1 files changed, 49 insertions, 0 deletions

diff --git a/cwd/shaders/sky.fs b/cwd/shaders/sky.fs
new file mode 100644
index 0000000..549d463
--- /dev/null
+++ b/cwd/shaders/sky.fs
@@ -0,0 +1,49 @@
+#version 330 core
+
+in vec2 uvPos;
+in vec3 pos;
+
+uniform sampler2D textureAtlas;
+uniform vec4 skyTexture;
+uniform float DayTime;
+uniform vec4 sunTexture;
+uniform vec4 moonTexture;
+
+const vec4 DaySkyColor = vec4(0.49,0.66,1, 1);
+
+const vec3 SunPos = vec3(0,0.1,0.5);
+
+const vec3 MoonPos = vec3(0,0.1,-0.5);
+
+vec2 TransformTextureCoord(vec4 TextureAtlasCoords, vec2 UvCoords) {
+    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);
+    return A + UvCoords * (B - A);
+}
+
+vec4 Sun() {
+    vec3 sunDelta = (pos - SunPos)*3.0f;
+    float distanceToSun = length(sunDelta);
+    vec4 sunColor = texture(textureAtlas,TransformTextureCoord(sunTexture,(vec2(sunDelta.xy)+0.5f)));
+    vec4 sun = mix(vec4(0,0,0,1),sunColor,clamp(1-distanceToSun*2.0f,0,1));
+    return sun;
+}
+
+vec4 Moon() {
+    vec3 moonDelta = (pos - MoonPos)*4.5f;
+    float distanceToMoon = length(moonDelta);
+    vec4 moonColor = texture(textureAtlas,TransformTextureCoord(moonTexture,(vec2(moonDelta.xy)+0.5f)));
+    vec4 moon = mix(vec4(0,0,0,1),moonColor,clamp(1-distanceToMoon*2.0f,0,1));
+    return moon;
+}
+
+void main() {
+    vec4 starColor = texture(textureAtlas,TransformTextureCoord(skyTexture,uvPos));
+    gl_FragColor = mix(starColor, DaySkyColor, DayTime);
+    gl_FragColor += Sun();
+    gl_FragColor += Moon();
+}
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