FilmicGrain.cpp

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#include <glad/glad.h>
#include <GLFW/glfw3.h>
 
#include "galaxy/core/Config.hpp"
#include "galaxy/core/ServiceLocator.hpp"
 
#include "FilmicGrain.hpp"
 
constexpr const char* const filmicgrain_vert = R"(
    #version 460 core
    layout (location = 0) in vec2 l_pos;
    layout (location = 1) in vec2 l_texels;
 
    void main()
    {
        gl_Position = vec4(l_pos, 0.0, 1.0);
    }
)";
 
constexpr const char* const filmicgrain_frag = R"(
    #version 460 core
    #define PI 3.1415926535897932384626433832795
    
    out vec4 io_frag_colour;
    
    uniform float u_amount;
    uniform float u_time;
    uniform sampler2D u_texture;
    
    void main()
    {
        vec2 tex_size = textureSize(u_texture, 0).xy;
        vec2 tex_coord = gl_FragCoord.xy / tex_size;
 
        vec4 colour = texture(u_texture, tex_coord);
 
        float intensity = fract(10000 * sin((gl_FragCoord.x + gl_FragCoord.y * u_time) * PI));
 
        colour.rgb += (u_amount * intensity);
        
        io_frag_colour = colour;
    }
)";
 
namespace galaxy
{
    namespace graphics
    {
        FilmicGrain::FilmicGrain(const int width, const int height)
            : m_amount {0.01}
        {
            m_fb.create(width, height);
 
            if (m_shader.parse(filmicgrain_vert, filmicgrain_frag))
            {
                m_shader.compile();
            }
 
            m_shader.set_uniform("u_texture", 0);
            m_shader.set_uniform("u_amount", m_amount);
            m_shader.set_uniform("u_time", static_cast<float>(glfwGetTime()));
        }
 
        void FilmicGrain::resize(const int width, const int height)
        {
            m_fb.recreate(width, height);
        }
 
        unsigned int FilmicGrain::render(const unsigned int input)
        {
            m_fb.bind(true);
            m_shader.bind();
 
            m_shader.set_uniform("u_time", static_cast<float>(glfwGetTime()));
 
            glActiveTexture(GL_TEXTURE0);
            glBindTexture(GL_TEXTURE_2D, input);
            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 
            return m_fb.texture();
        }
 
        void FilmicGrain::set_amount(const float amount)
        {
            m_amount = amount;
            m_shader.set_uniform("u_amount", m_amount);
        }
 
        bool FilmicGrain::is_enabled()
        {
            return core::ServiceLocator<core::Config>::ref().get<bool>("film_grain", "graphics.effects");
        }
    } // namespace graphics
} // namespace galaxy