+#include <assert.h>
+#include <vector>
+#include <gmath/gmath.h>
#include "game.h"
#include "screen.h"
#include "opengl.h"
+#include "texture.h"
+#include "sdr.h"
+
+/* NOTES:
+ * - whistle hhgg music
+ * - colliding particles merge
+ * - select objects and center camera on them
+ */
+
+struct Particle {
+ float radius;
+ float mass;
+ Vec2 pos;
+ Vec2 vel;
+};
+
+struct Emitter {
+ Vec2 pos;
+ float mass;
+ float rate, chunk;
+ float angle, spread;
+};
+
+struct Rect {
+ int x, y;
+ int width, height;
+};
+
+#define SIM_DT 0.016
+
+#define GRID_SIZE 2048
+#define GRID_BITS 12
+#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_RAD(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 float grid[GRID_SIZE * GRID_SIZE];
+static Particle grid_part[GRID_SIZE * GRID_SIZE];
+static Texture *grid_tex;
+
+static std::vector<Emitter*> emitters;
+
+static Texture *gvis_tex; // texture tile for visualizing a grid
+static unsigned int field_sdr;
+
+static float cam_theta;
+static float cam_dist = 100.0f;
+static Vec2 *targ_pos;
+static Mat4 view_matrix, proj_matrix;
+
+// emitter placement data (filled by event handlers, completed in update)
+static bool emit_place_pending;
+static Vec2 emit_place_pos;
+
bool GameScreen::init()
{
+ grid_tex = new Texture;
+ 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_int(field_sdr, "tess_level", 2);
+
+ // XXX DBG
+ emit_place_pos = Vec2(0, 0);
+ emit_place_pending = true;
+
return true;
}
void GameScreen::destroy()
{
+ delete gvis_tex;
}
+static void calc_contrib_bounds(const Emitter *em, Rect *rect)
+{
+ 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));
+
+ 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 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;
+ }
+
+ gptr[x] -= em->mass / dsq;
+ }
+
+ startpos.y += GRID_DELTA;
+ gptr += GRID_SIZE;
+ }
+ }
+
+ // 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()
+{
+ if(emit_place_pending) {
+ emit_place_pending = false;
+ Emitter *em = new Emitter;
+ em->pos = emit_place_pos;
+ em->mass = 100;
+ em->rate = 1;
+ em->chunk = 0.05;
+ em->angle = -1;
+ em->spread = 0;
+ emitters.push_back(em);
+
+ Rect cbox;
+ calc_contrib_bounds(em, &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
+ proj_matrix.perspective(deg_to_rad(60.0f), win_aspect, 0.5, 5000.0);
+
+ // update view matrix
+ Vec3 targ;
+ if(targ_pos) {
+ targ.x = targ_pos->x;
+ targ.z = targ_pos->y;
+ }
+
+ float theta = -deg_to_rad(cam_theta);
+ Vec3 camdir = Vec3(sin(theta) * cam_dist, pow(cam_dist * 0.1, 2.0) + 0.5, cos(theta) * cam_dist);
+ Vec3 campos = targ + camdir;
+
+ view_matrix.inv_lookat(campos, targ, Vec3(0, 1, 0));
+}
void GameScreen::draw()
{
- glClearColor(1, 0, 0, 1);
+ update();
+
+ glClearColor(0.01, 0.01, 0.01, 1);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+ glMatrixMode(GL_PROJECTION);
+ glLoadMatrixf(proj_matrix[0]);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadMatrixf(view_matrix[0]);
+
+ glPushAttrib(GL_ENABLE_BIT);
+ glDisable(GL_LIGHTING);
+ glDisable(GL_CULL_FACE);
+
+ glEnable(GL_TEXTURE_2D);
+ bind_texture(gvis_tex, 0);
+ bind_texture(grid_tex, 1);
+
+ glUseProgram(field_sdr);
+
+ float maxu = FIELD_SIZE / 32.0f;
+ float maxv = FIELD_SIZE / 32.0f;
+ float hsz = FIELD_SIZE * 0.5f;
+
+ glBegin(GL_QUADS);
+ glColor3f(1, 1, 1);
+
+ glMultiTexCoord2f(0, 0, 0);
+ glMultiTexCoord2f(1, 0, 0);
+ glVertex3f(-hsz, 0, -hsz);
+
+ glMultiTexCoord2f(0, maxu, 0);
+ glMultiTexCoord2f(1, 1, 0);
+ glVertex3f(hsz, 0, -hsz);
+
+ glMultiTexCoord2f(0, maxu, maxv);
+ glMultiTexCoord2f(1, 1, 1);
+ glVertex3f(hsz, 0, hsz);
+
+ glMultiTexCoord2f(0, 0, maxv);
+ glMultiTexCoord2f(1, 0, 1);
+ glVertex3f(-hsz, 0, hsz);
+ glEnd();
+
+ glUseProgram(0);
+
+ glPopAttrib();
}
+void GameScreen::reshape(int x, int y)
+{
+}
+
+
void GameScreen::keyboard(int key, bool pressed)
{
}
}
+static int prev_x, prev_y;
+
void GameScreen::mbutton(int bn, bool pressed, int x, int y)
{
+ prev_x = x;
+ prev_y = y;
}
void GameScreen::mmotion(int x, int y)
{
+ int dx = x - prev_x;
+ int dy = y - prev_y;
+ prev_x = x;
+ prev_y = y;
+
+ if(game_bnstate(2)) {
+ cam_theta += dx * 0.5;
+ }
}
void GameScreen::mwheel(int dir, int x, int y)
{
+ cam_dist -= dir * cam_dist * 0.05f;
+ if(cam_dist <= MIN_CAM_DIST) cam_dist = MIN_CAM_DIST;
+ if(cam_dist > MAX_CAM_DIST) cam_dist = MAX_CAM_DIST;
+}
+
+
+static int pos_to_grid(float x, float y)
+{
+ int gx = ((x / (float)FIELD_SIZE) + 0.5f) * (float)GRID_SIZE;
+ int gy = ((y / (float)FIELD_SIZE) + 0.5f) * (float)GRID_SIZE;
+
+ 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);
}
projects / ld42_outofspace / blobdiff