89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
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#include "camera.h"
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#include "types.h"
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#include "entity.h"
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#include "util/assert.h"
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static inline double dabs(double x) { return x < 0.0 ? -x : x; }
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static inline double dmin(double x, double y) { return x < y ? x : y; }
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System_Camera *camera_NewSystem(App *super) {
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System_Camera *sys = zero_malloc(sizeof(System_Camera));
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sys->super = super;
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Box2 default_screen = {
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.lefttop = {.x = 0.0, .y = 0.0},
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.size = {.x = 1280, .y = 720}};
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sys->cam = sys->screen = default_screen;
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return sys;
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}
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void camera_DeleteSystem(System_Camera *sys) {
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free(sys);
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}
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void camera_AddEntity(System_Camera *sys, Entity *e) {
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if (e->player) {
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ASSERT(!sys->player && "Two player entities are added! Did you forget to DeleteEntity for player?");
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sys->player = e->player;
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}
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}
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void camera_DeleteEntity(System_Camera *sys, uintptr_t id) {
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if (sys->player && sys->player->super->id == id)
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sys->player = NULL;
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}
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void camera_Advance(System_Camera *sys, Duration deltaTime) {
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Vec2 tocenter;
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if (sys->target.size.x > EPS)
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tocenter = box2_Center(sys->target);
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else if (sys->player)
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tocenter = vec2_Add(
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sys->player->super->position->position,
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vec2(0, -sys->player->super->hitbox->box.size.y));
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else
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return;
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double speed;
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if (dabs(sys->speed) < EPS)
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speed = 4.0;
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else
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speed = sys->speed;
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Vec2 oldcenter = box2_Center(sys->cam), oldsize = sys->cam.size;
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Vec2 newcenter, newsize;
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Vec2 diff = vec2_Minus(tocenter, oldcenter);
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if (dabs(diff.x) < EPS && dabs(diff.y) < EPS)
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newcenter = tocenter;
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else {
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Vec2 xdiff = vec2_Scale(diff, dmin(speed * duration_Seconds(deltaTime), 1.0));
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newcenter = vec2_Add(oldcenter, xdiff);
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}
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// TODO size scaling
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newsize = oldsize;
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sys->cam = box2_FromCenter(newcenter, newsize);
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}
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inline static Vec2 _camera_TransformSize(System_Camera *sys, Vec2 worldSize) {
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Vec2 result = {
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.x = worldSize.x / sys->cam.size.x * sys->screen.size.x,
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.y = worldSize.y / sys->cam.size.y * sys->screen.size.y};
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return result;
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}
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Vec2 camera_TransformVec2(System_Camera *sys, Vec2 world) {
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Vec2 relative = vec2_Minus(world, sys->cam.lefttop);
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return vec2_Add(sys->screen.lefttop, _camera_TransformSize(sys, relative));
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}
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Box2 camera_TransformBox2(System_Camera *sys, Box2 world) {
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Box2 result = {
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.lefttop = camera_TransformVec2(sys, world.lefttop),
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.size = _camera_TransformSize(sys, world.size)};
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return result;
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}
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