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-rw-r--r--themes/src/Snowflake.cpp61
-rw-r--r--themes/src/Snowflake.h15
2 files changed, 52 insertions, 24 deletions
diff --git a/themes/src/Snowflake.cpp b/themes/src/Snowflake.cpp
index 06e04ad..1eb6b74 100644
--- a/themes/src/Snowflake.cpp
+++ b/themes/src/Snowflake.cpp
@@ -5,6 +5,29 @@
#include <cstdio>
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);
+const Vector2 VELOCITY_RANGE_X = Vector2(-10.f, 10.f);
+const Vector2 VELOCITY_RANGE_Y = Vector2(-100.f, -85.f);
+const Vector2 ROTATION_VELOCITY_RANGE = Vector2(-PI / 8.f, PI / 8.f);
+const Vector2 WIND_VELOCITY_RANGE_X = Vector2(-3.f, 3.f);
+const Vector2 WIND_VELOCITY_RANGE_Y = Vector2(3.f, 10.f);
+const f32 GRAVITY = 5.f;
+
+inline void generateSnowflakeArm(f32 width, f32 height, f32 angle, matte::List<Vertex2D>* vertices, Mat4x4 transform = Mat4x4()) {
+ f32 halfWidth = width / 2.f;
+ Vector2 leftStart = transform * Vector2(-halfWidth, 0).rotate(angle);
+ Vector2 leftEnd = transform * Vector2(-halfWidth, height).rotate(angle);
+ Vector2 rightStart = transform * Vector2(halfWidth, 0).rotate(angle);
+ Vector2 rightEnd = transform * Vector2(halfWidth, height).rotate(angle);
+
+ vertices->add({ leftStart, snowColor, Mat4x4() });
+ vertices->add({ leftEnd, snowColor, Mat4x4() });
+ vertices->add({ rightEnd, snowColor, Mat4x4() });
+ vertices->add({ leftStart, snowColor, Mat4x4() });
+ vertices->add({ rightEnd, snowColor, Mat4x4() });
+ vertices->add({ rightStart, snowColor, Mat4x4() });
+}
/**
Fills in the vertices array vertices that represent a snowflake shape. The snowflake shape consists
@@ -25,30 +48,32 @@ inline void generateSnowflakeShape(matte::List<Vertex2D>* vertices, i32 numArms,
f32 dx = ((2 * PI) / numArms);
for (i32 armIndex = 0; armIndex < numArms; armIndex++) {
f32 armAngle = dx * armIndex;
- Vector2 leftStart = Vector2(-armWidthRatio * radius, 0).rotate(armAngle);
- Vector2 leftEnd = Vector2(-armWidthRatio * radius, radius).rotate(armAngle);
- Vector2 rightStart = Vector2(armWidthRatio * radius, 0).rotate(armAngle);
- Vector2 rightEnd = Vector2(armWidthRatio * radius, radius).rotate(armAngle);
-
- vertices->add({ leftStart, snowColor, Mat4x4() });
- vertices->add({ leftEnd, snowColor, Mat4x4() });
- vertices->add({ rightEnd, snowColor, Mat4x4() });
- vertices->add({ leftStart, snowColor, Mat4x4() });
- vertices->add({ rightEnd, snowColor, Mat4x4() });
- vertices->add({ rightStart, snowColor, Mat4x4() });
+ generateSnowflakeArm(armWidthRatio * radius, radius, armAngle, vertices);
+ f32 armLeftAngle = DEG_TO_RAD(60.f);
+ f32 armRightAngle = DEG_TO_RAD(-60.f);
+
+ const i32 NUM_SUB_ARMS = 4;
+ for (i32 subArmIndex = 0; subArmIndex < NUM_SUB_ARMS; subArmIndex++) {
+ f32 height = (radius / static_cast<f32>(subArmIndex));
+ f32 width = (armWidthRatio / (subArmIndex + 1)) * height;
+ f32 transY = (radius / (NUM_SUB_ARMS + 1)) * (subArmIndex + 1);
+ Vector2 translation = Vector2(0, transY).rotate(armAngle);
+ generateSnowflakeArm(width, height, armAngle, vertices, Mat4x4().translateByVec2(translation).rotate2D(armLeftAngle));
+ generateSnowflakeArm(width, height, armAngle, vertices, Mat4x4().translateByVec2(translation).rotate2D(armRightAngle));
+ }
}
}
inline void initFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData* ud) {
ud->vtxIdx = renderer->vertices.numElements;
generateSnowflakeShape(&renderer->vertices,
- 6,
- randomFloatBetween(8.f, 16.f));
+ randomFloatBetween(NUM_ARMS_RANGE.x, NUM_ARMS_RANGE.y),
+ randomFloatBetween(RADIUS_RANGE.x, RADIUS_RANGE.y));
ud->numVertices = renderer->vertices.numElements - ud->vtxIdx;
- ud->velocity = Vector2(randomFloatBetween(-10, 10), randomFloatBetween(-100, -85));
+ ud->velocity = Vector2(randomFloatBetween(VELOCITY_RANGE_X.x, VELOCITY_RANGE_X.y), randomFloatBetween(VELOCITY_RANGE_Y.x, VELOCITY_RANGE_Y.y));
ud->position = Vector2(randomFloatBetween(0, renderer->xMax), randomFloatBetween(renderer->yMax, 4 * renderer->yMax));
- ud->rotateVelocity = randomFloatBetween(-PI / 8.f, PI / 8.f);
+ ud->rotateVelocity = randomFloatBetween(ROTATION_VELOCITY_RANGE.x, ROTATION_VELOCITY_RANGE.y);
}
void SnowflakeParticleRenderer::load(SnowflakeLoadParameters params, Renderer2d* renderer) {
@@ -104,7 +129,8 @@ inline void resetFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData*
}
inline void updateFlake(SnowflakeParticleRenderer* renderer, SnowflakeUpdateData* ud, i32 s, f32 dtSeconds, bool addWind) {
- if (addWind) ud->velocity += renderer->windSpeed;
+ ud->velocity = ud->velocity + Vector2(0, -(GRAVITY * dtSeconds));
+ if (addWind) ud->velocity += renderer->windSpeed;
ud->position += ud->velocity * dtSeconds;
ud->rotation += ud->rotateVelocity * dtSeconds;
@@ -123,7 +149,8 @@ void SnowflakeParticleRenderer::update(f32 dtSeconds) {
timeUntilNextWindSeconds -= dtSeconds;
if (timeUntilNextWindSeconds < 0) {
timeUntilNextWindSeconds = windIntervalSeconds;
- windSpeed = Vector2(randomFloatBetween(-10, 10), randomFloatBetween(-10, 0));
+ 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;
}
diff --git a/themes/src/Snowflake.h b/themes/src/Snowflake.h
index 02673c1..2524483 100644
--- a/themes/src/Snowflake.h
+++ b/themes/src/Snowflake.h
@@ -1,3 +1,6 @@
+#ifndef SNOWFLAKE_H
+#define SNOWFLAKE_H
+
#include "types.h"
#include "mathlib.h"
#include "list.h"
@@ -6,15 +9,11 @@ struct Renderer2d;
struct Vertex2D;
struct SnowflakeLoadParameters {
- i32 numSnowflakes = 500;
- f32 rateOfSnowfall = 0.1f;
- Vector2 flakeV0 = { 0, 1 };
- Vector4 snowColor = { 0.8, 0.8, 0.8, 1.0 };
- f32 windIntervalSeconds = 1.5;
+ i32 numSnowflakes = 480;
+ f32 windIntervalSeconds = 1.5f;
};
struct SnowflakeUpdateData {
- Vector2 v0;
Vector2 velocity;
Vector2 position;
f32 rotateVelocity = 0.f;
@@ -30,8 +29,8 @@ struct SnowflakeParticleRenderer {
f32 windIntervalSeconds = 1.5;
i32 numSnowflakes = 0;
Vector2 windSpeed;
- SnowflakeUpdateData* updateData;
f32 timeUntilNextWindSeconds = 0;
+ SnowflakeUpdateData* updateData;
u32 vao;
u32 vbo;
@@ -43,3 +42,5 @@ struct SnowflakeParticleRenderer {
void render(Renderer2d* renderer);
void unload();
};
+
+#endif