1 files changed, 65 insertions, 0 deletions
diff --git a/cwd/assets/altcraft/shaders/frag/fwd_sky.fs b/cwd/assets/altcraft/shaders/frag/fwd_sky.fs
new file mode 100644
index 0000000..b6185fd
--- /dev/null
+++ b/cwd/assets/altcraft/shaders/frag/fwd_sky.fs
@@ -0,0 +1,65 @@
+#version 330 core
+
+in vec3 facePos;
+
+out vec4 fragColor;
+
+layout (std140) uniform Globals {
+    mat4 projView;
+    mat4 proj;
+    mat4 view;
+    uvec2 viewportSize;
+    vec4 ssaoKernels[64];
+    float globalTime;
+    float dayTime;
+    float gamma;
+};
+
+uniform sampler2DArray textureAtlas;
+uniform vec4 sunTexture;
+uniform float sunTextureLayer;
+uniform vec4 moonTexture;
+uniform float moonTextureLayer;
+
+const vec4 DaySkyColor = vec4(0.21, 0.4, 1, 1);
+
+const vec3 SunPos = vec3(0, 0.1, 0.5);
+
+const vec3 MoonPos = vec3(0, 0.1, -0.5);
+
+const vec4 NightSkyColor = vec4(0.0, 0.0008, 0.002, 1.0);
+
+vec3 TransformTextureCoord(vec4 TextureAtlasCoords, vec2 UvCoords, float Layer) {
+    float x = TextureAtlasCoords.x;
+    float y = TextureAtlasCoords.y;
+    float w = TextureAtlasCoords.z;
+    float h = TextureAtlasCoords.w;
+    vec2 A = vec2(x, 1 - y - h);
+    vec2 B = vec2(x + w, 1 - y);
+    vec2 transformed = A + UvCoords * (B - A);
+    return vec3(transformed.x, transformed.y, Layer);
+}
+
+vec4 Sun() {
+    vec3 sunDelta = (facePos - SunPos) * 3.0f;
+    float distanceToSun = length(sunDelta);
+    vec4 sunColor = texture(textureAtlas, TransformTextureCoord(sunTexture, (vec2(sunDelta.xy) + 0.5f), sunTextureLayer));
+    vec4 sun = mix(vec4(0, 0, 0, 1), sunColor, clamp(1 - distanceToSun * 2.0f, 0, 1));
+    return sun;
+}
+
+vec4 Moon() {
+    vec3 moonDelta = (facePos - MoonPos) * 4.5f;
+    float distanceToMoon = length(moonDelta);
+    vec4 moonColor = texture(textureAtlas, TransformTextureCoord(moonTexture, (vec2(moonDelta.xy) + 0.5f), moonTextureLayer));
+    vec4 moon = mix(vec4(0, 0, 0, 1),moonColor, clamp(1 - distanceToMoon * 2.0f, 0, 1));
+    return moon;
+}
+
+void main() {
+    fragColor = vec4(mix(NightSkyColor, DaySkyColor, dayTime).rgb, 1.0f);
+    fragColor += vec4(Sun().rgb, 1.0f);
+    fragColor += vec4(Moon().rgb, 1.0f);
+
+    fragColor.rgb = pow(fragColor.rgb, vec3(1.0f / gamma));
+}