partially done work on total source tree rework, separation of engine context and game context, generalization of renderer for different backends as well as web platform target
This commit is contained in:
439
src/twn_loop.c
Normal file
439
src/twn_loop.c
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@ -0,0 +1,439 @@
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#include "twn_loop.h"
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#include "townengine/context.h"
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#include "townengine/rendering.h"
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#include "townengine/input/internal_api.h"
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#include "townengine/util.h"
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#include "townengine/twn_game_object.h"
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#include "townengine/audio/internal_api.h"
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#include "townengine/textures/internal_api.h"
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#include "townengine/rendering/internal_api.h"
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#include <SDL2/SDL.h>
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#include <physfs.h>
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#include <stb_ds.h>
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#ifdef EMSCRIPTEN
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#include <GLES2/gl2.h>
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#else
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#include <glad/glad.h>
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#endif
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#include <stdlib.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <tgmath.h>
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#include <limits.h>
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static void poll_events(void) {
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SDL_Event e;
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ctx.window_size_has_changed = false;
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while (SDL_PollEvent(&e)) {
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switch (e.type) {
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case SDL_QUIT:
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ctx.is_running = false;
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break;
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case SDL_WINDOWEVENT:
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if (e.window.windowID != ctx.window_id)
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break;
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switch (e.window.event) {
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case SDL_WINDOWEVENT_SIZE_CHANGED:
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ctx.window_size_has_changed = true;
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break;
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default:
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break;
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}
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break;
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default:
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break;
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}
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}
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}
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#ifndef EMSCRIPTEN
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static void APIENTRY opengl_log(GLenum source,
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GLenum type,
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GLuint id,
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GLenum severity,
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GLsizei length,
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const GLchar* message,
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const void* userParam)
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{
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(void)source;
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(void)type;
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(void)id;
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(void)severity;
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(void)userParam;
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log_info("OpenGL: %.*s\n", length, message);
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}
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#endif
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static void main_loop(void) {
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/*
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if (!ctx.is_running) {
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end(ctx);
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clean_up(ctx);
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emscripten_cancel_main_loop();
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}
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*/
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/* frame timer */
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int64_t current_frame_time = SDL_GetPerformanceCounter();
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int64_t delta_time = current_frame_time - ctx.prev_frame_time;
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ctx.prev_frame_time = current_frame_time;
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ctx.delta_time = delta_time;
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/* handle unexpected timer anomalies (overflow, extra slow frames, etc) */
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if (delta_time > ctx.desired_frametime * 8) { /* ignore extra-slow frames */
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delta_time = ctx.desired_frametime;
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}
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delta_time = MAX(0, delta_time);
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/* vsync time snapping */
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/* get the refresh rate of the current display (it might not always be the same one) */
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int display_framerate = 60; /* a reasonable guess */
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SDL_DisplayMode current_display_mode;
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int current_display_index = SDL_GetWindowDisplayIndex(ctx.window);
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if (SDL_GetCurrentDisplayMode(current_display_index, ¤t_display_mode) == 0)
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display_framerate = current_display_mode.refresh_rate;
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int64_t snap_hz = display_framerate;
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if (snap_hz <= 0)
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snap_hz = 60;
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/* these are to snap delta time to vsync values if it's close enough */
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int64_t vsync_maxerror = (int64_t)((double)ctx.clocks_per_second * 0.0002);
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size_t snap_frequency_count = 8;
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for (size_t i = 0; i < snap_frequency_count; ++i) {
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int64_t frequency = (ctx.clocks_per_second / snap_hz) * (i+1);
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if (llabs(delta_time - frequency) < vsync_maxerror) {
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delta_time = frequency;
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break;
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}
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}
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/* delta time averaging */
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size_t time_averager_count = SDL_arraysize(ctx.time_averager);
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for (size_t i = 0; i < time_averager_count - 1; ++i) {
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ctx.time_averager[i] = ctx.time_averager[i+1];
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}
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ctx.time_averager[time_averager_count - 1] = delta_time;
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int64_t averager_sum = 0;
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for (size_t i = 0; i < time_averager_count; ++i) {
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averager_sum += ctx.time_averager[i];
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}
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delta_time = averager_sum / time_averager_count;
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ctx.delta_averager_residual += averager_sum % time_averager_count;
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delta_time += ctx.delta_averager_residual / time_averager_count;
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ctx.delta_averager_residual %= time_averager_count;
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/* add to the accumulator */
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ctx.frame_accumulator += delta_time;
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/* spiral of death protection */
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if (ctx.frame_accumulator > ctx.desired_frametime * 8) {
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ctx.resync_flag = true;
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}
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/* timer resync if requested */
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if (ctx.resync_flag) {
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ctx.frame_accumulator = 0;
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delta_time = ctx.desired_frametime;
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ctx.resync_flag = false;
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}
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/* finally, let's get to work */
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int frames = 0;
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while (ctx.frame_accumulator >= ctx.desired_frametime * ctx.update_multiplicity) {
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frames += 1;
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for (size_t i = 0; i < ctx.update_multiplicity; ++i) {
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/* TODO: disable rendering pushes on not-last ? */
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render_queue_clear();
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poll_events();
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if (ctx.window_size_has_changed) {
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t_vec2 size;
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SDL_GetWindowSize(ctx.window, &size.x, &size.y);
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ctx.window_w = size.x;
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ctx.window_h = size.y;
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}
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input_state_update(&ctx.input);
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game_object_tick();
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ctx.frame_accumulator -= ctx.desired_frametime;
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ctx.tick_count = (ctx.tick_count % ULLONG_MAX) + 1;
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ctx.initialization_needed = false;
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}
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}
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/* TODO: in some cases machine might want to assume frames will be fed as much as possible */
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/* which for now is broken as glBufferData with NULL is used all over right after render */
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if (frames != 0)
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render();
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}
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static bool initialize(void) {
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if (SDL_Init(SDL_INIT_EVERYTHING & ~SDL_INIT_HAPTIC) == -1) {
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CRY_SDL("SDL initialization failed.");
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return false;
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}
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/* TODO: recognize cli parameter to turn it on on release */
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/* debug mode _defaults_ to being enabled on debug builds. */
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/* you should be able to enable it at runtime on any build */
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#ifndef NDEBUG
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ctx.debug = true;
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#else
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ctx.debug = false;
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#endif
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#ifdef EMSCRIPTEN
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/* emscripten interpretes those as GL ES version against WebGL */
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
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#else
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 1);
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 5);
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if (ctx.debug)
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
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else
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SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_NO_ERROR);
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#endif
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SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 5);
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SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 6);
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SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 5);
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SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 0);
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SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
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SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
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SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, 1);
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/* init got far enough to create a window */
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ctx.window = SDL_CreateWindow("townengine",
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SDL_WINDOWPOS_CENTERED,
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SDL_WINDOWPOS_CENTERED,
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RENDER_BASE_WIDTH,
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RENDER_BASE_HEIGHT,
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// SDL_WINDOW_ALLOW_HIGHDPI |
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SDL_WINDOW_RESIZABLE |
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SDL_WINDOW_OPENGL);
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if (ctx.window == NULL) {
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CRY_SDL("Window creation failed.");
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goto fail;
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}
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ctx.gl_context = SDL_GL_CreateContext(ctx.window);
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if (!ctx.gl_context) {
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CRY_SDL("GL context creation failed.");
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goto fail;
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}
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if (SDL_GL_MakeCurrent(ctx.window, ctx.gl_context)) {
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CRY_SDL("GL context binding failed.");
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goto fail;
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}
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if (SDL_GL_SetSwapInterval(-1))
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SDL_GL_SetSwapInterval(1);
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#ifndef EMSCRIPTEN
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if (gladLoadGL() == 0) {
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CRY("Init", "GLAD failed");
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goto fail;
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}
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#endif
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log_info("OpenGL context: %s\n", glGetString(GL_VERSION));
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#ifndef EMSCRIPTEN
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glHint(GL_TEXTURE_COMPRESSION_HINT, GL_NICEST);
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glHint(GL_GENERATE_MIPMAP_HINT, GL_NICEST);
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glHint(GL_FOG_HINT, GL_FASTEST);
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#endif
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/* might need this to have multiple windows */
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ctx.window_id = SDL_GetWindowID(ctx.window);
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glViewport(0, 0, RENDER_BASE_WIDTH, RENDER_BASE_HEIGHT);
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/* TODO: */
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// SDL_GetRendererOutputSize(ctx.renderer, &ctx.window_w, &ctx.window_h);
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ctx.window_w = RENDER_BASE_WIDTH;
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ctx.window_h = RENDER_BASE_HEIGHT;
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/* audio initialization */
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{
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SDL_AudioSpec request, got;
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SDL_zero(request);
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request.freq = AUDIO_FREQUENCY;
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request.format = AUDIO_S16;
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request.channels = AUDIO_N_CHANNELS;
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request.callback = audio_callback;
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/* TODO: check for errors */
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ctx.audio_device = SDL_OpenAudioDevice(NULL, 0, &request, &got, 0);
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ctx.audio_stream_format = got.format;
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ctx.audio_stream_frequency = got.freq;
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ctx.audio_stream_channel_count = got.channels;
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SDL_PauseAudioDevice(ctx.audio_device, 0);
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}
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/* filesystem time */
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/* TODO: ANDROID: see the warning in physicsfs PHYSFS_init docs/header */
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if (!PHYSFS_init(ctx.argv[0]) ||
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!PHYSFS_setSaneConfig(ORGANIZATION_NAME, APP_NAME, PACKAGE_EXTENSION, false, true))
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{
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CRY_PHYSFS("Filesystem initialization failed.");
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goto fail;
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}
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/* you could change this at runtime if you wanted */
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ctx.update_multiplicity = 1;
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#ifndef EMSCRIPTEN
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/* hook up opengl debugging callback */
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if (ctx.debug) {
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glEnable(GL_DEBUG_OUTPUT);
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glDebugMessageCallback(opengl_log, NULL);
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}
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#endif
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/* random seeding */
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/* SDL_GetPerformanceCounter returns some platform-dependent number. */
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/* it should vary between game instances. i checked! random enough for me. */
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ctx.random_seed = SDL_GetPerformanceCounter();
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srand((unsigned int)ctx.random_seed);
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stbds_rand_seed(ctx.random_seed);
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/* main loop machinery */
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ctx.is_running = true;
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ctx.resync_flag = true;
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ctx.clocks_per_second = SDL_GetPerformanceFrequency();
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ctx.prev_frame_time = SDL_GetPerformanceCounter();
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ctx.desired_frametime = ctx.clocks_per_second / TICKS_PER_SECOND;
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ctx.frame_accumulator = 0;
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ctx.tick_count = 0;
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/* delta time averaging */
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ctx.delta_averager_residual = 0;
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for (size_t i = 0; i < SDL_arraysize(ctx.time_averager); ++i) {
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ctx.time_averager[i] = ctx.desired_frametime;
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}
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/* rendering */
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/* these are dynamic arrays and will be allocated lazily by stb_ds */
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ctx.render_queue_2d = NULL;
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ctx.uncolored_mesh_batches = NULL;
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textures_cache_init(&ctx.texture_cache, ctx.window);
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text_cache_init(&ctx.text_cache);
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/* input */
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input_state_init(&ctx.input);
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/* scripting */
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/*
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if (!scripting_init(ctx)) {
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goto fail;
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}
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*/
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return true;
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fail:
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SDL_Quit();
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return false;
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}
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/* will not be called on an abnormal exit */
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static void clean_up(void) {
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/*
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scripting_deinit(ctx);
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*/
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input_state_deinit(&ctx.input);
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/* if you're gonna remove this, it's also being done in rendering.c */
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for (size_t i = 0; i < arrlenu(ctx.render_queue_2d); ++i) {
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if (ctx.render_queue_2d[i].type == PRIMITIVE_2D_TEXT) {
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free(ctx.render_queue_2d[i].text.text);
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}
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}
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arrfree(ctx.render_queue_2d);
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text_cache_deinit(&ctx.text_cache);
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textures_cache_deinit(&ctx.texture_cache);
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PHYSFS_deinit();
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SDL_Quit();
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}
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static void reset_state(void) {
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input_reset_state(&ctx.input);
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textures_reset_state();
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}
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int enter_loop(int argc, char **argv) {
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ctx.argc = argc;
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ctx.argv = argv;
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if (!initialize())
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return EXIT_FAILURE;
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for (int i = 1; i < (argc - 1); ++i) {
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if (strcmp(argv[i], "--data-dir") == 0) {
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if (!PHYSFS_mount(argv[i+1], NULL, true)) {
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CRY_PHYSFS("Data dir mount override failed.");
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return EXIT_FAILURE;
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}
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}
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}
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game_object_load();
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ctx.was_successful = true;
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ctx.initialization_needed = true;
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while (ctx.is_running) {
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if (game_object_try_reloading()) {
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ctx.initialization_needed = true;
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reset_state();
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}
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main_loop();
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}
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game_object_unload();
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clean_up();
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return ctx.was_successful ? EXIT_SUCCESS : EXIT_FAILURE;
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}
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Reference in New Issue
Block a user