[apps/graph] Added tests for graph caching

Wrote some tests to check that the caching process does not lead to
aberrant values.

Change-Id: I28137e66f430dbcf4417733d1274319dbadfc9af

apps/Makefile

@@ -84,7 +84,7 @@ $(eval $(call depends_on_image,apps/title_bar_view.cpp,apps/exam_icon.png))
 $(call object_for,$(apps_src) $(tests_src)): $(BUILD_DIR)/apps/i18n.h
 $(call object_for,$(apps_src) $(tests_src)): $(BUILD_DIR)/python/port/genhdr/qstrdefs.generated.h
 
-apps_tests_src = $(app_calculation_test_src) $(app_code_test_src) $(app_probability_test_src) $(app_regression_test_src) $(app_sequence_test_src) $(app_shared_test_src) $(app_statistics_test_src) $(app_settings_test_src) $(app_solver_test_src)
+apps_tests_src = $(app_calculation_test_src) $(app_code_test_src) $(app_graph_test_src) $(app_probability_test_src) $(app_regression_test_src) $(app_sequence_test_src) $(app_shared_test_src) $(app_statistics_test_src) $(app_settings_test_src) $(app_solver_test_src)
 
 apps_tests_src += $(addprefix apps/,\
   alternate_empty_nested_menu_controller.cpp \

apps/graph/Makefile

@@ -1,9 +1,12 @@
 apps += Graph::App
 app_headers += apps/graph/app.h
 
+app_graph_test_src = $(addprefix apps/graph/,\
+  continuous_function_store.cpp \
+)
+
 app_graph_src = $(addprefix apps/graph/,\
   app.cpp \
-  continuous_function_store.cpp \
   graph/banner_view.cpp \
   graph/calculation_graph_controller.cpp \
   graph/calculation_parameter_controller.cpp \
@@ -31,8 +34,13 @@ app_graph_src = $(addprefix apps/graph/,\
   values/values_controller.cpp \
 )
 
+app_graph_src += $(app_graph_test_src)
 apps_src += $(app_graph_src)
 
 i18n_files += $(call i18n_without_universal_for,graph/base)
 
+tests_src += $(addprefix apps/graph/test/,\
+  caching.cpp\
+)
+
 $(eval $(call depends_on_image,apps/graph/app.cpp,apps/graph/graph_icon.png))

apps/graph/test/caching.cpp

@@ -0,0 +1,132 @@
+#include <quiz.h>
+#include "../app.h"
+#include <cmath>
+
+using namespace Poincare;
+using namespace Shared;
+
+namespace Graph {
+
+bool floatEquals(float a, float b, float tolerance = 1.f/static_cast<float>(Ion::Display::Height)) {
+  /* The default value for the tolerance is chosen so that the error introduced
+   * by caching would not typically be visible on screen. */
+  return a == b || std::abs(a - b) <= tolerance * std::abs(a + b) / 2.f || (std::isnan(a) && std::isnan(b));
+}
+
+ContinuousFunction * addFunction(ContinuousFunctionStore * store, ContinuousFunction::PlotType type, const char * definition, Context * context) {
+  Ion::Storage::Record::ErrorStatus err = store->addEmptyModel();
+  assert(err == Ion::Storage::Record::ErrorStatus::None);
+  (void) err; // Silence compilation warning about unused variable.
+  Ion::Storage::Record record = store->recordAtIndex(store->numberOfModels() - 1);
+  ContinuousFunction * f = static_cast<ContinuousFunction *>(store->modelForRecord(record).operator->());
+  f->setPlotType(type, Poincare::Preferences::AngleUnit::Degree, context);
+  f->setContent(definition, context);
+  return f;
+}
+
+void assert_check_cartesian_cache_against_function(ContinuousFunction * function, ContinuousFunctionCache * cache, Context * context, float tMin) {
+  /* We set the cache to nullptr to force the evaluation (otherwise we would be
+   * comparing the cache against itself). */
+  function->setCache(nullptr);
+
+  float t;
+  for (int i = 0; i < Ion::Display::Width; i++) {
+    t = tMin + i*cache->step();
+    Coordinate2D<float> cacheValues = cache->valueForParameter(function, context, t);
+    Coordinate2D<float> functionValues = function->evaluateXYAtParameter(t, context);
+    quiz_assert(floatEquals(t, cacheValues.x1()));
+    quiz_assert(floatEquals(t, functionValues.x1()));
+    quiz_assert(floatEquals(cacheValues.x2(), functionValues.x2()));
+  }
+  /* We set back the cache, so that it will not be invalidated in
+   * PrepareForCaching later. */
+  function->setCache(cache);
+}
+
+void assert_cartesian_cache_stays_valid_while_panning(ContinuousFunction * function, Context * context, InteractiveCurveViewRange * range, CurveViewCursor * cursor, ContinuousFunctionStore * store, float step) {
+  ContinuousFunctionCache * cache = store->cacheAtIndex(0);
+  assert(cache);
+
+  float tMin, tStep;
+  constexpr float margin = 0.04f;
+  constexpr int numberOfMoves = 30;
+  for (int i = 0; i < numberOfMoves; i++) {
+    cursor->moveTo(cursor->t() + step, cursor->x() + step, function->evaluateXYAtParameter(cursor->x() + step, context).x2());
+    range->panToMakePointVisible(cursor->x(), cursor->y(), margin, margin, margin, margin, (range->xMax() - range->xMin()) / (Ion::Display::Width - 1));
+    tMin = range->xMin();
+    tStep = (range->xMax() - range->xMin()) / (Ion::Display::Width - 1);
+    ContinuousFunctionCache::PrepareForCaching(function, cache, tMin, tStep);
+    assert_check_cartesian_cache_against_function(function, cache, context, tMin);
+  }
+}
+
+void assert_check_polar_cache_against_function(ContinuousFunction * function, Context * context, InteractiveCurveViewRange * range, ContinuousFunctionStore * store) {
+  ContinuousFunctionCache * cache = store->cacheAtIndex(0);
+  assert(cache);
+
+  float tMin = range->xMin();
+  float tMax = range->xMax();
+  float tStep = ((tMax - tMin) / Graph::GraphView::k_graphStepDenominator) / ContinuousFunctionCache::k_parametricStepFactor;
+  ContinuousFunctionCache::PrepareForCaching(function, cache, tMin, tStep);
+
+  // Fill the cache
+  float t;
+  for (int i = 0; i < Ion::Display::Width / 2; i++) {
+    t = tMin + i*cache->step();
+    function->evaluateXYAtParameter(t, context);
+  }
+
+  function->setCache(nullptr);
+  for (int i = 0; i < Ion::Display::Width / 2; i++) {
+    t = tMin + i*cache->step();
+    Coordinate2D<float> cacheValues = cache->valueForParameter(function, context, t);
+    Coordinate2D<float> functionValues = function->evaluateXYAtParameter(t, context);
+    quiz_assert(floatEquals(cacheValues.x1(), functionValues.x1()));
+    quiz_assert(floatEquals(cacheValues.x2(), functionValues.x2()));
+  }
+}
+
+void assert_cache_stays_valid(ContinuousFunction::PlotType type, const char * definition, float rangeXMin = -5, float rangeXMax = 5) {
+  GlobalContext globalContext;
+  ContinuousFunctionStore functionStore;
+
+  InteractiveCurveViewRange graphRange;
+  graphRange.setXMin(rangeXMin);
+  graphRange.setXMax(rangeXMax);
+  graphRange.setYMin(-3.f);
+  graphRange.setYMax(3.f);
+
+  CurveViewCursor cursor;
+  ContinuousFunction * function = addFunction(&functionStore, type, definition, &globalContext);
+  Coordinate2D<float> origin = function->evaluateXYAtParameter(0.f, &globalContext);
+  cursor.moveTo(0.f, origin.x1(), origin.x2());
+
+  if (type == ContinuousFunction::PlotType::Cartesian) {
+    assert_cartesian_cache_stays_valid_while_panning(function, &globalContext, &graphRange, &cursor, &functionStore, 2.f);
+    assert_cartesian_cache_stays_valid_while_panning(function, &globalContext, &graphRange, &cursor, &functionStore, -0.4f);
+  } else {
+    assert_check_polar_cache_against_function(function, &globalContext, &graphRange, &functionStore);
+  }
+
+  functionStore.removeAll();
+}
+
+QUIZ_CASE(graph_caching) {
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Cartesian, "x");
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Cartesian, "x^2");
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Cartesian, "sin(x)");
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Cartesian, "sin(x)", -1e6f, 2e8f);
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Cartesian, "sin(x^2)");
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Cartesian, "1/x");
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Cartesian, "1/x", -5e-5f, 5e-5f);
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Cartesian, "-ℯ^x");
+
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Polar, "1", 0.f, 360.f);
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Polar, "θ", 0.f, 360.f);
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Polar, "sin(θ)", 0.f, 360.f);
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Polar, "sin(θ)", 2e-4f, 1e-3f);
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Polar, "cos(5θ)", 0.f, 360.f);
+  assert_cache_stays_valid(ContinuousFunction::PlotType::Polar, "cos(5θ)", -1e8f, 1e8f);
+}
+
+}

apps/shared/Makefile

@@ -1,5 +1,7 @@
 app_shared_test_src = $(addprefix apps/shared/,\
   continuous_function.cpp\
+  continuous_function_cache.cpp \
+  curve_view_cursor.cpp \
   curve_view_range.cpp \
   curve_view.cpp \
   dots.cpp \
@@ -24,9 +26,7 @@ app_shared_src = $(addprefix apps/shared/,\
   buffer_function_title_cell.cpp \
   buffer_text_view_with_text_field.cpp \
   button_with_separator.cpp \
-  continuous_function_cache.cpp \
   cursor_view.cpp \
-  curve_view_cursor.cpp \
   editable_cell_table_view_controller.cpp \
   expression_field_delegate_app.cpp \
   expression_model_list_controller.cpp \