Code examples for opening windows for various purposes in very few bytes
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111 lines
2.1 KiB

#define GL_GLEXT_PROTOTYPES
#include<stdio.h>
#include<stdbool.h>
#include<stdlib.h>
#include<stdint.h>
#include <SDL2/SDL.h>
#include <GL/gl.h>
#include <GL/glx.h>
#include <GL/glu.h>
#include <GL/glext.h>
#include "shader.h"
#define CANVAS_WIDTH 1920
#define CANVAS_HEIGHT 1080
// #define KEY_HANDLING
// #define DEBUG
static void on_render ()
{
glRecti(-1,-1,1,1);
}
static void on_realize()
{
// compile shader
GLuint f = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(f, 1, &shader_frag, NULL);
glCompileShader(f);
#ifdef DEBUG
GLint isCompiled = 0;
glGetShaderiv(f, GL_COMPILE_STATUS, &isCompiled);
if(isCompiled == GL_FALSE) {
GLint maxLength = 0;
glGetShaderiv(f, GL_INFO_LOG_LENGTH, &maxLength);
char* error = malloc(maxLength);
glGetShaderInfoLog(f, maxLength, &maxLength, error);
printf("%s\n", error);
exit(-10);
}
#endif
// link shader
GLuint p = glCreateProgram();
glAttachShader(p,f);
glLinkProgram(p);
#ifdef DEBUG
GLint isLinked = 0;
glGetProgramiv(p, GL_LINK_STATUS, (int *)&isLinked);
if (isLinked == GL_FALSE) {
GLint maxLength = 0;
glGetProgramiv(p, GL_INFO_LOG_LENGTH, &maxLength);
char* error = malloc(maxLength);
glGetProgramInfoLog(p, maxLength, &maxLength,error);
printf("%s\n", error);
exit(-10);
}
#endif
glUseProgram(p);
}
void _start() {
asm volatile("sub $8, %rsp\n");
SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTS);
SDL_Window* mainwindow = SDL_CreateWindow(
"",
0,
0,
CANVAS_WIDTH,
CANVAS_HEIGHT,
SDL_WINDOW_OPENGL | SDL_WINDOW_FULLSCREEN
);
SDL_GL_CreateContext(mainwindow);
SDL_ShowCursor(false);
on_realize();
while (true) {
SDL_Event Event;
while (SDL_PollEvent(&Event)) {
if (Event.type == SDL_QUIT
#if defined(KEY_HANDLING)
|| (Event.type == SDL_KEYDOWN && Event.key.keysym.sym == SDLK_ESCAPE)
#endif
) {
exit(0);
}
if (Event.type == SDL_WINDOWEVENT) {
switch(Event.window.event) {
case SDL_WINDOWEVENT_EXPOSED:
on_render();
SDL_GL_SwapWindow(mainwindow);
default:
break;
}
}
}
}
__builtin_unreachable();
}