From 7d81e673ed7f399305ae12f69267190ade93064d Mon Sep 17 00:00:00 2001
From: Ray <raysan5@gmail.com>
Date: Sat, 15 Dec 2018 23:31:56 +0100
Subject: [PATCH] ADDED: GenMeshPoly()

To generate 2D polygonal shape
---
 examples/models/models_mesh_generation.c |  4 +-
 src/models.c                             | 62 ++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/examples/models/models_mesh_generation.c b/examples/models/models_mesh_generation.c
index c02bd91a..d64889bd 100644
--- a/examples/models/models_mesh_generation.c
+++ b/examples/models/models_mesh_generation.c
@@ -11,7 +11,7 @@
 
 #include "raylib.h"
 
-#define NUM_MODELS  7      // We generate 7 parametric 3d shapes
+#define NUM_MODELS  8      // We generate 8 parametric 3d shapes
 
 int main()
 {
@@ -36,6 +36,7 @@ int main()
     models[4] = LoadModelFromMesh(GenMeshCylinder(1, 2, 16));
     models[5] = LoadModelFromMesh(GenMeshTorus(0.25f, 4.0f, 16, 32));
     models[6] = LoadModelFromMesh(GenMeshKnot(1.0f, 2.0f, 16, 128));
+    models[7] = LoadModelFromMesh(GenMeshPoly(5, 2.0f));
     
     // Set checked texture as default diffuse component for all models material
     for (int i = 0; i < NUM_MODELS; i++) models[i].material.maps[MAP_DIFFUSE].texture = texture;
@@ -93,6 +94,7 @@ int main()
                 case 4: DrawText("CYLINDER", 680, 10, 20, DARKBLUE); break;
                 case 5: DrawText("TORUS", 680, 10, 20, DARKBLUE); break;
                 case 6: DrawText("KNOT", 680, 10, 20, DARKBLUE); break;
+                case 7: DrawText("POLY", 680, 10, 20, DARKBLUE); break;
                 default: break;
             }
 
diff --git a/src/models.c b/src/models.c
index 0955b7b0..e030166a 100644
--- a/src/models.c
+++ b/src/models.c
@@ -715,6 +715,68 @@ void ExportMesh(Mesh mesh, const char *fileName)
 }
 
 #if defined(SUPPORT_MESH_GENERATION)
+// Generate polygonal mesh
+Mesh GenMeshPoly(int sides, float radius)
+{
+    Mesh mesh = { 0 };
+    int vertexCount = sides*3;
+    
+    // Vertices definition
+    Vector3 *vertices = (Vector3 *)malloc(vertexCount*sizeof(Vector3));
+    for (int i = 0, v = 0; i < 360; i += 360/sides, v += 3)
+    {
+        vertices[v] = (Vector3){ 0.0f, 0.0f, 0.0f };
+        vertices[v + 1] = (Vector3){ sinf(DEG2RAD*i)*radius, 0.0f, cosf(DEG2RAD*i)*radius };
+        vertices[v + 2] = (Vector3){ sinf(DEG2RAD*(i + 360/sides))*radius, 0.0f, cosf(DEG2RAD*(i + 360/sides))*radius };
+    }    
+        
+    // Normals definition
+    Vector3 *normals = (Vector3 *)malloc(vertexCount*sizeof(Vector3));
+    for (int n = 0; n < vertexCount; n++) normals[n] = (Vector3){ 0.0f, 1.0f, 0.0f };   // Vector3.up;
+
+    // TexCoords definition        
+    Vector2 *texcoords = (Vector2 *)malloc(vertexCount*sizeof(Vector2));
+    for (int n = 0; n < vertexCount; n++) texcoords[n] = (Vector2){ 0.0f, 0.0f };
+
+    mesh.vertexCount = vertexCount;
+    mesh.triangleCount = sides;
+    mesh.vertices = (float *)malloc(mesh.vertexCount*3*sizeof(float));
+    mesh.texcoords = (float *)malloc(mesh.vertexCount*2*sizeof(float));
+    mesh.normals = (float *)malloc(mesh.vertexCount*3*sizeof(float));
+    
+    // Mesh vertices position array
+    for (int i = 0; i < mesh.vertexCount; i++)
+    {
+        mesh.vertices[3*i] = vertices[i].x;
+        mesh.vertices[3*i + 1] = vertices[i].y;
+        mesh.vertices[3*i + 2] = vertices[i].z;
+    }
+    
+    // Mesh texcoords array
+    for (int i = 0; i < mesh.vertexCount; i++)
+    {
+        mesh.texcoords[2*i] = texcoords[i].x;
+        mesh.texcoords[2*i + 1] = texcoords[i].y;
+    }
+    
+    // Mesh normals array
+    for (int i = 0; i < mesh.vertexCount; i++)
+    {
+        mesh.normals[3*i] = normals[i].x;
+        mesh.normals[3*i + 1] = normals[i].y;
+        mesh.normals[3*i + 2] = normals[i].z;
+    }
+    
+    free(vertices);
+    free(normals);
+    free(texcoords);
+
+    // Upload vertex data to GPU (static mesh)
+    rlLoadMesh(&mesh, false);  
+    
+    return mesh;
+}
+
 // Generate plane mesh (with subdivisions)
 Mesh GenMeshPlane(float width, float length, int resX, int resZ)
 {