Add ant presence texture for future spatial neighbor queries

src/Renderer.ts

@@ -79,6 +79,17 @@ export default class Renderer {
                     minFilter: THREE.NearestFilter,
                 },
             ),
+            antsPresenceRenderTarget: new THREE.WebGLRenderTarget(
+                Config.worldSize,
+                Config.worldSize,
+                {
+                    format: THREE.RGBAFormat,
+                    type: THREE.FloatType,
+                    depthBuffer: false,
+                    magFilter: THREE.NearestFilter,
+                    minFilter: THREE.NearestFilter,
+                },
+            ),
         };
     }
 
@@ -109,6 +120,9 @@ export default class Renderer {
             this.resources.worldRenderTarget.texture;
         this.renderer.render(scenes.worldBlur, scenes.worldBlur.camera);
 
+        this.renderer.setRenderTarget(this.resources.antsPresenceRenderTarget);
+        this.renderer.clear();
+
         this.setViewportFromRT(antsComputeTarget);
         this.renderer.setRenderTarget(antsComputeTarget);
         scenes.ants.material.uniforms.tLastState.value =
@@ -117,6 +131,8 @@ export default class Renderer {
             antsComputeSource.textures[1];
         scenes.ants.material.uniforms.tWorld.value =
             this.resources.worldBlurredRenderTarget.texture;
+        scenes.ants.material.uniforms.tPresence.value =
+            this.resources.antsPresenceRenderTarget.texture;
         this.renderer.render(scenes.ants, scenes.ants.camera);
 
         this.setViewportFromRT(this.resources.antsDiscreteRenderTarget);
@@ -266,6 +282,13 @@ export default class Renderer {
         this.renderer.setRenderTarget(this.resources.antsDiscreteRenderTarget);
         this.renderer.clear();
 
+        this.resources.antsPresenceRenderTarget.setSize(
+            Config.worldSize,
+            Config.worldSize,
+        );
+        this.renderer.setRenderTarget(this.resources.antsPresenceRenderTarget);
+        this.renderer.clear();
+
         for (const scene of Object.values(scenes)) {
             scene.recompileMaterials();
         }

src/scenes/AntsComputeScene.ts

@@ -21,6 +21,7 @@ export default class AntsComputeScene extends AbstractScene {
                 tLastState: { value: null },
                 tLastExtState: { value: null },
                 tWorld: { value: null },
+                tPresence: { value: null },
             },
             vertexShader,
             fragmentShader,

src/shaders/antsCompute.frag

@@ -12,6 +12,7 @@ uniform float uTime;
 uniform sampler2D tLastState;
 uniform sampler2D tLastExtState;
 uniform sampler2D tWorld;
+uniform sampler2D tPresence;
 
 const float sampleDistance = 20.;
 const float cellSize = 1. / WORLD_SIZE;