Merge pull request #11 from tum-pbs/fix-colormap-sanitization

Fix colormap sanitization

guide.md

@@ -646,4 +646,28 @@ particles.erase(std::remove_if(particles.begin(), particles.end(), [](const Part
 }), particles.end());
 ``` 
 
-You may also want to consider making the lifetime a GUI element or updating it based on the interactions, e.g., a particle that was dragged around has the lifetime counter reset.
+You may also want to consider making the lifetime a GUI element or updating it based on the interactions, e.g., a particle that was dragged around has the lifetime counter reset.
+
+## Colormapping
+
+If you would like to color things in your simulation based on some attribute then color mapping is a useful approach where our framework supports most common matplotlib colormaps you can find [here](https://matplotlib.org/stable/users/explain/colors/colormaps.html). A colormap within framework is consturcted by giving it a string for the colormap name and then calling it with a float in the range 0 to 1 (the input is clamped to this value, so you need to manually map the inputs), e.g.,
+```cpp
+auto cmap = Colormap("viridis");
+glm::vec3 color = cmap(0.5);
+```
+
+A way we can incorporate this into our example is by coloring spheres not randomly but based on their lifetime:
+
+```cpp
+// Scene1.cpp
+void Scene1::onDraw(Renderer& renderer){
+// ...
+    auto cmap = Colormap("viridis");
+
+    for (auto& particle : particles){
+        renderer.drawSphere(particle.position, 0.1f, glm::vec4(cmap(particle.lifetime / 1.5f), 1));
+    }
+}
+```
+Note that the colormap returns no alpha channel so we need to expand the returned color to be RGBA. Also note the division by 1.5, the expected maximum lifetime of a particle before deletion and needs to be kept in sync with other lifetime based parts of the code, which could be ensured by using a member of the Scene class to represent the maximum lifetime of a particle instead of hardcoding it.
+![image](https://github.com/user-attachments/assets/37f5c448-ea09-4c0f-884b-21101b8f02dd)

src/Colormap.cpp

@@ -53,7 +53,11 @@ void Colormap::init()
     std::string line;
     int offset = 0;
     while (std::getline(file, line))
-    {
+    {        
+        // Sanitize inputs in case the file contains windows line endings, i.e. \r\n instead of \n
+        line.erase(std::remove(line.begin(), line.end(), '\r' ), line.end());
+        line.erase(std::remove(line.begin(), line.end(), '\n' ), line.end());
+
         names.push_back(line);
         indices[line] = offset;
         offset++;