Fix #117771: Incorrect Cycles texture position on emissive triangles

Pull Request: https://projects.blender.org/blender/blender/pulls/117801

intern/cycles/kernel/light/triangle.h

@@ -237,7 +237,7 @@ ccl_device_forceinline bool triangle_light_sample(KernelGlobals kg,
     }
 
     const float t = 1.0f - u - v;
-    ls->P = u * V[0] + v * V[1] + t * V[2];
+    ls->P = t * V[0] + u * V[1] + v * V[2];
     /* compute incoming direction, distance and pdf */
     ls->D = normalize_len(ls->P - P, &ls->t);
     ls->pdf = triangle_light_pdf_area_sampling(ls->Ng, -ls->D, ls->t) / area;