stk-code_catmod/data/shaders/ssao.frag
2014-04-22 18:22:39 +02:00

71 lines
2.3 KiB
GLSL

uniform sampler2D ntex;
uniform sampler2D dtex;
uniform sampler2D noise_texture;
uniform mat4 invprojm;
uniform mat4 projm;
uniform vec4 samplePoints[16];
#if __VERSION__ >= 130
in vec2 uv;
out float AO;
#else
varying vec2 uv;
#define AO gl_FragColor.x
#endif
const float strengh = 5.;
const float radius = 1.f;
#define SAMPLES 16
const float invSamples = strengh / SAMPLES;
vec3 rand(vec2 co)
{
float noiseX = clamp(fract(sin(dot(co ,vec2(12.9898,78.233))) * 43758.5453),0.0,1.0)*2.0-1.0;
float noiseY = clamp(fract(sin(dot(co ,vec2(12.9898,78.233)*2.0)) * 43758.5453),0.0,1.0)*2.0-1.0;
return vec3(noiseX, noiseY, length(texture(noise_texture, co * pow(3.14159265359, 2.)).xyz));
}
vec3 DecodeNormal(vec2 n);
void main(void)
{
vec4 cur = texture(ntex, uv);
float curdepth = texture(dtex, uv).x;
vec4 FragPos = invprojm * (2.0f * vec4(uv, curdepth, 1.0f) - 1.0f);
FragPos /= FragPos.w;
// get the normal of current fragment
vec3 norm = normalize(DecodeNormal(2. * texture(ntex, uv).xy - 1.));
// Workaround for nvidia and skyboxes
float len = dot(vec3(1.0), abs(cur.xyz));
if (len < 0.2 || curdepth > 0.9955) discard;
// Make a tangent as random as possible
vec3 randvect = rand(uv);
vec3 tangent = normalize(cross(norm, randvect));
vec3 bitangent = cross(norm, tangent);
float bl = 0.0;
for(int i = 0; i < SAMPLES; ++i) {
vec3 sampleDir = samplePoints[i].x * tangent + samplePoints[i].y * bitangent + samplePoints[i].z * norm;
sampleDir *= samplePoints[i].w;
vec4 samplePos = FragPos + radius * vec4(sampleDir, 0.0);
vec4 sampleProj = projm * samplePos;
sampleProj /= sampleProj.w;
bool isInsideTexture = (sampleProj.x > -1.) && (sampleProj.x < 1.) && (sampleProj.y > -1.) && (sampleProj.y < 1.);
// get the depth of the occluder fragment
float occluderFragmentDepth = texture(dtex, (sampleProj.xy * 0.5) + 0.5).x;
// Position of the occluder fragment in worldSpace
vec4 occluderPos = invprojm * vec4(sampleProj.xy, 2.0 * occluderFragmentDepth - 1.0, 1.0f);
occluderPos /= occluderPos.w;
bool isOccluded = isInsideTexture && (sampleProj.z > (2. * occluderFragmentDepth - 1.0)) && (distance(FragPos, occluderPos) < radius);
bl += isOccluded ? samplePoints[i].z * smoothstep(5 * radius, 0, distance(samplePos, FragPos)) : 0.;
}
AO = max(1.0 - bl * invSamples, 0.);
}