diff --git a/.gitignore b/.gitignore
index 8c09441..154d693 100644
--- a/.gitignore
+++ b/.gitignore
@@ -34,3 +34,5 @@ roleplay
 *.spv
 
 .DS_Store
+
+client/test/test_*
diff --git a/client/Makefile b/client/Makefile
index b00340f..29ea8db 100644
--- a/client/Makefile
+++ b/client/Makefile
@@ -2,8 +2,12 @@ ROOT_DIR:=$(shell dirname $(realpath $(firstword $(MAKEFILE_LIST))))
 CFLAGS = -I $(ROOT_DIR)/include -I/usr/local/include -O0 -g -Wall -Wextra
 LDFLAGS = -lfreetype -lz -lglfw -lvulkan -ldl -Xlinker -rpath -Xlinker /opt/homebrew/lib
 
-SOURCES = src/main.c src/draw.c src/ui.c src/gpu.c src/hex.c lib/spng.c lib/vma.cpp
-OBJECTS = $(addsuffix .o, $(basename $(SOURCES)))
+SOURCES =  src/draw.c src/ui.c src/gpu.c src/hex.c src/hsv.h lib/spng.c lib/vma.cpp
+APP_SOURCES = src/main.c $(SOURCES)
+TEST_SOURCES = test/hsv.c $(SOURCES)
+APP_OBJECTS = $(addsuffix .o, $(basename $(APP_SOURCES)))
+TEST_OBJECTS = $(addsuffix .o, $(basename $(TEST_SOURCES)))
+
 VERT_SPV = $(addsuffix .vert.spv, $(basename $(wildcard shader/*.vert)))
 FRAG_SPV = $(addsuffix .frag.spv, $(basename $(wildcard shader/*.frag)))
 COMP_SPV = $(addsuffix .comp.spv, $(basename $(wildcard shader/*.comp)))
@@ -29,9 +33,17 @@ CXX ?= clang++
 .PHONY: all
 all: roleplay $(SPV_FILES)
 
-roleplay: $(OBJECTS)
+roleplay: $(APP_OBJECTS)
+	$(CXX) $(CFLAGS) $(LDFLAGS) -o $@ $^
+
+test/test_hsv: $(TEST_OBJECTS)
 	$(CXX) $(CFLAGS) $(LDFLAGS) -o $@ $^
 
+.PHONY: test
+test: test/test_hsv
+	./test/test_hsv
+
+
 %.o: %.cpp
 	$(CXX) $(CFLAGS) -std=c++17 -Wno-nullability-completeness -Wno-unused-parameter -Wno-missing-field-initializers -Wno-unused-private-field -Wno-unused-variable -c -o $@ $<
 
@@ -42,7 +54,8 @@ roleplay: $(OBJECTS)
 
 clean:
 	rm -f $(SPV_FILES)
-	rm -f $(OBJECTS)
+	rm -f $(APP_OBJECTS)
+	rm -f $(TEST_OBJECTS)
 	rm -f roleplay
 	rm -rf $(EXTRA_DEBUG_REQUIREMENTS)
 
diff --git a/client/include/hsv.h b/client/include/hsv.h
new file mode 100644
index 0000000..6f32a47
--- /dev/null
+++ b/client/include/hsv.h
@@ -0,0 +1,9 @@
+#ifndef HSV_H
+#define HSV_H
+
+#include "cglm/types.h"
+
+void hsv_to_rgb(double hsv[3], vec3 rgb);
+void rgb_to_hsv(vec3 rgb, double hsv[3]);
+
+#endif
diff --git a/client/src/hsv.c b/client/src/hsv.c
new file mode 100644
index 0000000..a5d5fc7
--- /dev/null
+++ b/client/src/hsv.c
@@ -0,0 +1,75 @@
+#include "hsv.h"
+#include "math.h"
+
+#define max(a, b) ((a > b) ? a : b)
+#define min(a, b) ((a < b) ? a : b)
+
+float floatmod(float a, float b) {
+  return a - b*floor(a/b);
+}
+
+void rgb_to_hsv(vec3 rgb, double hsv[3]) {
+  if(rgb[0] == 0 && rgb[1] == 0 && rgb[2] == 0) {
+    hsv[0] = 0;
+    hsv[1] = 0;
+    hsv[2] = 0;
+    return;
+  }
+
+  hsv[2] = max(rgb[0], max(rgb[1], rgb[2]));
+  float M = min(rgb[0], min(rgb[1], rgb[2]));
+  float C = hsv[2] - M;
+  hsv[1] = C / hsv[2];
+  float X;
+
+  if(hsv[2] == rgb[0] && M == rgb[2]) {
+    X = rgb[1] - M;
+    hsv[0] = (X/C + 0)/6;
+  } else if(hsv[2] == rgb[1] && M == rgb[2]) {
+    X = rgb[0] - M;
+    hsv[0] = (2 - X/C)/6;
+  } else if(hsv[2] == rgb[1] && M == rgb[0]) {
+    X = rgb[2] - M;
+    hsv[0] = (X/C + 2)/6;
+  } else if(hsv[2] == rgb[2] && M == rgb[0]) {
+    X = rgb[1] - M;
+    hsv[0] = (4 - X/C)/6;
+  } else if(hsv[2] == rgb[2] && M == rgb[1]) {
+    X = rgb[0] - M;
+    hsv[0] = (X/C + 4)/6;
+  } else if(hsv[2] == rgb[0] && M == rgb[1]) {
+    X = rgb[2] - M;
+    hsv[0] = (6 - X/C)/6;
+  }
+}
+
+void hsv_to_rgb(double hsv[3], vec3 rgb) {
+  float C = hsv[1] * hsv[2];
+  float H = hsv[0]*6;
+  float X = C * (1 - fabs(floatmod(H, 2) - 1));
+  vec4 temp = {0, 0, 0, 0};
+  if(0 <= H && H <= 1) {
+    temp[0] = C;
+    temp[1] = X;
+  } else if(1 <= H && H <= 2) {
+    temp[0] = X;
+    temp[1] = C;
+  } else if(2 <= H && H <= 3) {
+    temp[1] = C;
+    temp[2] = X;
+  } else if(3 <= H && H <= 4) {
+    temp[1] = X;
+    temp[2] = C;
+  } else if(4 <= H && H <= 5) {
+    temp[0] = X;
+    temp[2] = C;
+  } else if(5 <= H && H <= 6) {
+    temp[0] = C;
+    temp[2] = X;
+  }
+
+  float m = hsv[2] - C;
+   rgb[0] = temp[0] + m;
+   rgb[1] = temp[1] + m;
+   rgb[2] = temp[2] + m;
+}
diff --git a/client/src/main.c b/client/src/main.c
index cdbaf4b..fee9e9d 100644
--- a/client/src/main.c
+++ b/client/src/main.c
@@ -6,6 +6,7 @@
 #include "gpu.h"
 #include "draw.h"
 #include "hex.h"
+#include "hsv.h"
 
 #include "arpa/inet.h"
 #include "vk_mem_alloc.h"
@@ -93,55 +94,21 @@ uint32_t add_hex_region(ClientContext* context) {
 
 #define COLOR_PICK_CONTAINER_ID 0x03
 typedef struct ColorUIDataStruct {
-  vec3 current;
+  double current_hsv[3];
+  vec4 current;
   vec3 saved[12];
-  char string[8];
+  char string[10];
   int string_len;
 } ColorUIData;
 
-float floatmod(float a, float b) {
-  return a - b*floor(a/b);
-}
-
-void hsv_to_rgb(vec3 hsv, vec3 rgb) {
-  float C = hsv[1] * hsv[2];
-  float H = hsv[0]*6;
-  float X = C * (1 - fabs(floatmod(H, 2) - 1));
-  vec4 temp = {0, 0, 0, 0};
-  if(0 <= H && H <= 1) {
-    temp[0] = C;
-    temp[1] = X;
-  } else if(1 <= H && H <= 2) {
-    temp[0] = X;
-    temp[1] = C;
-  } else if(2 <= H && H <= 3) {
-    temp[1] = C;
-    temp[2] = X;
-  } else if(3 <= H && H <= 4) {
-    temp[1] = X;
-    temp[2] = C;
-  } else if(4 <= H && H <= 5) {
-    temp[0] = X;
-    temp[2] = C;
-  } else if(5 <= H && H <= 6) {
-    temp[0] = C;
-    temp[2] = X;
-  }
-
-  float m = hsv[2] - C;
-   rgb[0] = temp[0] + m;
-   rgb[1] = temp[1] + m;
-   rgb[2] = temp[2] + m;
-}
-
-void rgb_string_set(UIContext* ui, RenderContext* gpu, ColorUIData* data, vec3 hsv) {
-  vec3 rgb;
-  hsv_to_rgb(hsv, rgb);
-  snprintf(data->string, 8, "#%02X%02X%02X",
-      (uint)(rgb[0]*255),
-      (uint)(rgb[1]*255),
-      (uint)(rgb[2]*255));
-  data->string_len = 6;
+void set_rgb_from_hsv(UIContext* ui, RenderContext* gpu, ColorUIData* data, double hsv[3]) {
+  hsv_to_rgb(hsv, data->current);
+  snprintf(data->string, 10, "#%02X%02X%02X%02X",
+      (uint)(data->current[0]*255),
+      (uint)(data->current[1]*255),
+      (uint)(data->current[2]*255),
+      (uint)(data->current[3]*255));
+  data->string_len = 8;
   update_ui_string(data->string, COLOR_PICK_CONTAINER_ID, 0, 0, ui, gpu);
 }
 
@@ -152,8 +119,8 @@ void sv_square_pick(UIContext* ui, RenderContext* gpu, ColorUIData* data, float
   if(v < 0) v = 0;
   if(v > 1) v = 1;
 
-  data->current[1] = s;
-  data->current[2] = 1-v;
+  data->current_hsv[1] = s;
+  data->current_hsv[2] = 1-v;
 
   Container* container = context_container(COLOR_PICK_CONTAINER_ID, ui);
   Layer* layer = &container->layers[0];
@@ -199,7 +166,7 @@ void sv_square_pick(UIContext* ui, RenderContext* gpu, ColorUIData* data, float
       4*sizeof(vec4),
       gpu);
 
-  rgb_string_set(ui, gpu, data, select->color[0]);
+  set_rgb_from_hsv(ui, gpu, data, data->current_hsv);
 }
 
 void sv_square_button_callback(void* data, UIContext* ui, RenderContext* gpu, float x, float y, int button, int action, int mods) {
@@ -226,7 +193,7 @@ void hue_bar_set(UIContext* ui, RenderContext* gpu, ColorUIData* data, float y)
   if(y < 0) y = 0;
   if(y > 1) y = 1;
 
-  data->current[0] = y;
+  data->current_hsv[0] = y;
 
   Container* container = context_container(COLOR_PICK_CONTAINER_ID, ui);
   Layer* layer = &container->layers[0];
@@ -267,7 +234,7 @@ void hue_bar_set(UIContext* ui, RenderContext* gpu, ColorUIData* data, float y)
       1*sizeof(float),
       gpu);
 
-  rgb_string_set(ui, gpu, data, sv_select->color[0]);
+  set_rgb_from_hsv(ui, gpu, data, data->current_hsv);
 }
 
 void hue_bar_scroll_callback(void* data, UIContext* ui, RenderContext* gpu, double x, double y) {
@@ -330,57 +297,22 @@ void hex_string_text_callback(void* ptr, UIContext* ui, RenderContext* gpu, unsi
     return;
   }
 
-  if(data->string_len < 6) {
+  if(data->string_len < 8) {
     data->string_len += 1;
     data->string[data->string_len] = codepoint;
     update_ui_string(data->string, COLOR_PICK_CONTAINER_ID, 0, 0, ui, gpu);
   }
 }
 
-void rgb_to_hsv(vec3 rgb, vec3 hsv) {
-  hsv[2] = max(rgb[0], max(rgb[1], rgb[2]));
-  float M = min(rgb[0], min(rgb[1], rgb[2]));
-  float C = hsv[2] - M;
-  hsv[1] = C / hsv[2];
-  float X;
-
-  if(hsv[2] == rgb[0] && M == rgb[2]) {
-    X = rgb[1] - M;
-    hsv[0] = (X/C + 0)/6;
-    // H = [0, 1]
-  } else if(hsv[2] == rgb[1] && M == rgb[2]) {
-    X = 1 - rgb[0] - M;
-    hsv[0] = (X/C + 1)/6;
-    // H = [1, 2]
-  } else if(hsv[2] == rgb[1] && M == rgb[0]) {
-    X = rgb[2] - M;
-    hsv[0] = (X/C + 2)/6;
-    // H = [2, 3]
-  } else if(hsv[2] == rgb[2] && M == rgb[0]) {
-    X = 1 - rgb[1] - M;
-    hsv[0] = (X/C + 3)/6;
-    // H = [3, 4]
-  } else if(hsv[2] == rgb[2] && M == rgb[1]) {
-    X = rgb[0] - M;
-    hsv[0] = (X/C + 4)/6;
-    // H = [4, 5]
-  } else if(hsv[2] == rgb[0] && M == rgb[1]) {
-    X = 1 - rgb[2] - M;
-    hsv[0] = (X/C + 5)/6;
-    // H = [5, 6]
-  }
-}
-
 bool hex_string_key_callback(void* ptr, UIContext* ui, RenderContext* gpu, int key, int action, int mods) {
   (void)mods;
   ColorUIData* data = ptr;
   char tmp[3];
-  vec3 rgb;
 
   if(action == GLFW_PRESS) {
     switch(key) {
     case GLFW_KEY_ESCAPE:
-      rgb_string_set(ui, gpu, data, data->current);
+      set_rgb_from_hsv(ui, gpu, data, data->current_hsv);
       clear_active_element(ui, gpu);
       break;
     case GLFW_KEY_ENTER:
@@ -388,22 +320,26 @@ bool hex_string_key_callback(void* ptr, UIContext* ui, RenderContext* gpu, int k
       tmp[0] = data->string[1];
       tmp[1] = data->string[2];
       tmp[2] = 0;
-      rgb[0] = strtol(tmp, NULL, 16)/255.0;
+      data->current[0] = strtol(tmp, NULL, 16)/255.0;
 
       tmp[0] = data->string[3];
       tmp[1] = data->string[4];
       tmp[2] = 0;
-      rgb[1] = strtol(tmp, NULL, 16)/255.0;
+      data->current[1] = strtol(tmp, NULL, 16)/255.0;
 
       tmp[0] = data->string[5];
       tmp[1] = data->string[6];
       tmp[2] = 0;
-      rgb[2] = strtol(tmp, NULL, 16)/255.0;
+      data->current[2] = strtol(tmp, NULL, 16)/255.0;
 
-      rgb_to_hsv(rgb, data->current);
+      tmp[0] = data->string[7];
+      tmp[1] = data->string[8];
+      tmp[2] = 0;
+      data->current[3] = strtol(tmp, NULL, 16)/255.0;
 
-      hue_bar_set(ui, gpu, data, data->current[0]);
-      sv_square_pick(ui, gpu, data, data->current[1], 1-data->current[2]);
+      rgb_to_hsv(data->current, data->current_hsv);
+      hue_bar_set(ui, gpu, data, data->current_hsv[0]);
+      sv_square_pick(ui, gpu, data, data->current_hsv[1], 1-data->current_hsv[2]);
 
       clear_active_element(ui, gpu);
       break;
@@ -443,7 +379,7 @@ VkResult color_ui(ClientContext* context) {
       .color = {1, 1, 1, 1},
       .size = 16,
       .offset = 0,
-      .length = 7,
+      .length = 9,
       .font = 0,
     },
   };
@@ -565,7 +501,7 @@ VkResult color_ui(ClientContext* context) {
   };
 
   ColorUIData* data = malloc(sizeof(ColorUIData));
-  data->string_len = 6;
+  data->string_len = 8;
   data->string[0] = '#';
   data->string[1] = '0';
   data->string[2] = '0';
@@ -573,10 +509,13 @@ VkResult color_ui(ClientContext* context) {
   data->string[4] = '0';
   data->string[5] = '0';
   data->string[6] = '0';
-  data->string[7] = '\0';
+  data->string[7] = '0';
+  data->string[8] = '0';
+  data->string[9] = '\0';
   data->current[0] = 0;
   data->current[1] = 0;
   data->current[2] = 0;
+  data->current[3] = 0;
 
   UICallbacks callbacks[] = {
     {
diff --git a/client/test/hsv.c b/client/test/hsv.c
new file mode 100644
index 0000000..7c08740
--- /dev/null
+++ b/client/test/hsv.c
@@ -0,0 +1,70 @@
+#include "hsv.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+#define FAIL -1
+#define OK 0
+
+int test_conv(int r, int g, int b, double tolerance) {
+  vec3 rgb = {r/255.0, g/255.0, b/255.0};
+  double hsv[3];
+  vec3 out;
+  int test[3];
+  rgb_to_hsv(rgb, hsv);
+  hsv_to_rgb(hsv, out);
+  test[0] = out[0]*255.0;
+  test[1] = out[1]*255.0;
+  test[2] = out[2]*255.0;
+
+  if(fabs(rgb[0] - out[0]) > tolerance || fabs(rgb[1] - out[1]) > tolerance || fabs(rgb[2] - out[2]) > tolerance) {
+    fprintf(stderr, "FAIL:\t#%02X%02X%02X -> #%02X%02X%02X\nIN:\t(%.12f %.12f %.12f)\nOUT:\t(%.12f %.12f %.12f)\nDIF:\t(%.12f %.12f %.12f)\n",
+        r, g, b,
+        test[0], test[1], test[2],
+        rgb[0], rgb[1], rgb[2],
+        out[0], out[1], out[2],
+        rgb[0]-out[0], rgb[1]-out[1], rgb[2]-out[2]);
+    return FAIL;
+  } else {
+    return OK;
+  }
+}
+
+int main() {
+  for(int r = 0; r < 256; r++) {
+    for(int g = 0; g < 256; g++) {
+      for(int b = 0; b < 256; b++) {
+        if(test_conv(r, g, b, 0.001) != OK) {
+          return -1;
+        }
+      }
+    }
+  }
+}
+
+// To RGB steps:
+// 1. C = V * S <- maps to 3 in inv
+// 2. H' = H * 6 <- maps to 7 in inv
+// 3. X = C * (1 - abs(H' - 2*floor(H'/2) - 1))
+// 4. M = V - C <- maps to 4 in inv
+// 5. R = V, G = X + M, B = M
+
+// To HSV steps:
+// 1. V = max(R, G, B) <- maps to 5,R in inv
+// 2. M = min(R, G, B) <- maps to 5,B in inv
+// 3. S = C / V <- maps to 1 in inv
+// 4. C = V - M <- maps to 4 in inv
+// 5. X = G - M
+// 6. H' = X/C 
+// 7. H = H'/6 <- maps to 2 in inv
+//
+// So out of the two algos, the only step that doest match exactly so far is
+// RGB: X = C * (1 - abs(H' - 2*floor(H'/2) - 1))
+// HSV: X = G - M, H' = X/C
+//
+// After floor():
+// RGB: X = C * (1 - abs(H' - 1))
+//
+// After abs() assuming H' = [0, 1]:
+// RGB: X = C * (1 - (1 - H'))
+// RGB: X = C * H'