ADDED: example: `models_tesseract`

examples/models/models_tesseract_view.c

@@ -0,0 +1,124 @@
+/*******************************************************************************************
+*
+*   raylib [models] example - Tesseract view
+*
+*   NOTE: This example only works on platforms that support drag & drop (Windows, Linux, OSX, Html5?)
+*
+*   Example originally created with raylib 5.6-dev, last time updated with raylib 5.6-dev
+*
+*   Example licensed under an unmodified zlib/libpng license, which is an OSI-certified,
+*   BSD-like license that allows static linking with closed source software
+*
+*   Copyright (c) 2024-2025 raylib contributor (?) & Ramon Santamaria (@raysan5)
+*
+********************************************************************************************/
+
+#include "raylib.h"
+
+#include "raymath.h"
+
+//------------------------------------------------------------------------------------
+// Program main entry point
+//------------------------------------------------------------------------------------
+int main(void)
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const int screenWidth = 800;
+    const int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib [models] example - tesseract view");
+    
+    // Define the camera to look into our 3d world
+    Camera camera = { 0 };
+    camera.position = (Vector3){ 4.0f, 4.0f, 4.0f };    // Camera position
+    camera.target = (Vector3){ 0.0f, 0.0f, 0.0f };      // Camera looking at point
+    camera.up = (Vector3){ 0.0f, 0.0f, 1.0f };          // Camera up vector (rotation towards target)
+    camera.fovy = 50.0f;                                // Camera field-of-view Y
+    camera.projection = CAMERA_PERSPECTIVE;             // Camera mode type
+
+    // Find the coordinates by setting XYZW to +-1
+    Vector4 tesseract[16] = {
+        {  1,  1,  1, 1 }, {  1,  1,  1, -1 }, 
+        {  1,  1, -1, 1 }, {  1,  1, -1, -1 },
+        {  1, -1,  1, 1 }, {  1, -1,  1, -1 }, 
+        {  1, -1, -1, 1 }, {  1, -1, -1, -1 },
+        { -1,  1,  1, 1 }, { -1,  1,  1, -1 }, 
+        { -1,  1, -1, 1 }, { -1,  1, -1, -1 },
+        { -1, -1,  1, 1 }, { -1, -1,  1, -1 }, 
+        { -1, -1, -1, 1 }, { -1, -1, -1, -1 },
+    };
+    
+    float rotation = 0.0f;
+    Vector3 transformed[16] = { 0 };
+    float wValues[16] = { 0 };
+
+    SetTargetFPS(60);               // Set our game to run at 60 frames-per-second
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        rotation = DEG2RAD*45.0f*GetTime();
+        
+        for (int i = 0; i < 16; i++)
+        {
+            Vector4 p = tesseract[i];
+
+            // Rotate the XW part of the vector
+            Vector2 rotXW = Vector2Rotate((Vector2){ p.x, p.w }, rotation);
+            p.x = rotXW.x;
+            p.w = rotXW.y;
+
+            // Projection from XYZW to XYZ from perspective point (0, 0, 0, 3)
+            // NOTE: Trace a ray from (0, 0, 0, 3) > p and continue until W = 0
+            float c = 3/(3 - p.w);
+            p.x = c * p.x;
+            p.y = c * p.y;
+            p.z = c * p.z;
+
+            // Split XYZ coordinate and W values later for drawing
+            transformed[i] = (Vector3){ p.x, p.y, p.z };
+            wValues[i] = p.w;
+        }
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+        
+            ClearBackground(RAYWHITE);
+            
+            BeginMode3D(camera);
+                for (int i = 0; i < 16; i++)
+                {
+                    // Draw spheres to indicate the W value
+                    DrawSphere(transformed[i], fabsf(wValues[i]*0.1), RED);
+
+                    for (int j = 0; j < 16; j++)
+                    {
+                        // Two lines are connected if they differ by 1 coordinate
+                        // This way we dont have to keep an edge list
+                        Vector4 v1 = tesseract[i];
+                        Vector4 v2 = tesseract[j];
+                        int diff = (int)(v1.x == v2.x) + (int)(v1.y == v2.y) + (int)(v1.z == v2.z) + (int)(v1.w == v2.w);
+
+                        // Draw only differing by 1 coordinate and the lower index only (duplicate lines)
+                        if (diff == 3 && i < j) DrawLine3D(transformed[i], transformed[j], MAROON);
+                    }
+                }
+            EndMode3D();
+            
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    CloseWindow();          // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}