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#include <math.h>
#include <SDL2/SDL.h>
#include <glad/glad.h>
int main(int argc, char *argv[])
{
int width = 1920;
int height = 1080;
if (SDL_Init(SDL_INIT_VIDEO) != 0)
{
printf("Error initialising SDL2: %s\n", SDL_GetError());
return 0;
};
// initialise window with opengl flag
SDL_Window *window = SDL_CreateWindow("SDL Test",
SDL_WINDOWPOS_UNDEFINED,
SDL_WINDOWPOS_UNDEFINED,
width,
height,
SDL_WINDOW_OPENGL);
// create an opengl context
SDL_GLContext context = SDL_GL_CreateContext(window);
if (!context)
{
printf("OpenGL context creation failed: %s\n", SDL_GetError());
return -1;
}
// load glad
if (!gladLoadGLLoader((GLADloadproc)SDL_GL_GetProcAddress)) {
printf("Failed to initialize Glad\n");
return 1;
}
// opengl rendering and shader stuff here
// @todo:
// have to learn how to setup shaders and other things with modern opengl (4.5+)
const char* vertexSource =
"#version 330 core\n"
"layout(location = 0) in vec3 position;"
"void main() {"
" gl_Position = vec4(position, 1.0);"
"}";
const char* fragmentSource =
"#version 330 core\n"
"out vec4 fragColor;"
"void main() {"
" fragColor = vec4(1.0, 0.0, 0.0, 1.0);"
"}";
GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexSource, NULL);
glCompileShader(vertexShader);
GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentSource, NULL);
glCompileShader(fragmentShader);
GLuint shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
glUseProgram(shaderProgram);
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
GLfloat vertices[] = {
-0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.0f, 0.5f, 0.0f
};
GLuint VBO, VAO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
for(;;)
{
SDL_Event ev;
while(SDL_PollEvent(&ev))
{
if (ev.type == SDL_QUIT)
{
return 0;
}
}
// opengl rendering code here
// @note: this part is more or less the same
// as with my learn opengl experiments
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shaderProgram);
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 3);
glBindVertexArray(0);
SDL_GL_SwapWindow(window);
}
// opengl free calls
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glDeleteProgram(shaderProgram);
// sdl free calls
SDL_GL_DeleteContext(context);
SDL_DestroyWindow(window);
SDL_Quit();
return 0;
}
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