abstract multiple walkers
This commit is contained in:
Jakob Hördt
parent
9c58521ec6
commit
3212f868ec
1 changed files with 42 additions and 43 deletions
85
main.cpp
85
main.cpp
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@ -62,9 +62,9 @@ auto operator+(SDL_Point a, SDL_Point b) {
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using clock = std::chrono::steady_clock;
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constexpr int width = 1000;
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constexpr int height = 500;
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constexpr auto steps_per_second = 3;
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constexpr int width = 2000;
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constexpr int height = 1000;
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constexpr auto steps_per_second = 100'000;
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template <auto EF>
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struct [[nodiscard("give this a name so SDL_Quit is called at the end"
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@ -83,6 +83,11 @@ auto poll_events(bool& continu) {
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if (e.type == SDL_QUIT) { continu = false; }
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}
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}
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struct Walker {
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SDL_Point pos;
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SDL_Color col;
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};
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} // namespace
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template <typename Loopdata>
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@ -90,8 +95,7 @@ void mainloop(void* userData) {
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constexpr SDL_Point directions[] = {
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{.x = -1, .y = 0}, {.x = 1, .y = 0}, {.x = 0, .y = -1}, {.x = 0, .y = 1}
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};
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constexpr auto batchsize = 1;
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auto& [renderer, texture, pos, pos1, rne, dist, start_time, total_steps, next_poll_events_time, next_frame_render_time, frame_start, frame_time, continu] =
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auto& [renderer, texture, walkers, rne, dist, start_time, total_steps, next_poll_events_time, next_frame_render_time, frame_start, frame_time, continu] =
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*static_cast<Loopdata*>(userData);
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// measure frame_time
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@ -101,52 +105,39 @@ void mainloop(void* userData) {
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// possibly poll events
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if (now >= next_poll_events_time) {
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next_poll_events_time = now + std::chrono::milliseconds{200};
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next_poll_events_time = now + std::chrono::milliseconds{20};
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poll_events(continu);
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}
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// simulate steps for passed time
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// simulate steps for passed time //
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// roughly make a batch for every millisecond
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constexpr auto batchsize =
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std::clamp(steps_per_second / 1000 /*ms*/, 1, 1000);
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const auto total_time = now - start_time;
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const auto target_total_steps = total_time * steps_per_second /
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clock::duration{std::chrono::seconds{1}};
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std::print(
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"total_time={} total_steps={} target={}\r", total_time, total_steps,
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target_total_steps
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);
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for (; total_steps + batchsize <= target_total_steps;
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total_steps += batchsize) {
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std::array<SDL_Point, batchsize> point_batch;
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for (auto step = 0z; step < batchsize; ++step) {
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SDL_Point newpoint;
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do {
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newpoint = pos + directions[dist(rne)];
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} while (newpoint.x < 0 or newpoint.x >= width or newpoint.y < 0 or
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newpoint.y >= height);
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pos = newpoint;
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point_batch[step] = newpoint;
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}
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///// Render image
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sdl_check(SDL_SetRenderTarget(renderer, texture));
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sdl_check(SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_BLEND));
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sdl_check(SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0x00, 0xff));
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sdl_check(SDL_RenderDrawPoints(
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renderer, point_batch.data(), point_batch.size()
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));
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for (auto step = 0z; step < batchsize; ++step) {
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SDL_Point newpoint;
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do {
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newpoint = pos1 + directions[dist(rne)];
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} while (newpoint.x < 0 or newpoint.x >= width or newpoint.y < 0 or
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newpoint.y >= height);
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pos1 = newpoint;
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point_batch[step] = newpoint;
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for (auto& walker : walkers) {
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sdl_check(SDL_SetRenderDrawColor(
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renderer, walker.col.r, walker.col.g, walker.col.b, walker.col.a
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));
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std::array<SDL_Point, batchsize> point_batch;
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for (auto step = 0z; step < batchsize; ++step) {
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SDL_Point newpoint;
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do {
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newpoint = walker.pos + directions[dist(rne)];
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} while (newpoint.x < 0 or newpoint.x >= width or
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newpoint.y < 0 or newpoint.y >= height);
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walker.pos = newpoint;
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point_batch[step] = newpoint;
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}
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sdl_check(SDL_RenderDrawPoints(
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renderer, point_batch.data(), point_batch.size()
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));
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}
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sdl_check(SDL_SetRenderDrawColor(renderer, 0xff, 0xff, 0xff, 0xff));
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sdl_check(SDL_RenderDrawPoints(
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renderer, point_batch.data(), point_batch.size()
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));
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}
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///// Render screen
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@ -193,8 +184,16 @@ int main() try {
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);
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sdl_check(SDL_RenderClear(renderer));
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SDL_Point pos{.x = width / 2, .y = height / 2};
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SDL_Point pos1{.x = width / 2, .y = height / 2};
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auto walkers = std::to_array<Walker>(
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{{.pos = {.x = width / 2, .y = height / 2},
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.col = {.r = 0xff, .g = 0x00, .b = 0x00, .a = 0xff}},
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{.pos = {.x = width / 2, .y = height / 2},
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.col = {.r = 0x00, .g = 0xff, .b = 0x00, .a = 0xff}},
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{.pos = {.x = width / 2, .y = height / 2},
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.col = {.r = 0x00, .g = 0x00, .b = 0xff, .a = 0xff}},
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{.pos = {.x = width / 2, .y = height / 2},
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.col = {.r = 0x00, .g = 0x00, .b = 0x00, .a = 0xff}}}
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);
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std::mt19937_64 rne(std::random_device{}());
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std::uniform_int_distribution dist(0, 3);
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@ -207,7 +206,7 @@ int main() try {
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auto total_steps = 0ll;
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clock::duration frame_time;
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auto loopdata = std::tie(
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renderer, texture, pos, pos1, rne, dist, start_time, total_steps,
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renderer, texture, walkers, rne, dist, start_time, total_steps,
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next_poll_events_time, next_frame_render_time, frame_start, frame_time,
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continu
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);
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