initial commit for coom in opengl

sphere.hpp

@@ -0,0 +1,70 @@
+#ifndef SPHERE_H
+#define SPHERE_H
+
+#include <cmath>
+#include <glm/glm.hpp>
+#include <vector>
+
+struct SphereVertex {
+  glm::vec3 position;
+  glm::vec3 normal;   // Fixed: Must be vec3 for 3D directions
+  glm::vec2 texCoord; // Fixed: Must be vec2 for U,V coordinates
+};
+
+// Generates vertex and index data for a sphere
+inline void generateSphere(float radius, int sectors, int stacks,
+                           std::vector<SphereVertex> &vertices,
+                           std::vector<unsigned int> &indices) {
+  vertices.clear();
+  indices.clear();
+
+  float x, y, z, xy;
+  float nx, ny, nz, lengthInv = 1.0f / radius;
+  float s, t;
+
+  float sectorStep = 2 * M_PI / sectors;
+  float stackStep = M_PI / stacks;
+  float sectorAngle, stackAngle;
+
+  for (int i = 0; i <= stacks; ++i) {
+    stackAngle = M_PI / 2 - i * stackStep;
+    xy = radius * std::cos(stackAngle);
+    z = radius * std::sin(stackAngle);
+
+    for (int j = 0; j <= sectors; ++j) {
+      sectorAngle = j * sectorStep;
+
+      // Position
+      x = xy * std::cos(sectorAngle);
+      y = xy * std::sin(sectorAngle);
+
+      SphereVertex vertex;
+      vertex.position = glm::vec3(x, y, z);
+      // Normal is just the normalized position for a sphere at origin
+      vertex.normal = glm::vec3(x * lengthInv, y * lengthInv, z * lengthInv);
+      vertex.texCoord = glm::vec2((float)j / sectors, (float)i / stacks);
+
+      vertices.push_back(vertex);
+    }
+  }
+
+  // Index generation: connecting the stacks and sectors
+  for (int i = 0; i < stacks; ++i) {
+    int k1 = i * (sectors + 1);
+    int k2 = k1 + sectors + 1;
+    for (int j = 0; j < sectors; ++j, ++k1, ++k2) {
+      if (i != 0) {
+        indices.push_back(k1);
+        indices.push_back(k2);
+        indices.push_back(k1 + 1);
+      }
+      if (i != (stacks - 1)) {
+        indices.push_back(k1 + 1);
+        indices.push_back(k2);
+        indices.push_back(k2 + 1);
+      }
+    }
+  }
+}
+
+#endif