SSAO.cpp

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#include "SSAO.h"
 
#include <random>
#include <glad/glad.h>
 
#include "screen.vert.h"
#include "ssao.frag.h"
 
namespace dyno
{
    SSAO::SSAO()
    {
        mWidth = mHeight = 0;
 
        // shader programs
        mSSAOProgram = Program::createProgramSPIRV(
            SCREEN_VERT, sizeof(SCREEN_VERT),
            SSAO_FRAG, sizeof(SSAO_FRAG));
 
        // SSAO kernel
        mSSAOKernelUBO.create(GL_UNIFORM_BUFFER, GL_STATIC_DRAW);
        mSSAOKernelUBO.bindBufferBase(3);
 
        std::uniform_real_distribution<float> randomFloats(0.0, 1.0); // random floats between [0.0, 1.0]
        std::default_random_engine generator;
        std::vector<glm::vec3> ssaoKernel;
        for (unsigned int i = 0; i < 64; ++i)
        {
            glm::vec3 sample(
                randomFloats(generator) * 2.0 - 1.0,
                randomFloats(generator) * 2.0 - 1.0,
                randomFloats(generator)
            );
            sample = glm::normalize(sample);
            //sample *= randomFloats(generator);
            //ssaoKernel.push_back(sample);
            float scale = (float)i / 64.0;
            //scale = lerp(0.1f, 1.0f, scale * scale);
            scale = 0.1f + scale * scale * 0.9f;
            sample *= scale;
            ssaoKernel.push_back(sample);
        }
 
        mSSAOKernelUBO.load(ssaoKernel.data(), ssaoKernel.size() * sizeof(glm::vec3));
 
        // create SSAO noise here...
        std::vector<glm::vec3> ssaoNoise;
        for (unsigned int i = 0; i < 16; i++)
        {
            glm::vec3 noise(
                randomFloats(generator) * 2.0 - 1.0,
                randomFloats(generator) * 2.0 - 1.0,
                0.0f);
            ssaoNoise.push_back(noise);
        }
 
        mSSAONoiseTex.format = GL_RGB;
        mSSAONoiseTex.internalFormat = GL_RGB32F;
        mSSAONoiseTex.create();
        mSSAONoiseTex.load(4, 4, &ssaoNoise[0]);
    }
 
    SSAO::~SSAO()
    {
 
    }
 
    void SSAO::resize(unsigned int w, unsigned int h)
    {
        if (w == mWidth && h == mHeight)
            return;
 
        mWidth = w;
        mHeight = h;
    }
}