From 31858c81e045e619d62d015058ad46cc2376c7b5 Mon Sep 17 00:00:00 2001 From: John Tsiombikas Date: Tue, 14 Aug 2018 06:20:52 +0300 Subject: [PATCH] the universe is fucked --- sdr/field.p.glsl | 8 +-- src/gamescr.cc | 151 ++++++++++++++++++++++++++++++++++++++---------------- 2 files changed, 112 insertions(+), 47 deletions(-) diff --git a/sdr/field.p.glsl b/sdr/field.p.glsl index e14ba6f..b021a55 100644 --- a/sdr/field.p.glsl +++ b/sdr/field.p.glsl @@ -1,13 +1,15 @@ #version 410 compatibility -uniform sampler2D gvis_tex; +uniform sampler2D gvis_tex, field_tex; uniform float gvis_scale; void main() { - vec2 uv = gl_TexCoord[0].st * vec2(gvis_scale, gvis_scale); + vec2 uv = gl_TexCoord[0].st * vec2(gvis_scale, gvis_scale) * 10.0; vec3 gridcol = texture2D(gvis_tex, uv).rgb; - gl_FragColor.rgb = gridcol.rgb; + float foo = texture2D(field_tex, gl_TexCoord[0].st).x; + + gl_FragColor.rgb = gridcol.rgb + vec3(0.0, foo, 0.0); gl_FragColor.a = 1.0; } diff --git a/src/gamescr.cc b/src/gamescr.cc index d0fae08..abd7865 100644 --- a/src/gamescr.cc +++ b/src/gamescr.cc @@ -22,6 +22,8 @@ struct Particle { Vec2 pos; Vec2 vel; + float vis_height; + Particle *next, *prev; }; @@ -72,13 +74,15 @@ 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 Vec2 calc_field_grad(int gidx); + 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 void add_particle(Particle *p); +static void remove_particle(Particle *p); static Particle *alloc_particle(); void free_particle(Particle *p); @@ -86,15 +90,13 @@ static float grid[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 Particle *plist; static std::vector emitters; static Texture *gvis_tex; // texture tile for visualizing a grid static unsigned int field_sdr; -static int tess_level = 32; +static int tess_level = 64; static float field_scale = 16.0f; static QuadMesh field_mesh; @@ -170,6 +172,52 @@ void GameScreen::destroy() static void simstep() { + // move existing particles + Particle *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); + + p->vel += grad * SIM_DT; + p->pos += p->vel * SIM_DT; + + // 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; ipos, p->mass, &cbox); - add_influence(p->pos, p->mass, p->radius, cbox); - p = p->next; - } + 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 @@ -245,8 +290,8 @@ static void update() Emitter *em = new Emitter; em->pos = emit_place_pos; em->mass = 100; - em->rate = 1; - em->chunk = 0.05 * em->mass; + em->rate = 10; + em->chunk = 0.01 * em->mass; em->angle = -1; em->spread = 0; em->spawn_pending = 0; @@ -310,20 +355,18 @@ void GameScreen::draw() // draw particles glUseProgram(particle_sdr); - for(int i=0; ipos.x, p->pos.y); + Particle *p = plist; + 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); + glPushMatrix(); + glTranslatef(p->pos.x, p->vis_height, p->pos.y); + glScalef(p->radius, p->radius, p->radius); - pmesh->draw(); + pmesh->draw(); - glPopMatrix(); - p = p->next; - } + glPopMatrix(); + p = p->next; } glUseProgram(0); @@ -480,6 +523,24 @@ static void add_influence(const Vec2 &pos, float mass, float radius, const Rect } } +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) { @@ -594,32 +655,34 @@ static void spawn_particle(const Vec2 &pos, const Vec2 &vel, float mass) p->radius = MASS_TO_RADIUS(mass); grid_part[gidx] = p; - add_particle(p, gidx); + add_particle(p); } } -static void add_particle(Particle *p, int grid_idx) +static void add_particle(Particle *p) { - int listidx = GRID_IDX_PLIST(grid_idx); - p->next = plist[listidx]; + if(plist) plist->prev = p; + + p->next = plist; p->prev = 0; - plist[listidx] = p; + plist = p; } -static void remove_particle(Particle *p, int grid_idx) +static void remove_particle(Particle *p) { - Particle *prev = p->prev; - Particle *next = p->next; - - p->prev = p->next = 0; - if(next) next->prev = prev; + assert(plist->prev == 0); - if(prev) { - prev->next = next; - } else { - int listidx = GRID_IDX_PLIST(grid_idx); - plist[listidx] = next; + 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 -- 1.7.10.4