/*
-blender for the Gameboy Advance
-Copyright (C) 2021 John Tsiombikas <nuclear@member.fsf.org>
+gbajam22 entry for the Gameboy Advance
+Copyright (C) 2022 John Tsiombikas <nuclear@mutantstargoat.com>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include "xgl.h"
#include "polyfill.h"
#include "debug.h"
+#include "util.h"
#define MAT_STACK_SIZE 4
static unsigned int opt;
static int32_t ldir[3];
+static int cur_cidx;
+
static void draw_ptlines(int prim, const struct xvertex *varr, int vcount);
}
}
+#if 0
#define XSIN(x) (int32_t)(sin(x / 65536.0f) * 65536.0f)
#define XCOS(x) (int32_t)(cos(x / 65536.0f) * 65536.0f)
+#else
+#define XSIN(x) SIN(((x) << 8) / (X_2PI >> 8))
+#define XCOS(x) COS(((x) << 8) / (X_2PI >> 8))
+#endif
void xgl_translate(int32_t x, int32_t y, int32_t z)
{
xgl_mult_matrix(m);
}
-static void xform(struct xvertex *out, const struct xvertex *in, const int32_t *m)
+void xgl_index(int cidx)
+{
+ cur_cidx = cidx;
+}
+
+static inline void xform(struct xvertex *out, const struct xvertex *in, const int32_t *m)
{
out->x = XMUL(m[0], in->x) + XMUL(m[4], in->y) + XMUL(m[8], in->z) + m[12];
out->y = XMUL(m[1], in->x) + XMUL(m[5], in->y) + XMUL(m[9], in->z) + m[13];
out->z = XMUL(m[2], in->x) + XMUL(m[6], in->y) + XMUL(m[10], in->z) + m[14];
}
-static void xform_norm(struct xvertex *out, const struct xvertex *in, const int32_t *m)
+static inline void xform_norm(struct xvertex *out, const struct xvertex *in, const int32_t *m)
{
out->nx = XMUL(m[0], in->nx) + XMUL(m[4], in->ny) + XMUL(m[8], in->nz);
out->ny = XMUL(m[1], in->nx) + XMUL(m[5], in->ny) + XMUL(m[9], in->nz);
/* d = 1.0 / tan(fov/2) */
#define PROJ_D 0x20000
+/* near Z = 0.5 */
+#define NEAR_Z 0x18000
+ARM_IWRAM
void xgl_draw(int prim, const struct xvertex *varr, int vcount)
{
- int i, cidx;
- struct xvertex xv[4];
+ int i, cidx, clipnum;
+ struct xvertex xv[4], xvclip[8];
struct pvertex pv[4];
int32_t ndotl;
}
while(vcount >= prim) {
- cidx = varr->cidx;
+ cidx = cur_cidx;//varr->cidx;
xform(xv, varr, mat[mtop]);
xform_norm(xv, varr, mat[mtop]);
- if(xv->nz > 0) {
- /* backface */
- varr += prim;
- vcount -= prim;
- continue;
- }
-
+ /*
if(opt & XGL_LIGHTING) {
ndotl = (xv->nx >> 8) * ldir[0] + (xv->ny >> 8) * ldir[1] + (xv->nz >> 8) * ldir[2];
if(ndotl < 0) ndotl = 0;
cidx = 128 + (ndotl >> 9);
if(cidx > 255) cidx = 255;
}
+ */
- xv->x = (xv->x << 1) / (xv->z >> 8); /* assume aspect: ~2 */
- xv->y = (xv->y << 2) / (xv->z >> 8); /* the shift is * PROJ_D */
- /* projection result is 24.8 */
- /* viewport */
- pv->x = (((xv->x + 0x100) >> 1) * vp[2]) + (vp[0] << 8);
- pv->y = (((0x100 - xv->y) >> 1) * vp[3]) + (vp[1] << 8);
- varr++;
-
+ /* transform the rest of the vertices to view space */
for(i=1; i<prim; i++) {
- xform(xv + i, varr, mat[mtop]);
+ xform(xv + i, varr + i, mat[mtop]);
+ }
- xv[i].x = (xv[i].x << 1) / (xv[i].z >> 8); /* assume aspect: ~2 */
- xv[i].y = (xv[i].y << 2) / (xv[i].z >> 8); /* the shift is * PROJ_D */
- /* projection result is 24.8 */
+ /* clip against near plane */
+ xgl_clip_near(xvclip, &clipnum, xv, prim);
+
+ for(i=0; i<clipnum; i++) {
+ xvclip[i].x = (xvclip[i].x << 1) / (xvclip[i].z >> 8); /* assume aspect: ~2 */
+ xvclip[i].y = (xvclip[i].y << 2) / (xvclip[i].z >> 8); /* the shift is * PROJ_D */
+ /* transform result is 24.8 */
/* viewport */
- pv[i].x = (((xv[i].x + 0x100) >> 1) * vp[2]) + (vp[0] << 8);
- pv[i].y = (((0x100 - xv[i].y) >> 1) * vp[3]) + (vp[1] << 8);
- varr++;
+ pv[i].x = (((xvclip[i].x + 0x100) >> 1) * vp[2]) + (vp[0] << 8);
+ pv[i].y = (((0x100 - xvclip[i].y) >> 1) * vp[3]) + (vp[1] << 8);
}
- vcount -= prim;
- polyfill_flat(pv, prim, cidx);
+ polyfill_flat(pv, clipnum, cidx);
+skip_poly:
+ varr += prim;
+ vcount -= prim;
}
}
#ifndef ALT_LCLIP
clip_line((int*)&xv[0].x, (int*)&xv[0].y, (int*)&xv[1].x, (int*)&xv[1].y, vp[0], vp[1], vp[2] - 1, vp[3] - 1);
#endif
- draw_line(xv[0].x, xv[0].y, xv[1].x, xv[1].y, varr[-2].cidx);
+ draw_line(xv[0].x, xv[0].y, xv[1].x, xv[1].y, 0xff);
}
}
{
mat[mtop][12] = mat[mtop][13] = 0;
}
+
+#define ISECT_NEAR(v0, v1) ((((v0)->z - NEAR_Z) << 8) / ((v0)->z - (v1)->z))
+
+#define LERP_VATTR(res, v0, v1, t) \
+ do { \
+ (res)->x = (v0)->x + (((v1)->x - (v0)->x) >> 8) * (t); \
+ (res)->y = (v0)->y + (((v1)->y - (v0)->y) >> 8) * (t); \
+ (res)->z = (v0)->z + (((v1)->z - (v0)->z) >> 8) * (t); \
+ (res)->nx = (v0)->nx + (((v1)->nx - (v0)->nx) >> 8) * (t); \
+ (res)->ny = (v0)->ny + (((v1)->ny - (v0)->ny) >> 8) * (t); \
+ (res)->nz = (v0)->nz + (((v1)->nz - (v0)->nz) >> 8) * (t); \
+ (res)->tx = (v0)->tx + (((v1)->tx - (v0)->tx) >> 8) * (t); \
+ (res)->ty = (v0)->ty + (((v1)->ty - (v0)->ty) >> 8) * (t); \
+ (res)->lit = (v0)->lit + (((v1)->lit - (v0)->lit) >> 8) * (t); \
+ } while(0)
+
+ARM_IWRAM
+static int clip_edge_near(struct xvertex *poly, int *vnumptr, struct xvertex *v0, struct xvertex *v1)
+{
+ int vnum = *vnumptr;
+ int in0, in1;
+ int32_t t;
+ struct xvertex *vptr;
+
+ in0 = v0->z >= NEAR_Z ? 1 : 0;
+ in1 = v1->z >= NEAR_Z ? 1 : 0;
+
+ if(in0) {
+ /* start inside */
+ if(in1) {
+ /* all inside */
+ poly[vnum++] = *v1; /* append v1 */
+ *vnumptr = vnum;
+ return 1;
+ } else {
+ /* going out */
+ vptr = poly + vnum;
+ t = ISECT_NEAR(v0, v1); /* 24:8 */
+ LERP_VATTR(vptr, v0, v1, t);
+ ++vnum; /* append new vertex on the intersection point */
+ }
+ } else {
+ /* start outside */
+ if(in1) {
+ /* going in */
+ vptr = poly + vnum;
+ t = ISECT_NEAR(v0, v1);
+ LERP_VATTR(vptr, v0, v1, t);
+ ++vnum; /* append new vertex ... */
+ /* then append v1 */
+ poly[vnum++] = *v1;
+ } else {
+ /* all outside */
+ return -1;
+ }
+ }
+
+ *vnumptr = vnum;
+ return 0;
+}
+
+/* special case near-plane clipper */
+ARM_IWRAM
+int xgl_clip_near(struct xvertex *vout, int *voutnum, struct xvertex *vin, int vnum)
+{
+ int i, nextidx, res;
+ int edges_clipped = 0;
+
+ *voutnum = 0;
+
+ for(i=0; i<vnum; i++) {
+ nextidx = i + 1;
+ if(nextidx >= vnum) nextidx = 0;
+ res = clip_edge_near(vout, voutnum, vin + i, vin + nextidx);
+ if(res == 0) {
+ ++edges_clipped;
+ }
+ }
+
+ if(*voutnum <= 0) return -1;
+ return edges_clipped > 0 ? 0 : 1;
+}
projects / gbajam22 / blobdiff