texture_filters: update ScaleForce (#5270)
* texture_filters: update ScaleForce * texture_filters: optimize scale_force * texture_filters/scale_force: optimize final offset calculation
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Marshall Mohror
GitHub
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1 changed files with 69 additions and 44 deletions
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@ -1,7 +1,6 @@
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//? #version 320 es
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// from https://github.com/BreadFish64/ScaleFish/tree/master/scale_force
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// shader adapted to GLSL 320 es and debugging outputs stripped
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// MIT License
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//
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@ -27,15 +26,18 @@
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precision mediump float;
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in highp vec2 tex_coord;
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in vec2 tex_coord;
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out mediump vec4 frag_color;
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out vec4 frag_color;
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uniform sampler2D input_texture;
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vec2 tex_size;
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vec2 inv_tex_size;
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vec4 cubic(float v) {
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vec4 n = vec4(1.0, 2.0, 3.0, 4.0) - v;
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vec4 s = n * n * n;
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vec3 n = vec3(1.0, 2.0, 3.0) - v;
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vec3 s = n * n * n;
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float x = s.x;
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float y = s.y - 4.0 * s.x;
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float z = s.z - 4.0 * s.y + 6.0 * s.x;
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@ -43,14 +45,11 @@ vec4 cubic(float v) {
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return vec4(x, y, z, w) / 6.0;
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}
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vec4 textureBicubic(sampler2D sampler, vec2 tex_coords) {
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vec2 tex_size = vec2(textureSize(sampler, 0));
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vec2 inv_tex_size = 1.0 / tex_size;
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// Bicubic interpolation
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vec4 textureBicubic(vec2 tex_coords) {
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tex_coords = tex_coords * tex_size - 0.5;
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vec2 fxy = fract(tex_coords);
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tex_coords -= fxy;
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vec2 fxy = modf(tex_coords, tex_coords);
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vec4 xcubic = cubic(fxy.x);
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vec4 ycubic = cubic(fxy.y);
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@ -62,10 +61,10 @@ vec4 textureBicubic(sampler2D sampler, vec2 tex_coords) {
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offset *= inv_tex_size.xxyy;
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vec4 sample0 = texture(sampler, offset.xz);
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vec4 sample1 = texture(sampler, offset.yz);
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vec4 sample2 = texture(sampler, offset.xw);
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vec4 sample3 = texture(sampler, offset.yw);
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vec4 sample0 = textureLod(input_texture, offset.xz, 0.0);
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vec4 sample1 = textureLod(input_texture, offset.yz, 0.0);
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vec4 sample2 = textureLod(input_texture, offset.xw, 0.0);
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vec4 sample3 = textureLod(input_texture, offset.yw, 0.0);
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float sx = s.x / (s.x + s.y);
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float sy = s.z / (s.z + s.w);
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@ -73,40 +72,66 @@ vec4 textureBicubic(sampler2D sampler, vec2 tex_coords) {
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return mix(mix(sample3, sample2, sx), mix(sample1, sample0, sx), sy);
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}
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float ColorDist(vec4 a, vec4 b) {
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mat4x3 center_matrix;
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vec4 center_alpha;
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// Finds the distance between four colors and cc in YCbCr space
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vec4 ColorDist(vec4 A, vec4 B, vec4 C, vec4 D) {
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// https://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.2020_conversion
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const vec3 K = vec3(0.2627, 0.6780, 0.0593);
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const float luminance_weight = .6;
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const mat3 MATRIX = mat3(K * luminance_weight, -.5 * K.r / (1.0 - K.b), -.5 * K.g / (1.0 - K.b),
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.5, .5, -.5 * K.g / (1.0 - K.r), -.5 * K.b / (1.0 - K.r));
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vec4 diff = a - b;
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vec3 YCbCr = diff.rgb * MATRIX;
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float d = length(YCbCr) * length(vec3(1.0)) / length(vec3(luminance_weight, 1.0, 1.0));
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return sqrt(a.a * b.a * d * d + diff.a * diff.a);
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}
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const float LUMINANCE_WEIGHT = .6;
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const mat3 YCBCR_MATRIX =
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mat3(K * LUMINANCE_WEIGHT, -.5 * K.r / (1.0 - K.b), -.5 * K.g / (1.0 - K.b), .5, .5,
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-.5 * K.g / (1.0 - K.r), -.5 * K.b / (1.0 - K.r));
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const int radius = 2;
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mat4x3 colors = mat4x3(A.rgb, B.rgb, C.rgb, D.rgb) - center_matrix;
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mat4x3 YCbCr = YCBCR_MATRIX * colors;
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vec4 color_dist = vec3(1.0) * YCbCr;
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color_dist *= color_dist;
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vec4 alpha = vec4(A.a, B.a, C.a, D.a);
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return sqrt((color_dist + abs(center_alpha - alpha)) * alpha * center_alpha);
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}
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void main() {
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vec2 input_size = vec2(textureSize(input_texture, 0));
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vec4 center_texel = texture(input_texture, tex_coord);
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vec2 final_offset = vec2(0.0);
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float total_diff = 0.0;
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vec4 bl = textureLodOffset(input_texture, tex_coord, 0.0, ivec2(-1, -1));
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vec4 bc = textureLodOffset(input_texture, tex_coord, 0.0, ivec2(0, -1));
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vec4 br = textureLodOffset(input_texture, tex_coord, 0.0, ivec2(1, -1));
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vec4 cl = textureLodOffset(input_texture, tex_coord, 0.0, ivec2(-1, 0));
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vec4 cc = textureLod(input_texture, tex_coord, 0.0);
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vec4 cr = textureLodOffset(input_texture, tex_coord, 0.0, ivec2(1, 0));
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vec4 tl = textureLodOffset(input_texture, tex_coord, 0.0, ivec2(-1, 1));
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vec4 tc = textureLodOffset(input_texture, tex_coord, 0.0, ivec2(0, 1));
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vec4 tr = textureLodOffset(input_texture, tex_coord, 0.0, ivec2(1, 1));
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for (int y = -radius; y <= radius; ++y) {
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for (int x = -radius; x <= radius; ++x) {
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if (0 == (x | y))
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continue;
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vec2 offset = vec2(x, y);
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float weight = pow(length(offset), -length(offset));
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vec4 texel = texture(input_texture, tex_coord + offset / input_size);
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float diff = ColorDist(texel, center_texel) * weight;
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total_diff += diff;
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final_offset += diff * offset;
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}
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tex_size = vec2(textureSize(input_texture, 0));
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inv_tex_size = 1.0 / tex_size;
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center_matrix = mat4x3(cc.rgb, cc.rgb, cc.rgb, cc.rgb);
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center_alpha = cc.aaaa;
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vec4 offset_tl = ColorDist(tl, tc, tr, cr);
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vec4 offset_br = ColorDist(br, bc, bl, cl);
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// Calculate how different cc is from the texels around it
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float total_dist = dot(offset_tl + offset_br, vec4(1.0));
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// Add together all the distances with direction taken into account
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vec4 tmp = offset_tl - offset_br;
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vec2 total_offset = tmp.wy + tmp.zz + vec2(-tmp.x, tmp.x);
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if (total_dist == 0.0) {
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// Doing bicubic filtering just past the edges where the offset is 0 causes black floaters
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// and it doesn't really matter which filter is used when the colors aren't changing.
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frag_color = cc;
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} else {
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// When the image has thin points, they tend to split apart.
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// This is because the texels all around are different
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// and total_offset reaches into clear areas.
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// This works pretty well to keep the offset in bounds for these cases.
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float clamp_val = length(total_offset) / total_dist;
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vec2 final_offset = clamp(total_offset, -clamp_val, clamp_val) * inv_tex_size;
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frag_color = textureBicubic(tex_coord - final_offset);
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}
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float clamp_val = length(final_offset) / total_diff;
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final_offset = clamp(final_offset, -clamp_val, clamp_val);
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frag_color = textureBicubic(input_texture, tex_coord - final_offset / input_size);
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}
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