From 12829892b262a0c7fcccba9198e5b6b31b2a8015 Mon Sep 17 00:00:00 2001
From: Loic Guegan <manzerbredes@mailbox.org>
Date: Thu, 9 Jul 2020 13:02:31 +0200
Subject: Cleaning code

---
 resources/shaders/algorithms/normal.frag       | 24 ++++++++++++++++++++++++
 resources/shaders/algorithms/ray_marching.glsl |  5 -----
 resources/shaders/algorithms/raymarching.frag  | 26 ++++++++++++++++++++++++++
 3 files changed, 50 insertions(+), 5 deletions(-)
 create mode 100644 resources/shaders/algorithms/normal.frag
 delete mode 100644 resources/shaders/algorithms/ray_marching.glsl
 create mode 100644 resources/shaders/algorithms/raymarching.frag

(limited to 'resources/shaders/algorithms')

diff --git a/resources/shaders/algorithms/normal.frag b/resources/shaders/algorithms/normal.frag
new file mode 100644
index 0000000..0f61544
--- /dev/null
+++ b/resources/shaders/algorithms/normal.frag
@@ -0,0 +1,24 @@
+// Requirements:
+// #define NORMAL_ACCURACY 0.01
+// GetDist: (vec3 position) => float
+// GetDist should return the closest object point distance from position (in the whole scene)
+
+/**
+ * Compute the normal of an object at a given surface point
+ * this can be usefull for lighting etc..
+ * This function exploit the fact that the gradient on a given surface point in 3D space
+ * given the normal direction (source: https://fr.wikipedia.org/wiki/Gradient#Dimension_3_:_gradient_normal_%C3%A0_une_surface_en_un_point,_plan_tangent)
+ * 
+ * 
+ */
+vec3 GetNormal(vec3 point_position) {
+	float point_distance = GetDist(point_position);
+    vec2 epsilon = vec2(NORMAL_ACCURACY, 0); // Just a convenient way to use NORMAL_ACCURACY and 0
+    // Compute the gradient
+    vec3 gradient = point_distance - vec3(
+        GetDist(point_position-epsilon.xyy),
+        GetDist(point_position-epsilon.yxy),
+        GetDist(point_position-epsilon.yyx));
+    
+    return normalize(gradient);
+}
\ No newline at end of file
diff --git a/resources/shaders/algorithms/ray_marching.glsl b/resources/shaders/algorithms/ray_marching.glsl
deleted file mode 100644
index d984c0e..0000000
--- a/resources/shaders/algorithms/ray_marching.glsl
+++ /dev/null
@@ -1,5 +0,0 @@
-
-
-RayMarching(vec3 ro, vec3 rd){
-	
-}
\ No newline at end of file
diff --git a/resources/shaders/algorithms/raymarching.frag b/resources/shaders/algorithms/raymarching.frag
new file mode 100644
index 0000000..b8de515
--- /dev/null
+++ b/resources/shaders/algorithms/raymarching.frag
@@ -0,0 +1,26 @@
+// Requirements:
+// #define MAX_STEPS 100
+// #define MAX_DIST 100.
+// GetDist: (vec3 position) => float
+// GetDist should return the closest object point distance from position (in the whole scene)
+
+/**
+ * Ray Marching algorithm
+ * Please take a look at: https://www.youtube.com/watch?v=PGtv-dBi2wE&t=1367s
+ * This function return the distance reached by the ray:
+ * - If dist<MAX_DIST we hit something
+ */
+float RayMarch(vec3 ray_origin, vec3 ray_direction) {
+	float dist_origin=0.; // Ray start at the origin
+    for(int i=0; i<MAX_STEPS; i++) { // If we take to much time to converge (i>=MAX_STEPS)
+    	// We move the ray:
+    	vec3 ray_position = ray_origin + ray_direction*dist_origin;
+    	// We find the next closest point:
+        float closest_point = GetDist(ray_position);
+        // Increase the ray distance
+        dist_origin += closest_point;
+        // Check if we went to far or we are too close from a point (we hit a surface)
+        if(dist_origin>MAX_DIST || closest_point<SURF_DIST) break;
+    }
+    return dist_origin;
+}
\ No newline at end of file
-- 
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