gistfile1.cpp

#pragma mark -
#pragma mark Default shader
/***
 *      ____  _               _           
 *     / ___|| |__   __ _  __| | ___ _ __ 
 *     \___ \| '_ \ / _` |/ _` |/ _ \ '__|
 *      ___) | | | | (_| | (_| |  __/ |   
 *     |____/|_| |_|\__,_|\__,_|\___|_|
 *                                        
 */

const char* Game::vs_default = glsl(120,
    attribute vec4 a_coord;

    varying vec2 v_uv;
    
    void main() {
        v_uv = a_coord.zw;
        gl_Position = vec4(a_coord.x, a_coord.y, 0., 1.);
    }
);

const char* Game::fs_default = glsl(120,
    uniform sampler2D u_texture;
    
    varying vec2 v_uv;
    
    void main() {
        gl_FragColor = texture2D(u_texture, v_uv);
    }
);

#pragma mark SSAO Shader
const char* Game::vs_ssao = glsl(120,
    attribute vec4 a_coord;
    
    varying vec2 v_uv;
    
    void main() {
        v_uv = a_coord.zw;
        gl_Position = vec4(a_coord.x, a_coord.y, 0., 1.);
    }
);

const char* Game::fs_ssao = glsl(120,
    uniform sampler2D u_diffuse;
    uniform sampler2D u_normal;
    uniform sampler2D u_depth;
    uniform mat4 inv_mat;
    
    uniform float total_strength = .5;
    uniform float falloff = 0.005;
    uniform float radius = 0.2;
    uniform float base = 0.;
    uniform float area = 0.0000075;
    
    varying vec2 v_uv;
    
    const vec3 rvalues[16] = vec3[](
        vec3(0.53812504, 0.18565957, -0.43192),
        vec3(0.13790712, 0.24864247, 0.44301823),
        vec3(0.33715037, 0.56794053, -0.005789503),
        vec3(-0.6999805, -0.04511441, -0.0019965635),
        vec3(0.06896307, -0.15983082, -0.85477847),
        vec3(0.056099437, 0.006954967, -0.1843352),
        vec3(-0.014653638, 0.14027752, 0.0762037),
        vec3(0.010019933, -0.1924225, -0.034443386),
        vec3(-0.35775623, -0.5301969, -0.43581226),
        vec3(-0.3169221, 0.106360726, 0.015860917),
        vec3(0.010350345, -0.58698344, 0.0046293875),
        vec3(-0.08972908, -0.49408212, 0.3287904),
        vec3(0.7119986, -0.0154690035, -0.09183723),
        vec3(-0.053382345, 0.059675813, -0.5411899),
        vec3(0.035267662, -0.063188605, 0.54602677),
        vec3(-0.47761092, 0.2847911, -0.0271716)
    );
    const int SAMPLES = 10;
    
    float linear(sampler2D sampler, vec2 uv) {
        float n = 1.0;
        float f = 1000.0;
        float z = texture2D(sampler, uv).x;
        return (2.0 * n) / (f + n - z * (f - n));
    }
    
    float rand(vec2 co){
        return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
    }
    
    void main() {
        vec4 diffuse = texture2D(u_diffuse, v_uv);
        vec4 normal = texture2D(u_normal, v_uv);
        float depth = linear(u_depth, v_uv);
        
        vec3 rand = vec3(rand(v_uv), rand(1. - v_uv), rand(.5 * v_uv)) * .6;
        
        vec3 pos = vec3(v_uv.xy, depth);
        vec3 norm = normal.xyz;
        
        float occlusion = 0.;
        float radius_depth = radius / depth;
        
        for (int i = 0; i < SAMPLES; i++) {
            vec3 ray = radius_depth * reflect(rvalues[i], rand);
            vec3 hemi_ray = pos + sign(dot(ray, norm)) * ray;
    
            float occluder_depth = linear(u_depth, clamp(hemi_ray.xy, 0., 1.));
            float difference = depth - occluder_depth;
    
            occlusion += step(falloff, difference) * (1. - smoothstep(falloff, area, difference));
        }
        float ao = 1. - total_strength * occlusion * (1. / SAMPLES);
        gl_FragColor = vec4(vec3(clamp(ao, 0., 1.)), 1.) * diffuse;
    }
);
#pragma mark -