From 3f122e57f118db1229a4bad2c54be624f2f8f19c Mon Sep 17 00:00:00 2001
From: LaG1924 <lag1924@gmail.com>
Date: Sun, 5 Dec 2021 00:51:39 +0500
Subject: Added SSAO

---
 cwd/assets/altcraft/shaders/frag/ssao.fs | 55 ++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 cwd/assets/altcraft/shaders/frag/ssao.fs

(limited to 'cwd/assets/altcraft/shaders/frag/ssao.fs')

diff --git a/cwd/assets/altcraft/shaders/frag/ssao.fs b/cwd/assets/altcraft/shaders/frag/ssao.fs
new file mode 100644
index 0000000..f4fea34
--- /dev/null
+++ b/cwd/assets/altcraft/shaders/frag/ssao.fs
@@ -0,0 +1,55 @@
+#version 330 core
+
+out vec4 fragColor;
+
+in vec2 uv;
+
+uniform sampler2D normal;
+uniform sampler2D worldPos;
+uniform sampler2D ssaoNoise;
+
+layout (std140) uniform Globals {
+    mat4 projView;
+    mat4 proj;
+    mat4 view;
+    uvec2 viewportSize;
+    vec4 ssaoKernels[64];
+    float globalTime;
+    float dayTime;
+    float gamma;
+};
+
+const vec2 noiseScale = vec2(4.0f, 4.0f);
+const int kernelSize = 64;
+const float radius = 0.5f;
+const float bias = 0.025f;
+
+void main() {
+    vec3 normal = texture(normal, uv).xyz;
+    vec3 fragPos = texture(worldPos, uv).xyz;
+    vec2 noiseUv = uv * viewportSize / noiseScale;
+
+    vec3 randomVec = texture(ssaoNoise, noiseUv).xyz;
+
+    vec3 tangent = normalize(randomVec - normal * dot(randomVec, normal));
+    vec3 bitangent = cross(normal, tangent);
+    mat3 TBN = mat3(tangent, bitangent, normal);  
+
+    float occlusion = 0.0;
+    for(int i = 0; i < kernelSize; i++)
+    {
+        vec3 samplePos = TBN * ssaoKernels[i].xyz;
+        samplePos = fragPos + samplePos * radius; 
+
+        vec4 offset = vec4(samplePos, 1.0);
+        offset = proj * offset;
+        offset.xyz /= offset.w;
+        offset.xyz  = offset.xyz * 0.5 + 0.5;
+
+        float sampleDepth = texture(worldPos, offset.xy).z;
+        float rangeCheck = smoothstep(0.0, 1.0, radius / abs(fragPos.z - sampleDepth));
+        occlusion += (sampleDepth >= samplePos.z + bias ? 1.0 : 0.0) * rangeCheck;
+    }
+
+    fragColor = vec4(vec3(occlusion / kernelSize), 1.0f);
+}
-- 
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