81 lines
2.8 KiB
Text
81 lines
2.8 KiB
Text
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shader_type canvas_item;
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// Noise texture.
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uniform sampler3D noise: repeat_enable;
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// Planet.
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uniform float size = 100.; // Size in pixels, not including atmosphere.
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uniform float rotationSpeed = 0.05;
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uniform sampler2D albedo; // Left side = water color (deep to shallow), right size = terrain color (low to high).
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// Atmosphere.
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uniform vec4 atmosphereColor: source_color = vec4(0., .3, 1., .3);
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uniform float atmosphereSize = .3; // Range: [0, 1]
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// Weather.
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uniform float cloudsSize = 0.05;
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uniform float cloudsDensity = 0.22;
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uniform float cloudsTurbulence = 0.01;
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uniform float windSpeed = 0.03;
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// Zoom level assuming a planet of normalized size.
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varying float zoom;
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void vertex() {
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zoom = 4. / (size * CANVAS_MATRIX[0][0]);
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}
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vec4 blend(vec4 bg, vec4 fg) {
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float alpha = fg.a + bg.a * (1. - fg.a);
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vec3 color = (fg.rgb * fg.a + bg.rgb * bg.a * (1. - fg.a)) / alpha;
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return vec4(color, alpha);
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}
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vec4 drawPlanet(float r, vec3 p) {
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float angle = TIME * rotationSpeed;
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//mat3 rotX = mat3(vec3(1., 0., 0.), vec3(0., cos(angle), -sin(angle)), vec3(0., sin(angle), cos(angle)));
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mat3 rotY = mat3(vec3(cos(angle), 0., -sin(angle)), vec3(0., 1., 0.), vec3(sin(angle), 0., cos(angle)));
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//mat3 rotZ = mat3(vec3(cos(angle), -sin(angle), 0.), vec3(sin(angle), cos(angle), 0.), vec3(0., 0., 1.));
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float height = texture(noise, p * 0.3 * rotY).r;
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float rand = texture(noise, p * 0.3 * rotY + vec3(0.1, 0.2, 0.3)).r * .5 + .5;
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//float rand = texture(noise, p + vec3(n + TIME * 0.02)).r;
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vec3 color = texture(albedo, vec2(height, ((p.y + rand * sign(p.y)) * .5 + 1.) * .5)).rgb;
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vec3 lit = max(vec3(0.), color * dot(p, vec3(0., 0., 1.)));
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return vec4(lit, smoothstep(0., zoom, r));
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}
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vec4 drawClouds(float r, vec3 p) {
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float angle = TIME * 0.08;
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mat3 rotY = mat3(vec3(cos(angle), 0., -sin(angle)), vec3(0., 1., 0.), vec3(sin(angle), 0., cos(angle)));
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float angle2 = TIME * (rotationSpeed - windSpeed);
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mat3 rotY2 = mat3(vec3(cos(angle2), 0., -sin(angle2)), vec3(0., 1., 0.), vec3(sin(angle2), 0., cos(angle2)));
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float rand = texture(noise, p * 0.5 * rotY2 + vec3(0., 0., TIME * cloudsTurbulence)).r * .5 + .5;
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float rand2 = texture(noise, p * 0.8 * rotY2 + vec3(0., 0., rand)).r * .5 + .5;
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return vec4(vec3(1.), smoothstep(1. - cloudsDensity - cloudsSize, 1. - cloudsSize, rand2) * smoothstep(0., .3, r * 3.));
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}
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vec4 drawAtmosphere(float r) {
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return vec4(atmosphereColor.rgb, smoothstep(1.-atmosphereSize, 1., r + 1.) * atmosphereColor.a);
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}
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void fragment() {
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float r = length(UV - .25) * -8. + 1.;
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vec2 xy = UV * 8. - 2.;
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float z = sqrt(1. - xy.x*xy.x - xy.y*xy.y);
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vec3 p = vec3(xy, z);
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vec4 atmosphere = drawAtmosphere(r);
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vec4 planet = drawPlanet(r, p);
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vec4 clouds = drawClouds(r, p);
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COLOR = blend(blend(atmosphere, planet), clouds);
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// DEBUG
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//COLOR = vec4(p, smoothstep(0., zoom, r));
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}
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