Improved openGL and ImGUI implementation

source/shader/vertex.glsl

@@ -1,9 +1,18 @@
 #version 330 core
-layout (location = 0) in vec2 aPos;
+layout(location = 0) in vec3 aPos; // Position
+layout(location = 1) in vec4 aColor; // Color (RGBA)
+layout(location = 2) in float aLife; // Life
 
-out vec3 vColor;
+out vec4 vColor;
 
 void main() {
-    gl_Position = vec4(aPos, 0.0, 1.0);
+    float alpha = aLife;
+    if (aLife > 0.0) {
+        alpha = aLife / 10.0; // Fade mortal particles
+    } else if (aLife < 0.0) {
+        alpha = 1.0; // Eternal particles are fully opaque
+    }
+    vColor = vec4(aColor.rgb, aColor.a * alpha);
+    gl_Position = vec4(aPos, 1.0);
+    gl_PointSize = 10.0; // Make them big enough to see!
 }
-