advection2d

index.html

@@ -53,7 +53,7 @@
             }
 
             vec2 pxCenter = vec2(0.5, 0.5);
-            vec2 pos = fragCoord - pxCenter + u_dt*currentVelocity;
+            vec2 pos = fragCoord - pxCenter - u_dt*currentVelocity;
             if (pos.x < 0.0 || pos.x >= u_textureSize.x-1.0 || pos.y < 0.0 || pos.y >= u_textureSize.y-1.0){
                 //boundary
                 gl_FragColor = vec4(0);

main.js

@@ -97,6 +97,7 @@ function resetWindow(){
         for (var j=0;j<width;j++){
             var index = 4*(i*width+j);
             velocity[index] = i/100;
+            velocity[index+1] = j/100;
         }
     }
     GPU.initTextureFromData("velocity", width, height, "FLOAT", velocity, true);