Metaballs by atomek

Author: monkstone

processing_app/topics/shaders/data/metaballs.glsl

@@ -0,0 +1,49 @@
+#ifdef GL_ES
+precision mediump float;
+precision mediump int;
+#endif
+
+/** ----------------------
+After a sketch on shadertoy https://www.shadertoy.com/user/atomek
+**/
+
+uniform vec3      iResolution;           // viewport resolution (in pixels)
+uniform float     iTime;                 // shader playback time (in seconds)
+uniform vec4      iMouse;                // mouse pixel coords. xy: current (if MLB down), zw: click
+
+void main()
+{
+	// Hold the mouse and drag to adjust
+
+	float ratio = iResolution.y / iResolution.x;
+	float divider = float(iMouse.x / iResolution.x * 10.0) + 1.0;
+	float intensity = float(iMouse.y / iResolution.y * 10.0) + 1.0;
+
+	float coordX = gl_FragCoord.x / iResolution.x;
+	float coordY = gl_FragCoord.y / iResolution.x;
+
+	float ball1x = sin(iTime * 2.1) * 0.5 + 0.5;
+	float ball1y = cos(iTime * 1.0) * 0.5 + 0.5;
+	float ball1z = sin(iTime * 2.0) * 0.1 + 0.2;
+
+	float ball2x = sin(iTime * 1.0) * 0.5 + 0.5;
+	float ball2y = cos(iTime * 1.8) * 0.5 + 0.5;
+	float ball2z = cos(iTime * 2.0) * 0.1 + 0.2;
+
+	float ball3x = sin(iTime * 0.7) * 0.5 + 0.5;
+	float ball3y = cos(iTime * 1.5) * 0.5 + 0.5;
+	float ball3z = cos(iTime * 1.0) * 0.1 + 0.2;
+
+	vec3 ball1 = vec3(ball1x, ball1y * ratio, ball1z);
+	vec3 ball2 = vec3(ball2x, ball2y * ratio, ball2z);
+	vec3 ball3 = vec3(ball3x, ball3y * ratio, ball3z);
+
+	float sum = 0.0;
+	sum += ball1.z / distance(ball1.xy, vec2(coordX, coordY));
+	sum += ball2.z / distance(ball2.xy, vec2(coordX, coordY));
+	sum += ball3.z / distance(ball3.xy, vec2(coordX, coordY));
+
+    sum = pow(sum / intensity, divider);
+
+	gl_FragColor = vec4(sum * 0.2, sum * 0.2, sum * 0.4, 1.0);
+}

processing_app/topics/shaders/metaballs.rb

@@ -0,0 +1,36 @@
+attr_reader :last_mouse_position, :mouse_click_state, :mouse_dragged, :shader_t
+attr_reader :start
+
+def settings
+  size(640, 360, P2D)
+end
+
+def setup
+  sketch_title 'Shadertoy Metaballs'
+  @previous_time = 0.0
+  @mouse_dragged = false
+  @mouse_click_state = 0.0
+  # Load the shader file from the "data" folder
+  @shader_t = load_shader(data_path('metaballs.glsl'))
+  # Assume the dimension of the window will not change over time
+  shader_t.set('iResolution', width.to_f, height.to_f, 0.0)
+  @last_mouse_position = Vec2D.new(mouse_x, mouse_y)
+  @start = java.lang.System.current_time_millis
+end
+
+def draw
+  # shader playback time (in seconds)
+  current_time = (java.lang.System.current_time_millis - start) / 1000.0
+  shader_t.set('iTime', current_time)
+  if mouse_pressed?
+    @last_mouse_position = Vec2D.new(mouse_x, mouse_y)
+    @mouse_click_state = 1.0
+  else
+    @mouse_click_state = 0.0
+  end
+  shader_t.set('iMouse', last_mouse_position.x, last_mouse_position.y, mouse_click_state, mouse_click_state)
+  # Apply the specified shader to any geometry drawn from this point
+  shader(shader_t)
+  # Draw the output of the shader onto a rectangle that covers the whole viewport.
+  rect(0, 0, width, height)
+end