samplesGGX.cpp

#include <getopt.h>
#include <cstdio>
#include <cstdlib>
#include <iostream>

#include "Cubemap"

typedef unsigned int uint;
typedef unsigned char ubyte;

static int usage(const std::string& name) {
    std::cerr << "Usage: " << name << " outpufile nbsamples mip0Size nbSteps"
              << std::endl;
    std::cerr << "generate ggx samples by steps excluding level 0" << std::endl;
    return 1;
}

int main(int argc, char* argv[]) {
    uint mip0Size = 0;
    uint nbSteps = 0;
    uint samples = 4096;

    if (argc < 5) return usage(argv[0]);

    std::string output = std::string(argv[1]);
    samples = atoi(argv[2]);
    mip0Size = atoi(argv[3]);
    nbSteps = atoi(argv[4]) + 1;

    float step = 1.0 / (nbSteps - 1.0);

    FILE* file = fopen(output.c_str(), "wb");
    std::cout << "compute " << nbSteps << " levels sample GGX from roughness  "
              << step << " to 1.0" << std::endl;
    for (uint i = 1; i < nbSteps; i++) {
        float r = step * i;
        float roughnessLinear = r * r;
        std::cout << "precompute ggx for roughness " << roughnessLinear
                  << std::endl;
        precomputedLightInLocalSpace(samples, roughnessLinear, mip0Size);

        ubyte* buffer = (ubyte*)getPrecomputedLightCache();
        fwrite(buffer, samples * 4 * 4, 1, file);
    }

    return 0;
}