X-Git-Url: http://de.git.xonotic.org/?p=xonotic%2Fdarkplaces.git;a=blobdiff_plain;f=curves.c;h=de3f423ab0875659c9c6326c8b9be554692de106;hp=8378a4bafd222d55d2de5d84186698a32f446910;hb=19885358f4bd80bc7ed85931b766a197e54ce3a1;hpb=1b29ff9409bcfd21e842e81e1e44924de83ab4a2 diff --git a/curves.c b/curves.c index 8378a4ba..de3f423a 100644 --- a/curves.c +++ b/curves.c @@ -1,420 +1,191 @@ -// this code written by Forest Hale, on 2003-08-23, and placed into public domain -// this code deals with quadratic splines (minimum of 3 points), the same kind used in Quake3 maps. - -// LordHavoc's rant on misuse of the name 'bezier': many people seem to think that bezier is a generic term for splines, but it is not, it is a term for a specific type of spline (minimum of 4 control points, cubic spline). - -#include -#include "curves.h" -#include "zone.h" - -#if 0 -void QuadraticSplineSubdivideFloat(int inpoints, int components, const float *in, int instride, float *out, int outstride) +/* +this code written by Forest Hale, on 2004-10-17, and placed into public domain +this implements Quadratic BSpline surfaces as seen in Quake3 by id Software + +a small rant on misuse of the name 'bezier': many people seem to think that +bezier is a generic term for splines, but it is not, it is a term for a +specific type of bspline (4 control points, cubic bspline), bsplines are the +generalization of the bezier spline to support dimensions other than cubic. + +example equations for 1-5 control point bsplines being sampled as t=0...1 +1: flat (0th dimension) +o = a +2: linear (1st dimension) +o = a * (1 - t) + b * t +3: quadratic bspline (2nd dimension) +o = a * (1 - t) * (1 - t) + 2 * b * (1 - t) * t + c * t * t +4: cubic (bezier) bspline (3rd dimension) +o = a * (1 - t) * (1 - t) * (1 - t) + 3 * b * (1 - t) * (1 - t) * t + 3 * c * (1 - t) * t * t + d * t * t * t +5: quartic bspline (4th dimension) +o = a * (1 - t) * (1 - t) * (1 - t) * (1 - t) + 4 * b * (1 - t) * (1 - t) * (1 - t) * t + 6 * c * (1 - t) * (1 - t) * t * t + 4 * d * (1 - t) * t * t * t + e * t * t * t * t + +arbitrary dimension bspline +double factorial(int n) { - int s; - // the input (control points) is read as a stream of points, and buffered - // by the cpprev, cpcurr, and cpnext variables (to allow subdivision in - // overlapping memory buffers, even subdivision in-place with pre-spaced - // control points in the buffer) - // the output (resulting curve) is written as a stream of points - // this subdivision is meant to be repeated until the desired flatness - // level is reached - if (components == 1 && instride == (int)sizeof(float) && outstride == instride) - { - // simple case, single component and no special stride - float cpprev0 = 0, cpcurr0 = 0, cpnext0; - cpnext0 = *in++; - for (s = 0;s < inpoints - 1;s++) - { - cpprev0 = cpcurr0; - cpcurr0 = cpnext0; - if (s < inpoints - 1) - cpnext0 = *in++; - if (s > 0) - { - // 50% flattened control point - // cp1 = average(cp1, average(cp0, cp2)); - *out++ = (cpcurr0 + (cpprev0 + cpnext0) * 0.5f) * 0.5f; - } - else - { - // copy the control point directly - *out++ = cpcurr0; - } - // midpoint - // mid = average(cp0, cp1); - *out++ = (cpcurr0 + cpnext0) * 0.5f; - } - // copy the final control point - *out++ = cpnext0; - } - else - { - // multiple components or stride is used (complex case) - int c; - float cpprev[4], cpcurr[4], cpnext[4]; - // check if there are too many components for the buffers - if (components > 1) - { - // more components can be handled, but slowly, by calling self multiple times... - for (c = 0;c < components;c++, in++, out++) - QuadraticSplineSubdivideFloat(inpoints, 1, in, instride, out, outstride); - return; - } - for (c = 0;c < components;c++) - cpnext[c] = in[c]; - (unsigned char *)in += instride; - for (s = 0;s < inpoints - 1;s++) - { - for (c = 0;c < components;c++) - cpprev[c] = cpcurr[c]; - for (c = 0;c < components;c++) - cpcurr[c] = cpnext[c]; - for (c = 0;c < components;c++) - cpnext[c] = in[c]; - (unsigned char *)in += instride; - // the end points are copied as-is - if (s > 0) - { - // 50% flattened control point - // cp1 = average(cp1, average(cp0, cp2)); - for (c = 0;c < components;c++) - out[c] = (cpcurr[c] + (cpprev[c] + cpnext[c]) * 0.5f) * 0.5f; - } - else - { - // copy the control point directly - for (c = 0;c < components;c++) - out[c] = cpcurr[c]; - } - (unsigned char *)out += outstride; - // midpoint - // mid = average(cp0, cp1); - for (c = 0;c < components;c++) - out[c] = (cpcurr[c] + cpnext[c]) * 0.5f; - (unsigned char *)out += outstride; - } - // copy the final control point - for (c = 0;c < components;c++) - out[c] = cpnext[c]; - //(unsigned char *)out += outstride; - } + int i; + double f; + f = 1; + for (i = 1;i < n;i++) + f = f * i; + return f; } - -// note: out must have enough room! -// (see finalwidth/finalheight calcs below) -void QuadraticSplinePatchSubdivideFloatBuffer(int cpwidth, int cpheight, int xlevel, int ylevel, int components, const float *in, float *out) +double bsplinesample(int dimensions, double t, double *param) { - int finalwidth, finalheight, xstep, ystep, x, y, c; - float *o; - - // error out on various bogus conditions - if (xlevel < 0 || ylevel < 0 || xlevel > 16 || ylevel > 16 || cpwidth < 3 || cpheight < 3) - return; - - xstep = 1 << xlevel; - ystep = 1 << ylevel; - finalwidth = (cpwidth - 1) * xstep + 1; - finalheight = (cpheight - 1) * ystep + 1; - - for (y = 0;y < finalheight;y++) - for (x = 0;x < finalwidth;x++) - for (c = 0, o = out + (y * finalwidth + x) * components;c < components;c++) - o[c] = 0; - - if (xlevel == 1 && ylevel == 0) - { - for (y = 0;y < finalheight;y++) - QuadraticSplineSubdivideFloat(cpwidth, components, in + y * cpwidth * components, sizeof(float) * components, out + y * finalwidth * components, sizeof(float) * components); - return; - } - if (xlevel == 0 && ylevel == 1) - { - for (x = 0;x < finalwidth;x++) - QuadraticSplineSubdivideFloat(cpheight, components, in + x * components, sizeof(float) * cpwidth * components, out + x * components, sizeof(float) * finalwidth * components); - return; - } + double o = 0; + for (i = 0;i < dimensions + 1;i++) + o += param[i] * factorial(dimensions)/(factorial(i)*factorial(dimensions-i)) * pow(t, i) * pow(1 - t, dimensions - i); + return o; +} +*/ - // copy control points into correct positions in destination buffer - for (y = 0;y < finalheight;y += ystep) - for (x = 0;x < finalwidth;x += xstep) - for (c = 0, o = out + (y * finalwidth + x) * components;c < components;c++) - o[c] = *in++; +#include +#include "curves.h" - // subdivide in place in the destination buffer - while (xstep > 1 || ystep > 1) - { - if (xstep > 1) - { - xstep >>= 1; - for (y = 0;y < finalheight;y += ystep) - QuadraticSplineSubdivideFloat(cpwidth, components, out + y * finalwidth * components, sizeof(float) * xstep * 2 * components, out + y * finalwidth * components, sizeof(float) * xstep * components); - cpwidth = (cpwidth - 1) * 2 + 1; - } - if (ystep > 1) - { - ystep >>= 1; - for (x = 0;x < finalwidth;x += xstep) - QuadraticSplineSubdivideFloat(cpheight, components, out + x * components, sizeof(float) * ystep * 2 * finalwidth * components, out + x * components, sizeof(float) * ystep * finalwidth * components); - cpheight = (cpheight - 1) * 2 + 1; - } - } -} -#elif 1 -void QuadraticSplinePatchSubdivideFloatBuffer(int cpwidth, int cpheight, int xlevel, int ylevel, int components, const float *in, float *out) +// usage: +// to expand a 5x5 patch to 21x21 vertices (4x4 tesselation), one might use this call: +// Q3PatchSubdivideFloat(3, sizeof(float[3]), outvertices, 5, 5, sizeof(float[3]), patchvertices, 4, 4); +void Q3PatchTesselateFloat(int numcomponents, int outputstride, float *outputvertices, int patchwidth, int patchheight, int inputstride, float *patchvertices, int tesselationwidth, int tesselationheight) { - int c, x, y, outwidth, outheight, halfstep, xstep, ystep; - float prev, curr, next; - xstep = 1 << xlevel; - ystep = 1 << ylevel; - outwidth = ((cpwidth - 1) * xstep) + 1; - outheight = ((cpheight - 1) * ystep) + 1; - for (y = 0;y < cpheight;y++) - for (x = 0;x < cpwidth;x++) - for (c = 0;c < components;c++) - out[(y * ystep * outwidth + x * xstep) * components + c] = in[(y * cpwidth + x) * components + c]; - while (xstep > 1 || ystep > 1) + int k, l, x, y, component, outputwidth = (patchwidth-1)*tesselationwidth+1; + float px, py, *v, a, b, c, *cp[3][3], temp[3][64]; + // iterate over the individual 3x3 quadratic spline surfaces one at a time + // expanding them to fill the output array (with some overlap to ensure + // the edges are filled) + for (k = 0;k < patchheight-1;k += 2) { - if (xstep >= ystep) + for (l = 0;l < patchwidth-1;l += 2) { - // subdivide on X - halfstep = xstep >> 1; - for (y = 0;y < outheight;y += ystep) + // set up control point pointers for quicker lookup later + for (y = 0;y < 3;y++) + for (x = 0;x < 3;x++) + cp[y][x] = (float *)((unsigned char *)patchvertices + ((k+y)*patchwidth+(l+x)) * inputstride); + // for each row... + for (y = 0;y <= tesselationheight*2;y++) { - for (c = 0;c < components;c++) + // calculate control points for this row by collapsing the 3 + // rows of control points to one row using py + py = (float)y / (float)(tesselationheight*2); + // calculate quadratic spline weights for py + a = ((1.0f - py) * (1.0f - py)); + b = ((1.0f - py) * (2.0f * py)); + c = (( py) * ( py)); + for (component = 0;component < numcomponents;component++) { - x = xstep; - // fetch first two control points - prev = out[(y * outwidth + (x - xstep)) * components + c]; - curr = out[(y * outwidth + x) * components + c]; - // create first midpoint - out[(y * outwidth + (x - halfstep)) * components + c] = (curr + prev) * 0.5f; - for (;x < outwidth - xstep;x += xstep, prev = curr, curr = next) - { - // fetch next control point - next = out[(y * outwidth + (x + xstep)) * components + c]; - // flatten central control point - out[(y * outwidth + x) * components + c] = (curr + (prev + next) * 0.5f) * 0.5f; - // create following midpoint - out[(y * outwidth + (x + halfstep)) * components + c] = (curr + next) * 0.5f; - } + temp[0][component] = cp[0][0][component] * a + cp[1][0][component] * b + cp[2][0][component] * c; + temp[1][component] = cp[0][1][component] * a + cp[1][1][component] * b + cp[2][1][component] * c; + temp[2][component] = cp[0][2][component] * a + cp[1][2][component] * b + cp[2][2][component] * c; } - } - xstep >>= 1; - } - else - { - // subdivide on Y - halfstep = ystep >> 1; - for (x = 0;x < outwidth;x += xstep) - { - for (c = 0;c < components;c++) + // fetch a pointer to the beginning of the output vertex row + v = (float *)((unsigned char *)outputvertices + ((k * tesselationheight + y) * outputwidth + l * tesselationwidth) * outputstride); + // for each column of the row... + for (x = 0;x <= (tesselationwidth*2);x++) { - y = ystep; - // fetch first two control points - prev = out[((y - ystep) * outwidth + x) * components + c]; - curr = out[(y * outwidth + x) * components + c]; - // create first midpoint - out[((y - halfstep) * outwidth + x) * components + c] = (curr + prev) * 0.5f; - for (;y < outheight - ystep;y += ystep, prev = curr, curr = next) - { - // fetch next control point - next = out[((y + ystep) * outwidth + x) * components + c]; - // flatten central control point - out[(y * outwidth + x) * components + c] = (curr + (prev + next) * 0.5f) * 0.5f;; - // create following midpoint - out[((y + halfstep) * outwidth + x) * components + c] = (curr + next) * 0.5f; - } + // calculate point based on the row control points + px = (float)x / (float)(tesselationwidth*2); + // calculate quadratic spline weights for px + // (could be precalculated) + a = ((1.0f - px) * (1.0f - px)); + b = ((1.0f - px) * (2.0f * px)); + c = (( px) * ( px)); + for (component = 0;component < numcomponents;component++) + v[component] = temp[0][component] * a + temp[1][component] * b + temp[2][component] * c; + // advance to next output vertex using outputstride + // (the next vertex may not be directly following this + // one, as this may be part of a larger structure) + v = (float *)((unsigned char *)v + outputstride); } } - ystep >>= 1; - } - } - // flatten control points on X - for (y = 0;y < outheight;y += ystep) - { - for (c = 0;c < components;c++) - { - x = xstep; - // fetch first two control points - prev = out[(y * outwidth + (x - xstep)) * components + c]; - curr = out[(y * outwidth + x) * components + c]; - for (;x < outwidth - xstep;x += xstep, prev = curr, curr = next) - { - // fetch next control point - next = out[(y * outwidth + (x + xstep)) * components + c]; - // flatten central control point - out[(y * outwidth + x) * components + c] = (curr + (prev + next) * 0.5f) * 0.5f;; - } } } - // flatten control points on Y - for (x = 0;x < outwidth;x += xstep) - { - for (c = 0;c < components;c++) - { - y = ystep; - // fetch first two control points - prev = out[((y - ystep) * outwidth + x) * components + c]; - curr = out[(y * outwidth + x) * components + c]; - for (;y < outheight - ystep;y += ystep, prev = curr, curr = next) - { - // fetch next control point - next = out[((y + ystep) * outwidth + x) * components + c]; - // flatten central control point - out[(y * outwidth + x) * components + c] = (curr + (prev + next) * 0.5f) * 0.5f;; - } - } - } - - /* - for (y = ystep;y < outheight - ystep;y += ystep) - { - for (c = 0;c < components;c++) - { - for (x = xstep, outp = out + (y * outwidth + x) * components + c, prev = outp[-xstep * components], curr = outp[0], next = outp[xstep * components];x < outwidth;x += xstep, outp += ystep * outwidth * components, prev = curr, curr = next, next = outp[xstep * components]) - { - // midpoint - outp[-halfstep * components] = (prev + curr) * 0.5f; - // flatten control point - outp[0] = (curr + (prev + next) * 0.5f) * 0.5f; - // next midpoint (only needed for end segment) - outp[halfstep * components] = (next + curr) * 0.5f; - } - } - } - */ -} -#else -// unfinished code -void QuadraticSplinePatchSubdivideFloatBuffer(int cpwidth, int cpheight, int xlevel, int ylevel, int components, const float *in, float *out) -{ - int outwidth, outheight; - outwidth = ((cpwidth - 1) << xlevel) + 1; - outheight = ((cpheight - 1) << ylevel) + 1; - for (y = 0;y < cpheight;y++) +#if 0 + // enable this if you want results printed out + printf("vertices[%i][%i] =\n{\n", (patchheight-1)*tesselationheight+1, (patchwidth-1)*tesselationwidth+1); + for (y = 0;y < (patchheight-1)*tesselationheight+1;y++) { - for (x = 0;x < cpwidth;x++) + for (x = 0;x < (patchwidth-1)*tesselationwidth+1;x++) { - for (c = 0;c < components;c++) - { - inp = in + (y * cpwidth + x) * components + c; - outp = out + ((y< level1tolerance;level++) - deviation *= 0.25f; - return level; -} - -int QuadraticSplinePatchSubdivisionLevelOnX(int cpwidth, int cpheight, int components, const float *in, float level1tolerance, int levellimit) -{ - return QuadraticSplinePatchSubdivisionLevelForDeviation(QuadraticSplinePatchLargestDeviationOnX(cpwidth, cpheight, components, in), level1tolerance, levellimit); -} - -int QuadraticSplinePatchSubdivisionLevelOnY(int cpwidth, int cpheight, int components, const float *in, float level1tolerance, int levellimit) -{ - return QuadraticSplinePatchSubdivisionLevelForDeviation(QuadraticSplinePatchLargestDeviationOnY(cpwidth, cpheight, components, in), level1tolerance, levellimit); + int x, y, row0, row1; + for (y = 0;y < height - 1;y++) + { + row0 = firstvertex + (y + 0) * width; + row1 = firstvertex + (y + 1) * width; + for (x = 0;x < width - 1;x++) + { + *elements++ = row0; + *elements++ = row1; + *elements++ = row0 + 1; + *elements++ = row1; + *elements++ = row1 + 1; + *elements++ = row0 + 1; + row0++; + row1++; + } + } } -/* - d = a * (1 - 2 * t + t * t) + b * (2 * t - 2 * t * t) + c * t * t; - d = a * (1 + t * t + -2 * t) + b * (2 * t + -2 * t * t) + c * t * t; - d = a * 1 + a * t * t + a * -2 * t + b * 2 * t + b * -2 * t * t + c * t * t; - d = a * 1 + (a * t + a * -2) * t + (b * 2 + b * -2 * t) * t + (c * t) * t; - d = a + ((a * t + a * -2) + (b * 2 + b * -2 * t) + (c * t)) * t; - d = a + (a * (t - 2) + b * 2 + b * -2 * t + c * t) * t; - d = a + (a * (t - 2) + b * 2 + (b * -2 + c) * t) * t; - d = a + (a * (t - 2) + b * 2 + (c + b * -2) * t) * t; - d = a + a * (t - 2) * t + b * 2 * t + (c + b * -2) * t * t; - d = a * (1 + (t - 2) * t) + b * 2 * t + (c + b * -2) * t * t; - d = a * (1 + (t - 2) * t) + b * 2 * t + c * t * t + b * -2 * t * t; - d = a * 1 + a * (t - 2) * t + b * 2 * t + c * t * t + b * -2 * t * t; - d = a * 1 + a * t * t + a * -2 * t + b * 2 * t + c * t * t + b * -2 * t * t; - d = a * (1 - 2 * t + t * t) + b * 2 * t + c * t * t + b * -2 * t * t; - d = a * (1 - 2 * t) + a * t * t + b * 2 * t + c * t * t + b * -2 * t * t; - d = a + a * -2 * t + a * t * t + b * 2 * t + c * t * t + b * -2 * t * t; - d = a + a * -2 * t + a * t * t + b * 2 * t + b * -2 * t * t + c * t * t; - d = a + a * -2 * t + a * t * t + b * 2 * t + b * -2 * t * t + c * t * t; - d = a + a * -2 * t + b * 2 * t + b * -2 * t * t + a * t * t + c * t * t; - d = a + a * -2 * t + b * 2 * t + (a + c + b * -2) * t * t; - d = a + (a * -2 + b * 2) * t + (a + c + b * -2) * t * t; - d = a + ((a * -2 + b * 2) + (a + c + b * -2) * t) * t; - d = a + ((b + b - a - a) + (a + c - b - b) * t) * t; - d = a + (b + b - a - a) * t + (a + c - b - b) * t * t; - d = a + (b - a) * 2 * t + (a + c - b * 2) * t * t; - d = a + (b - a) * 2 * t + (a - b + c - b) * t * t; - - d = in[0] + (in[1] - in[0]) * 2 * t + (in[0] - in[1] + in[2] - in[1]) * t * t; -*/ -