opengl-setup-examples/sdl2-opengl.c

113 rindas
2.2 KiB
C

#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
) {
asm volatile(".intel_syntax noprefix");
asm volatile("push 231"); //exit_group
asm volatile("pop rax");
asm volatile("xor edi, edi");
asm volatile("syscall");
asm volatile(".att_syntax prefix");
__builtin_unreachable();
}
if (Event.type == SDL_WINDOWEVENT && Event.window.event == SDL_WINDOWEVENT_EXPOSED) {
on_render();
SDL_GL_SwapWindow(mainwindow);
}
}
}
__builtin_unreachable();
}