In November 1975, Ryszard Kapuściński telexed his editor in Warsaw to plead for permission to return home from Angola. The era of Portuguese colonialism was ending, the fight for independence that would become one of the many proxy battlefields of the cold war was intensifying and, after three months spent on dangerous roads and in a capital city growing more paranoid and hallucinatory by the day, the Polish Press Agency reporter was spent.

“My money ran out and I am barely alive,” he wrote. “It is more or less clear what will happen, which is that the Angolans will win, but it is going to take a while and I am on my last legs.”

Kapuściński, long acknowledged as one of the greatest journalists of the 20th century for his literary evocations of wars and revolutions in Africa and Latin America, was right on both counts.

He was haunted by what he had seen, what he had done – and what he had failed to do – while the nascent conflict he had chronicled would stagger on until 2002.

The experience provided him with the raw material for Another Day of Life, his deeply personal book “about being alone and lost” in the chaos and confusion of Angola.

Eleven years after Kapuściński’s death, the book has been adapted into an award-winning film that mixes animation and documentary to retell and update the story.

The idea came to the film’s co-director, Raúl de la Fuente, and his producer and partner, Amaia Remírez, when they were on holiday on Menorca 10 years ago. The Spaniards had loved Kapuściński since they were teenagers, and saw Another Day of Life as both a geopolitical parable and a portrait of a journalist enduring a dark night of the soul.

Ryszard Kapuściński and soldiers in Angola in 1975. Photograph: PAP/CAF/EPA

One of the main challenges they faced was how to evoke the sense of confusão “a state of absolute disorientation” – that permeates the book. The answer lay in Kapuściński’s two-notebook habit: one for straightforward, factual reporting; one for impressionistic observations and reflections.

While De la Fuente and Remírez travelled to Angola to shoot documentary footage and track down the book’s surviving protagonists, the Polish animator Damian Nenow took on the task of translating Kapuściński’s brutal poetry for the screen. “His descriptions of the world and how it changes are pure animation – they just cry out for animation,” says Nenow.

The journalist’s thoughts, fears and recollections are rendered in surreal sequences of disintegrating cities, bodies and even a fragmenting telex machine. In one of the film’s most stunning scenes, Kapuściński and an Angolan journalist, Artur, come across a long stretch of road littered with the corpses of civilians, and imagine them being slaughtered by a cloud of weapons that roils a red sky.

“We never debated whether it was right or wrong because it somehow felt natural in the context of Kapuściński’s writing,” says Nenow. “This guy wasn’t following facts per se; he was always showing the world through the prism of the emotions of the people he met. He was always adding a lot of allegorical magic and poetry to it.”

Accusations of “not following the facts per se” – or of simply inventing episodes – were levelled against Kapuściński in a biography published eight years ago, which claimed he had crossed the line between reportage and fiction.

Nenow acknowledges the controversy, but says Kapuściński remains an iconic figure in Poland, where, he says, people have long been aware of his approach. “Kapuściński’s books are obligatory in school; you have to read them when you’re a teenager. So it’s not a surprise for any Polish person – it’s not rocket science – that he was not strictly following facts.”

Another Day of Life ends with the journalist speculating as to the fates of some of those he met in the confusão of 1975: Artur, the bright young guerrilla Carlotta, and the Che Guevara-like figure of Comandante Farrusco, a Portuguese special forces soldier who swapped sides to fight for liberation.

Kapuściński and Carlotta in the animated sequences. Photograph: KANAKI FILMS

It was that epilogue that gave De la Fuente his way into the film, which is released in Spain this month and is due to reach British cinemas next year. “I had the chance to go back to Angola with my camera and look for them, and say, ‘Look Ryszard, here’s Artur’, who feels like the biggest loser in the war because the society he wanted never materialised, ‘here’s Farrusco’, who’s still a soldier, ‘here’s Carlotta’s sister’. I felt I had to fulfil a commitment to him and I wanted to answer his questions.”

Not long before he died in 2007, Kapuściński and Farrusco managed to speak by phone with the help of the Polish ambassador in Angola. The former commando, who still addresses people as “comrade”, is now 70 and his bones have begun to ache as he tends his garden.

Time, however, has done nothing to diminish his affection and admiration for the middle-aged Pole who materialised at his redoubt almost half a century ago, an unexpected emissary from a habitually indifferent world.

“Kapuściński was a born writer and he’s someone who’ll never be forgotten in Angola,” says Farrusco. “He knew what injustice was. He wasn’t just a journalist. Journalists sometimes do in-depth reporting from war zones but Kapuściński was a man of principle. I don’t have the words to describe exactly what his presence and personality meant.”