Impl. SparkEffect

SparkEffect is an additional effect that occurs when successfully
"hacking" a Walker.

Makefile

@@ -21,7 +21,8 @@ SOURCES = \
 		src/walker.cc \
 		src/surface_triangle.cc \
 		src/screen_walker_hack.cc \
-		src/electricity_effect.cc
+		src/electricity_effect.cc \
+		src/spark_effect.cc
 
 HEADERS = \
 		src/game.h \
@@ -33,7 +34,8 @@ HEADERS = \
 		src/walker.h \
 		src/surface_triangle.h \
 		src/screen_walker_hack.h \
-		src/electricity_effect.h
+		src/electricity_effect.h \
+		src/spark_effect.h
 
 OBJECTS = $(addprefix ${OBJDIR}/,$(subst .cc,.cc.o,${SOURCES}))
 

src/screen_trunner.cc

@@ -50,6 +50,7 @@ TRunnerScreen::TRunnerScreen(std::weak_ptr<ScreenStack> stack)
       mouse_hit{0.0F, 0.0F, 0.0F},
       surface_triangles(),
       electricityEffects(),
+      sparkEffects(),
       idx_hit(SURFACE_UNIT_WIDTH / 2 +
               (SURFACE_UNIT_HEIGHT / 2) * SURFACE_UNIT_WIDTH),
       controlled_walker_idx(std::nullopt),
@@ -105,6 +106,10 @@ bool TRunnerScreen::update(float dt, bool is_resized) {
           ELECTRICITY_EFFECT_RADIUS, ELECTRICITY_EFFECT_LINE_COUNT,
           ELECTRICITY_EFFECT_LIFETIME));
 
+      sparkEffects.push_back(
+          SparkEffect(SPARK_EFFECT_SPARK_COUNT, SPARK_EFFECT_LIFETIME,
+                      walkers[controlled_walker_idx.value()].get_body_pos(),
+                      SPARK_EFFECT_XZ_VARIANCE, SPARK_EFFECT_RADIUS));
     } else {
       controlled_walker_idx.reset();
     }
@@ -284,6 +289,7 @@ post_check_click:
                   SURFACE_UNIT_HEIGHT);
   }
 
+  {
     std::vector<decltype(electricityEffects.size())> to_remove;
     for (decltype(electricityEffects.size()) idx = 0;
          idx < electricityEffects.size(); ++idx) {
@@ -298,6 +304,24 @@ post_check_click:
       }
       electricityEffects.pop_back();
     }
+  }
+
+  {
+    std::vector<decltype(sparkEffects.size())> to_remove;
+    for (decltype(sparkEffects.size()) idx = 0; idx < sparkEffects.size();
+         ++idx) {
+      if (sparkEffects[idx].update(dt)) {
+        to_remove.push_back(idx);
+      }
+    }
+
+    for (auto iter = to_remove.rbegin(); iter != to_remove.rend(); ++iter) {
+      if (*iter != sparkEffects.size() - 1) {
+        sparkEffects[*iter] = *sparkEffects.rbegin();
+      }
+      sparkEffects.pop_back();
+    }
+  }
 
   return false;
 }
@@ -344,6 +368,10 @@ bool TRunnerScreen::draw(RenderTexture *render_texture) {
     ee.draw(GREEN);
   }
 
+  for (auto &se : sparkEffects) {
+    se.draw(GREEN);
+  }
+
   // TODO DEBUG
   if (!controlled_walker_idx.has_value() && !flags.test(0)) {
     DrawLine3D(Vector3{0.0F, 3.0F, 0.0F}, mouse_hit, BLACK);

src/screen_trunner.h

@@ -15,6 +15,7 @@
 // local includes
 #include "common_constants.h"
 #include "electricity_effect.h"
+#include "spark_effect.h"
 #include "surface_triangle.h"
 #include "walker.h"
 
@@ -33,6 +34,11 @@ constexpr int ELECTRICITY_EFFECT_LINE_COUNT = 35;
 constexpr float ELECTRICITY_EFFECT_RADIUS = 2.0F;
 constexpr float ELECTRICITY_EFFECT_LIFETIME = 3.0F;
 
+constexpr int SPARK_EFFECT_SPARK_COUNT = 30;
+constexpr float SPARK_EFFECT_RADIUS = 2.0F;
+constexpr float SPARK_EFFECT_XZ_VARIANCE = 0.5F;
+constexpr float SPARK_EFFECT_LIFETIME = ELECTRICITY_EFFECT_LIFETIME;
+
 class TRunnerScreen : public Screen {
  public:
   struct SurfaceUnit {
@@ -88,6 +94,7 @@ class TRunnerScreen : public Screen {
                              SURFACE_UNIT_WIDTH * SURFACE_UNIT_HEIGHT * 2> >
       surface_triangles;
   std::vector<ElectricityEffect> electricityEffects;
+  std::vector<SparkEffect> sparkEffects;
   unsigned int idx_hit;
   std::optional<unsigned int> controlled_walker_idx;
   const int left_text_width;

src/spark_effect.cc

@@ -0,0 +1,43 @@
+#include "spark_effect.h"
+
+// local includes
+#include "3d_helpers.h"
+#include "ems.h"
+
+SparkEffect::SparkEffect(int count, float lifetime, Vector3 pos,
+                         float pos_xz_variance, float radius)
+    : sparks(), lifetime(lifetime), timer(0.0F) {
+  Vector3 above_pos = pos;
+  above_pos.y += radius;
+  for (; count > 0; --count) {
+    sparks.push_back(Spark{
+        .pos = pos + Vector3{call_js_get_random() * pos_xz_variance * 2 -
+                                 pos_xz_variance,
+                             0.0F,
+                             call_js_get_random() * pos_xz_variance * 2 -
+                                 pos_xz_variance},
+        .vel =
+            from_edge_to_sphere_random(above_pos, pos, radius) *
+            (SPARK_VEL_RATE + call_js_get_random() * SPARK_VEL_VARIANCE * 2.0F -
+             SPARK_VEL_VARIANCE)});
+  }
+}
+
+bool SparkEffect::update(float dt) {
+  timer += dt;
+
+  for (auto &spark : sparks) {
+    spark.vel.y -= SPARK_ACC_RATE * dt;
+    spark.pos = spark.pos + spark.vel * dt;
+  }
+
+  return timer > lifetime;
+}
+
+void SparkEffect::draw(Color color) {
+  float ratio = timer < lifetime ? (1.0F - timer / lifetime) : 0.0F;
+
+  for (const auto &spark : sparks) {
+    DrawSphere(spark.pos, SPARK_RADIUS * ratio, color);
+  }
+}

src/spark_effect.h

@@ -0,0 +1,36 @@
+#ifndef JUMPARTIFACT_DOT_COM_DEMO_0_SPARK_EFFECT_H_
+#define JUMPARTIFACT_DOT_COM_DEMO_0_SPARK_EFFECT_H_
+
+// standard library includes
+#include <vector>
+
+// third party includes
+#include <raylib.h>
+
+constexpr float SPARK_RADIUS = 0.03F;
+constexpr float SPARK_VEL_RATE = 5.0F;
+constexpr float SPARK_VEL_VARIANCE = 1.0F;
+constexpr float SPARK_ACC_RATE = 10.0F;
+
+class SparkEffect {
+ public:
+  SparkEffect(int count, float lifetime, Vector3 pos, float pos_xz_variance,
+              float radius);
+
+  /// Returns true if end of lifetime.
+  bool update(float dt);
+
+  /// Assumes draw mode is active when called.
+  void draw(Color color);
+
+ private:
+  struct Spark {
+    Vector3 pos, vel;
+  };
+
+  std::vector<Spark> sparks;
+  float lifetime;
+  float timer;
+};
+
+#endif

wasm_build/Makefile

@@ -18,7 +18,8 @@ SOURCES = \
 		../src/walker.cc \
 		../src/surface_triangle.cc \
 		../src/screen_walker_hack.cc \
-		../src/electricity_effect.cc
+		../src/electricity_effect.cc \
+		../src/spark_effect.cc
 
 HEADERS = \
 		../src/ems.h \
@@ -30,7 +31,8 @@ HEADERS = \
 		../src/walker.h \
 		../src/surface_triangle.h \
 		../src/screen_walker_hack.h \
-		../src/electricity_effect.h
+		../src/electricity_effect.h \
+		../src/spark_effect.h
 
 OBJECTS = $(addprefix ${OBJDIR}/,$(subst ..,PREVDIR,$(subst .cc,.cc.o,${SOURCES})))