From 8e8fb66873636ac2dbe10ed4304ab7ae05561892 Mon Sep 17 00:00:00 2001
From: hodasemi <michaelh.95@t-online.de>
Date: Wed, 17 Oct 2018 13:14:24 +0200
Subject: [PATCH] Impl julia fractal

---
 exercise1/glsl/shader.frag | 30 +++++++++++++++++++++++++++++-
 exercise1/glsl/shader.vert |  2 ++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/exercise1/glsl/shader.frag b/exercise1/glsl/shader.frag
index f62db14..5f7d2b9 100644
--- a/exercise1/glsl/shader.frag
+++ b/exercise1/glsl/shader.frag
@@ -4,12 +4,40 @@
 #version 130
 
 in vec4 fragment_color;
+in vec2 vertex_pos;
 
 out vec4 color;
 
+const int i_max = 200;
+
 void main()
 {
-	color = fragment_color;
+	float m = 0.3;
+	vec2 c = vec2(0.5, 1.5);
+
+	vec2 z = vertex_pos * m;
+
+	int i = 0;
+
+	for(; i < i_max; i++) {
+		float x = (z.x * z.x - z.y * z.y) + c.x;
+		float y = (z.y * z.x - z.x * z.y) + c.y;
+
+		if (x*x + y*y > 4.0) {
+			break;
+		}
+
+		z.x = x;
+		z.y = y;
+	}
+
+	float alpha = 0.0;
+
+	if (i < i_max) {
+		alpha = float(i) / float(i_max);
+	}
+
+	color = vec4(alpha, alpha, alpha, alpha) * 10.0 * fragment_color;
 
 	 /**** Begin of tasks ***
 	 - 1.2.5
diff --git a/exercise1/glsl/shader.vert b/exercise1/glsl/shader.vert
index 9cad82e..e07b317 100644
--- a/exercise1/glsl/shader.vert
+++ b/exercise1/glsl/shader.vert
@@ -10,9 +10,11 @@ uniform mat4 view;
 uniform mat4 proj;
 
 out vec4 fragment_color;
+out vec2 vertex_pos;
 
 void main()
 {
+	vertex_pos = in_position.xy;
 	gl_Position = proj * view * in_position;
 	
 	fragment_color = in_color;