#include <stdio.h>
#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <alloca.h>
#include "polyfill.h"
#include "gfxutil.h"
#include "demo.h"
void (*fillfunc[])(struct pvertex*, int) = {
polyfill_wire,
- 0, 0, 0, 0
+ polyfill_flat,
+ 0, 0, 0
};
+struct pimage pimg_fb, pimg_texture;
+
void polyfill(int mode, struct pvertex *verts, int nverts)
{
#ifndef NDEBUG
void polyfill_wire(struct pvertex *verts, int nverts)
{
- int i;
+ int i, x0, y0, x1, y1;
struct pvertex *v = verts;
unsigned short color = ((v->r << 8) & 0xf800) |
((v->g << 3) & 0x7e0) | ((v->b >> 3) & 0x1f);
- for(i=0; i<nverts; i++) {
- int x0, y0, x1, y1;
+ for(i=0; i<nverts - 1; i++) {
x0 = v->x >> 8;
y0 = v->y >> 8;
++v;
x1 = v->x >> 8;
y1 = v->y >> 8;
- clip_line(&x0, &y0, &x1, &y1, 0, 0, fb_width, fb_height);
- draw_line(x0, y0, x1, y1, color);
+ if(clip_line(&x0, &y0, &x1, &y1, 0, 0, pimg_fb.width, pimg_fb.height)) {
+ draw_line(x0, y0, x1, y1, color);
+ }
+ }
+ x0 = verts[0].x >> 8;
+ y0 = verts[0].y >> 8;
+ if(clip_line(&x1, &y1, &x0, &y0, 0, 0, pimg_fb.width, pimg_fb.height)) {
+ draw_line(x1, y1, x0, y0, color);
+ }
+}
+
+static uint32_t scan_edge(struct pvertex *v0, struct pvertex *v1, struct pvertex *edge);
+
+#define NEXTIDX(x) (((x) - 1 + nverts) % nverts)
+#define PREVIDX(x) (((x) + 1) % nverts)
+
+void polyfill_flat(struct pvertex *pv, int nverts)
+{
+ int i;
+ int topidx = 0, botidx = 0, sltop = pimg_fb.height, slbot = 0;
+ struct pvertex *left, *right;
+ uint16_t color = PACK_RGB16(pv[0].r, pv[0].g, pv[0].b);
+
+ for(i=1; i<nverts; i++) {
+ if(pv[i].y < pv[topidx].y) topidx = i;
+ if(pv[i].y > pv[botidx].y) botidx = i;
+ }
+
+ left = (struct pvertex*)alloca(pimg_fb.height * sizeof *left);
+ right = (struct pvertex*)alloca(pimg_fb.height * sizeof *right);
+ memset(left, 0, pimg_fb.height * sizeof *left);
+ memset(right, 0, pimg_fb.height * sizeof *right);
+
+ for(i=0; i<nverts; i++) {
+ int next = NEXTIDX(i);
+ int32_t y0 = pv[i].y;
+ int32_t y1 = pv[next].y;
+
+ if((y0 >> 8) == (y1 >> 8)) {
+ if(y0 > y1) {
+ int idx = y0 >> 8;
+ left[idx].x = pv[i].x < pv[next].x ? pv[i].x : pv[next].x;
+ right[idx].x = pv[i].x < pv[next].x ? pv[next].x : pv[i].x;
+ }
+ } else {
+ struct pvertex *edge = y0 > y1 ? left : right;
+ uint32_t res = scan_edge(pv + i, pv + next, edge);
+ uint32_t tmp = (res >> 16) & 0xffff;
+ if(tmp > slbot) slbot = tmp;
+ if((tmp = res & 0xffff) < sltop) {
+ sltop = tmp;
+ }
+ }
}
+
+ for(i=sltop; i<=slbot; i++) {
+ int32_t x;
+ uint16_t *pixptr;
+
+ x = left[i].x;
+ pixptr = pimg_fb.pixels + i * pimg_fb.width + (x >> 8);
+
+ while(x <= right[i].x) {
+#ifdef DEBUG_POLYFILL
+ *pixptr++ += 15;
+#else
+ *pixptr++ = color;
+#endif
+ x += 256;
+ }
+ }
+}
+
+static uint32_t scan_edge(struct pvertex *v0, struct pvertex *v1, struct pvertex *edge)
+{
+ int i;
+ int32_t x, dx, dy, slope;
+ int32_t start_idx, end_idx;
+
+ if(v0->y > v1->y) {
+ struct pvertex *tmp = v0;
+ v0 = v1;
+ v1 = tmp;
+ }
+
+ dy = v1->y - v0->y;
+ dx = v1->x - v0->x;
+ slope = (dx << 8) / dy;
+
+ start_idx = v0->y >> 8;
+ end_idx = v1->y >> 8;
+
+ x = v0->x;
+ for(i=start_idx; i<end_idx; i++) {
+ edge[i].x = x;
+ x += slope;
+ }
+
+ return (uint32_t)start_idx | ((uint32_t)(end_idx - 1) << 16);
}