diff options
Diffstat (limited to 'raster/meshdraw.c')
| -rw-r--r-- | raster/meshdraw.c | 402 |
1 files changed, 402 insertions, 0 deletions
diff --git a/raster/meshdraw.c b/raster/meshdraw.c new file mode 100644 index 00000000..f5b1a3fb --- /dev/null +++ b/raster/meshdraw.c @@ -0,0 +1,402 @@ +#include <fitz.h> + +/* + * polygon clipping + */ + +enum { IN, OUT, ENTER, LEAVE }; +enum { MAXV = 3 + 4 }; +enum { MAXN = 2 + FZ_MAXCOLORS }; + +static int clipx(float val, int ismax, float *v1, float *v2, int n) +{ + float t; + int i; + int v1o = ismax ? v1[0] > val : v1[0] < val; + int v2o = ismax ? v2[0] > val : v2[0] < val; + if (v1o + v2o == 0) + return IN; + if (v1o + v2o == 2) + return OUT; + if (v2o) + { + t = (val - v1[0]) / (v2[0] - v1[0]); + v2[0] = val; + v2[1] = v1[1] + t * (v2[1] - v1[1]); + for (i = 2; i < n; i++) + v2[i] = v1[i] + t * (v2[i] - v1[i]); + return LEAVE; + } + else + { + t = (val - v2[0]) / (v1[0] - v2[0]); + v1[0] = val; + v1[1] = v2[1] + t * (v1[1] - v2[1]); + for (i = 2; i < n; i++) + v1[i] = v2[i] + t * (v1[i] - v2[i]); + return ENTER; + } +} + +static int clipy(float val, int ismax, float *v1, float *v2, int n) +{ + float t; + int i; + int v1o = ismax ? v1[1] > val : v1[1] < val; + int v2o = ismax ? v2[1] > val : v2[1] < val; + if (v1o + v2o == 0) + return IN; + if (v1o + v2o == 2) + return OUT; + if (v2o) + { + t = (val - v1[1]) / (v2[1] - v1[1]); + v2[0] = v1[0] + t * (v2[0] - v1[0]); + v2[1] = val; + for (i = 2; i < n; i++) + v2[i] = v1[i] + t * (v2[i] - v1[i]); + return LEAVE; + } + else + { + t = (val - v2[1]) / (v1[1] - v2[1]); + v1[0] = v2[0] + t * (v1[0] - v2[0]); + v1[1] = val; + for (i = 2; i < n; i++) + v1[i] = v2[i] + t * (v1[i] - v2[i]); + return ENTER; + } +} + +static inline void copyvert(float *dst, float *src, int n) +{ + while (n--) + *dst++ = *src++; +} + +static int clippoly(float src[MAXV][MAXN], + float dst[MAXV][MAXN], int len, int n, + float val, int isy, int ismax) +{ + float cv1[MAXN]; + float cv2[MAXN]; + int v1, v2, cp; + int r; + + v1 = len - 1; + cp = 0; + + for (v2 = 0; v2 < len; v2++) + { + copyvert(cv1, src[v1], n); + copyvert(cv2, src[v2], n); + + if (isy) + r = clipy(val, ismax, cv1, cv2, n); + else + r = clipx(val, ismax, cv1, cv2, n); + + switch (r) + { + case IN: + copyvert(dst[cp++], cv2, n); + break; + case OUT: + break; + case LEAVE: + copyvert(dst[cp++], cv2, n); + break; + case ENTER: + copyvert(dst[cp++], cv1, n); + copyvert(dst[cp++], cv2, n); + break; + } + v1 = v2; + } + + return cp; +} + +/* + * gouraud shaded polygon scan conversion + */ + +static inline void +drawscan(fz_pixmap *pix, int y, int x1, int x2, int *v1, int *v2, int n) +{ + unsigned char *p = pix->samples + ((y - pix->y) * pix->w + (x1 - pix->x)) * pix->n; + int v[FZ_MAXCOLORS]; + int dv[FZ_MAXCOLORS]; + int w = x2 - x1; + int k; + + assert(w >= 0); + assert(y >= pix->y); + assert(y < pix->y + pix->h); + assert(x1 >= pix->x); + assert(x2 <= pix->x + pix->w); + + if (w == 0) + return; + + for (k = 0; k < n; k++) + { + v[k] = v1[k]; + dv[k] = (v2[k] - v1[k]) / w; + } + + while (w--) + { + *p++ = 255; + for (k = 0; k < n; k++) + { + *p++ = v[k] >> 16; + v[k] += dv[k]; + } + } +} + +static inline int +findnext(int gel[MAXV][MAXN], int len, int a, int *s, int *e, int d) +{ + int b; + + while (1) + { + b = a + d; + if (b == len) + b = 0; + if (b == -1) + b = len - 1; + + if (gel[b][1] == gel[a][1]) + { + a = b; + continue; + } + + if (gel[b][1] > gel[a][1]) + { + *s = a; + *e = b; + return 0; + } + + return 1; + } +} + +static inline void +loadedge(int gel[MAXV][MAXN], int s, int e, int *ael, int *del, int n) +{ + int swp, k, dy; + + if (gel[s][1] > gel[s][1]) + { + swp = s; s = e; e = swp; + } + + dy = gel[e][1] - gel[s][1]; + + ael[0] = gel[s][0]; + del[0] = (gel[e][0] - gel[s][0]) / dy; + for (k = 2; k < n; k++) + { + ael[k] = gel[s][k]; + del[k] = (gel[e][k] - gel[s][k]) / dy; + } +} + +static inline void +stepedge(int *ael, int *del, int n) +{ + int k; + ael[0] += del[0]; + for (k = 2; k < n; k++) + ael[k] += del[k]; +} + +void +fz_drawtriangle(fz_pixmap *pix, float *av, float *bv, float *cv, int n) +{ + float poly[MAXV][MAXN]; + float temp[MAXV][MAXN]; + float cx0 = pix->x; + float cy0 = pix->y; + float cx1 = pix->x + pix->w; + float cy1 = pix->y + pix->h; + + int gel[MAXV][MAXN]; + int ael[2][MAXN]; + int del[2][MAXN]; + int y, s0, s1, e0, e1; + int top, bot, len; + + int i, k; + + copyvert(poly[0], av, n); + copyvert(poly[1], bv, n); + copyvert(poly[2], cv, n); + + len = clippoly(poly, temp, 3, n, cx0, 0, 0); + len = clippoly(temp, poly, len, n, cx1, 0, 1); + len = clippoly(poly, temp, len, n, cy0, 1, 0); + len = clippoly(temp, poly, len, n, cy1, 1, 1); + + if (len < 3) + return; + + for (i = 0; i < len; i++) + { + gel[i][0] = fz_floor(poly[i][0] + 0.5) * 65536; /* trunc and fix */ + gel[i][1] = fz_floor(poly[i][1] + 0.5); /* y is not fixpoint */ + for (k = 2; k < n; k++) + gel[i][k] = poly[i][k] * 65536; /* fix with precision */ + } + + top = bot = 0; + for (i = 0; i < len; i++) + { + if (gel[i][1] < gel[top][1]) + top = i; + if (gel[i][1] > gel[bot][1]) + bot = i; + } + + if (gel[bot][1] - gel[top][1] == 0) + return; + + y = gel[top][1]; + + if (findnext(gel, len, top, &s0, &e0, 1)) + return; + if (findnext(gel, len, top, &s1, &e1, -1)) + return; + + loadedge(gel, s0, e0, ael[0], del[0], n); + loadedge(gel, s1, e1, ael[1], del[1], n); + + while (1) + { + int x0 = ael[0][0] >> 16; + int x1 = ael[1][0] >> 16; + + if (ael[0][0] < ael[1][0]) + drawscan(pix, y, x0, x1, ael[0]+2, ael[1]+2, n-2); + else + drawscan(pix, y, x1, x0, ael[1]+2, ael[0]+2, n-2); + + stepedge(ael[0], del[0], n); + stepedge(ael[1], del[1], n); + y ++; + + if (y >= gel[e0][1]) + { + if (findnext(gel, len, e0, &s0, &e0, 1)) + return; + loadedge(gel, s0, e0, ael[0], del[0], n); + } + + if (y >= gel[e1][1]) + { + if (findnext(gel, len, e1, &s1, &e1, -1)) + return; + loadedge(gel, s1, e1, ael[1], del[1], n); + } + } +} + +/* + * mesh drawing + */ + +fz_error * +fz_rendershade(fz_shade *shade, fz_matrix ctm, fz_colorspace *destcs, fz_pixmap *dest) +{ + unsigned char clut[256][3]; + unsigned char *s, *d; + fz_error *error; + fz_pixmap *temp; + float rgb[3]; + float tri[3][MAXN]; + fz_point p; + int i, j, k, n; + + assert(dest->n == 4); + + ctm = fz_concat(shade->matrix, ctm); + + if (shade->usefunction) + { + n = 3; + error = fz_newpixmap(&temp, dest->x, dest->y, dest->w, dest->h, 2); + if (error) + return error; + } + else if (shade->cs != destcs) + { + n = 2 + shade->cs->n; + error = fz_newpixmap(&temp, dest->x, dest->y, dest->w, dest->h, + shade->cs->n + 1); + if (error) + return error; + } + else + { + n = 2 + shade->cs->n; + temp = dest; + } + + fz_clearpixmap(temp); + + for (i = 0; i < shade->meshlen; i++) + { + for (k = 0; k < 3; k++) + { + p.x = shade->mesh[(i * 3 + k) * n + 0]; + p.y = shade->mesh[(i * 3 + k) * n + 1]; + p = fz_transformpoint(ctm, p); + tri[k][0] = p.x; + tri[k][1] = p.y; + for (j = 2; j < n; j++) + tri[k][j] = shade->mesh[( i * 3 + k) * n + j] * 255; + } + fz_drawtriangle(temp, tri[0], tri[1], tri[2], n); + } + + if (shade->usefunction) + { + for (i = 0; i < 256; i++) + { + fz_convertcolor(shade->cs, shade->function[i], destcs, rgb); + clut[i][0] = rgb[0] * 255; + clut[i][1] = rgb[1] * 255; + clut[i][2] = rgb[2] * 255; + } + + n = temp->w * temp->h; + s = temp->samples; + d = dest->samples; + + while (n--) + { + d[0] = s[0]; + d[1] = fz_mul255(s[0], clut[s[1]][0]); + d[2] = fz_mul255(s[0], clut[s[1]][1]); + d[3] = fz_mul255(s[0], clut[s[1]][2]); + s += 2; + d += 4; + } + + fz_droppixmap(temp); + } + + else if (shade->cs != destcs) + { + fz_convertpixmap(shade->cs, temp, destcs, dest); + fz_droppixmap(temp); + } + + return nil; +} + |