63 lines
1.6 KiB
Text
63 lines
1.6 KiB
Text
shader_type canvas_item;
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#include "res://addons/zylann.hterrain/shaders/include/heightmap_rgb8_encoding.gdshaderinc"
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uniform sampler2D u_src_texture;
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uniform vec4 u_src_rect;
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uniform float u_opacity = 1.0;
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uniform vec4 u_color = vec4(1.0);
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vec2 get_src_uv(vec2 screen_uv) {
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vec2 uv = u_src_rect.xy + screen_uv * u_src_rect.zw;
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return uv;
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}
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// float get_noise(vec2 pos) {
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// return fract(sin(dot(pos.xy ,vec2(12.9898,78.233))) * 43758.5453);
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// }
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float get_height(sampler2D heightmap, vec2 uv) {
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return decode_height_from_rgb8_unorm(texture(heightmap, uv).rgb);
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}
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float erode(sampler2D heightmap, vec2 uv, vec2 pixel_size, float weight) {
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float r = 3.0;
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// Divide so the shader stays neighbor dependent 1 pixel across.
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// For this to work, filtering must be enabled.
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vec2 eps = pixel_size / (0.99 * r);
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float h = get_height(heightmap, uv);
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float eh = h;
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//float dh = h;
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// Morphology with circular structuring element
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for (float y = -r; y <= r; ++y) {
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for (float x = -r; x <= r; ++x) {
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vec2 p = vec2(x, y);
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float nh = get_height(heightmap, uv + p * eps);
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float s = max(length(p) - r, 0);
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eh = min(eh, nh + s);
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//s = min(r - length(p), 0);
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//dh = max(dh, nh + s);
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}
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}
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eh = mix(h, eh, weight);
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//dh = mix(h, dh, u_weight);
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float ph = eh;//mix(eh, dh, u_dilation);
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return ph;
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}
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void fragment() {
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float brush_value = u_opacity * texture(TEXTURE, UV).r;
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vec2 src_pixel_size = 1.0 / vec2(textureSize(u_src_texture, 0));
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float ph = erode(u_src_texture, get_src_uv(SCREEN_UV), src_pixel_size, brush_value);
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//ph += brush_value * 0.35;
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COLOR = vec4(encode_height_to_rgb8_unorm(ph), 1.0);
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}
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