Minor fixes and added texture filtering

Author: MichaelMoroz

assets/frag.glsl

@@ -40,7 +40,8 @@
 #define SUN_SHARPNESS 2.0
 #define SUN_SIZE 0.004
 #define VIGNETTE_STRENGTH 0.5
-#define FRACTAL_ITER 16
+#define FRACTAL_ITER 14
+#define ENABLE_FILTERING 1
 
 uniform mat4 iMat;
 uniform vec2 iResolution;
@@ -198,7 +199,7 @@ vec4 col_scene(vec4 p) {
 //   Main code
 //##########################################
 
-//A faster formula to find the gradient/normal diraction of the DE(the w component is the average DE)
+//A faster formula to find the gradient/normal direction of the DE(the w component is the average DE)
 //credit to http://www.iquilezles.org/www/articles/normalsSDF/normalsSDF.htm
 vec4 calcGrad(vec4 p, float dx) 
 {
@@ -209,6 +210,16 @@ vec4 calcGrad(vec4 p, float dx)
 	    k.xxxx*DE(p + k.xxxz*dx)) / vec4(4*dx,4*dx,4*dx,4);
 }
 
+//find the average color of the fractal in a radius dx
+vec4 smoothColor(vec4 p, float dx)
+{
+	const vec3 k = vec3(1,-1,0);
+    return (COL(p + k.xyyz*dx) + 
+			COL(p + k.yyxz*dx) + 
+			COL(p + k.yxyz*dx) + 
+			COL(p + k.xxxz*dx))/4;
+}
+
 vec4 ray_march(inout vec4 p, vec4 ray, float sharpness) {
 	//March the ray
 	float d = DE(p);
@@ -222,8 +233,8 @@ vec4 ray_march(inout vec4 p, vec4 ray, float sharpness) {
 	for (; s < MAX_MARCHES; s += 1.0) {
 		//if the distance from the surface is less than the distance per pixel we stop
 		float min_dist = max(FOVperPixel*td, MIN_DIST);
-		if (d < min_dist ) {
-   		        s += 0.14*d / min_dist ;
+		if (d < min_dist) {
+			s += 0.1*d /min_dist;
 			break;
 		} else if (td > MAX_DIST) {
 			break;
@@ -245,21 +256,24 @@ vec4 scene(inout vec4 p, inout vec4 ray, float vignette) {
 
 	//Determine the color for this pixel
 	vec4 col = vec4(0.0);
-	
 	float min_dist = max(FOVperPixel*td, MIN_DIST);
 	if (d < min_dist) {
 		//Get the surface normal
-		vec4 grad = calcGrad(p,td*FOVperPixel*0.2);
+		vec4 grad = calcGrad(p,min_dist*0.5);
 		vec3 n = normalize(grad.xyz);
 
 		//find closest surface point, without this we get weird coloring artifacts
 		p.xyz -= n*d;
-		
-		vec3 reflected = ray.xyz - 2.0*dot(ray.xyz, n) * n;
 
+		vec3 reflected = ray.xyz - 2.0*dot(ray.xyz, n) * n;
+		
 		//Get coloring
-		vec4 orig_col = clamp(COL(p), 0.0, 1.0);
-    col.w = orig_col.w;
+		#if ENABLE_FILTERING
+			vec4 orig_col = clamp(smoothColor(p, min_dist*0.5), 0.0, 1.0);
+		#else 
+			vec4 orig_col = clamp(COL(p), 0.0, 1.0);
+		#endif
+        col.w = orig_col.w;
 
 		//Get if this point is in shadow
 		float k = 1.0;
@@ -325,7 +339,7 @@ void main() {
 			vec2 screen_pos = (gl_FragCoord.xy + delta) / iResolution.xy;
 
 			//Calculate the view angle per pixel
-			FOVperPixel = 90*PI/(180*iResolution.x);
+			FOVperPixel = 1*90*PI/(180*iResolution.x);
 
 			vec2 uv = 2*screen_pos - 1;
 			uv.x *= iResolution.x / iResolution.y;