New MousePointer Brownian

src/MousePointer.cpp

@@ -17,6 +17,7 @@
  * along with this program. If not, see <https://www.gnu.org/licenses/>.
 **/
 
+#include <glm/geometric.hpp>
 #include <glm/gtc/random.hpp> // for diskRand
 
 #include "imgui.h"
@@ -37,6 +38,7 @@ std::vector< std::tuple<int, int, std::string, std::string> > Pointer::Modes = {
     { ICON_POINTER_LINEAR,  "Line",    "Speed" },
     { ICON_POINTER_SPRING,  "Spring",  "Mass" },
     { ICON_POINTER_WIGGLY,  "Wiggly",  "Radius" },
+    { ICON_POINTER_BROWNIAN,  "Brownian",  "Radius" },
     { ICON_POINTER_METRONOME, "Metronome", "Jump" }
 };
 
@@ -138,6 +140,49 @@ void PointerWiggly::draw()
     ImGui::GetBackgroundDrawList()->AddCircle(IMVEC_IO(current_), max * 0.5f, color, 0, 2.f + 4.f * strength_);
 }
 
+void PointerBrownian::update(const glm::vec2 &pos, float)
+{
+    current_ = pos;
+    radius_ = (POINTER_WIGGLY_MAX_RADIUS - POINTER_WIGGLY_MIN_RADIUS) * strength_;
+    radius_ += POINTER_WIGGLY_MIN_RADIUS;
+
+    // Brownian motion: add small random displacement in 2D
+    // Generate random step using gaussian distribution for each axis
+    glm::vec2 random_step = glm::gaussRand(glm::vec2(0.0f), glm::vec2(1.f) );
+
+    // Scale by radius and apply damping to keep motion bounded
+    float factor = 0.3f;    
+    if (TabletInput::instance().hasPressure() && TabletInput::instance().isPressed()) {
+        factor *= TabletInput::instance().getPressure();
+    }
+    float damping = 0.92f;    
+    brownian_offset_ = brownian_offset_ * damping + random_step * radius_ * factor;
+
+    // Clamp offset to stay within maximum radius
+    float offset_length = glm::length(brownian_offset_);
+    if (offset_length > radius_) {
+        brownian_offset_ = brownian_offset_ * (radius_ / offset_length);
+    }
+
+    glm::vec2 p = pos + brownian_offset_;
+
+    // smooth a little and apply
+    const float emaexp = 2.0 / float( POINTER_WIGGLY_SMOOTHING + 1);
+    target_ = emaexp * p + (1.f - emaexp) * target_;
+}
+
+void PointerBrownian::draw()
+{
+    const ImU32 color = ImGui::GetColorU32(ImGuiCol_HeaderActive);
+    ImGui::GetBackgroundDrawList()->AddLine(IMVEC_IO(current_), IMVEC_IO(target_), color, 5.f);
+
+    const float max = POINTER_WIGGLY_MIN_RADIUS + (POINTER_WIGGLY_MAX_RADIUS - POINTER_WIGGLY_MIN_RADIUS) * strength_;
+    if (TabletInput::instance().hasPressure() && TabletInput::instance().isPressed())
+        ImGui::GetBackgroundDrawList()->AddCircle(IMVEC_IO(current_), radius_ * 0.8f, color, 0);
+    ImGui::GetBackgroundDrawList()->AddCircle(IMVEC_IO(current_), max * 0.8f, color, 0, 2.f + 4.f * strength_);
+}
+
+
 #define POINTER_METRONOME_RADIUS 36.f
 
 void PointerMetronome::initiate(const glm::vec2 &pos)
@@ -256,6 +301,7 @@ MousePointer::MousePointer() : mode_(Pointer::POINTER_DEFAULT)
     pointer_[Pointer::POINTER_LINEAR]  = new PointerLinear;
     pointer_[Pointer::POINTER_SPRING]  = new PointerSpring;
     pointer_[Pointer::POINTER_WIGGLY]  = new PointerWiggly;
+    pointer_[Pointer::POINTER_BROWNIAN]  = new PointerBrownian;
     pointer_[Pointer::POINTER_METRONOME] = new PointerMetronome;
 }
 
@@ -266,5 +312,6 @@ MousePointer::~MousePointer()
     delete pointer_[Pointer::POINTER_LINEAR];
     delete pointer_[Pointer::POINTER_SPRING];
     delete pointer_[Pointer::POINTER_WIGGLY];
+    delete pointer_[Pointer::POINTER_BROWNIAN];
     delete pointer_[Pointer::POINTER_METRONOME];
 }

src/MousePointer.h

@@ -12,6 +12,7 @@
 #define ICON_POINTER_LINEAR 14, 9
 #define ICON_POINTER_GRID   15, 9
 #define ICON_POINTER_WIGGLY 16, 9
+#define ICON_POINTER_BROWNIAN 11, 9
 #define ICON_POINTER_METRONOME 6, 13
 
 ///
@@ -33,6 +34,7 @@ public:
         POINTER_LINEAR,
         POINTER_SPRING,
         POINTER_WIGGLY,
+        POINTER_BROWNIAN,
         POINTER_METRONOME,
         POINTER_INVALID
     } Mode;
@@ -104,7 +106,21 @@ class PointerWiggly : public Pointer
 {
     float radius_;
 public:
-    PointerWiggly() {}
+    PointerWiggly() : radius_(0.0f) {}
+    void update(const glm::vec2 &pos, float) override;
+    void draw() override;
+};
+
+///
+/// \brief The PointerBrownian moves with a Brownian movement
+/// Strength modulates the radius of the movement
+///
+class PointerBrownian : public Pointer
+{
+    float radius_;
+    glm::vec2 brownian_offset_;
+public:
+    PointerBrownian() : brownian_offset_(0.0f, 0.0f) {}
     void update(const glm::vec2 &pos, float) override;
     void draw() override;
 };