Mouse Wheel zoom. Zoom is scaled to be relative to current zoom level.

include/FractalApp.hpp

@@ -118,6 +118,10 @@ public:
     /// Passes the current window size to subordinate objects, such as the JUI scene.
     void PropagateWindowSize();
 
+    void ZoomIn(float rate);
+
+    void ZoomOut(float rate);
+
     /// Performs a logic update.
     void Update(float elapsed);
 
@@ -144,6 +148,15 @@ public:
     /// Called by the ReWindow base when the user presses a key.
     void OnKeyUp(const ReWindow::KeyUpEvent &e) override;
 
+    void OnMouseWheel(const ReWindow::MouseWheelEvent &e) override {
+        if (e.WheelMovement > 0) {
+            ZoomOut(0.1);
+        }
+        if (e.WheelMovement < 0) {
+            ZoomIn(0.1);
+        }
+    }
+
 protected:
 private:
 };

shaders/mandelbrot.frag.glsl

@@ -68,6 +68,7 @@ float iterate_mandelbrot(vec2 p) {
 void main() {
     vec2 R = u_resolution.xy;
 
+
     // Unused as of yet, see TODOs for what and why.
     float scale = (3.0 - u_scale);
 

src/FractalApp.cpp

@@ -404,6 +404,25 @@ void FractalInspectorApp::PropagateWindowSize() {
     //canvas->Resize(vSize);
 }
 
+
+void FractalInspectorApp::ZoomIn(float rate) {
+
+    rate = rate * u_scale;
+
+    u_scale -= rate;
+    // Stupid hack to make zoom originate at the center of the screen.
+    u_translation -= Vector2(0.5f, 0.5f)*rate;
+}
+
+void FractalInspectorApp::ZoomOut(float rate) {
+
+    rate = rate * u_scale;
+
+    u_scale += rate;
+    // Stupid hack to make zoom originate at the center of the screen.
+    u_translation += Vector2(0.5f, 0.5f)*rate;
+}
+
 void FractalInspectorApp::Update(float elapsed) {
     scene->Update(elapsed);
 
@@ -413,7 +432,7 @@ void FractalInspectorApp::Update(float elapsed) {
     }
 
     // TODO: Vary the rate appropriately.
-    float rate = elapsed * 0.25f;
+    float rate = elapsed * 0.5f;
 
     if (IsKeyDown(Keys::LeftShift))
         rate *= 0.125f;
@@ -421,17 +440,12 @@ void FractalInspectorApp::Update(float elapsed) {
     if (IsKeyDown(Keys::LeftControl))
         rate *= 0.125f;
 
-    if (IsKeyDown(Keys::Minus)) {
-        u_scale += rate;
-        // Stupid hack to make zoom originate at the center of the screen.
-        u_translation += Vector2(0.5f, 0.5f)*rate;
-    }
+    if (IsKeyDown(Keys::Minus))
+        ZoomOut(rate);
+
+    if (IsKeyDown(Keys::Equals))
+        ZoomIn(rate);
 
-    if (IsKeyDown(Keys::Equals)) {
-        u_scale -= rate;
-        // Stupid hack to make zoom originate at the center of the screen.
-        u_translation -= Vector2(0.5f, 0.5f)*rate;
-    }
 
 
     if (IsKeyDown(Keys::DownArrow))