116 lines
2.8 KiB
C
116 lines
2.8 KiB
C
#include "engine.h"
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#include <stdio.h>
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//errors here should be fatal
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static void error(Engine* engine, char* message) {
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fprintf(stderr, message);
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exit(-1);
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}
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//exposed functions
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void initEngine(Engine* engine) {
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//clear
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engine->root = NULL;
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engine->running = true;
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//init SDL
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if (SDL_Init(0) != 0) {
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error(engine, "Failed to initialize SDL2");
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}
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//init the window
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engine->window = SDL_CreateWindow(
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"Caption",
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SDL_WINDOWPOS_UNDEFINED,
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SDL_WINDOWPOS_UNDEFINED,
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engine->screenWidth,
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engine->screenHeight,
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SDL_WINDOW_RESIZABLE
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);
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if (engine->window == NULL) {
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error(engine, "Failed to initialize the window");
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}
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//init the renderer
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engine->renderer = SDL_CreateRenderer(engine->window, -1, 0);
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if (engine->renderer == NULL) {
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error(engine, "Failed to initialize the renderer");
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}
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SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "best");
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SDL_RenderSetLogicalSize(engine->renderer, engine->screenWidth, engine->screenHeight);
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}
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void freeEngine(Engine* engine) {
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SDL_DestroyRenderer(engine->renderer);
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SDL_DestroyWindow(engine->window);
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SDL_Quit();
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engine->renderer = NULL;
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engine->window = NULL;
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}
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static void execStep(Engine* engine) {
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//DEBUG: for now, just poll events
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SDL_Event event;
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while (SDL_PollEvent(&event)) {
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switch(event.type) {
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//quit
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case SDL_QUIT: {
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engine->running = false;
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}
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break;
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//window events are handled internally
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case SDL_WINDOWEVENT: {
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switch(event.window.event) {
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case SDL_WINDOWEVENT_RESIZED:
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engine->screenWidth = event.window.data1;
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engine->screenHeight = event.window.data2;
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SDL_RenderSetLogicalSize(engine->renderer, engine->screenWidth, engine->screenHeight);
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break;
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}
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}
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break;
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//TODO: input
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}
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}
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}
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//the heart of the engine
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void execEngine(Engine* engine) {
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//set up time
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gettimeofday(&engine->realTime, NULL);
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engine->simTime = engine->realTime;
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struct timeval delta = { .tv_sec = 0, .tv_usec = 1000 * 1000 / 60 }; //60 frames per second
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while (engine->running) {
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//calc the time passed
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gettimeofday(&engine->realTime, NULL);
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//if not enough time has passed
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if (engine->simTime.tv_sec < engine->realTime.tv_sec && engine->simTime.tv_usec < engine->realTime.tv_usec) {
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//while not enough time has passed
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while(engine->simTime.tv_sec < engine->realTime.tv_sec && engine->simTime.tv_usec < engine->realTime.tv_usec) {
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//simulate the world
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execStep(engine);
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//calc the time simulation
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timeradd(&delta, &engine->simTime, &engine->simTime);
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}
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}
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else {
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SDL_Delay(10); //let the machine sleep, 10ms
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}
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//render the world
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SDL_SetRenderDrawColor(engine->renderer, 0, 0, 0, 255); //NOTE: This line can be disabled later
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SDL_RenderClear(engine->renderer); //NOTE: This line can be disabled later
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SDL_RenderPresent(engine->renderer);
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}
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}
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