From 6351a677037a7361df77d8d027b612bd1e2e3645 Mon Sep 17 00:00:00 2001
From: Andras Schmelczer <andras@schmelczer.dev>
Date: Sat, 20 May 2023 11:45:11 +0100
Subject: [PATCH] Use angle instead of direction

---
 src/game-loop/spawn-agents.ts          |  2 +-
 src/pipelines/agents/agent-pipeline.ts |  3 ++-
 src/pipelines/agents/agent.ts          |  2 +-
 src/pipelines/agents/agent.wgsl        | 24 +++++++++++++-----------
 src/settings.ts                        |  4 ++--
 5 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/src/game-loop/spawn-agents.ts b/src/game-loop/spawn-agents.ts
index 0770008..7420a3b 100644
--- a/src/game-loop/spawn-agents.ts
+++ b/src/game-loop/spawn-agents.ts
@@ -18,7 +18,7 @@ export const spawnAgents = (canvasSize: vec2, agentCount: number): Array<Agent>
 
     return {
       position,
-      direction: vec2.fromValues(Math.cos(angle + Math.PI), Math.sin(angle + Math.PI)),
+      angle: angle + Math.PI,
       species: 0,
       timeToLive: Random.randomBetween(10, 15000),
     };
diff --git a/src/pipelines/agents/agent-pipeline.ts b/src/pipelines/agents/agent-pipeline.ts
index 1e3c156..5096ec1 100644
--- a/src/pipelines/agents/agent-pipeline.ts
+++ b/src/pipelines/agents/agent-pipeline.ts
@@ -52,7 +52,8 @@ export class AgentPipeline {
     new Float32Array(this.agentsBuffer.getMappedRange()).set(
       agents.flatMap((agent) => [
         ...agent.position,
-        ...agent.direction,
+        agent.angle,
+        0, // padding
         agent.species,
         agent.timeToLive,
       ])
diff --git a/src/pipelines/agents/agent.ts b/src/pipelines/agents/agent.ts
index 84e463d..2f4cd1a 100644
--- a/src/pipelines/agents/agent.ts
+++ b/src/pipelines/agents/agent.ts
@@ -2,7 +2,7 @@ import { vec2 } from 'gl-matrix';
 
 export interface Agent {
   position: vec2;
-  direction: vec2;
+  angle: number;
   species: number;
   timeToLive: number;
 }
diff --git a/src/pipelines/agents/agent.wgsl b/src/pipelines/agents/agent.wgsl
index e0dad82..c063fb9 100644
--- a/src/pipelines/agents/agent.wgsl
+++ b/src/pipelines/agents/agent.wgsl
@@ -1,6 +1,6 @@
 struct Agent {
   position: vec2<f32>,
-  direction: vec2<f32>,
+  angle: f32,
   species: f32,
   timeToLive: f32
 }
@@ -37,7 +37,7 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
     // agent.species = 1;
     // agent.timeToLive = 1000;
     // agents[id] = agent;
-    return;
+    // return;
   }
 
   let random = random_with_seed(agent.position, f32(id) + state.time);
@@ -55,9 +55,9 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
   }
 
   
-  let trailForward = sense(agent.position, agent.direction, settings.sensorOffset, 0);
-  let trailLeft = sense(agent.position, agent.direction, settings.sensorOffset, settings.sensorAngle);
-  let trailRight = sense(agent.position, agent.direction, settings.sensorOffset, -settings.sensorAngle);
+  let trailForward = sense(agent.position, agent.angle, settings.sensorOffset, 0);
+  let trailLeft = sense(agent.position, agent.angle, settings.sensorOffset, settings.sensorAngle);
+  let trailRight = sense(agent.position, agent.angle, settings.sensorOffset, -settings.sensorAngle);
 
   var weightForward: f32 = trailForward.a * settings.brushTrailWeight;
   var weightLeft: f32 = trailLeft.a * settings.brushTrailWeight;
@@ -81,13 +81,14 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
     rotation = random * settings.turnRate * state.deltaTime;
   }
 
-  var nextDirection = agent.direction * mat2x2<f32>(cos(rotation), sin(rotation), -sin(rotation), cos(rotation));
+  var nextAngle = agent.angle + rotation;
 
-  var nextPosition = agent.position + agent.direction * settings.moveRate * state.deltaTime;
+  let direction = vec2(cos(agent.angle), sin(agent.angle));
+  var nextPosition = agent.position + direction * settings.moveRate * state.deltaTime;
   nextPosition = clamp(nextPosition, vec2<f32>(0, 0), state.size);
   if nextPosition.x == 0 || nextPosition.x == state.size.x || nextPosition.y == 0 || nextPosition.y == state.size.y {
     rotation = 3.14159265359 + random - 0.5;
-    nextDirection = agent.direction * mat2x2<f32>(cos(rotation), sin(rotation), -sin(rotation), cos(rotation));
+    nextAngle = agent.angle + rotation;
   }
 
   var trail = vec4<f32>(0, 1, 0, 0);
@@ -99,13 +100,14 @@ fn main(@builtin(global_invocation_id) global_id: vec3<u32>) {
   textureStore(trailMapOut, vec2<i32>(nextPosition), vec4(trail.rgb + current.rgb, 0));
 
   agent.position = nextPosition;
-  agent.direction = nextDirection;
+  agent.angle = nextAngle;
   agent.timeToLive -= state.deltaTime;
   agents[id] = agent;
 }
 
-fn sense(agentPosition: vec2<f32>, agentDirection: vec2<f32>, sensorOffset: f32, sensorOffsetAngle: f32) -> vec4<f32> {
-  let sensorDirection = agentDirection * mat2x2<f32>(cos(sensorOffsetAngle), sin(sensorOffsetAngle), -sin(sensorOffsetAngle), cos(sensorOffsetAngle));
+fn sense(agentPosition: vec2<f32>, agentAngle: f32, sensorOffset: f32, sensorOffsetAngle: f32) -> vec4<f32> {
+  let sensorAngle = agentAngle + sensorOffsetAngle;
+  let sensorDirection = vec2(cos(sensorAngle), sin(sensorAngle));
   let sensorPosition = vec2<i32>(agentPosition + sensorDirection * sensorOffset);
   return textureLoad(trailMapIn, sensorPosition, 0); 
 }
diff --git a/src/settings.ts b/src/settings.ts
index 126c301..f2ed019 100644
--- a/src/settings.ts
+++ b/src/settings.ts
@@ -29,8 +29,8 @@ export const settings: GameLoopSettings &
   brushWidthRandomness: 8,
 
   brushTrailWeight: 5,
-  moveSpeed: 50,
-  turnSpeed: 10,
+  moveSpeed: 40,
+  turnSpeed: 20,
   sensorOffsetAngle: 30,
   sensorOffsetDistance: 60,