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complete emscripten port

Browse source 
https://wiki.libsdl.org/SDL2/README/emscripten
was still up-to-date
This commit is contained in:
Jakob Hördt 2024-08-06 00:49:10 +02:00
parent 78471c21f0
commit 8a3913c74c
4 changed files with 110 additions and 76 deletions
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4
.gitignore vendored
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@ -3,4 +3,6 @@
!.gitignore
!main.cpp
!screenshot.png
!screenshot.png
!build.sh
!build-web.sh

2
build-web.sh Executable file
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@ -0,0 +1,2 @@
#!/bin/bash
/usr/lib/emscripten/em++ -std=c++26 --use-port=sdl2 -O2 --emrun -sASSERTIONS -o index.html main.cpp

2
build.sh Executable file
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@ -0,0 +1,2 @@
#!/bin/bash
clang++ -Wall -std=c++26 -O2 -g -o main main.cpp -fuse-ld=mold `pkg-config --libs --cflags sdl2`

178
main.cpp
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@ -9,6 +9,12 @@
#include <random>
#include <source_location>
#include <stdexcept>
#include <thread>
#ifdef __EMSCRIPTEN__
#include <emscripten.h>
#include <emscripten/html5.h>
#endif
namespace {
@ -53,10 +59,11 @@ auto operator+(SDL_Point a, SDL_Point b) {
return SDL_Point{.x = a.x + b.x, .y = a.y + b.y};
}
// constexpr int width = 1000;
// constexpr int height = 1000;
constexpr int width = 3440;
constexpr int height = 1440;
constexpr int width = 1000;
constexpr int height = 500;
// constexpr int width = 3440;
// constexpr int height = 1440;
template <auto EF>
struct [[nodiscard("give this a name so SDL_Quit is called at the end"
@ -79,13 +86,87 @@ auto poll_events(bool& continu) {
}
} // namespace
template <typename Loopdata>
void mainloop(void* userData) {
constexpr SDL_Point directions[] = {
{.x = -1, .y = 0}, {.x = 1, .y = 0}, {.x = 0, .y = -1}, {.x = 0, .y = 1}
};
constexpr auto batchsize = 1000;
auto& [renderer, texture, pos, pos1, rne, dist, start_time, next_poll_events_time, next_frame_render_time, frame_start, frame_time, continu] =
*static_cast<Loopdata*>(userData);
// measure frame_time
const auto now = clock::now();
frame_time = now - frame_start;
frame_start = now;
if (now >= next_poll_events_time) {
next_poll_events_time = now + std::chrono::milliseconds{200};
poll_events(continu);
std::println("last frame_time={} batchsize={}", frame_time, batchsize);
}
std::array<SDL_Point, batchsize> point_batch;
for (auto step = 0z; step < batchsize; ++step) {
SDL_Point newpoint;
do {
newpoint = pos + directions[dist(rne)];
} while (newpoint.x < 0 or newpoint.x >= width or newpoint.y < 0 or
newpoint.y >= height);
pos = newpoint;
point_batch[step] = newpoint;
}
///// Render image
sdl_check(SDL_SetRenderTarget(renderer, texture));
sdl_check(SDL_SetRenderDrawBlendMode(
renderer,
SDL_ComposeCustomBlendMode(
SDL_BLENDFACTOR_SRC_ALPHA, SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
SDL_BLENDOPERATION_ADD, SDL_BLENDFACTOR_ZERO, SDL_BLENDFACTOR_ONE,
SDL_BLENDOPERATION_ADD
)
));
sdl_check(SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0x00, 32));
sdl_check(
SDL_RenderDrawPoints(renderer, point_batch.data(), point_batch.size())
);
for (auto step = 0z; step < batchsize; ++step) {
SDL_Point newpoint;
do {
newpoint = pos1 + directions[dist(rne)];
} while (newpoint.x < 0 or newpoint.x >= width or newpoint.y < 0 or
newpoint.y >= height);
pos1 = newpoint;
point_batch[step] = newpoint;
}
sdl_check(SDL_SetRenderDrawColor(renderer, 0xff, 0xff, 0xff, 32));
sdl_check(
SDL_RenderDrawPoints(renderer, point_batch.data(), point_batch.size())
);
// sdl_check(SDL_SetRenderDrawColor(renderer, 0xff, 0xff, 0xff,
// 32)); sdl_check(SDL_RenderFillRect(renderer, nullptr));
// SDL_RenderCopy(renderer, fade_texture, nullptr, nullptr);
///// Render screen
sdl_check(SDL_SetRenderTarget(renderer, nullptr));
sdl_check(
SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0x00, SDL_ALPHA_OPAQUE)
);
SDL_RenderClear(renderer);
sdl_check(SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_NONE));
// sdl_check(SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_NONE));
sdl_check(SDL_RenderCopy(renderer, texture, nullptr, nullptr));
SDL_RenderPresent(renderer);
}
int main() try {
sdl_check(SDL_Init(SDL_INIT_VIDEO));
Defer<SDL_Quit> defer_SDL_Quit;
window_t window{SDL_CreateWindow(
"random walk", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width,
height, SDL_WINDOW_FULLSCREEN
height, 0 // SDL_WINDOW_FULLSCREEN
)};
renderer_t renderer{SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED)
};
@ -114,85 +195,32 @@ int main() try {
SDL_Point pos{.x = width / 2, .y = height / 2};
SDL_Point pos1{.x = width / 2, .y = height / 2};
constexpr SDL_Point directions[] = {
{.x = -1, .y = 0}, {.x = 1, .y = 0}, {.x = 0, .y = -1}, {.x = 0, .y = 1}
};
std::mt19937_64 rne(std::random_device{}());
std::uniform_int_distribution dist(0, 3);
constexpr auto batchsize = 10000;
bool continu = true;
const auto start_time = clock::now();
auto next_poll_events_time = start_time;
auto next_frame_render_time = start_time;
auto frame_start = start_time;
clock::duration frame_time;
for (bool continu = true; continu;) {
// measure frame_time
const auto now = clock::now();
frame_time = now - frame_start;
frame_start = now;
if (now >= next_poll_events_time) {
next_poll_events_time = now + std::chrono::milliseconds{200};
poll_events(continu);
std::println(
"last frame_time={} batchsize={}", frame_time, batchsize
);
}
std::array<SDL_Point, batchsize> point_batch;
for (auto step = 0z; step < batchsize; ++step) {
SDL_Point newpoint;
do {
newpoint = pos + directions[dist(rne)];
} while (newpoint.x < 0 or newpoint.x >= width or newpoint.y < 0 or
newpoint.y >= height);
pos = newpoint;
point_batch[step] = newpoint;
}
///// Render image
sdl_check(SDL_SetRenderTarget(renderer, texture));
sdl_check(SDL_SetRenderDrawBlendMode(
renderer,
SDL_ComposeCustomBlendMode(
SDL_BLENDFACTOR_SRC_ALPHA, SDL_BLENDFACTOR_ONE_MINUS_SRC_ALPHA,
SDL_BLENDOPERATION_ADD, SDL_BLENDFACTOR_ZERO,
SDL_BLENDFACTOR_ONE, SDL_BLENDOPERATION_ADD
)
));
sdl_check(SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0x00, 32));
sdl_check(SDL_RenderDrawPoints(
renderer, point_batch.data(), point_batch.size()
));
for (auto step = 0z; step < batchsize; ++step) {
SDL_Point newpoint;
do {
newpoint = pos1 + directions[dist(rne)];
} while (newpoint.x < 0 or newpoint.x >= width or newpoint.y < 0 or
newpoint.y >= height);
pos1 = newpoint;
point_batch[step] = newpoint;
}
sdl_check(SDL_SetRenderDrawColor(renderer, 0xff, 0xff, 0xff, 32));
sdl_check(SDL_RenderDrawPoints(
renderer, point_batch.data(), point_batch.size()
));
// sdl_check(SDL_SetRenderDrawColor(renderer, 0xff, 0xff, 0xff, 32));
// sdl_check(SDL_RenderFillRect(renderer, nullptr));
// SDL_RenderCopy(renderer, fade_texture, nullptr, nullptr);
///// Render screen
sdl_check(SDL_SetRenderTarget(renderer, nullptr));
sdl_check(
SDL_SetRenderDrawColor(renderer, 0x00, 0x00, 0x00, SDL_ALPHA_OPAQUE)
);
SDL_RenderClear(renderer);
sdl_check(SDL_SetRenderDrawBlendMode(renderer, SDL_BLENDMODE_NONE));
// sdl_check(SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_NONE));
sdl_check(SDL_RenderCopy(renderer, texture, nullptr, nullptr));
SDL_RenderPresent(renderer);
auto loopdata = std::tie(
renderer, texture, pos, pos1, rne, dist, start_time,
next_poll_events_time, next_frame_render_time, frame_start, frame_time,
continu
);
std::puts("initialization complete");
#ifdef __EMSCRIPTEN__
// Receives a function to call and some user data to provide it.
emscripten_set_main_loop_arg(mainloop<decltype(loopdata)>, &loopdata, 0, 1);
#else
while (continu) {
mainloop<decltype(loopdata)>(&loopdata);
std::this_thread::sleep_until(next_frame_render_time);
next_frame_render_time += std::chrono::nanoseconds{16666666};
}
#endif
// leaking memory, nothing I can do
} catch (const std::exception& e) {