1 files changed, 168 insertions, 0 deletions
diff --git a/src/crepe/system/RenderSystem.cpp b/src/crepe/system/RenderSystem.cpp
new file mode 100644
index 0000000..30bb422
--- /dev/null
+++ b/src/crepe/system/RenderSystem.cpp
@@ -0,0 +1,168 @@
+#include <algorithm>
+#include <cassert>
+#include <cmath>
+#include <functional>
+#include <optional>
+#include <stdexcept>
+#include <vector>
+
+#include "../api/Camera.h"
+#include "../api/ParticleEmitter.h"
+#include "../api/Sprite.h"
+#include "../api/Text.h"
+#include "../api/Transform.h"
+#include "../facade/Font.h"
+#include "../facade/SDLContext.h"
+#include "../facade/Texture.h"
+#include "../manager/ComponentManager.h"
+#include "../manager/ResourceManager.h"
+#include "api/Text.h"
+#include "facade/Font.h"
+#include "util/AbsolutePosition.h"
+
+#include "RenderSystem.h"
+#include "types.h"
+
+using namespace crepe;
+using namespace std;
+
+void RenderSystem::clear_screen() {
+	SDLContext & ctx = this->mediator.sdl_context;
+	ctx.clear_screen();
+}
+
+void RenderSystem::present_screen() {
+	SDLContext & ctx = this->mediator.sdl_context;
+	ctx.present_screen();
+}
+
+void RenderSystem::update_camera() {
+	ComponentManager & mgr = this->mediator.component_manager;
+	SDLContext & ctx = this->mediator.sdl_context;
+	RefVector<Camera> cameras = mgr.get_components_by_type<Camera>();
+
+	if (cameras.size() == 0) throw std::runtime_error("No cameras in current scene");
+
+	for (Camera & cam : cameras) {
+		if (!cam.active) continue;
+		const Transform & transform
+			= mgr.get_components_by_id<Transform>(cam.game_object_id).front().get();
+		vec2 new_camera_pos = transform.position + cam.data.postion_offset;
+		ctx.update_camera_view(cam, new_camera_pos);
+		return;
+	}
+	throw std::runtime_error("No active cameras in current scene");
+}
+
+bool sorting_comparison(const Sprite & a, const Sprite & b) {
+	if (a.data.sorting_in_layer != b.data.sorting_in_layer)
+		return a.data.sorting_in_layer < b.data.sorting_in_layer;
+	if (a.data.order_in_layer != b.data.order_in_layer)
+		return a.data.order_in_layer < b.data.order_in_layer;
+
+	return false;
+}
+
+RefVector<Sprite> RenderSystem::sort(RefVector<Sprite> & objs) const {
+	RefVector<Sprite> sorted_objs(objs);
+	std::sort(sorted_objs.begin(), sorted_objs.end(), sorting_comparison);
+
+	return sorted_objs;
+}
+
+void RenderSystem::frame_update() {
+	this->clear_screen();
+	this->render();
+	this->render_text();
+	this->present_screen();
+}
+
+void RenderSystem::render_text() {
+	SDLContext & ctx = this->mediator.sdl_context;
+	ComponentManager & mgr = this->mediator.component_manager;
+	ResourceManager & resource_manager = this->mediator.resource_manager;
+
+	RefVector<Text> texts = mgr.get_components_by_type<Text>();
+
+	for (Text & text : texts) {
+		if (!text.active) continue;
+		if (!text.font.has_value())
+			text.font.emplace(ctx.get_font_from_name(text.font_family));
+
+		const Font & font = resource_manager.get<Font>(text.font.value());
+		const auto & transform
+			= mgr.get_components_by_id<Transform>(text.game_object_id).front().get();
+		ctx.draw_text(SDLContext::RenderText {
+			.text = text,
+			.font = font,
+			.transform = transform,
+		});
+	}
+}
+
+bool RenderSystem::render_particle(const Sprite & sprite, const Transform & transform) {
+	ComponentManager & mgr = this->mediator.component_manager;
+	SDLContext & ctx = this->mediator.sdl_context;
+	ResourceManager & resource_manager = this->mediator.resource_manager;
+	Texture & res = resource_manager.get<Texture>(sprite.source);
+
+	vector<reference_wrapper<ParticleEmitter>> emitters
+		= mgr.get_components_by_id<ParticleEmitter>(sprite.game_object_id);
+
+	bool rendering_particles = false;
+
+	for (const ParticleEmitter & em : emitters) {
+		if (&em.sprite != &sprite) continue;
+		rendering_particles = true;
+		if (!em.active) continue;
+
+		for (const Particle & p : em.particles) {
+			if (!p.active) continue;
+			if (p.time_in_life < em.data.begin_lifespan) continue;
+
+			ctx.draw(SDLContext::RenderContext {
+				.sprite = sprite,
+				.texture = res,
+				.pos = p.position,
+				.angle = p.angle + transform.rotation,
+				.scale = transform.scale,
+			});
+		}
+	}
+	return rendering_particles;
+}
+void RenderSystem::render_normal(const Sprite & sprite, const Transform & transform) {
+	SDLContext & ctx = this->mediator.sdl_context;
+	ResourceManager & resource_manager = this->mediator.resource_manager;
+	const Texture & res = resource_manager.get<Texture>(sprite.source);
+	vec2 pos = AbsolutePosition::get_position(transform, sprite.data.position_offset);
+	ctx.draw(SDLContext::RenderContext {
+		.sprite = sprite,
+		.texture = res,
+		.pos = pos,
+		.angle = transform.rotation,
+		.scale = transform.scale,
+	});
+}
+
+void RenderSystem::render() {
+	ComponentManager & mgr = this->mediator.component_manager;
+	this->update_camera();
+
+	RefVector<Sprite> sprites = mgr.get_components_by_type<Sprite>();
+	ResourceManager & resource_manager = this->mediator.resource_manager;
+	RefVector<Sprite> sorted_sprites = this->sort(sprites);
+	RefVector<Text> text_components = mgr.get_components_by_type<Text>();
+
+	for (const Sprite & sprite : sorted_sprites) {
+		if (!sprite.active) continue;
+		const Transform & transform
+			= mgr.get_components_by_id<Transform>(sprite.game_object_id).front().get();
+
+		bool rendered_particles = this->render_particle(sprite, transform);
+
+		if (rendered_particles) continue;
+
+		this->render_normal(sprite, transform);
+	}
+}