From 5ea18b9426823e92f1fc16e686702f2caadf83c9 Mon Sep 17 00:00:00 2001
From: raysan5 <raysan5@gmail.com>
Date: Sat, 5 Mar 2016 15:40:08 +0100
Subject: [PATCH] Support 2d camera system -IN PROGRESS-

---
 examples/core_2d_camera.c | 71 +++++++++++++++++++++++++++++++++++++++
 src/core.c                | 21 ++++++++++--
 src/raylib.h              | 11 +++++-
 3 files changed, 100 insertions(+), 3 deletions(-)
 create mode 100644 examples/core_2d_camera.c

diff --git a/examples/core_2d_camera.c b/examples/core_2d_camera.c
new file mode 100644
index 00000000..71c474f0
--- /dev/null
+++ b/examples/core_2d_camera.c
@@ -0,0 +1,71 @@
+/*******************************************************************************************
+*
+*   raylib [core] example - 2d camera
+*
+*   This example has been created using raylib 1.5 (www.raylib.com)
+*   raylib is licensed under an unmodified zlib/libpng license (View raylib.h for details)
+*
+*   Copyright (c) 2016 Ramon Santamaria (@raysan5)
+*
+********************************************************************************************/
+
+#include "raylib.h"
+
+int main()
+{
+    // Initialization
+    //--------------------------------------------------------------------------------------
+    int screenWidth = 800;
+    int screenHeight = 450;
+
+    InitWindow(screenWidth, screenHeight, "raylib [core] example - 2d camera");
+    
+    Camera2D camera;
+    
+    camera.position = (Vector2){ 0, 0 };
+    camera.origin = (Vector2){ 100, 100 };
+    camera.rotation = 0.0f;
+    camera.zoom = 1.0f;
+    
+    SetTargetFPS(60);
+    //--------------------------------------------------------------------------------------
+
+    // Main game loop
+    while (!WindowShouldClose())    // Detect window close button or ESC key
+    {
+        // Update
+        //----------------------------------------------------------------------------------
+        if (IsKeyDown(KEY_RIGHT)) camera.position.x--;
+        else if (IsKeyDown(KEY_LEFT)) camera.position.x++;
+        else if (IsKeyDown(KEY_UP)) camera.position.y++;
+        else if (IsKeyDown(KEY_DOWN)) camera.position.y--;
+        
+        if (IsKeyDown(KEY_R)) camera.rotation--;
+        else if (IsKeyDown(KEY_F)) camera.rotation++;
+        
+        if (IsKeyDown(KEY_W)) camera.zoom += 0.005f;
+        if (IsKeyDown(KEY_S)) camera.zoom -= 0.005f;
+        //----------------------------------------------------------------------------------
+
+        // Draw
+        //----------------------------------------------------------------------------------
+        BeginDrawingEx(camera);
+
+            ClearBackground(RAYWHITE);
+
+            DrawText("2D CAMERA TEST", 20, 20, 20, GRAY);
+            
+            DrawRectangle(0, 300, screenWidth, 50, GRAY);
+            DrawRectangle(400, 250, 40, 40, RED);
+
+        EndDrawing();
+        //----------------------------------------------------------------------------------
+    }
+
+    // De-Initialization
+    //--------------------------------------------------------------------------------------   
+    CloseWindow();        // Close window and OpenGL context
+    //--------------------------------------------------------------------------------------
+
+    return 0;
+}
\ No newline at end of file
diff --git a/src/core.c b/src/core.c
index a8cc593a..870ca3b4 100644
--- a/src/core.c
+++ b/src/core.c
@@ -560,8 +560,25 @@ void BeginDrawing(void)
                                         // NOTE: Not required with OpenGL 3.3+
 }
 
-// Setup drawing canvas with extended parameters
-void BeginDrawingEx(int blendMode, Shader shader, Matrix transform)
+// Setup drawing canvas with 2d camera
+void BeginDrawingEx(Camera2D camera)
+{
+    BeginDrawing();
+    
+    // TODO: Consider origin offset on position, rotation, scaling
+    
+    Matrix matRotation = MatrixRotate((Vector3){ 0.0f, 0.0f, 1.0f }, camera.rotation*DEG2RAD);
+    Matrix matScale = MatrixScale(camera.zoom, camera.zoom, 1.0f);
+    Matrix matTranslation = MatrixTranslate(camera.position.x, camera.position.y, 0.0f);
+    Matrix matOrigin = MatrixTranslate(-camera.origin.x, -camera.origin.y, 0.0f);
+
+    Matrix matTransform = MatrixMultiply(MatrixMultiply(matScale, matRotation), matTranslation);
+    
+    rlMultMatrixf(MatrixToFloat(matTransform));
+}
+
+// Setup drawing canvas with pro parameters
+void BeginDrawingPro(int blendMode, Shader shader, Matrix transform)
 {
     BeginDrawing();
     
diff --git a/src/raylib.h b/src/raylib.h
index b6cf98fe..7173a556 100644
--- a/src/raylib.h
+++ b/src/raylib.h
@@ -315,6 +315,14 @@ typedef struct Camera {
     float fovy;             // Field-Of-View apperture in Y (degrees)
 } Camera;
 
+// Camera2D type, defines a 2d camera
+typedef struct Camera2D {
+    Vector2 position;       // Camera position
+    Vector2 origin;         // Camera origin (for rotation and zoom)
+    float rotation;         // Camera rotation in degrees
+    float zoom;             // Camera zoom (scaling), should be 1.0f by default
+} Camera2D;
+
 // Bounding box type
 typedef struct BoundingBox {
     Vector3 min;
@@ -528,7 +536,8 @@ int GetScreenHeight(void);                                  // Get current scree
 
 void ClearBackground(Color color);                          // Sets Background Color
 void BeginDrawing(void);                                    // Setup drawing canvas to start drawing
-void BeginDrawingEx(int blendMode, Shader shader, Matrix transform);   // Setup drawing canvas with extended parameters
+void BeginDrawingEx(Camera2D camera);                       // Setup drawing canvas with 2d camera
+void BeginDrawingPro(int blendMode, Shader shader, Matrix transform);   // Setup drawing canvas with pro parameters
 void EndDrawing(void);                                      // End canvas drawing and Swap Buffers (Double Buffering)
 
 void Begin3dMode(Camera camera);                            // Initializes 3D mode for drawing (Camera setup)