Merge pull request SFTtech#138 from franciscod/debug_overlay_grid

game: add debug overlay grid, togglable with F4

cpp/game_main.cpp

@@ -101,6 +101,7 @@ GameMain::GameMain(Engine *engine)
 	:
 	editor_current_terrain{0},
 	editor_current_building{0},
+	debug_grid_active{false},
 	clicking_active{true},
 	ctrl_active{false},
 	scrolling_active{false},
@@ -512,6 +513,10 @@ bool GameMain::on_input(SDL_Event *e) {
 			engine.drawing_debug_overlay = !engine.drawing_debug_overlay;
 			break;
 
+		case SDLK_F4:
+			this->debug_grid_active = !this->debug_grid_active;
+			break;
+
 		case SDLK_SPACE:
 			this->terrain->blending_enabled = !terrain->blending_enabled;
 			break;
@@ -589,6 +594,10 @@ bool GameMain::on_draw() {
 	// draw terrain
 	terrain->draw(&engine);
 
+	if (this->debug_grid_active) {
+		this->draw_debug_grid();
+	}
+
 	return true;
 }
 
@@ -607,6 +616,57 @@ bool GameMain::on_drawhud() {
 	return true;
 }
 
+void GameMain::draw_debug_grid() {
+	Engine &e = Engine::get();
+
+	coord::camgame camera = coord::tile{0, 0}.to_tile3().to_phys3().to_camgame();
+
+	int cam_offset_x = util::mod(camera.x, e.tile_halfsize.x * 2);
+	int cam_offset_y = util::mod(camera.y, e.tile_halfsize.y * 2);
+
+	int line_half_width = e.window_size.x / 2;
+	int line_half_height = e.window_size.y / 2;
+
+	// rounding so we get 2:1 proportion needed for the isometric perspective
+
+	if (line_half_width > line_half_height * 2) {
+
+		if (line_half_width & 1) {
+			line_half_width += 1; // round up if it's odd
+		}
+
+		line_half_height = line_half_width / 2;
+
+	} else {
+		line_half_width = line_half_height * 2;
+	}
+
+	// quantity of lines to draw to each side from the center
+	int k = line_half_width / (e.tile_halfsize.x);
+
+	int tilesize_x = e.tile_halfsize.x * 2;
+	int common_x   = cam_offset_x + e.tile_halfsize.x;
+	int x0         = common_x     - line_half_width;
+	int x1         = common_x     + line_half_width;
+	int y0         = cam_offset_y - line_half_height;
+	int y1         = cam_offset_y + line_half_height;
+
+	glLineWidth(1);
+	glColor3f(0.0, 0.0, 0.0);
+	glBegin(GL_LINES); {
+
+		for (int i = -k; i < k; i++) {
+				glVertex3f(i * tilesize_x + x0, y1, 0);
+				glVertex3f(i * tilesize_x + x1, y0, 0);
+
+				glVertex3f(i * tilesize_x + x0, y0 - 1, 0);
+				glVertex3f(i * tilesize_x + x1, y1 - 1, 0);
+		}
+
+	} glEnd();
+
+}
+
 void TestSound::play() {
 	if (this->sound_items.size() <= 0) {
 		return;

cpp/game_main.h

@@ -88,10 +88,16 @@ class GameMain :
 	 */
 	std::unordered_set<openage::TerrainObject *> placed_buildings;
 
+	/**
+	 * debug function that draws a simple overlay grid
+	 */
+	void draw_debug_grid();
+
 	// currently selected terrain id
 	openage::terrain_t editor_current_terrain;
 	int editor_current_building;
 
+	bool debug_grid_active;
 	bool clicking_active;
 	bool ctrl_active;
 	bool scrolling_active;