Merge pull request #229 from lvlonggame/v3

add Camera::project

cocos/2d/CCCamera.cpp

@@ -245,9 +245,27 @@ bool Camera::initOrthographic(float zoomX, float zoomY, float nearPlane, float f
     return true;
 }
 
+void Camera::project(const Size& viewport, Vec3* src, Vec2* dst) const
+{
+    GP_ASSERT(src);
+    GP_ASSERT(dst);
+    
+    Vec4 clipPos;
+    getViewProjectionMatrix().transformVector(Vec4(src->x, src->y, src->z, 1.0f), &clipPos);
+    
+    GP_ASSERT(clipPos.w != 0.0f);
+    float ndcX = clipPos.x / clipPos.w;
+    float ndcY = clipPos.y / clipPos.w;
+    
+    dst->x = (ndcX + 1.0f) * 0.5f * viewport.width;
+    dst->y = (1.0f - (ndcY + 1.0f) * 0.5f) * viewport.height;
+}
+
 void Camera::unproject(const Size& viewport, Vec3* src, Vec3* dst) const
 {
-    assert(dst);
+    GP_ASSERT(src);
+    GP_ASSERT(dst);
+    
     Vec4 screen(src->x / viewport.width, ((viewport.height - src->y)) / viewport.height, src->z, 1.0f);
     screen.x = screen.x * 2.0f - 1.0f;
     screen.y = screen.y * 2.0f - 1.0f;

cocos/2d/CCCamera.h

@@ -132,8 +132,21 @@ public:
     const Mat4& getViewProjectionMatrix() const;
 
     /**
-    * Convert the specified point of viewport from screenspace coordinate into the worldspace coordinate.
-    */
+     * convert the specified point of viewport from world-space coordinates into the screen-space coordinates.
+     *
+     * @param viewport The viewport size to use.
+     * @param src The world-space position.
+     * @param dst The screen-space position.
+     */
+    void project(const Size& viewport, Vec3* src, Vec2* dst) const;
+    
+    /**
+     * Convert the specified point of viewport from screen-space coordinate into the world-space coordinate.
+     *
+     * @param viewport The viewport size to use.
+     * @param src The screen-space position.
+     * @param dst The world-space position.
+     */
     void unproject(const Size& viewport, Vec3* src, Vec3* dst) const;
     
     /**