#include "opengl.h"
#include "texture.h"
#include "sdr.h"
+#include "mesh.h"
+#include "meshgen.h"
/* NOTES:
* - whistle hhgg music
* - colliding particles merge
* - select objects and center camera on them
+ * - tesselate only where necessary
*/
struct Particle {
float mass;
Vec2 pos;
Vec2 vel;
+
+ Particle *next, *prev;
};
struct Emitter {
float mass;
float rate, chunk;
float angle, spread;
+
+ float spawn_pending;
};
struct Rect {
#define SIM_DT 0.016
#define GRID_SIZE 2048
-#define GRID_BITS 12
+#define GRID_BITS 11
#define GRID_X(idx) (((idx) >> GRID_BITS) & (GRID_SIZE - 1))
#define GRID_Y(idx) ((idx) & (GRID_SIZE - 1))
#define GRID_DELTA ((float)FIELD_SIZE / (float)GRID_SIZE)
#define MIN_CAM_DIST 1.0f
#define MAX_CAM_DIST 350.0f
-#define MASS_TO_RAD(m) log((m) + 1.0)
+#define MASS_TO_RADIUS(m) log((m) + 1.0)
#define CONTRIB_THRES 0.005
#define CONTRIB_RANGE(m) sqrt((m) / CONTRIB_THRES)
static int pos_to_grid(float x, float y);
static Vec2 grid_to_pos(int gx, int gy);
+static void calc_contrib_bounds(const Vec2 &pos, float mass, Rect *rect);
+static void add_influence(const Vec2 &pos, float mass, float radius, const Rect &cbox);
+
static void destroy_quadmesh(QuadMesh *m);
static void draw_quadmesh(const QuadMesh *m, unsigned int prim = GL_QUADS);
static void gen_quad_plane(QuadMesh *mesh, float width, float height, int usub, int vsub);
+static void spawn_particle(const Vec2 &pos, const Vec2 &vel, float mass);
+static void add_particle(Particle *p, int grid_idx);
+static void remove_particle(Particle *p, int grid_idx);
+static Particle *alloc_particle();
+void free_particle(Particle *p);
+
static float grid[GRID_SIZE * GRID_SIZE];
-static Particle grid_part[GRID_SIZE * GRID_SIZE];
+static Particle *grid_part[GRID_SIZE * GRID_SIZE];
static Texture *grid_tex;
+#define NUM_PARTICLE_LISTS 16
+static Particle *plist[NUM_PARTICLE_LISTS];
+#define GRID_IDX_PLIST(idx) ((idx) * NUM_PARTICLE_LISTS / (GRID_SIZE * GRID_SIZE))
+
static std::vector<Emitter*> emitters;
static Texture *gvis_tex; // texture tile for visualizing a grid
static QuadMesh field_mesh;
+static Mesh *pmesh;
+static unsigned int particle_sdr;
+
static float cam_theta;
static float cam_dist = 100.0f;
static Vec2 *targ_pos;
gen_quad_plane(&field_mesh, FIELD_SIZE, FIELD_SIZE, 32, 32);
+ pmesh = new Mesh;
+ gen_geosphere(pmesh, 1.0, 2);
+
+ if(!(particle_sdr = create_program_load("sdr/sph.v.glsl", "sdr/sph.p.glsl"))) {
+ return false;
+ }
+
// XXX DBG
emit_place_pos = Vec2(0, 0);
emit_place_pending = true;
delete gvis_tex;
delete grid_tex;
destroy_quadmesh(&field_mesh);
+ delete pmesh;
}
-static void calc_contrib_bounds(const Emitter *em, Rect *rect)
+static void simstep()
{
- int gidx = pos_to_grid(em->pos.x, em->pos.y);
- int gx = GRID_X(gidx);
- int gy = GRID_Y(gidx);
- int maxrange = (int)ceil(CONTRIB_RANGE(em->mass));
+ // spawn particles
+ int num_emitters = emitters.size();
+ for(int i=0; i<num_emitters; i++) {
+ Emitter *em = emitters[i];
+ em->spawn_pending += em->rate * SIM_DT;
+ while(em->spawn_pending >= 1.0f && em->mass > 0.0f) {
+ Vec2 pvel; // XXX calc eject velocity
- int sx = gx - maxrange;
- int sy = gy - maxrange;
- int ex = gx + maxrange;
- int ey = gy + maxrange;
+ float angle = (float)rand() / (float)RAND_MAX * (M_PI * 2.0);
+ float emradius = MASS_TO_RADIUS(em->mass);
+ Vec2 ppos = em->pos + Vec2(cos(angle), sin(angle)) * emradius * 1.00001;
- if(ex > GRID_SIZE) ex = GRID_SIZE;
- if(ey > GRID_SIZE) ey = GRID_SIZE;
+ float pmass = em->chunk > em->mass ? em->mass : em->chunk;
+ spawn_particle(ppos, pvel, pmass);
+ em->mass -= pmass;
- rect->x = sx < 0 ? 0 : sx;
- rect->y = sy < 0 ? 0 : sy;
- rect->width = ex - sx;
- rect->height = ey - sy;
-}
+ em->spawn_pending -= 1.0f;
+ }
+ }
+
+ // remove dead emitters
+ std::vector<Emitter*>::iterator it = emitters.begin();
+ while(it != emitters.end()) {
+ Emitter *em = *it;
+
+ if(em->mass <= 0.0f) {
+ printf("emitter depleted\n");
+ it = emitters.erase(it);
+ delete em;
+ } else {
+ it++;
+ }
+ }
-static void simstep()
-{
// calculate gravitational field - assume field within radius constant: m / r^2
// first clear the field, and then add contributions
memset(grid, 0, sizeof grid);
// contribution of emitters
- int num_emitters = emitters.size();
for(int i=0; i<num_emitters; i++) {
Emitter *em = emitters[i];
Rect cbox;
- calc_contrib_bounds(em, &cbox);
- float emradius = MASS_TO_RAD(em->mass);
-
- float *gptr = grid + cbox.y * GRID_SIZE + cbox.x;
- Vec2 startpos = grid_to_pos(cbox.x, cbox.y);
-
- for(int y=0; y<cbox.height; y++) {
- for(int x=0; x<cbox.width; x++) {
- Vec2 cellpos = Vec2(startpos.x + (float)x * GRID_DELTA, startpos.y);
-
- Vec2 dir = cellpos - em->pos;
- float dsq = dot(dir, dir);
- float radsq = emradius * emradius;
- if(dsq < radsq) {
- dsq = radsq;
- }
+ calc_contrib_bounds(em->pos, em->mass, &cbox);
+ float emradius = MASS_TO_RADIUS(em->mass);
- gptr[x] -= em->mass / dsq;
- }
+ add_influence(em->pos, -em->mass, emradius, cbox);
+ }
- startpos.y += GRID_DELTA;
- gptr += GRID_SIZE;
+ // contribution of particles
+ for(int i=0; i<NUM_PARTICLE_LISTS; i++) {
+ Particle *p = plist[i];
+ while(p) {
+ Rect cbox;
+ calc_contrib_bounds(p->pos, p->mass, &cbox);
+ add_influence(p->pos, p->mass, p->radius, cbox);
+ p = p->next;
}
}
em->pos = emit_place_pos;
em->mass = 100;
em->rate = 1;
- em->chunk = 0.05;
+ em->chunk = 0.05 * em->mass;
em->angle = -1;
em->spread = 0;
+ em->spawn_pending = 0;
emitters.push_back(em);
Rect cbox;
- calc_contrib_bounds(em, &cbox);
+ calc_contrib_bounds(em->pos, em->mass, &cbox);
printf("bounds: %d,%d %dx%d\n", cbox.x, cbox.y, cbox.width, cbox.height);
}
glLoadMatrixf(view_matrix[0]);
glPushAttrib(GL_ENABLE_BIT);
- glDisable(GL_LIGHTING);
glDisable(GL_CULL_FACE);
+ // draw gravitational field
glEnable(GL_TEXTURE_2D);
bind_texture(gvis_tex, 0);
bind_texture(grid_tex, 1);
glUseProgram(field_sdr);
- assert(glGetError() == GL_NO_ERROR);
-
glPatchParameteri(GL_PATCH_VERTICES, 4);
draw_quadmesh(&field_mesh, GL_PATCHES);
+ // draw particles
+ glUseProgram(particle_sdr);
+
+ for(int i=0; i<NUM_PARTICLE_LISTS; i++) {
+ Particle *p = plist[i];
+ while(p) {
+ int gidx = pos_to_grid(p->pos.x, p->pos.y);
+
+ glPushMatrix();
+ glTranslatef(p->pos.x, -grid[gidx] * field_scale, p->pos.y);
+ glScalef(p->radius, p->radius, p->radius);
+
+ pmesh->draw();
+
+ glPopMatrix();
+ p = p->next;
+ }
+ }
+
glUseProgram(0);
glPopAttrib();
return Vec2(x, y);
}
+static void calc_contrib_bounds(const Vec2 &pos, float mass, Rect *rect)
+{
+ int gidx = pos_to_grid(pos.x, pos.y);
+ int gx = GRID_X(gidx);
+ int gy = GRID_Y(gidx);
+ int maxrange = (int)ceil(CONTRIB_RANGE(mass));
+
+ int sx = gx - maxrange;
+ int sy = gy - maxrange;
+ int ex = gx + maxrange;
+ int ey = gy + maxrange;
+
+ if(ex > GRID_SIZE) ex = GRID_SIZE;
+ if(ey > GRID_SIZE) ey = GRID_SIZE;
+
+ rect->x = sx < 0 ? 0 : sx;
+ rect->y = sy < 0 ? 0 : sy;
+ rect->width = ex - sx;
+ rect->height = ey - sy;
+}
+
+static void add_influence(const Vec2 &pos, float mass, float radius, const Rect &cbox)
+{
+ float *gptr = grid + cbox.y * GRID_SIZE + cbox.x;
+ Vec2 startpos = grid_to_pos(cbox.x, cbox.y);
+
+ for(int y=0; y<cbox.height; y++) {
+ for(int x=0; x<cbox.width; x++) {
+ Vec2 cellpos = Vec2(startpos.x + (float)x * GRID_DELTA, startpos.y);
+
+ Vec2 dir = cellpos - pos;
+ float dsq = dot(dir, dir);
+ float radsq = radius * radius;
+ if(dsq < radsq) {
+ dsq = radsq;
+ }
+
+ gptr[x] += mass / dsq;
+ }
+
+ startpos.y += GRID_DELTA;
+ gptr += GRID_SIZE;
+ }
+}
+
+
static void destroy_quadmesh(QuadMesh *m)
{
glDeleteBuffers(1, &m->vbo_v);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
}
+
+static void spawn_particle(const Vec2 &pos, const Vec2 &vel, float mass)
+{
+ int gidx = pos_to_grid(pos.x, pos.y);
+
+ if(grid_part[gidx]) {
+ // merge with existing
+ Particle *p = grid_part[gidx];
+ p->vel += vel;
+ p->mass += mass;
+ p->radius = MASS_TO_RADIUS(p->mass);
+
+ } else {
+ Particle *p = alloc_particle();
+ p->pos = pos;
+ p->vel = vel;
+ p->mass = mass;
+ p->radius = MASS_TO_RADIUS(mass);
+ grid_part[gidx] = p;
+
+ add_particle(p, gidx);
+ }
+}
+
+static void add_particle(Particle *p, int grid_idx)
+{
+ int listidx = GRID_IDX_PLIST(grid_idx);
+ p->next = plist[listidx];
+ p->prev = 0;
+ plist[listidx] = p;
+}
+
+static void remove_particle(Particle *p, int grid_idx)
+{
+ Particle *prev = p->prev;
+ Particle *next = p->next;
+
+ p->prev = p->next = 0;
+ if(next) next->prev = prev;
+
+ if(prev) {
+ prev->next = next;
+ } else {
+ int listidx = GRID_IDX_PLIST(grid_idx);
+ plist[listidx] = next;
+ }
+}
+
+// particle allocator
+#define MAX_PFREE_SIZE 256
+static Particle *pfree_list;
+static int pfree_size;
+
+static Particle *alloc_particle()
+{
+ if(pfree_list) {
+ Particle *p = pfree_list;
+ pfree_list = pfree_list->next;
+ pfree_size--;
+ return p;
+ }
+
+ return new Particle;
+}
+
+void free_particle(Particle *p)
+{
+ if(pfree_size < MAX_PFREE_SIZE) {
+ p->next = pfree_list;
+ p->prev = 0;
+ pfree_list = p;
+ pfree_size++;
+ } else {
+ delete p;
+ }
+}
projects / ld42_outofspace / commitdiff