Improve directional shadow filtering by using linear interpolation

drivers/gles3/rasterizer_scene_gles3.cpp

@@ -4515,8 +4515,8 @@ void RasterizerSceneGLES3::initialize() {
 		glGenTextures(1, &directional_shadow.depth);
 		glBindTexture(GL_TEXTURE_2D, directional_shadow.depth);
 		glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT24, directional_shadow.size, directional_shadow.size, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_INT, NULL);
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);