X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;ds=sidebyside;f=src%2Fmesh.c;fp=src%2Fmesh.c;h=0027ccfeaed0c2a35e4365e73c3911e358e6b562;hb=8cee0ffb00cce3d81487f1161286ac299db7d044;hp=0000000000000000000000000000000000000000;hpb=9ed338a5e703fc819cede5cb797e82e08046ac17;p=dosdemo

diff --git a/src/mesh.c b/src/mesh.c
new file mode 100644
index 0000000..0027ccf
--- /dev/null
+++ b/src/mesh.c
@@ -0,0 +1,233 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include "mesh.h"
+#include "3dgfx.h"
+
+int load_mesh(struct g3d_mesh *mesh, const char *fname)
+{
+	return -1;	/* TODO */
+}
+
+static struct {
+	struct g3d_vertex *varr;
+	const float *xform;
+} zsort_cls;
+
+static int zsort_cmp(const void *aptr, const void *bptr)
+{
+	const float *m = zsort_cls.xform;
+
+	const struct g3d_vertex *va = (const struct g3d_vertex*)aptr;
+	const struct g3d_vertex *vb = (const struct g3d_vertex*)bptr;
+
+	float za = m[2] * va->x + m[6] * va->y + m[10] * va->z + m[14];
+	float zb = m[2] * vb->x + m[6] * vb->y + m[10] * vb->z + m[14];
+
+	++va;
+	++vb;
+
+	za += m[2] * va->x + m[6] * va->y + m[10] * va->z + m[14];
+	zb += m[2] * vb->x + m[6] * vb->y + m[10] * vb->z + m[14];
+
+	return za - zb;
+}
+
+static int zsort_indexed_cmp(const void *aptr, const void *bptr)
+{
+	const int16_t *a = (const int16_t*)aptr;
+	const int16_t *b = (const int16_t*)bptr;
+
+	const float *m = zsort_cls.xform;
+
+	const struct g3d_vertex *va = zsort_cls.varr + a[0];
+	const struct g3d_vertex *vb = zsort_cls.varr + b[0];
+
+	float za = m[2] * va->x + m[6] * va->y + m[10] * va->z + m[14];
+	float zb = m[2] * vb->x + m[6] * vb->y + m[10] * vb->z + m[14];
+
+	va = zsort_cls.varr + a[2];
+	vb = zsort_cls.varr + b[2];
+
+	za += m[2] * va->x + m[6] * va->y + m[10] * va->z + m[14];
+	zb += m[2] * vb->x + m[6] * vb->y + m[10] * vb->z + m[14];
+
+	return za - zb;
+}
+
+
+void zsort_mesh(struct g3d_mesh *m)
+{
+	zsort_cls.varr = m->varr;
+	zsort_cls.xform = g3d_get_matrix(G3D_MODELVIEW, 0);
+
+	if(m->iarr) {
+		int nfaces = m->icount / m->prim;
+		qsort(m->iarr, nfaces, m->prim * sizeof *m->iarr, zsort_indexed_cmp);
+	} else {
+		int nfaces = m->vcount / m->prim;
+		qsort(m->varr, nfaces, m->prim * sizeof *m->varr, zsort_cmp);
+	}
+}
+
+
+void draw_mesh(struct g3d_mesh *mesh)
+{
+	if(mesh->iarr) {
+		g3d_draw_indexed(mesh->prim, mesh->varr, mesh->vcount, mesh->iarr, mesh->icount);
+	} else {
+		g3d_draw(mesh->prim, mesh->varr, mesh->vcount);
+	}
+}
+
+
+#define NORMAL(vp, x, y, z) do { vp->nx = x; vp->ny = y; vp->nz = z; } while(0)
+#define COLOR(vp, cr, cg, cb) do { vp->r = cr; vp->g = cg; vp->b = cb; } while(0)
+#define TEXCOORD(vp, tu, tv) do { vp->u = tu; vp->v = tv; } while(0)
+#define VERTEX(vp, vx, vy, vz) \
+	do { \
+		vp->x = vx; vp->y = vy; vp->z = vz; vp->w = 1.0f; \
+		++vp; \
+	} while(0)
+
+int gen_cube(struct g3d_mesh *mesh, float sz, int sub)
+{
+	struct g3d_vertex *vptr;
+	float hsz = sz / 2.0;
+
+	mesh->prim = G3D_QUADS;
+	mesh->iarr = 0;
+	mesh->icount = 0;
+
+	mesh->vcount = 24;
+	if(!(mesh->varr = malloc(mesh->vcount * sizeof *mesh->varr))) {
+		return -1;
+	}
+	vptr = mesh->varr;
+
+	/* -Z */
+	NORMAL(vptr, 0, 0, -1);
+	COLOR(vptr, 255, 0, 255);
+	VERTEX(vptr, hsz, -hsz, -hsz);
+	VERTEX(vptr, -hsz, -hsz, -hsz);
+	VERTEX(vptr, -hsz, hsz, -hsz);
+	VERTEX(vptr, hsz, hsz, -hsz);
+	/* -Y */
+	NORMAL(vptr, 0, -1, 0);
+	COLOR(vptr, 0, 255, 255);
+	VERTEX(vptr, -hsz, -hsz, -hsz);
+	VERTEX(vptr, hsz, -hsz, -hsz);
+	VERTEX(vptr, hsz, -hsz, hsz);
+	VERTEX(vptr, -hsz, -hsz, hsz);
+	/* -X */
+	NORMAL(vptr, -1, 0, 0);
+	COLOR(vptr, 255, 255, 0);
+	VERTEX(vptr, -hsz, -hsz, -hsz);
+	VERTEX(vptr, -hsz, -hsz, hsz);
+	VERTEX(vptr, -hsz, hsz, hsz);
+	VERTEX(vptr, -hsz, hsz, -hsz);
+	/* +X */
+	NORMAL(vptr, 1, 0, 0);
+	COLOR(vptr, 255, 0, 0);
+	VERTEX(vptr, hsz, -hsz, hsz);
+	VERTEX(vptr, hsz, -hsz, -hsz);
+	VERTEX(vptr, hsz, hsz, -hsz);
+	VERTEX(vptr, hsz, hsz, hsz);
+	/* +Y */
+	NORMAL(vptr, 0, 1, 0);
+	COLOR(vptr, 0, 255, 0);
+	VERTEX(vptr, -hsz, hsz, hsz);
+	VERTEX(vptr, hsz, hsz, hsz);
+	VERTEX(vptr, hsz, hsz, -hsz);
+	VERTEX(vptr, -hsz, hsz, -hsz);
+	/* +Z */
+	NORMAL(vptr, 0, 0, 1);
+	COLOR(vptr, 0, 0, 255);
+	VERTEX(vptr, -hsz, -hsz, hsz);
+	VERTEX(vptr, hsz, -hsz, hsz);
+	VERTEX(vptr, hsz, hsz, hsz);
+	VERTEX(vptr, -hsz, hsz, hsz);
+
+	return 0;
+}
+
+static void torusvec(float *res, float theta, float phi, float mr, float rr)
+{
+	float rx, ry, rz;
+	theta = -theta;
+
+	rx = -cos(phi) * rr + mr;
+	ry = sin(phi) * rr;
+	rz = 0.0f;
+
+	res[0] = rx * sin(theta) + rz * cos(theta);
+	res[1] = ry;
+	res[2] = -rx * cos(theta) + rz * sin(theta);
+}
+
+int gen_torus(struct g3d_mesh *mesh, float rad, float ringrad, int usub, int vsub)
+{
+	int i, j;
+	int nfaces, uverts, vverts;
+	struct g3d_vertex *vptr;
+	int16_t *iptr;
+
+	mesh->prim = G3D_QUADS;
+
+	if(usub < 4) usub = 4;
+	if(vsub < 2) vsub = 2;
+
+	uverts = usub + 1;
+	vverts = vsub + 1;
+
+	mesh->vcount = uverts * vverts;
+	nfaces = usub * vsub;
+	mesh->icount = nfaces * 4;
+
+	printf("generating torus with %d faces (%d vertices)\n", nfaces, mesh->vcount);
+
+	if(!(mesh->varr = malloc(mesh->vcount * sizeof *mesh->varr))) {
+		return -1;
+	}
+	if(!(mesh->iarr = malloc(mesh->icount * sizeof *mesh->iarr))) {
+		return -1;
+	}
+	vptr = mesh->varr;
+	iptr = mesh->iarr;
+
+	for(i=0; i<uverts; i++) {
+		float u = (float)i / (float)(uverts - 1);
+		float theta = u * 2.0 * M_PI;
+		float rcent[3];
+
+		torusvec(rcent, theta, 0, rad, 0);
+
+		for(j=0; j<vverts; j++) {
+			float v = (float)j / (float)(vverts - 1);
+			float phi = v * 2.0 * M_PI;
+			int chess = (i & 1) == (j & 1);
+
+			torusvec(&vptr->x, theta, phi, rad, ringrad);
+
+			vptr->nx = (vptr->x - rcent[0]) / ringrad;
+			vptr->ny = (vptr->y - rcent[1]) / ringrad;
+			vptr->nz = (vptr->z - rcent[2]) / ringrad;
+			vptr->u = u;
+			vptr->v = v;
+			vptr->r = chess ? 255 : 64;
+			vptr->g = 128;
+			vptr->b = chess ? 64 : 255;
+			++vptr;
+
+			if(i < usub && j < vsub) {
+				int idx = i * vverts + j;
+				*iptr++ = idx;
+				*iptr++ = idx + 1;
+				*iptr++ = idx + vverts + 1;
+				*iptr++ = idx + vverts;
+			}
+		}
+	}
+	return 0;
+}
+