// 根据 render_state 绘制原始三角形
void device_draw_primitive(device_t *device, const vertex_t *v1,
const vertex_t *v2, const vertex_t *v3) {
point_t p1, p2, p3, c1, c2, c3;
int render_state = device->render_state;
// 按照 Transform 变化
transform_apply(&device->transform, &c1, &v1->pos);
transform_apply(&device->transform, &c2, &v2->pos);
transform_apply(&device->transform, &c3, &v3->pos);
// 裁剪，注意此处可以完善为具体判断几个点在 cvv内以及同cvv相交平面的坐标比例
// 进行进一步精细裁剪，将一个分解为几个完全处在 cvv内的三角形
if (transform_check_cvv(&c1) != 0) return;
if (transform_check_cvv(&c2) != 0) return;
if (transform_check_cvv(&c3) != 0) return;
// 归一化
transform_homogenize(&device->transform, &p1, &c1);
transform_homogenize(&device->transform, &p2, &c2);
transform_homogenize(&device->transform, &p3, &c3);
// 纹理或者色彩绘制
if (render_state & (RENDER_STATE_TEXTURE | RENDER_STATE_COLOR)) {
vertex_t t1 = *v1, t2 = *v2, t3 = *v3;
trapezoid_t traps[2];
int n;
t1.pos = p1;
t2.pos = p2;
t3.pos = p3;
t1.pos.w = c1.w;
t2.pos.w = c2.w;
t3.pos.w = c3.w;
vertex_rhw_init(&t1); // 初始化 w
vertex_rhw_init(&t2); // 初始化 w
vertex_rhw_init(&t3); // 初始化 w
// 拆分三角形为0-2个梯形，并且返回可用梯形数量
n = trapezoid_init_triangle(traps, &t1, &t2, &t3);
if (n >= 1) device_render_trap(device, &traps[0]);
if (n >= 2) device_render_trap(device, &traps[1]);
}
if (render_state & RENDER_STATE_WIREFRAME) { // 线框绘制
device_draw_line(device, (int)p1.x, (int)p1.y, (int)p2.x, (int)p2.y, device->foreground);
device_draw_line(device, (int)p1.x, (int)p1.y, (int)p3.x, (int)p3.y, device->foreground);
device_draw_line(device, (int)p3.x, (int)p3.y, (int)p2.x, (int)p2.y, device->foreground);
}
}
char character_buildAt(character_t* c, kindOf_building_t* t, float x, float y)
{
if (!transform_check(&t->build, &c->inventory))
return 0;
character_delHome(c);
building_t* b = world_addBuilding(c->w, x, y, t, c);
if (b == NULL)
return 0;
transform_apply(&t->build, &c->inventory, 1);
c->hasBuilding = b->o.uuid;
return 1;
}