void mesh_map_xy_to_uv(struct mesh *m)
{
float u0, v0, u1, v1, u2, v2, r;
int i;
r = mesh_calculate_xy_radius(m);
if (m->tex)
free(m->tex);
m->tex = malloc(sizeof(*m->tex) * m->ntriangles * 3);
if (!m->tex)
return;
for (i = 0; i < m->ntriangles; i++) {
struct vertex *vtx0, *vtx1, *vtx2;
vtx0 = m->t[i].v[0];
vtx1 = m->t[i].v[1];
vtx2 = m->t[i].v[2];
u0 = vtx0->x / (r * 2.0) + 0.5;
v0 = vtx0->y / (r * 2.0) + 0.5;
u1 = vtx1->x / (r * 2.0) + 0.5;
v1 = vtx1->y / (r * 2.0) + 0.5;
u2 = vtx2->x / (r * 2.0) + 0.5;
v2 = vtx2->y / (r * 2.0) + 0.5;
mesh_set_triangle_texture_coords(m, i, u0, v0, u1, v1, u2, v2);
}
mesh_graph_dev_init(m);
}
/* this has a known issue mapping vertices of tris that span the "international date line" */
void mesh_sphere_uv_map(struct mesh *m)
{
float u0, v0, u1, v1, u2, v2;
int i;
if (m->tex)
free(m->tex);
m->tex = malloc(sizeof(*m->tex) * m->ntriangles * 3);
if (!m->tex)
return;
for (i = 0; i < m->ntriangles; i++) {
struct vertex *vtx0, *vtx1, *vtx2;
vtx0 = m->t[i].v[0];
vtx1 = m->t[i].v[1];
vtx2 = m->t[i].v[2];
u0 = acosf(vtx0->z) / M_PI;
v0 = (atan2f(vtx0->y, vtx0->x) + M_PI) / (2.0 * M_PI);
u1 = acosf(vtx1->z) / M_PI;
v1 = (atan2f(vtx1->y, vtx1->x) + M_PI) / (2.0 * M_PI);
u2 = acosf(vtx2->z) / M_PI;
v2 = (atan2f(vtx2->y, vtx2->x) + M_PI) / (2.0 * M_PI);
mesh_set_triangle_texture_coords(m, i, u0, v0, u1, v1, u2, v2);
}
mesh_graph_dev_init(m);
}
static void mesh_uv_map_planetary_ring(struct mesh *m)
{
float u0, u1, u2, r;
int i;
r = mesh_calculate_xy_radius(m);
if (m->tex)
free(m->tex);
m->tex = malloc(sizeof(*m->tex) * m->ntriangles * 3);
if (!m->tex)
return;
for (i = 0; i < m->ntriangles; i++) {
struct vertex *vtx0, *vtx1, *vtx2;
vtx0 = m->t[i].v[0];
vtx1 = m->t[i].v[1];
vtx2 = m->t[i].v[2];
/* v will be a per-instance constant passed as uniform to the shader */
u0 = (float) outside_edge_of_ring(vtx0, r);
u1 = (float) outside_edge_of_ring(vtx1, r);
u2 = (float) outside_edge_of_ring(vtx2, r);
mesh_set_triangle_texture_coords(m, i, u0, 0.0f, u1, 0.0f, u2, 0.0f);
}
mesh_graph_dev_init(m);
}
struct mesh *init_line_mesh(double x1, double y1, double z1, double x2, double y2, double z2)
{
struct mesh *my_mesh = malloc(sizeof(*my_mesh));
if (!my_mesh)
return my_mesh;
memset(my_mesh, 0, sizeof(*my_mesh));
my_mesh->geometry_mode = MESH_GEOMETRY_LINES;
my_mesh->nvertices = 2;
my_mesh->ntriangles = 0;
my_mesh->nlines = 1;
my_mesh->t = 0;
my_mesh->v = malloc(sizeof(*my_mesh->v) * 2);
my_mesh->l = malloc(sizeof(*my_mesh->l) * 1);
my_mesh->tex = 0;
my_mesh->radius = fmax(dist3d(x1, y1, z1), dist3d(x2, y2, z2));
my_mesh->graph_ptr = 0;
my_mesh->v[0].x = x1;
my_mesh->v[0].y = y1;
my_mesh->v[0].z = -z1;
my_mesh->v[1].x = x2;
my_mesh->v[1].y = y2;
my_mesh->v[1].z = -z2;
my_mesh->l[0].start = &my_mesh->v[0];
my_mesh->l[0].end = &my_mesh->v[1];
my_mesh->l[0].flag = 0;
mesh_graph_dev_init(my_mesh);
return my_mesh;
}
void mesh_rotate(struct mesh *m, union quat *q)
{
int i;
for (i = 0; i < m->nvertices; i++)
vertex_rotate(&m->v[i], q);
for (i = 0; i < m->ntriangles; i++)
triangle_rotate_normals(&m->t[i], q);
mesh_graph_dev_init(m);
}
void mesh_scale(struct mesh *m, float scale)
{
int i;
for (i = 0; i < m->nvertices; i++) {
m->v[i].x *= scale;
m->v[i].y *= scale;
m->v[i].z *= scale;
}
m->radius = mesh_compute_radius(m);
mesh_graph_dev_init(m);
}
static void copy_mesh_contents(struct mesh *copy, struct mesh *original)
{
int i;
copy->geometry_mode = original->geometry_mode;
copy->ntriangles = original->ntriangles;
copy->nvertices = original->nvertices;
copy->nlines = original->nlines;
copy->graph_ptr = 0;
for (i = 0; i < original->nvertices; i++)
copy->v[i] = original->v[i];
for (i = 0; i < original->ntriangles; i++) {
int v0, v1, v2;
v0 = lookup_vertex(original, original->t[i].v[0]);
v1 = lookup_vertex(original, original->t[i].v[1]);
v2 = lookup_vertex(original, original->t[i].v[2]);
copy->t[i].v[0] = ©->v[v0];
copy->t[i].v[1] = ©->v[v1];
copy->t[i].v[2] = ©->v[v2];
copy->t[i].n = original->t[i].n;
copy->t[i].vnormal[0] = original->t[i].vnormal[0];
copy->t[i].vnormal[1] = original->t[i].vnormal[1];
copy->t[i].vnormal[2] = original->t[i].vnormal[2];
}
for (i = 0; i < original->nlines; i++) {
int v0, v1;
v0 = lookup_vertex(original, original->l[i].start);
v1 = lookup_vertex(original, original->l[i].end);
copy->l[i].start = ©->v[v0];
copy->l[i].end = ©->v[v1];
copy->l[i].flag = original->l[i].flag;
copy->l[i].additivity = original->l[i].additivity;
copy->l[i].opacity = original->l[i].opacity;
copy->l[i].tint_color = original->l[i].tint_color;
copy->l[i].time_offset = original->l[i].time_offset;
}
if (original->tex)
memcpy(copy->tex, original->tex, sizeof(*copy->tex) * original->ntriangles * 3);
copy->radius = original->radius;
if (original->material) {
copy->material = malloc(sizeof(*copy->material));
*copy->material = *original->material;
}
mesh_graph_dev_init(copy);
}
struct mesh *init_burst_rod_mesh(int streaks, double h, double r1, double r2)
{
struct mesh *my_mesh = malloc(sizeof(*my_mesh));
if (!my_mesh)
return my_mesh;
memset(my_mesh, 0, sizeof(*my_mesh));
my_mesh->geometry_mode = MESH_GEOMETRY_PARTICLE_ANIMATION;
my_mesh->nlines = streaks;
my_mesh->nvertices = my_mesh->nlines * 2;
my_mesh->ntriangles = 0;
my_mesh->t = 0;
my_mesh->v = malloc(sizeof(*my_mesh->v) * my_mesh->nvertices);
my_mesh->l = malloc(sizeof(*my_mesh->l) * my_mesh->nlines);
my_mesh->tex = 0;
my_mesh->radius = fmax(sqrt(h * h / 4.0 + r1 * r1), sqrt(h * h / 4.0 + r2 * r2));
my_mesh->graph_ptr = 0;
int line_index;
for (line_index = 0; line_index < streaks; line_index++) {
float p = fabs(snis_random_float());
float pr = p * (r2 - r1) + r1;
float ph = p * h - h / 2.0;
float pa = fabs(snis_random_float()) * 2.0 * M_PI;
int v_index = line_index * 2;
my_mesh->v[v_index + 0].x = ph;
my_mesh->v[v_index + 0].y = 0;
my_mesh->v[v_index + 0].z = 0;
my_mesh->v[v_index + 1].x = ph;
my_mesh->v[v_index + 1].y = sin(pa) * pr;
my_mesh->v[v_index + 1].z = cos(pa) * pr;
my_mesh->l[line_index].start = &my_mesh->v[v_index + 0];
my_mesh->l[line_index].end = &my_mesh->v[v_index + 1];
my_mesh->l[line_index].flag = 0;
my_mesh->l[line_index].additivity = 1.0;
my_mesh->l[line_index].opacity = 1.0;
my_mesh->l[line_index].tint_color.red = 1.0;
my_mesh->l[line_index].tint_color.green = 1.0;
my_mesh->l[line_index].tint_color.blue = 1.0;
my_mesh->l[line_index].time_offset = fabs(snis_random_float());
}
mesh_graph_dev_init(my_mesh);
return my_mesh;
}
struct mesh *init_radar_circle_xz_plane_mesh(double x, double z, double r, int ticks, double tick_radius)
{
int i;
struct mesh *my_mesh = malloc(sizeof(*my_mesh));
if (!my_mesh)
return my_mesh;
memset(my_mesh, 0, sizeof(*my_mesh));
my_mesh->geometry_mode = MESH_GEOMETRY_LINES;
my_mesh->nvertices = 0;
my_mesh->ntriangles = 0;
my_mesh->nlines = 0;
my_mesh->t = 0;
my_mesh->v = malloc(sizeof(*my_mesh->v) * (360 / 2 + 1 + ticks*2));
my_mesh->l = malloc(sizeof(*my_mesh->l) * (1 + ticks));
my_mesh->radius = dist3d(x, 0, z) + r;
my_mesh->tex = 0;
my_mesh->graph_ptr = 0;
for (i = 0; i <= 360; i += 2) {
my_mesh->v[my_mesh->nvertices].x = x + cos(i * M_PI / 180.0) * r;
my_mesh->v[my_mesh->nvertices].y = 0;
my_mesh->v[my_mesh->nvertices].z = z + sin(i * M_PI / 180.0) * r;
my_mesh->nvertices++;
}
my_mesh->l[0].start = &my_mesh->v[0];
my_mesh->l[0].end = &my_mesh->v[my_mesh->nvertices - 1];
my_mesh->l[0].flag = MESH_LINE_STRIP;
my_mesh->nlines++;
for (i = 0; i < ticks; ++i) {
double c = cos(i * 2.0 * M_PI / (double)ticks);
double s = sin(i * 2.0 * M_PI / (double)ticks);
mesh_add_point(my_mesh, x + c * (r - tick_radius), 0, z + s * (r - tick_radius));
mesh_add_point(my_mesh, x + c * r, 0, z + s * r);
mesh_add_line_last_2(my_mesh, MESH_LINE_DOTTED);
}
mesh_graph_dev_init(my_mesh);
return my_mesh;
}
struct mesh *init_circle_mesh(double x, double z, double r, int npoints, double angle)
{
int i;
float increment;
struct mesh *my_mesh = malloc(sizeof(*my_mesh));
if (!my_mesh)
return my_mesh;
memset(my_mesh, 0, sizeof(*my_mesh));
my_mesh->geometry_mode = MESH_GEOMETRY_LINES;
my_mesh->nvertices = 0;
my_mesh->ntriangles = 0;
my_mesh->nlines = 1;
my_mesh->t = 0;
my_mesh->v = malloc(sizeof(*my_mesh->v) * (npoints + 1));
my_mesh->l = malloc(sizeof(*my_mesh->l) * 1);
my_mesh->tex = 0;
my_mesh->radius = r;
my_mesh->graph_ptr = 0;
increment = angle / (float) npoints;
for (i = 0; i <= npoints; i++) {
float a = i * increment;
my_mesh->v[my_mesh->nvertices].x = x + cos(a) * r;
my_mesh->v[my_mesh->nvertices].y = 0;
my_mesh->v[my_mesh->nvertices].z = z + sin(a) * r;
my_mesh->nvertices++;
}
/* close the mesh */
my_mesh->v[my_mesh->nvertices - 1].x = my_mesh->v[0].x;
my_mesh->v[my_mesh->nvertices - 1].y = my_mesh->v[0].y;
my_mesh->v[my_mesh->nvertices - 1].z = my_mesh->v[0].z;
my_mesh->l[0].start = &my_mesh->v[0];
my_mesh->l[0].end = &my_mesh->v[my_mesh->nvertices - 1];
my_mesh->l[0].flag = MESH_LINE_STRIP;
mesh_graph_dev_init(my_mesh);
return my_mesh;
}
void mesh_derelict(struct mesh *m, float distortion)
{
int i;
for (i = 0; i < m->nvertices; i++) {
float dx, dy, dz;
dx = (float) (snis_randn(1000) / 1000.0 - 0.5) * distortion;
dy = (float) (snis_randn(1000) / 1000.0 - 0.5) * (distortion / 10.0) - 0.5;
dz = (float) (snis_randn(1000) / 1000.0 - 0.5) * (distortion / 10.0) - 0.5;
if (m->v[i].x < 0) {
m->v[i].x = dx;
m->v[i].y += dy;
m->v[i].z += dz;
}
}
m->radius = mesh_compute_radius(m);
for (i = 0; i < m->nvertices; i++)
m->v[i].x -= m->radius / 2.0;
m->radius = mesh_compute_radius(m);
mesh_set_flat_shading_vertex_normals(m);
mesh_graph_dev_init(m);
}
/* fabricate a tube of length h, radius r, with nfaces, parallel to x axis */
struct mesh *mesh_tube(float h, float r, float nfaces)
{
struct mesh *m;
int ntris = nfaces * 2;
int nvertices = nfaces * 2;
int i, j;
float angle, da;
float l = h / 2.0;
m = allocate_mesh_for_copy(ntris, nvertices, 0, 1);
if (!m)
return m;
m->geometry_mode = MESH_GEOMETRY_TRIANGLES;
da = 2 * M_PI / (float) nfaces;
angle = 0.0;
for (i = 0; i < nvertices; i += 2) {
m->v[i].x = -l;
m->v[i].y = r * cos(angle);
m->v[i].z = r * -sin(angle);
m->v[i + 1].x = l;
m->v[i + 1].y = m->v[i].y;
m->v[i + 1].z = m->v[i].z;
angle += da;
}
m->nvertices = nvertices;
for (i = 0; i < ntris; i += 2) {
m->t[i].v[2] = &m->v[i % nvertices];
m->t[i].v[1] = &m->v[(i + 1) % nvertices];
m->t[i].v[0] = &m->v[(i + 2) % nvertices];
m->t[i + 1].v[2] = &m->v[(i + 2) % nvertices];
m->t[i + 1].v[1] = &m->v[(i + 1) % nvertices];
m->t[i + 1].v[0] = &m->v[(i + 3) % nvertices];
}
m->ntriangles = ntris;
for (i = 0; i < ntris; i++) {
union vec3 normal;
normal = compute_triangle_normal(&m->t[i]);
m->t[i].n.x = normal.v.x;
m->t[i].n.y = normal.v.y;
m->t[i].n.z = normal.v.z;
for (j = 0; j < 3; j++) {
union vec3 normal = { { 0, -m->t[i].v[j]->y, -m->t[i].v[j]->z } };
vec3_normalize_self(&normal);
m->t[i].vnormal[j].x = normal.v.x;
m->t[i].vnormal[j].y = normal.v.y;
m->t[i].vnormal[j].z = normal.v.z;
}
}
mesh_set_flat_shading_vertex_normals(m);
for (i = 0; i < ntris; i += 2) {
mesh_set_triangle_texture_coords(m, i,
0.0, (float) ((int) ((i + 2) / 2)) * 1.0 / (float) nfaces,
1.0, (float) ((int) (i / 2)) / (float) nfaces,
0.0, (float) ((int) (i / 2)) / (float) nfaces);
mesh_set_triangle_texture_coords(m, i + 1,
1.0, (float) ((int) ((i + 2) / 2)) / (float) nfaces,
1.0, (float) ((int) (i / 2)) / (float) nfaces,
0.0, (float) ((int) ((i + 2) / 2)) / (float) nfaces);
}
m->nlines = 0;
m->radius = mesh_compute_radius(m);
mesh_graph_dev_init(m);
return m;
}
void mesh_distort_and_random_uv_map(struct mesh *m, float distortion)
{
mesh_distort_helper(m, distortion);
mesh_random_uv_map(m);
mesh_graph_dev_init(m);
}
/* See: http://blog.andreaskahler.com/2009/06/creating-icosphere-mesh-in-code.html */
struct mesh *mesh_unit_icosohedron(void)
{
const double tau = (1.0 + sqrt(5.0)) / 2.0;
const double scale = 1.0 / sqrt(1.0 + tau * tau);
struct mesh *m;
m = malloc(sizeof(*m));
if (!m)
return m;
memset(m, 0, sizeof(*m));
m->nvertices = 12;
m->ntriangles = 20;
m->t = malloc(sizeof(*m->t) * m->ntriangles);
if (!m->t)
goto bail;
memset(m->t, 0, sizeof(*m->t) * m->ntriangles);
m->v = malloc(sizeof(*m->v) * m->nvertices);
if (!m->v)
goto bail;
memset(m->v, 0, sizeof(*m->v) * m->nvertices);
m->tex = 0;
/* m->tex = malloc(sizeof(*m->tex) * m->ntriangles * 3);
if (!m->tex)
goto bail;
memset(m->tex, 0, sizeof(*m->tex) * m->ntriangles * 3); */
m->l = NULL;
m->geometry_mode = MESH_GEOMETRY_TRIANGLES;
m->v[0].x = scale * -1.0;
m->v[0].y = scale * tau;
m->v[0].z = scale * 0.0;
m->v[1].x = scale * 1.0;
m->v[1].y = scale * tau;
m->v[1].z = scale * 0.0;
m->v[2].x = scale * -1.0;
m->v[2].y = scale * -tau;
m->v[2].z = scale * 0.0;
m->v[3].x = scale * 1.0;
m->v[3].y = scale * -tau;
m->v[3].z = scale * 0.0;
m->v[4].x = scale * 0.0;
m->v[4].y = scale * -1.0;
m->v[4].z = scale * tau;
m->v[5].x = scale * 0.0;
m->v[5].y = scale * 1.0;
m->v[5].z = scale * tau;
m->v[6].x = scale * 0.0;
m->v[6].y = scale * -1.0;
m->v[6].z = scale * -tau;
m->v[7].x = scale * 0.0;
m->v[7].y = scale * 1.0;
m->v[7].z = scale * -tau;
m->v[8].x = scale * tau;
m->v[8].y = scale * 0.0;
m->v[8].z = scale * -1.0;
m->v[9].x = scale * tau;
m->v[9].y = scale * 0.0;
m->v[9].z = scale * 1.0;
m->v[10].x = scale * -tau;
m->v[10].y = scale * 0.0;
m->v[10].z = scale * -1.0;
m->v[11].x = scale * -tau;
m->v[11].y = scale * 0.0;
m->v[11].z = scale * 1.0;
m->t[0].v[0] = &m->v[0];
m->t[0].v[1] = &m->v[11];
m->t[0].v[2] = &m->v[5];
m->t[1].v[0] = &m->v[0];
m->t[1].v[1] = &m->v[5];
m->t[1].v[2] = &m->v[1];
m->t[2].v[0] = &m->v[0];
m->t[2].v[1] = &m->v[1];
m->t[2].v[2] = &m->v[7];
m->t[3].v[0] = &m->v[0];
m->t[3].v[1] = &m->v[7];
m->t[3].v[2] = &m->v[10];
m->t[4].v[0] = &m->v[0];
m->t[4].v[1] = &m->v[10];
m->t[4].v[2] = &m->v[11];
m->t[5].v[0] = &m->v[1];
m->t[5].v[1] = &m->v[5];
m->t[5].v[2] = &m->v[9];
m->t[6].v[0] = &m->v[5];
m->t[6].v[1] = &m->v[11];
m->t[6].v[2] = &m->v[4];
m->t[7].v[0] = &m->v[11];
m->t[7].v[1] = &m->v[10];
m->t[7].v[2] = &m->v[2];
m->t[8].v[0] = &m->v[10];
m->t[8].v[1] = &m->v[7];
m->t[8].v[2] = &m->v[6];
m->t[9].v[0] = &m->v[7];
m->t[9].v[1] = &m->v[1];
m->t[9].v[2] = &m->v[8];
m->t[10].v[0] = &m->v[3];
m->t[10].v[1] = &m->v[9];
m->t[10].v[2] = &m->v[4];
m->t[11].v[0] = &m->v[3];
m->t[11].v[1] = &m->v[4];
m->t[11].v[2] = &m->v[2];
m->t[12].v[0] = &m->v[3];
m->t[12].v[1] = &m->v[2];
m->t[12].v[2] = &m->v[6];
m->t[13].v[0] = &m->v[3];
m->t[13].v[1] = &m->v[6];
m->t[13].v[2] = &m->v[8];
m->t[14].v[0] = &m->v[3];
m->t[14].v[1] = &m->v[8];
m->t[14].v[2] = &m->v[9];
m->t[15].v[0] = &m->v[4];
m->t[15].v[1] = &m->v[9];
m->t[15].v[2] = &m->v[5];
m->t[16].v[0] = &m->v[2];
m->t[16].v[1] = &m->v[4];
m->t[16].v[2] = &m->v[11];
m->t[17].v[0] = &m->v[6];
m->t[17].v[1] = &m->v[2];
m->t[17].v[2] = &m->v[10];
m->t[18].v[0] = &m->v[8];
m->t[18].v[1] = &m->v[6];
m->t[18].v[2] = &m->v[7];
m->t[19].v[0] = &m->v[9];
m->t[19].v[1] = &m->v[8];
m->t[19].v[2] = &m->v[1];
m->radius = mesh_compute_radius(m);
mesh_set_flat_shading_vertex_normals(m);
mesh_graph_dev_init(m);
return m;
bail:
mesh_free(m);
return NULL;
}
void mesh_distort(struct mesh *m, float distortion)
{
mesh_distort_helper(m, distortion);
mesh_graph_dev_init(m);
}
struct mesh *mesh_fabricate_billboard(float cx, float cy, float width, float height)
{
struct mesh *m;
m = malloc(sizeof(*m));
if (!m)
return m;
memset(m, 0, sizeof(*m));
m->nvertices = 4;
m->ntriangles = 2;
m->t = malloc(sizeof(*m->t) * m->ntriangles);
if (!m->t)
goto bail;
memset(m->t, 0, sizeof(*m->t) * m->ntriangles);
m->v = malloc(sizeof(*m->v) * m->nvertices);
if (!m->v)
goto bail;
memset(m->v, 0, sizeof(*m->v) * m->nvertices);
m->tex = malloc(sizeof(*m->tex) * m->ntriangles * 3);
if (!m->tex)
goto bail;
memset(m->tex, 0, sizeof(*m->tex) * m->ntriangles * 3);
m->l = NULL;
m->geometry_mode = MESH_GEOMETRY_TRIANGLES;
m->v[0].x = -width / 2.0f + cx;
m->v[0].y = height / 2.0f + cy;
m->v[0].z = 0;
m->v[1].x = width / 2.0f + cx;
m->v[1].y = height / 2.0f + cy;
m->v[1].z = 0;
m->v[2].x = width / 2.0f + cx;
m->v[2].y = -height / 2.0f + cy;
m->v[2].z = 0;
m->v[3].x = -width / 2.0f + cx;
m->v[3].y = -height / 2.0f + cy;
m->v[3].z = 0;
m->t[0].v[0] = &m->v[0];
m->t[0].v[1] = &m->v[2];
m->t[0].v[2] = &m->v[1];
m->t[0].flag = TRIANGLE_0_1_COPLANAR;
mesh_set_triangle_texture_coords(m, 0, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f);
m->t[1].v[0] = &m->v[0];
m->t[1].v[1] = &m->v[3];
m->t[1].v[2] = &m->v[2];
m->t[1].flag = TRIANGLE_0_2_COPLANAR;
mesh_set_triangle_texture_coords(m, 1, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f);
m->radius = mesh_compute_radius(m);
mesh_set_flat_shading_vertex_normals(m);
mesh_graph_dev_init(m);
return m;
bail:
mesh_free(m);
return NULL;
}
/* mesh_fabricate_crossbeam fabricates a mesh like so, out of 8 triangles:
* 0
* |\
* | \
* | \
* 4______| \__5
* \ \ \ \
* \ \ |3 \
* \ \ | \
* \ 1 \ | \
* \_____\|_____\6
* 7 \ |
* \ |
* \ |
* \|
* 2
* centered on origin, length axis parallel to x axis.
* length is the distance betwee 0 and 3, above, and
* radius is the distance between the center of the cross
* beam and 2,6,7,3 and 0,4,5,1.
*
* 8 triangles are needed because we need to prevent backface
* culling, so we wind one set of tris one way, and the other,
* the other.
*/
struct mesh *mesh_fabricate_crossbeam(float length, float radius)
{
struct mesh *m;
m = malloc(sizeof(*m));
if (!m)
return m;
memset(m, 0, sizeof(*m));
m->nvertices = 8;
m->ntriangles = 8;
m->t = malloc(sizeof(*m->t) * m->ntriangles);
if (!m->t)
goto bail;
memset(m->t, 0, sizeof(*m->t) * m->ntriangles);
m->v = malloc(sizeof(*m->v) * m->nvertices);
if (!m->v)
goto bail;
memset(m->v, 0, sizeof(*m->v) * m->nvertices);
m->tex = malloc(sizeof(*m->tex) * m->ntriangles * 3);
if (!m->tex)
goto bail;
memset(m->tex, 0, sizeof(*m->tex) * m->ntriangles * 3);
m->l = NULL;
m->geometry_mode = MESH_GEOMETRY_TRIANGLES;
m->v[0].x = -length / 2.0f;
m->v[0].y = radius;
m->v[0].z = 0.0f;
m->v[1].x = -length / 2.0f;
m->v[1].y = -radius;
m->v[1].z = 0.0f;
m->v[2].x = length / 2.0f;
m->v[2].y = -radius;
m->v[2].z = 0.0f;
m->v[3].x = length / 2.0f;
m->v[3].y = radius;
m->v[3].z = 0.0f;
m->v[4].x = -length / 2.0f;
m->v[4].y = 0.0f;
m->v[4].z = radius;
m->v[5].x = -length / 2.0f;
m->v[5].y = 0.0f;
m->v[5].z = -radius;
m->v[6].x = length / 2.0f;
m->v[6].y = 0.0f;
m->v[6].z = -radius;
m->v[7].x = length / 2.0f;
m->v[7].y = 0.0f;
m->v[7].z = radius;
m->t[0].v[0] = &m->v[0];
m->t[0].v[1] = &m->v[1];
m->t[0].v[2] = &m->v[2];
mesh_set_triangle_texture_coords(m, 0, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f);
m->t[1].v[0] = &m->v[2];
m->t[1].v[1] = &m->v[3];
m->t[1].v[2] = &m->v[0];
mesh_set_triangle_texture_coords(m, 1, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f);
m->t[2].v[0] = &m->v[4];
m->t[2].v[1] = &m->v[5];
m->t[2].v[2] = &m->v[6];
mesh_set_triangle_texture_coords(m, 2, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f);
m->t[3].v[0] = &m->v[6];
m->t[3].v[1] = &m->v[7];
m->t[3].v[2] = &m->v[4];
mesh_set_triangle_texture_coords(m, 3, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f);
m->t[4].v[0] = &m->v[2];
m->t[4].v[1] = &m->v[1];
m->t[4].v[2] = &m->v[0];
mesh_set_triangle_texture_coords(m, 4, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 0.0f);
m->t[5].v[0] = &m->v[0];
m->t[5].v[1] = &m->v[3];
m->t[5].v[2] = &m->v[2];
mesh_set_triangle_texture_coords(m, 5, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f);
m->t[6].v[0] = &m->v[6];
m->t[6].v[1] = &m->v[5];
m->t[6].v[2] = &m->v[4];
mesh_set_triangle_texture_coords(m, 6, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f);
m->t[7].v[0] = &m->v[4];
m->t[7].v[1] = &m->v[7];
m->t[7].v[2] = &m->v[6];
mesh_set_triangle_texture_coords(m, 7, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f);
mesh_compute_radius(m);
mesh_set_flat_shading_vertex_normals(m);
mesh_graph_dev_init(m);
return m;
bail:
mesh_free(m);
return NULL;
}
