[CORE,RLGL] Fix scale issues when ending a mode (#3746)

* Only restore GL scale back to screen scale if we are returning to a screen, not a render texture.

* blankspace

* reset back to default screen scale when ending a render texture since we are back on the default fbo

Author: JeffM2501

src/rcore.c

@@ -952,9 +952,6 @@ void BeginMode2D(Camera2D camera)
 
     // Apply 2d camera transformation to modelview
     rlMultMatrixf(MatrixToFloat(GetCameraMatrix2D(camera)));
-
-    // Apply screen scaling if required
-    rlMultMatrixf(MatrixToFloat(CORE.Window.screenScale));
 }
 
 // Ends 2D mode with custom camera
@@ -963,7 +960,9 @@ void EndMode2D(void)
     rlDrawRenderBatchActive();      // Update and draw internal render batch
 
     rlLoadIdentity();               // Reset current matrix (modelview)
-    rlMultMatrixf(MatrixToFloat(CORE.Window.screenScale)); // Apply screen scaling if required
+
+    if (rlGetActiveFramebuffer() == 0)
+        rlMultMatrixf(MatrixToFloat(CORE.Window.screenScale)); // Apply screen scaling if required
 }
 
 // Initializes 3D mode with custom camera (3D)
@@ -1016,7 +1015,8 @@ void EndMode3D(void)
     rlMatrixMode(RL_MODELVIEW);     // Switch back to modelview matrix
     rlLoadIdentity();               // Reset current matrix (modelview)
 
-    rlMultMatrixf(MatrixToFloat(CORE.Window.screenScale)); // Apply screen scaling if required
+    if (rlGetActiveFramebuffer() == 0)
+        rlMultMatrixf(MatrixToFloat(CORE.Window.screenScale)); // Apply screen scaling if required
 
     rlDisableDepthTest();           // Disable DEPTH_TEST for 2D
 }
@@ -1062,6 +1062,11 @@ void EndTextureMode(void)
     // Set viewport to default framebuffer size
     SetupViewport(CORE.Window.render.width, CORE.Window.render.height);
 
+    // go back to the modelview state from BeginDrawing since we are back to the default FBO
+	rlMatrixMode(RL_MODELVIEW);     // Switch back to modelview matrix
+	rlLoadIdentity();               // Reset current matrix (modelview)
+    rlMultMatrixf(MatrixToFloat(CORE.Window.screenScale)); // Apply screen scaling if required
+
     // Reset current fbo to screen size
     CORE.Window.currentFbo.width = CORE.Window.render.width;
     CORE.Window.currentFbo.height = CORE.Window.render.height;

src/rlgl.h

@@ -621,6 +621,7 @@ RLAPI void rlDisableShader(void);                       // Disable shader progra
 // Framebuffer state
 RLAPI void rlEnableFramebuffer(unsigned int id);        // Enable render texture (fbo)
 RLAPI void rlDisableFramebuffer(void);                  // Disable render texture (fbo), return to default framebuffer
+RLAPI unsigned int rlGetActiveFramebuffer(void);        // Returns the active render texture (fbo), 0 for default framebuffer
 RLAPI void rlActiveDrawBuffers(int count);              // Activate multiple draw color buffers
 RLAPI void rlBlitFramebuffer(int srcX, int srcY, int srcWidth, int srcHeight, int dstX, int dstY, int dstWidth, int dstHeight, int bufferMask); // Blit active framebuffer to main framebuffer
 RLAPI void rlBindFramebuffer(unsigned int target, unsigned int framebuffer); // Bind framebuffer (FBO) 
@@ -1725,6 +1726,17 @@ void rlEnableFramebuffer(unsigned int id)
 #endif
 }
 
+// return the active render texture (fbo)
+unsigned int rlGetActiveFramebuffer(void)
+{
+#if (defined(GRAPHICS_API_OPENGL_33) || defined(GRAPHICS_API_OPENGL_ES3)) && defined(RLGL_RENDER_TEXTURES_HINT)
+    GLint fboId = 0;
+    glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &fboId);
+    return fboId;
+#endif
+    return 0;
+}
+
 // Disable rendering to texture
 void rlDisableFramebuffer(void)
 {