52 lines
1.6 KiB
GLSL
52 lines
1.6 KiB
GLSL
#include paint_header
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// BEGIN_PATTERN
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float brush_function(vec2 uv) {
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return clamp(max(0.0, 1.0-length(2.0*(uv-vec2(0.5)))) / (0.5), 0.0, 1.0);
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}
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uniform sampler2D brush_texture : hint_white;
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vec4 pattern_function(vec2 uv) {
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return texture(brush_texture, uv);
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}
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// END_PATTERN
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float brush(vec2 uv) {
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return clamp(brush_opacity*brush_function(uv)/(1.0-brush_hardness), 0.0, 1.0);
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}
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void fragment() {
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// Get UV from seams texture
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vec2 seams_value = texture(seams, UV).xy-vec2(0.5);
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vec2 uv = fract(UV+seams_value*seams_multiplier/texture_size);
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// Get View position
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vec4 tex2view = texture(tex2view_tex, uv);
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vec2 xy = tex2view.xy;
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// Get distance to brush center
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vec2 b = brush_pos/brush_size;
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vec2 bv = (brush_ppos-brush_pos)/brush_size;
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vec2 p = xy/brush_size;
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float x = clamp(dot(p-b, bv)/dot(bv, bv), 0.0, 1.0);
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// Get position in brush
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vec2 local_uv = p-(b+x*bv);
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mat2 texture_rotation = mat2(vec2(cos(pattern_angle), sin(pattern_angle)), vec2(-sin(pattern_angle), cos(pattern_angle)));
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local_uv = texture_rotation*local_uv;
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vec2 local_uv2 = p-b-bv;
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local_uv2 = texture_rotation*local_uv2;
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vec2 stamp_limit = step(abs(local_uv), vec2(1.0));
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vec4 color = pattern_function(0.5*local_uv2+vec2(0.5));
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float a = fill ? 1.0 : stamp_limit.x*stamp_limit.y*brush(0.5*local_uv+vec2(0.5))*color.a*tex2view.z;
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vec4 screen_color = texture(SCREEN_TEXTURE, UV);
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if (erase) {
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COLOR = vec4(screen_color.xyz, max(screen_color.a-a, 0.0));
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} else if (reset) {
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COLOR = vec4(color.xyz, a);
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} else {
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float alpha_sum = min(1.0, a + screen_color.a);
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COLOR = vec4((color.xyz*a+screen_color.xyz*(vec3(alpha_sum)-a))/alpha_sum, alpha_sum);
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}
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}
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