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#include <SDL2/SDL_events.h>
#include <SDL2/SDL_pixels.h>
#include <SDL2/SDL_rect.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include "SDL2/SDL.h"
#include "SDL2/SDL_video.h"
#include "SDL2/SDL_render.h"
#include "glad/glad.h"
const float vertices[] = {
0.0f, 0.5f, 0.0f, // x,y,z of first point.
0.5f, -0.5f, 0.0f, // x,y,z of second point.
-0.5f, -0.5f, 0.0f // x,y,z of third point.
};
const char* fragment_shader =
"#version 410 core\n"
"out vec4 frag_colour;"
"in vec3 color;"
"void main() {"
" frag_colour = vec4( color, 1.0 );"
"}";
const char* vertex_shader =
"#version 410 core\n"
"in vec3 vp;"
"out vec3 color;"
"void main() {"
" gl_Position = vec4( vp, 1.0 );"
" color = vp;"
"}";
GLuint shader_init() {
GLuint vs = glCreateShader( GL_VERTEX_SHADER );
glShaderSource( vs, 1, &vertex_shader, NULL );
glCompileShader( vs );
GLuint fs = glCreateShader( GL_FRAGMENT_SHADER );
glShaderSource( fs, 1, &fragment_shader, NULL );
glCompileShader( fs );
GLuint shader_program = glCreateProgram();
glAttachShader( shader_program, fs );
glAttachShader( shader_program, vs );
glLinkProgram( shader_program );
return shader_program;
}
GLuint vbo;
void quit(int _val) {
fprintf(stderr, "Quitting");
exit(1);
}
void gl_buffer_init() {
//tell opengl we want mem for 1 buffer object
glGenBuffers(1, &vbo);
// set aray_buffer to above
glBindBuffer(GL_ARRAY_BUFFER, vbo);
// copy vertex data to gpu memory
glBufferData(GL_ARRAY_BUFFER, 9* sizeof(float), vertices, GL_STATIC_DRAW);
// cleanup
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
int main() {
signal(SIGINT, quit);
SDL_Init(SDL_INIT_VIDEO);
// This will call SDL_GL_LoadLibrary so you don't need glad to do anything
SDL_Window* window = SDL_CreateWindow("Junkcraft", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 800, 600, SDL_WINDOW_OPENGL);
SDL_GLContext* ctx = SDL_GL_CreateContext(window);
// Let GLAD use the SDL GetProcAddress loader instead of using its own
int version = gladLoadGLLoader(SDL_GL_GetProcAddress);
if (version == 0) {
printf("Failed to initialize OpenGL context\n");
return -1;
}
printf("Loaded OpenGL %d\n", version);
if (window == NULL) {
perror("Failed to create window!");
SDL_DestroyWindow(window);
SDL_Quit();
return -1;
}
SDL_Renderer* render = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
if (render == NULL) {
perror("Failed to create renderer!");
SDL_DestroyWindow(window);
SDL_Quit();
return -1;
}
// SDL_RenderClear(render);
// SDL_Rect rect = { 0, 0, 100, 100 };
// SDL_SetRenderDrawColor(render, 255, 0, 0, SDL_ALPHA_OPAQUE);
SDL_ShowWindow(window);
// SDL_RenderFillRect(render, &rect);
gl_buffer_init();
GLuint array;
// Create VAO
glGenVertexArrays(1, &array);
glBindVertexArray(array);
// set array_buffer to pos buffer obj
glBindBuffer(GL_ARRAY_BUFFER, vbo);
/// allow vertex shader
// describe data and enable
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, 0);
// draw data as a triangle
//glDrawArrays(GL_TRIANGLES, 0, 3);
// set viewport
//glViewport(0, 0, 200, 100);
//final
GLuint shader_program = shader_init();
while (1) {
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram( shader_program );
glBindVertexArray(array);
glDrawArrays(GL_TRIANGLES, 0, 3);
SDL_RenderPresent(render);
}
return 0;
}
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