From e5a8f88556f2c551464b4b50bdbb1558ff23eeb4 Mon Sep 17 00:00:00 2001
From: Seth Hamilton <shamilton@the-embedded-lab.com>
Date: Mon, 25 Aug 2025 03:43:30 -0500
Subject: [PATCH] Enable alpha blending. main reads from stdin

---
 src/live_plotter.cpp      |  8 ++++-
 src/main.cpp              | 62 +++++++++++++++------------------------
 src/shaders/fragment.glsl |  2 +-
 3 files changed, 32 insertions(+), 40 deletions(-)

diff --git a/src/live_plotter.cpp b/src/live_plotter.cpp
index e7785a3..9511973 100644
--- a/src/live_plotter.cpp
+++ b/src/live_plotter.cpp
@@ -19,6 +19,7 @@
 #include <pthread.h>
 #include <string>
 #include <winnt.h>
+#include <algorithm>
 
 #include "util.hpp"
 #include "shaders.hpp"
@@ -143,6 +144,7 @@ DllExport void __cdecl update_point(pointid id, float x, float y, float z) {
     Point* p = id_to_point[id];
     p->targetloc = { x, y, z };
     p->startloc = p->b.pose[3];
+    p->start_s = _time();
     LeaveCriticalSection(&cs);
 }
 
@@ -218,6 +220,8 @@ DWORD _win_thread(LPVOID args) {
     glClear(GL_COLOR_BUFFER_BIT); // Write to back buffer again (former front buf)
     glDisable(GL_CULL_FACE);
     glEnable(GL_DEPTH_TEST);
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
     while (!(glfwWindowShouldClose(win) || stop_flag))
         _refresh_win();
@@ -264,10 +268,12 @@ void _refresh_win() {
             // Perform fade
             double elapsed_time_s = _time() - p->start_s;
             float t = elapsed_time_s / p->lifetime_s;
-            p->b.color[3] = lerp(1.0, 0.0, t);
+            t = std::clamp(t, 0.0f, 1.0f);
+            p->b.color.w = lerp(1.0, 0.0, t);
 
             // Lerp position
             t = elapsed_time_s / LERP_MOVE_PERIOD_S;
+            t = std::clamp(t, 0.0f, 1.0f);
             p->b.pose[3] = glm::vec4(lerp(p->startloc, p->targetloc, t), 1);
             draw_body(p->b);
         }
diff --git a/src/main.cpp b/src/main.cpp
index 3229801..50493b9 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,43 +1,11 @@
+#include <iostream>
+#include <string>
+#include <map>
 
 #include "camera_poses.hpp"
 #include "live_plotter.hpp"
 
-//void* process_cin(void* args) {
-//    std::string line;
-//    while (true) {
-//        std::getline(std::cin, line);
-//        Array<char*> words = split_str(line.c_str());
-//        if (!words.len == 4)
-//            return NULL;
-//        printf("Received: %s, %s, %s, %s\n", words[0], words[1], words[2], words[3]); // echo for debugging
-//        float x = atof(words[1]);
-//        float y = atof(words[2]);
-//        float z = atof(words[3]);
-//        glm::vec3 new_loc = glm::vec3(x, y, z);
-//        bool found_match = false;
-//        for (int i = 0; i < camera_bodies.size(); i++) {
-//            if (strcmp(words[0], camera_bodies[i].name) == 0 && camera_bodies[i].b) {
-//                Body& b = *camera_bodies[i].b;
-//                glm::vec4& transl = b.pose[3];
-//                transl = (0.8f * transl) + (0.2f * glm::vec4(new_loc, 1)); // lp filter
-//                int color_i = i + 1;
-//                b.color = glm::vec4(color_i & 0x4, color_i & 0x2, color_i & 0x1, 1); // reset alpha to 1
-//                camera_bodies[i].hp = max_hp;
-//                found_match = true;
-//            } else if (camera_bodies[i].b) {
-//                float& cur_hp = camera_bodies[i].hp;
-//                if (cur_hp > 0)
-//                    cur_hp -= 1;
-//                camera_bodies[i].b->color = glm::vec4(i & 0x4, i & 0x2, i & 0x1, cur_hp / max_hp);
-//            }
-//        }
-//        if (!found_match) {
-//            auto read = BarcodeRead { words[0], (Body*)NULL, max_hp };
-//            camera_bodies.push_back(read);
-//        }
-//    }
-//}
-
+static std::map<std::string, pointid> name_to_id;
 
 int main() {
     Array<glm::mat2x3> camera_pose_axes = { NULL, 0 };
@@ -55,6 +23,24 @@ int main() {
         set_scale(id, 10);
     }
 
-    while (true)
-        ;
+    while (true) {
+        std::string line;
+        std::getline(std::cin, line);
+        Array<char*> words = split_str(line.c_str());
+        if (!words.len == 4)
+            return NULL;
+        printf("Received: %s, %s, %s, %s\n", words[0], words[1], words[2], words[3]); // echo for debugging
+        std::string name = std::string(words[0]);
+        float x = atof(words[1]);
+        float y = atof(words[2]);
+        float z = atof(words[3]);
+
+        if (auto it = name_to_id.find(name); it != name_to_id.end()) {
+            update_point(it->second, x, y, z);
+        } else {
+            name_to_id[name] = create_point(x, y, z);
+            set_lifetime(name_to_id[name], 0.2);
+            set_scale(name_to_id[name], 15);
+        }
+    }
 }
diff --git a/src/shaders/fragment.glsl b/src/shaders/fragment.glsl
index 323267a..d64db91 100644
--- a/src/shaders/fragment.glsl
+++ b/src/shaders/fragment.glsl
@@ -10,7 +10,7 @@ void main() {
     vec3 dx = dFdx(frag_pos) * 500;
     vec3 dy = dFdy(frag_pos) * 500;
     vec3 N = normalize(cross(dFdx(frag_pos), dFdy(frag_pos)));
-    frag_color = color + vec4(N/2, 1)/2;
+    frag_color = color;
     //frag_color = vec4(length(dx), length(dy), length(dy), 1.0);
     //frag_color += color;
 }