Add some examples

examples/core/input_mouse.zig

@@ -0,0 +1,57 @@
+//
+// input_mouse
+// Zig version: 
+// Author: Nikolas Wipper
+// Date: 2020-02-16
+//
+
+usingnamespace @import("raylib");
+
+pub fn main() anyerror!void
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    const screenWidth = 800;
+    const screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, c"raylib-zig [core] example - mouse input");
+
+    var ballPosition = Vector2 { .x = -100.0, .y = -100.0 };
+    var ballColor = DARKBLUE;
+
+    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
+        //----------------------------------------------------------------------------------
+        ballPosition = GetMousePosition();
+
+        if (IsMouseButtonPressed(MouseButton.MOUSE_LEFT_BUTTON)) { ballColor = MAROON; }
+        else if (IsMouseButtonPressed(MouseButton.MOUSE_MIDDLE_BUTTON)) { ballColor = LIME; }
+        else if (IsMouseButtonPressed(MouseButton.MOUSE_RIGHT_BUTTON)) { ballColor = DARKBLUE; }
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawing();
+
+            ClearBackground(RAYWHITE);
+
+            DrawCircle(@floatToInt(c_int, ballPosition.x), @floatToInt(c_int, ballPosition.y), 50, ballColor);
+            //DrawCircleV(ballPosition, 40, ballColor);
+
+            DrawText(c"move ball with mouse and click mouse button to change color", 10, 10, 20, DARKGRAY);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------
+    CloseWindow();        // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+}
+