, 0.25f, 0.3f, 0.8f,
+ 0.75f, 1.0f, 1.0f, 0.2f,
+ };
+ float expected_data[] = {
+ 0.0f, 0.3f,
+ };
+ float out_data[2];
+ EffectChainTester tester(nullptr, 2, 1);
+ tester.add_input(data, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR, 4, 2);
+
+ RewritingEffect<Downscale2xComputeEffect> *downscale_effect = new RewritingEffect<Downscale2xComputeEffect>();
+ tester.get_chain()->add_effect(downscale_effect);
+ tester.get_chain()->add_effect(new OneToOneEffect());
+ tester.get_chain()->add_effect(new BouncingIdentityEffect());
+ tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ expect_equal(expected_data, out_data, 2, 1);
+
+ Phase *phase = downscale_effect->replaced_node->containing_phase;
+ EXPECT_EQ(2u, phase->output_width);
+ EXPECT_EQ(1u, phase->output_height);
+}
+