X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=dosdemo;a=blobdiff_plain;f=src%2Fmetaball.c;fp=src%2Fmetaball.c;h=a6dec99c454a70661358c6e12922fb85e1ec6d20;hp=0000000000000000000000000000000000000000;hb=134c9e63e9a7602cd2e0a3c05557edb0c9753c74;hpb=157a4056159e45cd61e9427e126807aaa8bd3d9a

diff --git a/src/metaball.c b/src/metaball.c
new file mode 100644
index 0000000..a6dec99
--- /dev/null
+++ b/src/metaball.c
@@ -0,0 +1,296 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <assert.h>
+#include "screen.h"
+#include "demo.h"
+#include "3dgfx.h"
+#include "gfxutil.h"
+#include "util.h"
+#include "metasurf.h"
+#include "dynarr.h"
+
+struct mesh {
+	int prim;
+	struct g3d_vertex *varr;
+	int16_t *iarr;
+	int vcount, icount;
+};
+
+struct metaball {
+	float energy;
+	float pos[3];
+};
+
+static int init(void);
+static void destroy(void);
+static void start(long trans_time);
+static void draw(void);
+static void draw_mesh(struct mesh *mesh);
+static void zsort(struct mesh *m);
+
+static void calc_voxel_field(void);
+static float eval(struct metasurface *ms, float x, float y, float z);
+static void emit_vertex(struct metasurface *ms, float x, float y, float z);
+
+static struct screen scr = {
+	"metaballs",
+	init,
+	destroy,
+	start, 0,
+	draw
+};
+
+static float cam_theta, cam_phi = 25;
+static float cam_dist = 3;
+static struct mesh mmesh;
+
+static struct metasurface *msurf;
+
+#define VOL_SZ	32
+#define VOL_SCALE	10.0f
+#define VOL_HALF_SCALE	(VOL_SCALE * 0.5f)
+static float *volume;
+#define VOXEL(x, y, z)	(volume[(z) * VOL_SZ * VOL_SZ + (y) * VOL_SZ + (x)])
+
+#define NUM_MBALLS	3
+static struct metaball mball[NUM_MBALLS];
+
+
+struct screen *metaballs_screen(void)
+{
+	return &scr;
+}
+
+static int init(void)
+{
+	if(!(volume = malloc(VOL_SZ * VOL_SZ * VOL_SZ * sizeof *volume))) {
+		fprintf(stderr, "failed to allocate %dx%dx%d voxel field\n", VOL_SZ, VOL_SZ, VOL_SZ);
+		return -1;
+	}
+
+	mball[0].energy = 1.2;
+	mball[1].energy = 0.8;
+	mball[2].energy = 1.0;
+
+	if(!(msurf = msurf_create())) {
+		fprintf(stderr, "failed to initialize metasurf\n");
+		return -1;
+	}
+	msurf_set_resolution(msurf, VOL_SZ, VOL_SZ, VOL_SZ);
+	msurf_set_bounds(msurf, 0, 0, 0, VOL_SCALE, VOL_SCALE, VOL_SCALE);
+	msurf_eval_func(msurf, eval);
+	msurf_set_threshold(msurf, 0.5);
+	msurf_set_inside(msurf, MSURF_GREATER);
+	msurf_vertex_func(msurf, emit_vertex);
+
+	mmesh.prim = G3D_TRIANGLES;
+	mmesh.varr = 0;
+	mmesh.iarr = 0;
+	mmesh.vcount = mmesh.icount = 0;
+
+	return 0;
+}
+
+static void destroy(void)
+{
+	dynarr_free(mmesh.varr);
+}
+
+static void start(long trans_time)
+{
+	g3d_matrix_mode(G3D_PROJECTION);
+	g3d_load_identity();
+	g3d_perspective(50.0, 1.3333333, 0.5, 100.0);
+
+	g3d_enable(G3D_CULL_FACE);
+	g3d_enable(G3D_LIGHTING);
+	g3d_enable(G3D_LIGHT0);
+
+	g3d_polygon_mode(G3D_WIRE);
+}
+
+static void update(void)
+{
+	static int prev_mx, prev_my;
+	static unsigned int prev_bmask;
+
+	if(mouse_bmask) {
+		if((mouse_bmask ^ prev_bmask) == 0) {
+			int dx = mouse_x - prev_mx;
+			int dy = mouse_y - prev_my;
+
+			if(dx || dy) {
+				if(mouse_bmask & 1) {
+					cam_theta += dx * 1.0;
+					cam_phi += dy * 1.0;
+
+					if(cam_phi < -90) cam_phi = -90;
+					if(cam_phi > 90) cam_phi = 90;
+				}
+				if(mouse_bmask & 4) {
+					cam_dist += dy * 0.5;
+
+					if(cam_dist < 0) cam_dist = 0;
+				}
+			}
+		}
+	}
+	prev_mx = mouse_x;
+	prev_my = mouse_y;
+	prev_bmask = mouse_bmask;
+
+	{
+		int i, j;
+		float tsec = time_msec / 1000.0f;
+		static float phase[] = {0.0, M_PI / 3.0, M_PI * 0.8};
+		static float speed[] = {0.8, 1.4, 1.0};
+		static float scale[][3] = {{1, 2, 0.8}, {0.5, 1.6, 0.6}, {1.5, 0.7, 0.5}};
+		static float offset[][3] = {{0, 0, 0}, {0.25, 0, 0}, {-0.2, 0.15, 0.2}};
+
+		for(i=0; i<NUM_MBALLS; i++) {
+			float t = (tsec + phase[i]) * speed[i];
+
+			for(j=0; j<3; j++) {
+				float x = sin(t + j * M_PI / 2.0);
+				mball[i].pos[j] = offset[i][j] + x * scale[i][j];
+			}
+		}
+	}
+
+	calc_voxel_field();
+
+	dynarr_free(mmesh.varr);
+	mmesh.varr = dynarr_alloc(0, sizeof *mmesh.varr);
+	msurf_polygonize(msurf);
+}
+
+static void draw(void)
+{
+	update();
+
+	memset(fb_pixels, 0, fb_width * fb_height * 2);
+
+	g3d_matrix_mode(G3D_MODELVIEW);
+	g3d_load_identity();
+	g3d_translate(0, 0, -cam_dist);
+	g3d_rotate(cam_phi, 1, 0, 0);
+	g3d_rotate(cam_theta, 0, 1, 0);
+
+	/*g3d_light_pos(0, -10, 10, 20);*/
+
+	/*zsort(&metamesh);*/
+
+	/*g3d_mtl_diffuse(0.6, 0.6, 0.6);*/
+
+	draw_mesh(&mmesh);
+
+	swap_buffers(fb_pixels);
+}
+
+static void draw_mesh(struct 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);
+	}
+}
+
+static struct {
+	struct g3d_vertex *varr;
+	const float *xform;
+} zsort_cls;
+
+static int zsort_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;
+}
+
+static void zsort(struct mesh *m)
+{
+	int nfaces = m->icount / m->prim;
+
+	zsort_cls.varr = m->varr;
+	zsort_cls.xform = g3d_get_matrix(G3D_MODELVIEW, 0);
+
+	qsort(m->iarr, nfaces, m->prim * sizeof *m->iarr, zsort_cmp);
+}
+
+static void calc_voxel_field(void)
+{
+	int i, j, k, b;
+	float *voxptr = volume;
+
+	for(i=0; i<VOL_SZ; i++) {
+		float z = VOL_SCALE * ((float)i / (float)VOL_SZ - 0.5);
+
+		for(j=0; j<VOL_SZ; j++) {
+			float y = VOL_SCALE * ((float)j / (float)VOL_SZ - 0.5);
+
+			for(k=0; k<VOL_SZ; k++) {
+				float x = VOL_SCALE * ((float)k / (float)VOL_SZ - 0.5);
+
+				float val = 0.0f;
+				for(b=0; b<NUM_MBALLS; b++) {
+					float dx = mball[b].pos[0] - x;
+					float dy = mball[b].pos[1] - y;
+					float dz = mball[b].pos[2] - z;
+
+					float lensq = dx * dx + dy * dy + dz * dz;
+
+					val += lensq == 0.0f ? 1024.0f : mball[b].energy / lensq;
+				}
+
+				*voxptr++ = val;
+			}
+		}
+	}
+}
+
+static float eval(struct metasurface *ms, float x, float y, float z)
+{
+	int xidx = cround64(x);
+	int yidx = cround64(y);
+	int zidx = cround64(z);
+
+	assert(xidx >= 0 && xidx < VOL_SZ);
+	assert(yidx >= 0 && yidx < VOL_SZ);
+	assert(zidx >= 0 && zidx < VOL_SZ);
+
+	return VOXEL(xidx, yidx, zidx);
+}
+
+static void emit_vertex(struct metasurface *ms, float x, float y, float z)
+{
+	struct g3d_vertex v;
+
+	v.x = x - VOL_HALF_SCALE;
+	v.y = y - VOL_HALF_SCALE;
+	v.z = z - VOL_HALF_SCALE;
+	v.r = cround64(255.0 * x / VOL_SCALE);
+	v.g = cround64(255.0 * y / VOL_SCALE);
+	v.b = cround64(255.0 * z / VOL_SCALE);
+
+	mmesh.varr = dynarr_push(mmesh.varr, &v);
+	assert(mmesh.varr);
+	++mmesh.vcount;
+}