From ae44554bf40bcc4bf6cd11c954661d33cdafde11 Mon Sep 17 00:00:00 2001
From: Amy Retzerau <amy.retzerau@gmail.com>
Date: Wed, 27 Aug 2025 13:52:51 +0200
Subject: [PATCH] feat: ray marching now works with ray structs, allowing for
 color

---
 sdf.fs | 69 ++++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 55 insertions(+), 14 deletions(-)

diff --git a/sdf.fs b/sdf.fs
index bd53af9..402d79b 100644
--- a/sdf.fs
+++ b/sdf.fs
@@ -7,29 +7,70 @@ in vec2 texCoords;
 vec3 center = vec3(0.0f,0.0f,20.0f);
 float radius = 5.0f;
 
-float sphereMin(vec3 pos){
-    return length(pos - center) - radius;
+float planeHeight = -7.0f;
+
+struct Ray {
+    vec3 dir;
+    vec3 pos;
+    float min;
+    float len;
+    vec3 color;
+};
+        
+Ray applyMin(Ray ray) {
+    vec3 off = ray.dir * ray.min;
+    ray.pos = ray.pos + off;
+    ray.len = ray.len +  ray.min;
+    return ray;
+}
+
+
+Ray planeMin(Ray ray){
+    ray.min = ray.pos.y - planeHeight;
+    ray.color = vec3(1.0,1.0,1.0);
+    return applyMin(ray);
+}
+
+Ray sphereMin(Ray ray){
+    ray.min = length(ray.pos - center) - radius;
+    ray.color = vec3(1.0,0.0,0.0);
+    return applyMin(ray);
+}
+
+Ray minFn(Ray ray){
+    Ray sp = sphereMin(ray);
+    Ray pl = planeMin(ray);
+
+    if (sp.min < pl.min){
+        return sp;
+    } else {
+        return pl;
+    }
 }
 
 void main()
 {
-    vec3 ray = vec3(texCoords.x, texCoords.y,2.0f);
-    ray = (ray - 0.5f) * 2;
-    vec3 pos = ray;
-    float min = sphereMin(ray);
+    vec3 dir = vec3(texCoords.x, texCoords.y,2.0f);
+    dir = (dir - 0.5f) * 2;
+    vec3 pos = dir;
+    Ray ray = Ray(pos,normalize(dir),.0,.0,vec3(.0));
 
-    while( (min < 100.0f) && (min > 0.1f) ) {
-        ray = normalize(ray);
-        ray = ray * min;
-        pos = pos + ray;
-        min = sphereMin(pos);
+
+    ray = minFn(ray);
+
+    while( (ray.min < 100.0f) && (ray.min > 0.1f) ) {
+        //ray.dir = normalize(ray.dir);
+        ray = minFn(ray);
+        //vec3 off = ray.dir * min;
+        //ray.pos = ray.pos + off;
+        
     }
     
     
-    if(min <= 0.2f){
-        FragColor = vec4(texCoords.x, texCoords.y, 0.2f, 1.0f);
+    if(ray.min <= 0.2f){
+        FragColor = vec4(ray.color, 1.0f);
     } else {
-        FragColor = vec4(0.0f,0.0f,0.0f,1.0f);
+        FragColor = vec4(.0,0.0f,0.0f,1.0f);
     }
 
 }