move shaders into .glsl files and add #include feature

data/shaders/stroke.glsl

@@ -0,0 +1,93 @@
+[[vertex]]
+uniform mat4 mvp;
+in vec4 pos;
+in vec2 uvs;
+in vec2 uvs2;
+out vec2 uv;
+out vec2 uv_2;
+out float q;
+void main()
+{
+   uv = uvs;
+   uv_2 = uvs2;
+   q = pos.w;
+   gl_Position = mvp * vec4(pos.xy, 0.0, 1.0);
+};
+
+[[fragment]]
+#include "include/ext-fb-fetch.glsl"
+#include "include/rand.glsl"
+#include "include/color.glsl"
+
+uniform mediump sampler2D tex;
+uniform mediump sampler2D tex_bg;
+uniform mediump sampler2D tex_mix;
+uniform mediump vec4 col;
+uniform mediump vec2 resolution;
+uniform mediump float alpha;
+uniform mediump float noise;
+uniform mediump float mix_alpha;
+uniform mediump float wet;
+
+uniform bool use_pattern;
+uniform mediump sampler2D tex_pattern;
+uniform mediump vec2 pattern_scale;
+uniform mediump float pattern_bright;
+uniform mediump float pattern_contr;
+uniform mediump float pattern_depth;
+uniform mediump vec2 pattern_offset;
+uniform mediump bool pattern_invert;
+
+in mediump vec2 uv;
+in mediump vec2 uv_2;
+in mediump float q;
+#if defined(GL_EXT_shader_framebuffer_fetch)
+   inout mediump vec4 frag;
+#else
+   out mediump vec4 frag;
+#endif
+
+void main()
+{
+   mediump vec2 uv2 = gl_FragCoord.st / resolution;
+   mediump float brush_alpha = ( 1.0 - texture(tex, uv/q).r ) * alpha;
+   mediump vec4 fg = vec4(col.rgb, brush_alpha);
+   if (use_pattern)
+   {
+       mediump vec2 rscale = resolution / vec2(512.0);
+       mediump float patt = texture(tex_pattern, uv2 * (0.5 / pattern_scale) * rscale + pattern_offset).r;
+       if (pattern_invert)
+           patt = 1.0 - patt;
+       patt = patt * pattern_depth + (1.0 - pattern_depth);
+       if (pattern_bright != 0.5)
+           patt = brightness1(patt, 1.0 - pattern_bright);
+       if (pattern_contr != 0.5)
+           patt = contrast1(patt, pattern_contr);
+       fg.a = mix(fg.a, fg.a * patt, pattern_depth);
+   }
+
+#if defined(GL_EXT_shader_framebuffer_fetch)
+   mediump vec4 bg = frag;
+#elif defined(GL_ARM_shader_framebuffer_fetch)
+   mediump vec4 bg = gl_LastFragColorARM;
+#else
+   mediump vec4 bg = texture(tex_bg, uv2);
+#endif
+
+   fg.a *= 1.0-rand(uv2+uv)*noise;
+   if (fg.a == 0.0) discard;
+   if (mix_alpha > 0.0)
+   {
+       mediump vec2 uv_mix = uv_2 / q;
+       if (uv_mix.x < 0.0 || uv_mix.x > 1.0 || uv_mix.y < 0.0 || uv_mix.y > 1.0) discard;
+       mediump vec4 mbg = texture(tex_mix, uv_mix);
+       fg.rgb = mix(fg.rgb, mbg.rgb, mix_alpha * mbg.a);
+   }
+   mediump float contribution = (1.0 - bg.a) * fg.a;
+   mediump float alpha_tot = bg.a + contribution;
+   mediump vec3 rgb = mix(bg.rgb, fg.rgb, fg.a / alpha_tot);
+   mediump vec4 frag_wet = vec4(rgb, max(bg.a, fg.a * 1.2));
+   mediump vec4 frag_dry = vec4(rgb, alpha_tot);
+   frag = mix(frag_dry, frag_wet, wet);
+};
+