From 9a5dddc311d890c30474d8ac28e6887ffd11688e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lu=C3=ADs=20Almeida?=
 <60551627+luis605@users.noreply.github.com>
Date: Sun, 4 Feb 2024 10:37:10 +0000
Subject: [PATCH] Added viewport independent raycast (#3709)

* added viewport independent raycast

* Renamed GetMouseRayEx to GetViewRay
---
 src/raylib.h |  1 +
 src/rcore.c  | 16 +++++++++++-----
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/raylib.h b/src/raylib.h
index 4c4b191c0..e2404a324 100644
--- a/src/raylib.h
+++ b/src/raylib.h
@@ -1050,6 +1050,7 @@ RLAPI void UnloadShader(Shader shader);                                    // Un
 
 // Screen-space-related functions
 RLAPI Ray GetMouseRay(Vector2 mousePosition, Camera camera);      // Get a ray trace from mouse position
+RLAPI Ray GetViewRay(Vector2 mousePosition, Camera camera, float width, float height);      // Get a ray trace from mouse position in a viewport
 RLAPI Matrix GetCameraMatrix(Camera camera);                      // Get camera transform matrix (view matrix)
 RLAPI Matrix GetCameraMatrix2D(Camera2D camera);                  // Get camera 2d transform matrix
 RLAPI Vector2 GetWorldToScreen(Vector3 position, Camera camera);  // Get the screen space position for a 3d world space position
diff --git a/src/rcore.c b/src/rcore.c
index 784b9b621..48c863f56 100644
--- a/src/rcore.c
+++ b/src/rcore.c
@@ -1404,14 +1404,20 @@ void SetShaderValueTexture(Shader shader, int locIndex, Texture2D texture)
 //----------------------------------------------------------------------------------
 
 // Get a ray trace from mouse position
-Ray GetMouseRay(Vector2 mouse, Camera camera)
+Ray GetMouseRay(Vector2 mousePosition, Camera camera)
+{
+    return GetViewRay(mousePosition, camera, GetScreenWidth(), GetScreenHeight());
+}
+
+// Get a ray trace from the mouse position within a specific section of the screen
+Ray GetViewRay(Vector2 mousePosition, Camera camera, float width, float height)
 {
     Ray ray = { 0 };
 
     // Calculate normalized device coordinates
     // NOTE: y value is negative
-    float x = (2.0f*mouse.x)/(float)GetScreenWidth() - 1.0f;
-    float y = 1.0f - (2.0f*mouse.y)/(float)GetScreenHeight();
+    float x = (2.0f*mousePosition.x)/width - 1.0f;
+    float y = 1.0f - (2.0f*mousePosition.y)/height;
     float z = 1.0f;
 
     // Store values in a vector
@@ -1425,11 +1431,11 @@ Ray GetMouseRay(Vector2 mouse, Camera camera)
     if (camera.projection == CAMERA_PERSPECTIVE)
     {
         // Calculate projection matrix from perspective
-        matProj = MatrixPerspective(camera.fovy*DEG2RAD, ((double)GetScreenWidth()/(double)GetScreenHeight()), RL_CULL_DISTANCE_NEAR, RL_CULL_DISTANCE_FAR);
+        matProj = MatrixPerspective(camera.fovy*DEG2RAD, ((double)width/(double)height), RL_CULL_DISTANCE_NEAR, RL_CULL_DISTANCE_FAR);
     }
     else if (camera.projection == CAMERA_ORTHOGRAPHIC)
     {
-        double aspect = (double)CORE.Window.screen.width/(double)CORE.Window.screen.height;
+        double aspect = (double)width/(double)height;
         double top = camera.fovy/2.0;
         double right = top*aspect;