MenuMode.cpp

#include "MenuMode.hpp"

//for the GL_ERRORS() macro:
#include "gl_errors.hpp"

//for easy sprite drawing:
#include "DrawSprites.hpp"

#include <random>

MenuMode::MenuMode(std::vector< Item > const &items_) : items(items_) {

	//select first item which can be selected:
	for (uint32_t i = 0; i < items.size(); ++i) {
		if (items[i].on_select) {
			selected = i;
			break;
		}
	}
}

MenuMode::~MenuMode() {
}

bool MenuMode::handle_event(SDL_Event const &evt, glm::uvec2 const &window_size) {
    if (background) {
        if (background->handle_event(evt, window_size)) {
            return true;
        }
    }

	if (evt.type == SDL_KEYDOWN) {
		if (evt.key.keysym.sym == SDLK_UP) {
			//skip non-selectable items:
			for (uint32_t i = selected - 1; i < items.size(); --i) {
				if (items[i].on_select) {
					selected = i;
					break;
				}
			}
			return true;
		} else if (evt.key.keysym.sym == SDLK_DOWN) {
			//note: skips non-selectable items:
			for (uint32_t i = selected + 1; i < items.size(); ++i) {
				if (items[i].on_select) {
					selected = i;
					break;
				}
			}
			return true;
		} else if (evt.key.keysym.sym == SDLK_RETURN) {
			if (selected < items.size() && items[selected].on_select) {
				items[selected].on_select(items[selected]);
				return true;
			}
		}
	}

    return false;
}

void MenuMode::update(float elapsed) {

	//TODO: selection bounce update

	if (background) {
		background->update(elapsed);
	}
}

void MenuMode::draw(glm::uvec2 const &drawable_size) {
	if (background) {
		std::shared_ptr< Mode > hold_me = shared_from_this();
		background->draw(drawable_size);
		//it is an error to remove the last reference to this object in background->draw():
		assert(hold_me.use_count() > 1);
	} else {
		glClearColor(0.5f, 0.5f, 0.5f, 0.0f);
		glClear(GL_COLOR_BUFFER_BIT);
	}

	//use alpha blending:
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	//don't use the depth test:
	glDisable(GL_DEPTH_TEST);

	{ //draw the menu using DrawSprites:
		assert(atlas && "it is an error to try to draw a menu without an atlas");
		DrawSprites draw_sprites(*atlas, view_min, view_max, drawable_size, DrawSprites::AlignPixelPerfect);

		for (auto const &item : items) {
			bool is_selected = (&item == &items[0] + selected);
			glm::u8vec4 color = (is_selected ? glm::u8vec4(0xff, 0x00, 0xff, 0xff) : glm::u8vec4(0x00, 0x00, 0x00, 0xff));
			float left, right;
			if (!item.sprite) {
				//draw item.name as text:
				draw_sprites.draw_text(
					item.name, item.at, item.scale, color
				);
				glm::vec2 min,max;
				draw_sprites.get_text_extents(
					item.name, item.at, item.scale, &min, &max
				);
				left = min.x;
				right = max.x;
			} else {
				draw_sprites.draw(*item.sprite, item.at, item.scale, color);
				left = item.at.x + item.scale * (item.sprite->min_px.x - item.sprite->anchor_px.x);
				right = item.at.x + item.scale * (item.sprite->max_px.x - item.sprite->anchor_px.x);
			}
			if (is_selected) {
				if (left_select) {
					draw_sprites.draw(*left_select, glm::vec2(left, item.at.y), item.scale);
				}
				if (right_select) {
					draw_sprites.draw(*right_select, glm::vec2(right, item.at.y), item.scale);
				}
			}
			
		}
	} //<-- gets drawn here!


	GL_ERRORS(); //PARANOIA: print errors just in case we did something wrong.
}