mirror of https://github.com/bkaradzic/bgfx
Added SDF.
This commit is contained in:
Branimir Karadžić
parent
5dca5791c5
commit
bc399eb317
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@ -0,0 +1,22 @@
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The MIT License (MIT)
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Copyright (C) 2014 Mikko Mononen (memon@inside.org)
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Copyright (C) 2009-2012 Stefan Gustavson (stefan.gustavson@gmail.com)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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@ -0,0 +1,334 @@
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/*
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Copyright (C) 2014 Mikko Mononen (memon@inside.org)
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Copyright (C) 2009-2012 Stefan Gustavson (stefan.gustavson@gmail.com)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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*/
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#ifndef SDF_H
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#define SDF_H
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// Sweep-and-update Euclidean distance transform of an antialised image for contour textures.
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// Based on edtaa3func.c by Stefan Gustavson.
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//
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// White (255) pixels are treated as object pixels, zero pixels are treated as background.
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// An attempt is made to treat antialiased edges correctly. The input image must have
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// pixels in the range [0,255], and the antialiased image should be a box-filter
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// sampling of the ideal, crisp edge. If the antialias region is more than 1 pixel wide,
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// the result from this transform will be inaccurate.
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// Pixels at image border are not calculated and are set to 0.
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//
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// The output distance field is encoded as bytes, where 0 = maxdist (outside) and 255 = -maxdist (inside).
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// Input and output can be the same buffer.
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// out - Output of the distance transform, one byte per pixel.
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// outstride - Bytes per row on output image.
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// maxdist - The extents of the output distance range in pixels.
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// img - Input image, one byte per pixel.
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// width - Width if the image.
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// height - Height if the image.
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// stride - Bytes per row on input image.
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int sdfBuild(unsigned char* out, int outstride, float maxdist,
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const unsigned char* img, int width, int height, int stride);
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// Same as distXform, but does not allocate any memory.
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// The 'temp' array should be enough to fit width * height * sizeof(float) bytes.
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void sdfBuildNoAlloc(unsigned char* out, int outstride, float maxdist,
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const unsigned char* img, int width, int height, int stride,
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unsigned char* temp);
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void sdfCoverageToDistance(unsigned char* out, int outstride, float maxdist,
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const unsigned char* img, int width, int height, int stride);
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#endif //SDF_H
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#ifdef SDF_IMPLEMENTATION
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#include <math.h>
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#include <stdlib.h>
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#define SDF_MAX_PASSES 10 // Maximum number of distance transform passes
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#define SDF_SLACK 0.001f // Controls how much smaller the neighbour value must be to cosnider, too small slack increse iteration count.
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#define SDF_SQRT2 1.4142136f // sqrt(2)
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#define SDF_BIG 1e+37f // Big value used to initialize the distance field.
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static float sdf__edgedf(float gx, float gy, float a)
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{
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float df, a1;
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if ((gx == 0) || (gy == 0)) {
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// Either A) gu or gv are zero, or B) both
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// Linear approximation is A) correct or B) a fair guess
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df = 0.5f - a;
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} else {
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// Everything is symmetric wrt sign and transposition,
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// so move to first octant (gx>=0, gy>=0, gx>=gy) to
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// avoid handling all possible edge directions.
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gx = fabsf(gx);
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gy = fabsf(gy);
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if (gx < gy) {
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float temp = gx;
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gx = gy;
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gy = temp;
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}
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a1 = 0.5f*gy/gx;
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if (a < a1) { // 0 <= a < a1
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df = 0.5f*(gx + gy) - sqrtf(2.0f*gx*gy*a);
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} else if (a < (1.0-a1)) { // a1 <= a <= 1-a1
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df = (0.5f-a)*gx;
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} else { // 1-a1 < a <= 1
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df = -0.5f*(gx + gy) + sqrt(2.0f*gx*gy*(1.0f-a));
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}
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}
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return df;
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}
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struct SDFpoint {
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float x,y;
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};
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static float sdf__distsqr(struct SDFpoint* a, struct SDFpoint* b)
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{
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float dx = b->x - a->x, dy = b->y - a->y;
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return dx*dx + dy*dy;
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}
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static float sdf__clamp01(float x)
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{
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return x < 0.0f ? 0.0f : (x > 1.0f ? 1.0f : x);
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}
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void sdfCoverageToDistance(unsigned char* out, int outstride, float maxdist,
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const unsigned char* img, int width, int height, int stride)
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{
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int x, y;
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// Zero out borders
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for (x = 0; x < width; x++)
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out[x] = 0;
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for (y = 1; y < height; y++) {
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out[y*stride] = 0;
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out[width-1+y*stride] = 0;
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}
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for (x = 0; x < width; x++)
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out[x+(height-1)*stride] = 0;
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// Calculate position of the anti-aliased pixels and distance to the boundary of the shape.
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for (y = 1; y < height-1; y++) {
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for (x = 1; x < width-1; x++) {
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int k = x + y * stride;
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float d, gx, gy, glen;
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// Calculate gradient direction
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gx = -(float)img[k-stride-1] - SDF_SQRT2*(float)img[k-1] - (float)img[k+stride-1] + (float)img[k-stride+1] + SDF_SQRT2*(float)img[k+1] + (float)img[k+stride+1];
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gy = -(float)img[k-stride-1] - SDF_SQRT2*(float)img[k-stride] - (float)img[k+stride-1] + (float)img[k-stride+1] + SDF_SQRT2*(float)img[k+stride] + (float)img[k+stride+1];
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if (fabsf(gx) > 0.001f && fabsf(gy) > 0.001f) {
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glen = gx*gx + gy*gy;
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glen = 1.0f / sqrtf(glen);
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gx *= glen;
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gy *= glen;
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// Find nearest point on contour.
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d = sdf__edgedf(gx, gy, (float)img[k]/255.0f);
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d = fabsf(d);
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if (img[x+y*stride] > 127) d = -d;
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out[x+y*outstride] = (unsigned char)(sdf__clamp01(0.5f - d*0.5f) * 255.0f);
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} else {
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out[x+y*outstride] = img[x+y*stride] > 127 ? 255 : 0;
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}
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}
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}
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}
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void sdfBuildNoAlloc(unsigned char* out, int outstride, float maxdist,
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const unsigned char* img, int width, int height, int stride,
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unsigned char* temp)
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{
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int i, x, y, pass;
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float scale;
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float* tdist = (float*)&temp[0];
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struct SDFpoint* tpt = (struct SDFpoint*)&temp[width * height * sizeof(float)];
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// Initialize buffers
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for (i = 0; i < width*height; i++) {
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tpt[i].x = 0;
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tpt[i].y = 0;
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tdist[i] = SDF_BIG;
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}
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// Calculate position of the anti-aliased pixels and distance to the boundary of the shape.
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for (y = 1; y < height-1; y++) {
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for (x = 1; x < width-1; x++) {
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int k = x + y * stride;
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if (img[k] > 0 && img[k] < 255) {
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struct SDFpoint c = { (float)x, (float)y };
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float d, gx, gy, glen;
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// Calculate gradient direction
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gx = -(float)img[k-stride-1] - SDF_SQRT2*(float)img[k-1] - (float)img[k+stride-1] + (float)img[k-stride+1] + SDF_SQRT2*(float)img[k+1] + (float)img[k+stride+1];
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gy = -(float)img[k-stride-1] - SDF_SQRT2*(float)img[k-stride] - (float)img[k+stride-1] + (float)img[k-stride+1] + SDF_SQRT2*(float)img[k+stride] + (float)img[k+stride+1];
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if (fabsf(gx) < 0.001f && fabsf(gy) < 0.001f) continue;
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glen = gx*gx + gy*gy;
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if (glen > 0.0001f) {
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glen = 1.0f / sqrtf(glen);
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gx *= glen;
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gy *= glen;
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}
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// Find nearest point on contour.
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d = sdf__edgedf(gx, gy, (float)img[k]/255.0f);
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tpt[k].x = x + gx*d;
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tpt[k].y = y + gy*d;
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tdist[k] = sdf__distsqr(&c, &tpt[k]);
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}
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}
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}
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// Calculate distance transform using sweep-and-update.
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for (pass = 0; pass < SDF_MAX_PASSES; pass++){
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int changed = 0;
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// Bottom-left to top-right.
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for (y = 1; y < height-1; y++) {
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for (x = 1; x < width-1; x++) {
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int k = x+y*width, kn, ch = 0;
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struct SDFpoint c = { (float)x, (float)y }, pt;
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float pd = tdist[k], d;
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// (-1,-1)
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kn = k - 1 - width;
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if (tdist[kn] < pd) {
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d = sdf__distsqr(&c, &tpt[kn]);
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if (d + SDF_SLACK < pd) {
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pt = tpt[kn];
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pd = d;
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ch = 1;
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}
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}
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// (0,-1)
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kn = k - 1 - width;
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if (tdist[kn] < pd) {
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d = sdf__distsqr(&c, &tpt[kn]);
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if (d + SDF_SLACK < pd) {
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pt = tpt[kn];
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pd = d;
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ch = 1;
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}
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}
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// (1,-1)
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kn = k + 1 - width;
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if (tdist[kn] < pd) {
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d = sdf__distsqr(&c, &tpt[kn]);
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if (d + SDF_SLACK < pd) {
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pt = tpt[kn];
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pd = d;
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ch = 1;
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}
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}
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// (-1,0)
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kn = k - 1;
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if (tdist[kn] < tdist[k]) {
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d = sdf__distsqr(&c, &tpt[kn]);
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if (d + SDF_SLACK < pd) {
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pt = tpt[kn];
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pd = d;
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ch = 1;
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}
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}
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if (ch) {
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tpt[k] = pt;
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tdist[k] = pd;
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changed++;
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}
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}
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}
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// Top-right to bottom-left.
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for (y = height-2; y > 0 ; y--) {
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for (x = width-2; x > 0; x--) {
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int k = x+y*width, kn, ch = 0;
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struct SDFpoint c = { (float)x, (float)y }, pt;
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float pd = tdist[k], d;
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// (1,0)
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kn = k + 1;
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if (tdist[kn] < pd) {
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d = sdf__distsqr(&c, &tpt[kn]);
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if (d + SDF_SLACK < pd) {
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pt = tpt[kn];
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pd = d;
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ch = 1;
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}
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}
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// (-1,1)
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kn = k - 1 + width;
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if (tdist[kn] < pd) {
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d = sdf__distsqr(&c, &tpt[kn]);
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if (d + SDF_SLACK < pd) {
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pt = tpt[kn];
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pd = d;
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ch = 1;
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}
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}
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// (0,1)
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kn = k + width;
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if (tdist[kn] < pd) {
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d = sdf__distsqr(&c, &tpt[kn]);
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if (d + SDF_SLACK < pd) {
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pt = tpt[kn];
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pd = d;
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ch = 1;
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}
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}
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// (1,1)
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kn = k + 1 + width;
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if (tdist[kn] < pd) {
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d = sdf__distsqr(&c, &tpt[kn]);
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if (d + SDF_SLACK < pd) {
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pt = tpt[kn];
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pd = d;
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ch = 1;
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}
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}
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if (ch) {
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tpt[k] = pt;
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tdist[k] = pd;
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changed++;
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}
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}
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}
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if (changed == 0) break;
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}
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// Map to good range.
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scale = 1.0f / maxdist;
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for (y = 0; y < height; y++) {
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for (x = 0; x < width; x++) {
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float d = sqrtf(tdist[x+y*width]) * scale;
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if (img[x+y*stride] > 127) d = -d;
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out[x+y*outstride] = (unsigned char)(sdf__clamp01(0.5f - d*0.5f) * 255.0f);
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}
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}
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}
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int sdfBuild(unsigned char* out, int outstride, float maxdist,
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const unsigned char* img, int width, int height, int stride)
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{
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unsigned char* temp = (unsigned char*)malloc(width*height*sizeof(float)*3);
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if (temp == NULL) return 0;
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sdfBuildNoAlloc(out, outstride, maxdist, img, width, height, stride, temp);
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free(temp);
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return 1;
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}
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#endif //SDF_IMPLEMENTATION
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@ -3,11 +3,21 @@
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* License: http://www.opensource.org/licenses/BSD-2-Clause
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*/
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#define USE_EDTAA3 1
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#include "../common.h"
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#include <bgfx.h>
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#include <freetype/freetype.h>
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#include <edtaa3/edtaa3func.cpp>
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#include <math.h>
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#if USE_EDTAA3
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# include <edtaa3/edtaa3func.cpp>
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#else
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# define SDF_IMPLEMENTATION
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# include <sdf/sdf.h>
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#endif // USE_EDTAA3
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#include <wchar.h> // wcslen
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#include <tinystl/allocator.h>
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@ -247,6 +257,7 @@ bool TrueTypeFont::bakeGlyphSubpixel(CodePoint _codePoint, GlyphInfo& _glyphInfo
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static void makeDistanceMap(const uint8_t* _img, uint8_t* _outImg, uint32_t _width, uint32_t _height)
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{
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#if USE_EDTAA3
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int16_t* xdist = (int16_t*)malloc(_width * _height * sizeof(int16_t) );
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int16_t* ydist = (int16_t*)malloc(_width * _height * sizeof(int16_t) );
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double* gx = (double*)calloc(_width * _height, sizeof(double) );
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@ -335,6 +346,9 @@ static void makeDistanceMap(const uint8_t* _img, uint8_t* _outImg, uint32_t _wid
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free(data);
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free(outside);
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free(inside);
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#else
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sdfBuild(_outImg, _width, 2.0f, _img, _width, _height, _width);
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#endif // USE_EDTAA3
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}
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bool TrueTypeFont::bakeGlyphDistance(CodePoint _codePoint, GlyphInfo& _glyphInfo, uint8_t* _outBuffer)
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