shaders

Author: monkstone

processing_app/topics/shaders/data/edges.glsl

@@ -0,0 +1,40 @@
+#ifdef GL_ES
+precision mediump float;
+precision mediump int;
+#endif
+
+#define PROCESSING_TEXTURE_SHADER
+
+uniform sampler2D texture;
+uniform vec2 texOffset;
+
+varying vec4 vertColor;
+varying vec4 vertTexCoord;
+
+void main(void) {
+  // Grouping texcoord variables in order to make it work in the GMA 950. See post #13
+  // in this thread:
+  // http://www.idevgames.com/forums/thread-3467.html
+  vec2 tc0 = vertTexCoord.st + vec2(-texOffset.s, -texOffset.t);
+  vec2 tc1 = vertTexCoord.st + vec2(         0.0, -texOffset.t);
+  vec2 tc2 = vertTexCoord.st + vec2(+texOffset.s, -texOffset.t);
+  vec2 tc3 = vertTexCoord.st + vec2(-texOffset.s,          0.0);
+  vec2 tc4 = vertTexCoord.st + vec2(         0.0,          0.0);
+  vec2 tc5 = vertTexCoord.st + vec2(+texOffset.s,          0.0);
+  vec2 tc6 = vertTexCoord.st + vec2(-texOffset.s, +texOffset.t);
+  vec2 tc7 = vertTexCoord.st + vec2(         0.0, +texOffset.t);
+  vec2 tc8 = vertTexCoord.st + vec2(+texOffset.s, +texOffset.t);
+  
+  vec4 col0 = texture2D(texture, tc0);
+  vec4 col1 = texture2D(texture, tc1);
+  vec4 col2 = texture2D(texture, tc2);
+  vec4 col3 = texture2D(texture, tc3);
+  vec4 col4 = texture2D(texture, tc4);
+  vec4 col5 = texture2D(texture, tc5);
+  vec4 col6 = texture2D(texture, tc6);
+  vec4 col7 = texture2D(texture, tc7);
+  vec4 col8 = texture2D(texture, tc8);
+
+  vec4 sum = 8.0 * col4 - (col0 + col1 + col2 + col3 + col5 + col6 + col7 + col8); 
+  gl_FragColor = vec4(sum.rgb, 1.0) * vertColor;
+}

processing_app/topics/shaders/data/edgesfrag.glsl

@@ -0,0 +1,37 @@
+#ifdef GL_ES
+precision mediump float;
+precision mediump int;
+#endif
+
+uniform sampler2D texture;
+uniform vec2 texOffset;
+
+varying vec4 vertColor;
+varying vec4 vertTexCoord;
+
+const vec4 lumcoeff = vec4(0.299, 0.587, 0.114, 0);
+
+void main() {
+  vec2 tc0 = vertTexCoord.st + vec2(-texOffset.s, -texOffset.t);
+  vec2 tc1 = vertTexCoord.st + vec2(         0.0, -texOffset.t);
+  vec2 tc2 = vertTexCoord.st + vec2(+texOffset.s, -texOffset.t);
+  vec2 tc3 = vertTexCoord.st + vec2(-texOffset.s,          0.0);
+  vec2 tc4 = vertTexCoord.st + vec2(         0.0,          0.0);
+  vec2 tc5 = vertTexCoord.st + vec2(+texOffset.s,          0.0);
+  vec2 tc6 = vertTexCoord.st + vec2(-texOffset.s, +texOffset.t);
+  vec2 tc7 = vertTexCoord.st + vec2(         0.0, +texOffset.t);
+  vec2 tc8 = vertTexCoord.st + vec2(+texOffset.s, +texOffset.t);
+  
+  vec4 col0 = texture2D(texture, tc0);
+  vec4 col1 = texture2D(texture, tc1);
+  vec4 col2 = texture2D(texture, tc2);
+  vec4 col3 = texture2D(texture, tc3);
+  vec4 col4 = texture2D(texture, tc4);
+  vec4 col5 = texture2D(texture, tc5);
+  vec4 col6 = texture2D(texture, tc6);
+  vec4 col7 = texture2D(texture, tc7);
+  vec4 col8 = texture2D(texture, tc8);
+
+  vec4 sum = 8.0 * col4 - (col0 + col1 + col2 + col3 + col5 + col6 + col7 + col8); 
+  gl_FragColor = vec4(sum.rgb, 1.0) * vertColor; 
+}

processing_app/topics/shaders/data/leaves.jpg

@@ -0,0 +1,30 @@
+#!/usr/bin/env jruby -v -W2
+# frozen_string_literal: true
+require 'propane'
+
+class EdgeDetect < Propane::App
+  attr_reader :edges, :img , :enabled
+
+  def setup
+    sketch_title 'Edge detect'
+    @enabled = true
+    @img = load_image(data_path('leaves.jpg'))
+    @edges = load_shader(data_path('edges.glsl'))
+  end
+
+  def draw
+    shader(edges) if enabled
+    image(img, 0, 0)
+  end
+
+  def mouse_pressed
+    @enabled = !enabled
+    reset_shader if !enabled
+  end
+
+  def settings
+    size(640, 360, P2D)
+  end
+end
+
+EdgeDetect.new

processing_app/topics/shaders/edge_detect.rb

@@ -0,0 +1,41 @@
+#!/usr/bin/env jruby -v -W2
+# frozen_string_literal: true
+require 'propane'
+
+class EdgeFilter < Propane::App
+  attr_reader :edges, :apply_filter
+
+  def setup
+    sketch_title 'Edge Filter'
+    @apply_filter = true
+    @edges = load_shader(data_path('edges.glsl'))
+    no_stroke
+  end
+
+  def draw
+    background(0)
+    lights
+    translate(width / 2, height / 2)
+    push_matrix
+    rotate_x(frame_count * 0.01)
+    rotate_y(frame_count * 0.01)
+    box(120)
+    pop_matrix
+    filter(edges) if apply_filter
+    # The sphere doesn't have the edge detection applied
+    # on it because it is drawn after filter is called.
+    rotate_y(frame_count * 0.02)
+    translate(150, 0)
+    sphere(40)
+  end
+
+  def mouse_pressed
+    @apply_filter = !apply_filter
+  end
+
+  def settings
+    size(640, 360, P3D)
+  end
+end
+
+EdgeFilter.new