4 files changed, 86 insertions, 10 deletions

diff --git a/themes/src/Snowflake.cpp b/themes/src/Snowflake.cpp
index 1eb6b74..452a716 100644
--- a/themes/src/Snowflake.cpp
+++ b/themes/src/Snowflake.cpp
@@ -4,6 +4,16 @@
 #include "list.h"
 #include <cstdio>
 
+/*
+
+  What else to do?
+
+  - Windstream that blows a certain selection of snowflakes in a loop-dee-loop pattern
+  - Snowflakes that land on the ground and melt
+  - Snowflakes that spin along the Y-axis for a three dimensional effect
+  
+ */
+
 const Vector4 snowColor = Vector4(1.0, 0.98, 0.98, 1);
 const Vector2 NUM_ARMS_RANGE = Vector2(6.f, 8.f);
 const Vector2 RADIUS_RANGE = Vector2(8.f, 32.f);
@@ -65,10 +75,11 @@ inline void generateSnowflakeShape(matte::List<Vertex2D>* vertices, i32 numArms,
 }
 
 inline void initFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData* ud) {
+    ud->radius = randomFloatBetween(RADIUS_RANGE.x, RADIUS_RANGE.y);
 	ud->vtxIdx = renderer->vertices.numElements;
 	generateSnowflakeShape(&renderer->vertices,
                            randomFloatBetween(NUM_ARMS_RANGE.x, NUM_ARMS_RANGE.y),
-                           randomFloatBetween(RADIUS_RANGE.x, RADIUS_RANGE.y));
+                           ud->radius);
     
 	ud->numVertices = renderer->vertices.numElements - ud->vtxIdx;
 	ud->velocity = Vector2(randomFloatBetween(VELOCITY_RANGE_X.x, VELOCITY_RANGE_X.y), randomFloatBetween(VELOCITY_RANGE_Y.x, VELOCITY_RANGE_Y.y));
@@ -126,9 +137,10 @@ void SnowflakeParticleRenderer::load(SnowflakeLoadParameters params, Renderer2d*
 inline void resetFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData* ud) {
     ud->position.y = 2 * renderer->yMax;
     ud->velocity = Vector2(randomFloatBetween(-10, 10), randomFloatBetween(-100, -85));
+    ud->rotation = 0;
 }
 
-inline void updateFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData* ud, i32 s, f32 dtSeconds, bool addWind) {
+inline void updateFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData* ud, i32 s, f32 dtSeconds) {
     ud->velocity = ud->velocity + Vector2(0, -(GRAVITY * dtSeconds));
 	if (addWind) ud->velocity += renderer->windSpeed;	
 	ud->position += ud->velocity * dtSeconds;
@@ -139,24 +151,20 @@ inline void updateFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData
 		renderer->vertices.data[v].vMatrix = m;
 	}
 
-    if (ud->position.y <= -256) {
+    if (ud->position.y <= -ud->radius) {
         resetFlake(renderer, ud);
     }
 }
 
 void SnowflakeParticleRenderer::update(f32 dtSeconds) {
-	bool addWind = false;
 	timeUntilNextWindSeconds -= dtSeconds;
 	if (timeUntilNextWindSeconds < 0) {
-		timeUntilNextWindSeconds = windIntervalSeconds;
-		windSpeed = Vector2(randomFloatBetween(WIND_VELOCITY_RANGE_X.x, WIND_VELOCITY_RANGE_X.y),
-                            randomFloatBetween(WIND_VELOCITY_RANGE_Y.x, WIND_VELOCITY_RANGE_Y.y));
-		addWind = true;
+		timeUntilNextWindSeconds = randomFloatBetween(2.5f, 10.f);
 	}
 
     for (i32 s = 0; s < numSnowflakes; s++) {
         SnowflakeUpdateData* ud = &updateData[s];
-        updateFlake(this, ud, s, dtSeconds, addWind);
+        updateFlake(this, ud, s, dtSeconds);
     }
 }
 
diff --git a/themes/src/Snowflake.h b/themes/src/Snowflake.h
index 2524483..c147469 100644
--- a/themes/src/Snowflake.h
+++ b/themes/src/Snowflake.h
@@ -4,6 +4,7 @@
 #include "types.h"
 #include "mathlib.h"
 #include "list.h"
+#include "Windfield.hpp"
 
 struct Renderer2d;
 struct Vertex2D;
@@ -18,6 +19,7 @@ struct SnowflakeUpdateData {
 	Vector2 position;
     f32 rotateVelocity = 0.f;
 	f32 rotation = 0;
+    f32 radius;
 
 	i32 vtxIdx = 0;
 	i32 numVertices = 0;
@@ -28,8 +30,8 @@ struct SnowflakeParticleRenderer {
 	f32 yMax = 0;
 	f32 windIntervalSeconds = 1.5;
 	i32 numSnowflakes = 0;
-    Vector2 windSpeed;
 	f32 timeUntilNextWindSeconds = 0;
+    WindField wind;
 	SnowflakeUpdateData* updateData;
 
 	u32 vao;
diff --git a/themes/src/Windfield.cpp b/themes/src/Windfield.cpp
new file mode 100644
index 0000000..3a7563f
--- /dev/null
+++ b/themes/src/Windfield.cpp
@@ -0,0 +1,28 @@
+#include "Windfield.hpp"
+
+    
+template <i32 Width, i32 Height, i32 CellDimension>
+void WindField<Width, Height, CellDimension>::load(f32 ttl, Vector2 origin) {
+    this->ttl = ttl;
+    this->origin = origin;
+    this->end = this->origin + Vector2(Width * CellDimension, Height * CellDimension);
+}
+
+template <i32 Width, i32 Height, i32 CellDimension>
+bool WindField<Width, Height, CellDimension>::addVector(i32 x, i32 y, Vector2& v) {
+    field[x][y] = v;
+    return false;
+}
+
+template <i32 Width, i32 Height, i32 CellDimension>
+Vector2 WindField<Width, Height, CellDimension>::getWindFactor(Vector2& v) {
+    if (v.x >= origin.x && v.x <= end.x
+        && v.y >= origin.y && v.y <= end.y) {
+        Vector2 positionInField = v - this->origin;
+        i32 cellX = static_cast<i32>(Width / positionInField.x);
+        i32 cellY = static_cast<i32>(Height / positionInField.y);
+        return field[cellX, cellY];
+    }
+    
+    return Vector2();
+}
diff --git a/themes/src/Windfield.hpp b/themes/src/Windfield.hpp
new file mode 100644
index 0000000..5935c5d
--- /dev/null
+++ b/themes/src/Windfield.hpp
@@ -0,0 +1,38 @@
+#ifndef WIND_FIELD_HPP
+#define WIND_FIELD_HPP
+#include "types.h"
+#include "mathlib.h"
+
+/**
+   A Windfield represents a field of vectors in a rectangular region.
+   The Width and Height are given in units of CellDimenions. The CellDimension
+   is given in pixels.
+ */
+struct WindField {
+    f32 ttl = 0.f;
+    Vector2 origin;
+    Vector2 end;
+
+    /*
+      Granularity of each cell in pixels.
+     */
+    const f32 cellDimension = CellDimension;
+
+    /*
+      Width of the vector field in CellDimensions.
+     */
+    const f32 width = Width;
+
+    /*
+      Height of the vector vield in CellDimensions.
+     */
+    const f32 height = Height;
+
+    Vector2** field;
+
+    void load(f32 cellSizePixels, i32 fieldWithCells, i32 fieldHeightCells, f32 ttl, Vector2 origin);
+    bool addVector(i32 x, i32 y, Vector2& v);
+    Vector2 getWindFactor(Vector2& v);
+};
+
+#endif