7 files changed, 111 insertions, 49 deletions

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
diff --git a/resources/shaders/julia.frag b/resources/shaders/julia.frag
new file mode 100644
index 0000000..12d923b
--- /dev/null
+++ b/resources/shaders/julia.frag
@@ -0,0 +1,48 @@
+// ----- Vertex Shader -----
+#version 410 core
+
+layout(location = 0) in vec3 position;
+uniform mat4 projection;
+uniform mat4 model;
+
+void main(){
+  gl_Position =  projection * model * vec4(position,1);
+}
+
+// ----- Fragment Shader -----
+
+#version 410 core
+
+uniform vec2 resolution;
+uniform float time;
+
+out vec3 color;
+
+#define ACCURACY 1000
+#define LIMIT 1000
+
+vec2 cmult(vec2 z1,vec2 z2){
+	return(vec2(z1.x*z2.x-z1.y*z2.y,z1.x*z2.y+z1.y*z2.x));
+}
+
+vec2 IsDiverging(vec2 coord){
+	vec2 z=vec2(coord.x,coord.y);
+	int i;
+	for(i=0;i<ACCURACY;i++){
+		z=cmult(z,z)+vec2(-0.3,0.5);
+		if(length(z) > LIMIT)
+			break;
+				
+	}
+	return(z);
+}
+
+
+void main()
+{
+	vec2 coord=gl_FragCoord.xy/resolution.xy;
+	coord-=0.5;
+	coord/=(time/10);
+	float d=length(IsDiverging(coord));
+	color=vec3(LIMIT/(d*2),0,0);
+}
diff --git a/resources/shaders/main.glsl b/resources/shaders/main.frag
index 2888d56..590b849 100644
--- a/resources/shaders/main.glsl
+++ b/resources/shaders/main.frag
@@ -1,16 +1,3 @@
-// ----- Vertex Shader -----
-#version 330 core
-
-layout(location = 0) in vec3 position;
-uniform mat4 projection;
-uniform mat4 model;
-
-void main(){
-  gl_Position =  projection * model * vec4(position,1);
-}
-
-// ----- Fragment Shader -----
-
 #version 330 core
 
 uniform vec2 resolution;
@@ -18,45 +5,24 @@ uniform float time;
 
 out vec3 color;
 
-
 #define MAX_STEPS 100
 #define MAX_DIST 100.
 #define SURF_DIST .01
+#define NORMAL_ACCURACY 0.01
 
+#include "objects/sphere.frag"
 float GetDist(vec3 p) {
-	vec4 s = vec4(0, 1, 6, 1);
-    
-    float sphereDist =  length(p-s.xyz)-s.w;
+    float sphereDist =  SphereSDF(p,vec3(0, 1, 6),1);
     float planeDist = p.y;
     
     float d = min(sphereDist, planeDist);
     return d;
 }
 
-float RayMarch(vec3 ro, vec3 rd) {
-	float dO=0.;
-    
-    for(int i=0; i<MAX_STEPS; i++) {
-    	vec3 p = ro + rd*dO;
-        float dS = GetDist(p);
-        dO += dS;
-        if(dO>MAX_DIST || dS<SURF_DIST) break;
-    }
-    
-    return dO;
-}
+#include "algorithms/raymarching.frag"
+#include "algorithms/normal.frag"
+
 
-vec3 GetNormal(vec3 p) {
-	float d = GetDist(p);
-    vec2 e = vec2(.01, 0);
-    
-    vec3 n = d - vec3(
-        GetDist(p-e.xyy),
-        GetDist(p-e.yxy),
-        GetDist(p-e.yyx));
-    
-    return normalize(n);
-}
 
 float GetLight(vec3 p) {
     vec3 lightPos = vec3(0, 5, 6);
diff --git a/resources/shaders/objects/sphere.frag b/resources/shaders/objects/sphere.frag
new file mode 100644
index 0000000..e69deaa
--- /dev/null
+++ b/resources/shaders/objects/sphere.frag
@@ -0,0 +1,7 @@
+/**
+ * Compute the Signed Distance Function (SDF)
+ * of a sphere.
+ */
+float SphereSDF(vec3 ray_position, vec3 sphere_position, float radius){
+	return(length(ray_position - sphere_position)-radius);
+}
\ No newline at end of file
diff --git a/resources/shaders/objects/sphere.glsl b/resources/shaders/objects/sphere.glsl
deleted file mode 100644
index a3d25eb..0000000
--- a/resources/shaders/objects/sphere.glsl
+++ /dev/null
@@ -1,4 +0,0 @@
-
-float Sphere(vec3 ray_position, vec3 sphere_position){
-	
-}
\ No newline at end of file