Implementar figura ICOSAHEDRON (D20 poliedro) - Tecla U

- Nueva clase IcosahedronShape con 12 vértices golden ratio
- Vértices basados en 3 rectángulos áureos ortogonales
- Subdivisión de caras para más de 12 puntos
- Rotación triple simultánea (X, Y, Z)
- Proyección a esfera circunscrita
- Compatible con física spring-damper y z-sorting

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

source/defines.h

@@ -126,6 +126,12 @@ constexpr float CYLINDER_RADIUS_FACTOR = 0.25f;    // Radio del cilindro (propor
 constexpr float CYLINDER_HEIGHT_FACTOR = 0.5f;     // Altura del cilindro (proporción de altura)
 constexpr float CYLINDER_ROTATION_SPEED_Y = 1.0f;  // Velocidad rotación eje Y (rad/s)
 
+// Configuración de Icosahedron (icosaedro D20)
+constexpr float ICOSAHEDRON_RADIUS_FACTOR = 0.30f; // Radio de la esfera circunscrita
+constexpr float ICOSAHEDRON_ROTATION_SPEED_X = 0.4f; // Velocidad rotación eje X (rad/s)
+constexpr float ICOSAHEDRON_ROTATION_SPEED_Y = 0.7f; // Velocidad rotación eje Y (rad/s)
+constexpr float ICOSAHEDRON_ROTATION_SPEED_Z = 0.2f; // Velocidad rotación eje Z (rad/s)
+
 // Control manual de escala de figuras 3D (Numpad +/-)
 constexpr float SHAPE_SCALE_MIN = 0.3f;            // Escala mínima (30%)
 constexpr float SHAPE_SCALE_MAX = 3.0f;            // Escala máxima (300%)

source/engine.cpp

@@ -23,12 +23,13 @@
 #include "ball.h"              // for Ball
 #include "external/dbgtxt.h"   // for dbg_init, dbg_print
 #include "external/texture.h"  // for Texture
-#include "shapes/sphere_shape.h"     // for SphereShape
+#include "shapes/sphere_shape.h"        // for SphereShape
-#include "shapes/cube_shape.h"       // for CubeShape
+#include "shapes/cube_shape.h"          // for CubeShape
-#include "shapes/helix_shape.h"      // for HelixShape
+#include "shapes/helix_shape.h"         // for HelixShape
-#include "shapes/wave_grid_shape.h"  // for WaveGridShape
+#include "shapes/wave_grid_shape.h"     // for WaveGridShape
-#include "shapes/torus_shape.h"      // for TorusShape
+#include "shapes/torus_shape.h"         // for TorusShape
-#include "shapes/cylinder_shape.h"   // for CylinderShape
+#include "shapes/cylinder_shape.h"      // for CylinderShape
+#include "shapes/icosahedron_shape.h"   // for IcosahedronShape
 
 // Función auxiliar para obtener la ruta del directorio del ejecutable
 std::string getExecutableDirectory() {
@@ -1084,6 +1085,9 @@ void Engine::activateShape(ShapeType type) {
         case ShapeType::CYLINDER:
             active_shape_ = std::make_unique<CylinderShape>();
             break;
+        case ShapeType::ICOSAHEDRON:
+            active_shape_ = std::make_unique<IcosahedronShape>();
+            break;
         // Futuras figuras se añadirán aquí
         default:
             active_shape_ = std::make_unique<SphereShape>();  // Fallback

source/shapes/icosahedron_shape.cpp

@@ -0,0 +1,151 @@
+#include "icosahedron_shape.h"
+#include "../defines.h"
+#include <cmath>
+#include <vector>
+
+void IcosahedronShape::generatePoints(int num_points, float screen_width, float screen_height) {
+    num_points_ = num_points;
+    radius_ = screen_height * ICOSAHEDRON_RADIUS_FACTOR;
+    // Los 12 vértices del icosaedro se calculan en getPoint3D()
+}
+
+void IcosahedronShape::update(float delta_time, float screen_width, float screen_height) {
+    // Recalcular radio por si cambió resolución (F4)
+    radius_ = screen_height * ICOSAHEDRON_RADIUS_FACTOR;
+
+    // Actualizar ángulos de rotación (triple rotación XYZ)
+    angle_x_ += ICOSAHEDRON_ROTATION_SPEED_X * delta_time;
+    angle_y_ += ICOSAHEDRON_ROTATION_SPEED_Y * delta_time;
+    angle_z_ += ICOSAHEDRON_ROTATION_SPEED_Z * delta_time;
+}
+
+void IcosahedronShape::getPoint3D(int index, float& x, float& y, float& z) const {
+    // Proporción áurea (golden ratio)
+    const float phi = (1.0f + sqrtf(5.0f)) / 2.0f;
+
+    // 12 vértices del icosaedro regular normalizado
+    // Basados en 3 rectángulos áureos ortogonales
+    static const float vertices[12][3] = {
+        // Rectángulo XY
+        {-1.0f,  phi,  0.0f},
+        { 1.0f,  phi,  0.0f},
+        {-1.0f, -phi,  0.0f},
+        { 1.0f, -phi,  0.0f},
+        // Rectángulo YZ
+        { 0.0f, -1.0f,  phi},
+        { 0.0f,  1.0f,  phi},
+        { 0.0f, -1.0f, -phi},
+        { 0.0f,  1.0f, -phi},
+        // Rectángulo ZX
+        { phi,  0.0f, -1.0f},
+        { phi,  0.0f,  1.0f},
+        {-phi,  0.0f, -1.0f},
+        {-phi,  0.0f,  1.0f}
+    };
+
+    // Normalizar para esfera circunscrita
+    const float normalization = sqrtf(1.0f + phi * phi);
+
+    // Si tenemos 12 o menos puntos, usar solo vértices
+    if (num_points_ <= 12) {
+        int vertex_index = index % 12;
+        float x_base = vertices[vertex_index][0] / normalization * radius_;
+        float y_base = vertices[vertex_index][1] / normalization * radius_;
+        float z_base = vertices[vertex_index][2] / normalization * radius_;
+
+        // Aplicar rotaciones
+        applyRotations(x_base, y_base, z_base, x, y, z);
+        return;
+    }
+
+    // Para más de 12 puntos: subdividir caras triangulares
+    // Distribuir puntos entre vértices (primero) y caras (después)
+    if (index < 12) {
+        // Primeros 12 puntos: vértices del icosaedro
+        float x_base = vertices[index][0] / normalization * radius_;
+        float y_base = vertices[index][1] / normalization * radius_;
+        float z_base = vertices[index][2] / normalization * radius_;
+        applyRotations(x_base, y_base, z_base, x, y, z);
+        return;
+    }
+
+    // Puntos restantes: distribuir en caras usando interpolación
+    // El icosaedro tiene 20 caras triangulares
+    int remaining_points = index - 12;
+    int points_per_face = (num_points_ - 12) / 20;
+    if (points_per_face < 1) points_per_face = 1;
+
+    int face_index = remaining_points / points_per_face;
+    if (face_index >= 20) face_index = 19;
+
+    int point_in_face = remaining_points % points_per_face;
+
+    // Definir algunas caras del icosaedro (usando índices de vértices)
+    // Solo necesitamos generar puntos, no renderizar caras completas
+    static const int faces[20][3] = {
+        {0, 11, 5}, {0, 5, 1}, {0, 1, 7}, {0, 7, 10}, {0, 10, 11},
+        {1, 5, 9}, {5, 11, 4}, {11, 10, 2}, {10, 7, 6}, {7, 1, 8},
+        {3, 9, 4}, {3, 4, 2}, {3, 2, 6}, {3, 6, 8}, {3, 8, 9},
+        {4, 9, 5}, {2, 4, 11}, {6, 2, 10}, {8, 6, 7}, {9, 8, 1}
+    };
+
+    // Obtener vértices de la cara
+    int v0 = faces[face_index][0];
+    int v1 = faces[face_index][1];
+    int v2 = faces[face_index][2];
+
+    // Interpolar dentro del triángulo usando coordenadas baricéntricas simples
+    float t = static_cast<float>(point_in_face) / static_cast<float>(points_per_face + 1);
+    float u = sqrtf(t);
+    float v = t - u;
+
+    float x_interp = vertices[v0][0] * (1.0f - u - v) + vertices[v1][0] * u + vertices[v2][0] * v;
+    float y_interp = vertices[v0][1] * (1.0f - u - v) + vertices[v1][1] * u + vertices[v2][1] * v;
+    float z_interp = vertices[v0][2] * (1.0f - u - v) + vertices[v1][2] * u + vertices[v2][2] * v;
+
+    // Proyectar a la esfera
+    float len = sqrtf(x_interp * x_interp + y_interp * y_interp + z_interp * z_interp);
+    if (len > 0.0001f) {
+        x_interp /= len;
+        y_interp /= len;
+        z_interp /= len;
+    }
+
+    float x_base = x_interp * radius_;
+    float y_base = y_interp * radius_;
+    float z_base = z_interp * radius_;
+
+    applyRotations(x_base, y_base, z_base, x, y, z);
+}
+
+void IcosahedronShape::applyRotations(float x_in, float y_in, float z_in, float& x_out, float& y_out, float& z_out) const {
+    // Aplicar rotación en eje X
+    float cos_x = cosf(angle_x_);
+    float sin_x = sinf(angle_x_);
+    float y_rot_x = y_in * cos_x - z_in * sin_x;
+    float z_rot_x = y_in * sin_x + z_in * cos_x;
+
+    // Aplicar rotación en eje Y
+    float cos_y = cosf(angle_y_);
+    float sin_y = sinf(angle_y_);
+    float x_rot_y = x_in * cos_y - z_rot_x * sin_y;
+    float z_rot_y = x_in * sin_y + z_rot_x * cos_y;
+
+    // Aplicar rotación en eje Z
+    float cos_z = cosf(angle_z_);
+    float sin_z = sinf(angle_z_);
+    float x_final = x_rot_y * cos_z - y_rot_x * sin_z;
+    float y_final = x_rot_y * sin_z + y_rot_x * cos_z;
+
+    x_out = x_final;
+    y_out = y_final;
+    z_out = z_rot_y;
+}
+
+float IcosahedronShape::getScaleFactor(float screen_height) const {
+    // Factor de escala para física: proporcional al radio
+    // Radio base = 72px (0.30 * 240px en resolución 320x240)
+    const float BASE_RADIUS = 72.0f;
+    float current_radius = screen_height * ICOSAHEDRON_RADIUS_FACTOR;
+    return current_radius / BASE_RADIUS;
+}

source/shapes/icosahedron_shape.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include "shape.h"
+
+// Figura: Icosaedro 3D (D20, poliedro regular de 20 caras)
+// Comportamiento: 12 vértices distribuidos uniformemente con rotación triple
+// Geometría: Basado en proporción áurea (golden ratio)
+class IcosahedronShape : public Shape {
+private:
+    float angle_x_ = 0.0f;           // Ángulo de rotación en eje X (rad)
+    float angle_y_ = 0.0f;           // Ángulo de rotación en eje Y (rad)
+    float angle_z_ = 0.0f;           // Ángulo de rotación en eje Z (rad)
+    float radius_ = 0.0f;            // Radio de la esfera circunscrita (píxeles)
+    int num_points_ = 0;             // Cantidad de puntos generados
+
+    // Helper para aplicar rotaciones triple XYZ
+    void applyRotations(float x_in, float y_in, float z_in, float& x_out, float& y_out, float& z_out) const;
+
+public:
+    void generatePoints(int num_points, float screen_width, float screen_height) override;
+    void update(float delta_time, float screen_width, float screen_height) override;
+    void getPoint3D(int index, float& x, float& y, float& z) const override;
+    const char* getName() const override { return "ICOSAHEDRON"; }
+    float getScaleFactor(float screen_height) const override;
+};