+#include <assert.h>
#include <vector>
#include <gmath/gmath.h>
#include "game.h"
#include "screen.h"
#include "opengl.h"
#include "texture.h"
+#include "sdr.h"
+#include "mesh.h"
+#include "meshgen.h"
+#include "goatkit/goatkit.h"
/* NOTES:
* - whistle hhgg music
- * - colliding particles merge
* - select objects and center camera on them
+ * - we need to rely on actual collisions instead of grid occupancy
*/
struct Particle {
+ float radius;
float mass;
Vec2 pos;
Vec2 vel;
+
+ float vis_height;
+
+ Particle *next, *prev;
};
struct Emitter {
float mass;
float rate, chunk;
float angle, spread;
+
+ float spawn_pending;
};
+struct Rect {
+ int x, y;
+ int width, height;
+};
+
+struct QuadMesh {
+ Vec3 *v;
+ Vec2 *uv;
+ uint16_t *idx;
+
+ int num_verts, num_idx, num_quads;
+
+ unsigned int vbo_v, vbo_uv, ibo;
+};
#define SIM_DT 0.016
-#define GRID_SIZE 4096
-#define GRID_BITS 12
+#define GRID_SIZE 2048
+#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 FIELD_SIZE 2048
#define MIN_CAM_DIST 1.0f
#define MAX_CAM_DIST 350.0f
+#define MASS_TO_RADIUS(m) log((m) + 1.0)
+
+#define CONTRIB_THRES 0.005
+#define CONTRIB_RANGE(m) sqrt((m) / CONTRIB_THRES)
+
+/* gravitational strength */
+#define GRAV_STR 16.0f
+
+#define INIT_MASS_BUDGET 600.0f
+#define EM_MASS_DEFAULT 100.0f
+
+static int pos_to_grid_x_noclamp(float x);
+static int pos_to_grid_y_noclamp(float y);
static int pos_to_grid(float x, float y);
+static Vec2 grid_to_pos(int gx, int gy);
-static float grid[GRID_SIZE * GRID_SIZE];
-static Particle grid_part[GRID_SIZE * GRID_SIZE];
+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 Vec2 calc_field_grad(int gidx);
-static std::vector<Emitter> emitters;
+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);
+static void remove_particle(Particle *p);
+static Particle *alloc_particle();
+void free_particle(Particle *p);
+
+static bool pause;
+
+static float grid[GRID_SIZE * GRID_SIZE];
+static Particle *grid_part[GRID_SIZE * GRID_SIZE];
static Texture *grid_tex;
+static Particle *plist;
+
+static std::vector<Emitter*> emitters;
+
+static Texture *gvis_tex; // texture tile for visualizing a grid
+static unsigned int field_sdr;
+static int tess_level = 64;
+static float field_scale = 16.0f;
+
+static QuadMesh field_mesh;
+
+static Mesh *pmesh;
+static unsigned int particle_sdr;
+
+static Vec2 cam_pos;
static float cam_theta;
static float cam_dist = 100.0f;
-static Vec2 *targ_pos;
+static Vec2 *targ_pos = &cam_pos;
static Mat4 view_matrix, proj_matrix;
+static bool wireframe;
+static int mouse_x, mouse_y;
+
+// emitter placement data (filled by event handlers, completed in update)
+static bool emit_place_pending;
+static Vec2 emit_place_pos;
+
+static bool placing_emitter;
+
+static float mass_left;
+
+// UI
+static void ui_handler(goatkit::Widget *w, const goatkit::Event &ev, void *cls);
+static int ui_virt_width = 800;
+static int ui_virt_height = 600;
+static goatkit::Screen *ui;
+static goatkit::Button *bn_emitter;
+static goatkit::Slider *slider_mass;
+static bool mouse_over_ui;
+
bool GameScreen::init()
{
grid_tex = new Texture;
- if(!grid_tex->load("data/purple_grid.png")) {
+ grid_tex->create(GRID_SIZE, GRID_SIZE, TEX_2D, GL_LUMINANCE32F_ARB);
+ grid_tex->set_anisotropy(glcaps.max_aniso);
+
+ gvis_tex = new Texture;
+ if(!gvis_tex->load("data/purple_grid.png")) {
+ return false;
+ }
+ gvis_tex->set_anisotropy(glcaps.max_aniso);
+
+ unsigned int vsdr, tcsdr, tesdr, psdr;
+
+ if(!(vsdr = load_vertex_shader("sdr/field.v.glsl")) ||
+ !(tcsdr = load_tessctl_shader("sdr/field.tc.glsl")) ||
+ !(tesdr = load_tesseval_shader("sdr/field.te.glsl")) ||
+ !(psdr = load_pixel_shader("sdr/field.p.glsl"))) {
+ return false;
+ }
+
+ if(!(field_sdr = create_program_link(vsdr, tcsdr, tesdr, psdr, 0))) {
+ return false;
+ }
+ set_uniform_int(field_sdr, "gvis_tex", 0);
+ set_uniform_int(field_sdr, "field_tex", 1);
+ set_uniform_float(field_sdr, "gvis_scale", FIELD_SIZE / 32.0f);
+ set_uniform_int(field_sdr, "tess_level", tess_level);
+ set_uniform_float(field_sdr, "field_scale", field_scale);
+
+ 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;
}
- grid_tex->set_anisotropy(glcaps.max_aniso);
+ mass_left = INIT_MASS_BUDGET;
+
+ ui = new goatkit::Screen;
+ ui->hide();
+
+ bn_emitter = new goatkit::Button;
+ bn_emitter->set_position(5, 5);
+ bn_emitter->set_size(250, 30);
+ bn_emitter->set_text("new white hole");
+ bn_emitter->set_callback(goatkit::EV_CLICK, ui_handler);
+ ui->add_widget(bn_emitter);
+
+ slider_mass = new goatkit::Slider;
+ slider_mass->set_position(300, 5);
+ slider_mass->set_size(400, 30);
+ slider_mass->set_continuous_change(false);
+ slider_mass->set_range(0, mass_left);
+ slider_mass->set_value(EM_MASS_DEFAULT);
+ slider_mass->set_callback(goatkit::EV_CHANGE, ui_handler);
+ ui->add_widget(slider_mass);
+
+ ui->set_visibility_transition(300);
+
+ assert(glGetError() == GL_NO_ERROR);
return true;
}
void GameScreen::destroy()
{
+ free_program(field_sdr);
+ delete gvis_tex;
delete grid_tex;
+ destroy_quadmesh(&field_mesh);
+ delete pmesh;
+
+ delete bn_emitter;
+}
+
+void GameScreen::start()
+{
+ ui->show();
+ slider_mass->hide();
+}
+
+void GameScreen::stop()
+{
}
static void simstep()
{
+ if(pause) return;
+
+ // distribute forces
+ Particle *p = plist;
+ while(p) {
+ int num_emitters = emitters.size();
+ for(int i=0; i<num_emitters; i++) {
+ Emitter *em = emitters[i];
+ Vec2 dir = p->pos - em->pos;
+ p->vel += dir * em->mass * GRAV_STR * 0.01 / dot(dir, dir) * SIM_DT;
+ }
+
+ Particle *q = plist;
+ while(q) {
+ if(p != q) {
+ Vec2 dir = q->pos - p->pos;
+ float accel = GRAV_STR * q->mass / dot(dir, dir);
+ p->vel += dir * accel * SIM_DT;
+ }
+ q = q->next;
+ }
+ p = p->next;
+ }
+
+ // move existing particles
+ p = plist;
+ while(p) {
+ // calculate the field gradient at the particle position
+ int gidx = pos_to_grid(p->pos.x, p->pos.y);
+ //Vec2 grad = calc_field_grad(gidx) * GRAV_STR;
+
+ //p->vel += grad * SIM_DT;
+ p->pos += p->vel * SIM_DT;
+
+ // if it moved outside of the simulation field, remove it
+ int gx = pos_to_grid_x_noclamp(p->pos.x);
+ int gy = pos_to_grid_y_noclamp(p->pos.y);
+ if(gx < 0 || gx >= GRID_SIZE || gy < 0 || gy >= GRID_SIZE) {
+ Particle *next = p->next;
+ grid_part[gidx] = 0;
+ remove_particle(p);
+ free_particle(p);
+ p = next;
+ continue;
+ }
+
+ // find the grid cell it's moving to
+ int gidx_next = pos_to_grid(p->pos.x, p->pos.y);
+ p->vis_height = 0.0f;//-grid[gidx_next] * field_scale;
+
+ if(gidx_next == gidx) {
+ p = p->next;
+ continue;
+ }
+
+ Particle *destp = grid_part[gidx_next];
+ if(destp) {
+ assert(destp != p);
+ // another particle at the destination, merge them
+ destp->vel += p->vel;
+ destp->mass += p->mass;
+ destp->radius = MASS_TO_RADIUS(destp->mass);
+
+ // ... and remove it
+ grid_part[gidx] = 0;
+ Particle *next = p->next;
+ remove_particle(p);
+ free_particle(p);
+ p = next;
+ } else {
+ // destination is empty, go there
+ if(gidx != gidx_next) {
+ grid_part[gidx] = 0;
+ grid_part[gidx_next] = p;
+ }
+
+ p = p->next;
+ }
+ }
+
+ // TODO destroy particles which left the simulation field
+
+ // 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
+
+ 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;
+
+ float pmass = em->chunk > em->mass ? em->mass : em->chunk;
+ spawn_particle(ppos, pvel, pmass);
+ em->mass -= pmass;
+
+ 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++;
+ }
+ }
+
+ // 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
+ for(int i=0; i<num_emitters; i++) {
+ Emitter *em = emitters[i];
+ Rect cbox;
+ calc_contrib_bounds(em->pos, em->mass, &cbox);
+ float emradius = MASS_TO_RADIUS(em->mass);
+
+ add_influence(em->pos, -em->mass, emradius, cbox);
+ }
+
+ // contribution of particles
+ p = plist;
+ while(p) {
+ Rect cbox;
+ calc_contrib_bounds(p->pos, p->mass, &cbox);
+ add_influence(p->pos, p->mass, p->radius, cbox);
+ p = p->next;
+ }
+
+ // update texture
+ assert(glGetError() == GL_NO_ERROR);
+ grid_tex->bind();
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, GRID_SIZE, GRID_SIZE, GL_LUMINANCE,
+ GL_FLOAT, grid);
+ assert(glGetError() == GL_NO_ERROR);
}
static void update()
{
- static float interval;
+ if(placing_emitter) {
+ float x = (float)mouse_x / (float)win_width;
+ float y = 1.0f - (float)mouse_y / (float)win_height;
+ Ray pick_ray = mouse_pick_ray(x, y, view_matrix, proj_matrix);
+
+ float ndotdir = pick_ray.dir.y;
+ if(fabs(ndotdir) > 1e-6f) {
+ float ndotpdir = -pick_ray.origin.y;
+ float t = ndotpdir / ndotdir;
+
+ x = pick_ray.origin.x + pick_ray.dir.x * t;
+ y = pick_ray.origin.z + pick_ray.dir.z * t;
+
+ if(x >= -FIELD_SIZE / 2 && x < FIELD_SIZE / 2 &&
+ y >= -FIELD_SIZE / 2 && y < FIELD_SIZE / 2) {
+ emit_place_pos = Vec2(x, y);
+ }
+ }
+ }
+ if(emit_place_pending) {
+ emit_place_pending = false;
+ Emitter *em = new Emitter;
+ em->pos = emit_place_pos;
+ em->mass = slider_mass->get_value();
+ em->rate = 10;
+ em->chunk = 0.001 * em->mass;
+ em->angle = -1;
+ em->spread = 0;
+ em->spawn_pending = 0;
+ emitters.push_back(em);
+
+ mass_left -= em->mass;
+ if(mass_left < 0.0f) mass_left = 0.0f;
+
+ Rect cbox;
+ calc_contrib_bounds(em->pos, em->mass, &cbox);
+ printf("bounds: %d,%d %dx%d\n", cbox.x, cbox.y, cbox.width, cbox.height);
+ }
+
+ // update simulation
+ static float interval;
interval += frame_dt;
if(interval >= SIM_DT) {
interval -= SIM_DT;
simstep();
+ assert(glGetError() == GL_NO_ERROR);
}
// update projection matrix
glMatrixMode(GL_MODELVIEW);
glLoadMatrixf(view_matrix[0]);
- glPushAttrib(GL_ENABLE_BIT);
- glDisable(GL_LIGHTING);
- glDisable(GL_CULL_FACE);
+ // draw gravitational field
+ if(wireframe) {
+ glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+
+ float amb[] = {0.5, 0.5, 0.5, 1.0};
+ glLightModelfv(GL_LIGHT_MODEL_AMBIENT, amb);
+ } else {
+ float amb[] = {0.01, 0.01, 0.01, 1.0};
+ glLightModelfv(GL_LIGHT_MODEL_AMBIENT, amb);
+ }
+
+ bind_texture(gvis_tex, 0);
+ bind_texture(grid_tex, 1);
+
+ glUseProgram(field_sdr);
+ glPatchParameteri(GL_PATCH_VERTICES, 4);
+ draw_quadmesh(&field_mesh, GL_PATCHES);
+
+ if(wireframe) {
+ glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+ }
+
+ // draw particles
+ glUseProgram(particle_sdr);
+
+ Particle *p = plist;
+ while(p) {
+ int gidx = pos_to_grid(p->pos.x, p->pos.y);
+
+ glPushMatrix();
+ glTranslatef(p->pos.x, p->vis_height, p->pos.y);
+ glScalef(p->radius, p->radius, p->radius);
+
+ pmesh->draw();
+
+ glPopMatrix();
+ p = p->next;
+ }
+
+ glUseProgram(0);
+
+ // draw emitter placement marker if we are in placement mode
+ if(placing_emitter && !mouse_over_ui) {
+ glPushMatrix();
+ glTranslatef(emit_place_pos.x, 0, emit_place_pos.y);
+
+ glBegin(GL_LINES);
+ glColor3f(0, 1, 0);
+ glVertex3f(0, -1000, 0);
+ glVertex3f(0, 1000, 0);
+ glEnd();
+
+ float s = MASS_TO_RADIUS(slider_mass->get_value());
+ if(s < 0.1) s = 0.1;
+ glScalef(s, s, s);
+
+ glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+ pmesh->draw();
+ glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+
+ glPopMatrix();
+ }
+
+ // draw the UI
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(0, ui_virt_width, ui_virt_height, 0, -1, 1);
- glEnable(GL_TEXTURE_2D);
- bind_texture(grid_tex);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
- float maxu = FIELD_SIZE / 32.0f;
- float maxv = FIELD_SIZE / 32.0f;
- float hsz = FIELD_SIZE * 0.5f;
+ ui->draw();
- glBegin(GL_QUADS);
- glColor3f(1, 1, 1);
- glTexCoord2f(0, 0);
- glVertex3f(-hsz, 0, -hsz);
- glTexCoord2f(maxu, 0);
- glVertex3f(hsz, 0, -hsz);
- glTexCoord2f(maxu, maxv);
- glVertex3f(hsz, 0, hsz);
- glTexCoord2f(0, maxv);
- glVertex3f(-hsz, 0, hsz);
- glEnd();
- glPopAttrib();
+ assert(glGetError() == GL_NO_ERROR);
}
void GameScreen::reshape(int x, int y)
{
+ ui_virt_width = x;
+ ui_virt_height = y;
+ ui->set_size(ui_virt_width, ui_virt_height);
}
pop_screen();
break;
+ case ']':
+ if(tess_level < glcaps.max_tess_level) {
+ tess_level++;
+ printf("tessellation level: %d\n", tess_level);
+ set_uniform_int(field_sdr, "tess_level", tess_level);
+ glUseProgram(0);
+ }
+ break;
+
+ case '[':
+ if(tess_level > 1) {
+ tess_level--;
+ printf("tessellation level: %d\n", tess_level);
+ set_uniform_int(field_sdr, "tess_level", tess_level);
+ glUseProgram(0);
+ }
+ break;
+
+ case '=':
+ field_scale += 0.5;
+ printf("field scale: %f\n", field_scale);
+ set_uniform_float(field_sdr, "field_scale", field_scale);
+ break;
+
+ case '-':
+ field_scale -= 0.5;
+ if(field_scale < 0.0f) {
+ field_scale = 0.0f;
+ }
+ printf("field scale: %f\n", field_scale);
+ set_uniform_float(field_sdr, "field_scale", field_scale);
+ break;
+
+ case 'w':
+ wireframe = !wireframe;
+ break;
+
+ case ' ':
+ pause = !pause;
+ break;
+
default:
break;
}
}
}
-static int prev_x, prev_y;
+#define UI_HEIGHT 50
void GameScreen::mbutton(int bn, bool pressed, int x, int y)
{
- prev_x = x;
- prev_y = y;
+ mouse_x = x;
+ mouse_y = y;
+
+ mouse_over_ui = y < UI_HEIGHT;
+
+ ui->sysev_mouse_button(bn, pressed, x * ui_virt_width / win_width,
+ y * ui_virt_height / win_height);
+
+ if(placing_emitter && bn == 0 && pressed && !mouse_over_ui) {
+ emit_place_pending = true;
+ placing_emitter = false;
+ slider_mass->hide();
+ }
}
void GameScreen::mmotion(int x, int y)
{
- int dx = x - prev_x;
- int dy = y - prev_y;
- prev_x = x;
- prev_y = y;
+ int dx = x - mouse_x;
+ int dy = y - mouse_y;
+ mouse_x = x;
+ mouse_y = y;
+
+ mouse_over_ui = y < UI_HEIGHT;
+
+ ui->sysev_mouse_motion(x * ui_virt_width / win_width, y * ui_virt_height / win_height);
+ if(ui->get_mouse_grab()) {
+ return;
+ }
+
+ if(game_bnstate(0)) {
+ float pan_speed = pow(cam_dist, 1.5) * 0.00035; // magic
+ Vec2 dir = rotate(Vec2(dx, dy) * pan_speed, deg_to_rad(cam_theta));
+ cam_pos.x -= dir.x;
+ cam_pos.y -= dir.y;
+ }
if(game_bnstate(2)) {
cam_theta += dx * 0.5;
if(cam_dist <= MIN_CAM_DIST) cam_dist = MIN_CAM_DIST;
if(cam_dist > MAX_CAM_DIST) cam_dist = MAX_CAM_DIST;
}
+
+static void ui_handler(goatkit::Widget *w, const goatkit::Event &ev, void *cls)
+{
+ if(w == bn_emitter) {
+ if(placing_emitter) {
+ placing_emitter = false;
+ slider_mass->hide();
+ } else {
+ if(mass_left > 0.0f) {
+ placing_emitter = true;
+ slider_mass->set_range(0, mass_left);
+ slider_mass->set_value(mass_left >= EM_MASS_DEFAULT ? EM_MASS_DEFAULT : mass_left);
+ slider_mass->show();
+ }
+ }
+ return;
+ }
+
+ if(w == slider_mass) {
+ printf("foo: %f\n", slider_mass->get_value());
+ }
+}
+
+static int pos_to_grid_x_noclamp(float x)
+{
+ return ((x / (float)FIELD_SIZE) + 0.5f) * (float)GRID_SIZE;
+}
+
+static int pos_to_grid_y_noclamp(float y)
+{
+ return ((y / (float)FIELD_SIZE) + 0.5f) * (float)GRID_SIZE;
+}
+
+static int pos_to_grid(float x, float y)
+{
+ int gx = pos_to_grid_x_noclamp(x);
+ int gy = pos_to_grid_y_noclamp(y);
+
+ if(gx < 0) gx = 0;
+ if(gx >= GRID_SIZE) gx = GRID_SIZE - 1;
+ if(gy < 0) gy = 0;
+ if(gy >= GRID_SIZE) gy = GRID_SIZE - 1;
+
+ return (gx << GRID_BITS) | gy;
+}
+
+static Vec2 grid_to_pos(int gx, int gy)
+{
+ float x = (((float)gx / (float)GRID_SIZE) - 0.5f) * (float)FIELD_SIZE;
+ float y = (((float)gy / (float)GRID_SIZE) - 0.5f) * (float)FIELD_SIZE;
+
+ 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 Vec2 calc_field_grad(int gidx)
+{
+ int gx = GRID_X(gidx);
+ int gy = GRID_Y(gidx);
+
+ int nidx = ((gx + 1 >= GRID_SIZE ? gx : gx + 1) << GRID_BITS) | gy;
+ int pidx = ((gx > 0 ? gx - 1 : gx) << GRID_BITS) | gy;
+ float dfdx = grid[nidx] - grid[pidx];
+
+ nidx = (gx << GRID_BITS) | (gy + 1 >= GRID_SIZE ? gy : gy + 1);
+ pidx = (gx << GRID_BITS) | (gy > 0 ? gy - 1 : gy);
+ float dfdy = grid[nidx] - grid[pidx];
+
+ return Vec2(dfdx, dfdy);
+}
+
+
+// ---- quad mesh operations ----
+
+static void destroy_quadmesh(QuadMesh *m)
+{
+ glDeleteBuffers(1, &m->vbo_v);
+ glDeleteBuffers(1, &m->vbo_uv);
+ glDeleteBuffers(1, &m->ibo);
+
+ delete [] m->v;
+ delete [] m->uv;
+ delete [] m->idx;
+}
+
+static void draw_quadmesh(const QuadMesh *m, unsigned int prim)
+{
+ glEnableClientState(GL_VERTEX_ARRAY);
+ glEnableClientState(GL_TEXTURE_COORD_ARRAY);
+
+ glBindBuffer(GL_ARRAY_BUFFER, m->vbo_v);
+ glVertexPointer(3, GL_FLOAT, 0, 0);
+
+ glBindBuffer(GL_ARRAY_BUFFER, m->vbo_uv);
+ glTexCoordPointer(2, GL_FLOAT, 0, 0);
+
+ glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+ glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m->ibo);
+ glDrawElements(prim, m->num_idx, GL_UNSIGNED_SHORT, 0);
+ glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+
+ glDisableClientState(GL_VERTEX_ARRAY);
+ glDisableClientState(GL_TEXTURE_COORD_ARRAY);
+}
+
+static void gen_quad_plane(QuadMesh *m, float width, float height, int usub, int vsub)
+{
+ Vec3 *vptr;
+ Vec2 *uvptr;
+ uint16_t *iptr;
+
+ if(usub < 1) usub = 1;
+ if(vsub < 1) vsub = 1;
+
+ int uverts = usub + 1;
+ int vverts = vsub + 1;
+ m->num_verts = uverts * vverts;
+ m->num_quads = usub * vsub;
+ m->num_idx = m->num_quads * 4;
+
+ vptr = m->v = new Vec3[m->num_verts];
+ uvptr = m->uv = new Vec2[m->num_verts];
+ iptr = m->idx = new uint16_t[m->num_idx];
+
+ float du = 1.0f / (float)usub;
+ float dv = 1.0f / (float)vsub;
+
+ float u = 0.0f;
+ for(int i=0; i<uverts; i++) {
+ float x = (u - 0.5f) * width;
+ float v = 0.0f;
+ for(int j=0; j<vverts; j++) {
+ float y = (v - 0.5f) * height;
+
+ *vptr++ = Vec3(x, 0, y);
+ *uvptr++ = Vec2(u, v);
+
+ if(i < usub && j < vsub) {
+ int idx = i * vverts + j;
+
+ *iptr++ = idx;
+ *iptr++ = idx + 1;
+ *iptr++ = idx + vverts + 1;
+ *iptr++ = idx + vverts;
+ }
+
+ v += dv;
+ }
+ u += du;
+ }
+
+ glGenBuffers(1, &m->vbo_v);
+ glBindBuffer(GL_ARRAY_BUFFER, m->vbo_v);
+ glBufferData(GL_ARRAY_BUFFER, m->num_verts * 3 * sizeof(float), m->v, GL_STATIC_DRAW);
+
+ glGenBuffers(1, &m->vbo_uv);
+ glBindBuffer(GL_ARRAY_BUFFER, m->vbo_uv);
+ glBufferData(GL_ARRAY_BUFFER, m->num_verts * 2 * sizeof(float), m->uv, GL_STATIC_DRAW);
+
+ glGenBuffers(1, &m->ibo);
+ glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m->ibo);
+ glBufferData(GL_ELEMENT_ARRAY_BUFFER, m->num_idx * sizeof(uint16_t), m->idx, GL_STATIC_DRAW);
+
+ 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);
+ }
+}
+
+static void add_particle(Particle *p)
+{
+ if(plist) plist->prev = p;
+
+ p->next = plist;
+ p->prev = 0;
+ plist = p;
+}
+
+static void remove_particle(Particle *p)
+{
+ assert(plist->prev == 0);
+
+ if(plist == p) {
+ assert(p->prev == 0);
+ plist = p->next;
+ }
+ if(p->prev) {
+ p->prev->next = p->next;
+ }
+ if(p->next) {
+ p->next->prev = p->prev;
+ }
+ p->prev = p->next = 0;
+}
+
+// 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 / blobdiff