abdelrahman/mike-shah-opengl-series
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Cleanup, extra comments and error logging

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Abdelrahman Said 2024-09-15 23:20:10 +01:00
parent aa75721e94
commit 0b7da3fad7
1 changed files with 34 additions and 9 deletions
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43
src/main.cc
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@ -38,6 +38,7 @@ struct App {
GLuint vbo;
GLuint shader_program;
bool running;
};
int init (App &app);
@ -55,8 +56,10 @@ int main() {
return result;
}
// Setup the geometry
create_vertex_spec(app);
// Setup graphics pipeline. At the very minimum creating vertex and fragment shaders
create_graphics_pipeline(app);
run_main_loop(app);
@ -92,7 +95,7 @@ int init(App &app) {
return EXIT_CODE_OPENGL_CONTEXT_FAILED;
}
// Init glad
// Init GLAD
if (!gladLoadGLLoader(SDL_GL_GetProcAddress)) {
fprintf(stderr, "Failed to initialise glad");
return EXIT_CODE_GLAD_LOADER_FAILED;
@ -110,11 +113,12 @@ int init(App &app) {
void create_vertex_spec(App &app) {
const std::vector<GLfloat> vertices = {
-0.8f, -0.8f, 0.0f,
0.8f, -0.8f, 0.0f,
0.0f, 0.8f, 0.0f,
-0.8f, -0.8f, 0.0f, // position
0.8f, -0.8f, 0.0f, // position
0.0f, 0.8f, 0.0f, // position
};
// Create and activate the VAO
glGenVertexArrays(1, &app.vao);
glBindVertexArray(app.vao);
@ -134,7 +138,8 @@ void create_vertex_spec(App &app) {
// for each vertex and the offset of the first instance of the component in the buffer
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void *)0);
// Cleanup. The order matters. Unbind VAO first then disable the attributes. If you do it the
// Cleanup.
// The order matters. Unbind VAO first then disable the attributes. If you do it the
// other way around, the VAO will store that the attributes are disabled and nothing will be
// drawn during the rendering stage
glBindVertexArray(0);
@ -160,13 +165,13 @@ void create_graphics_pipeline(App &app) {
}
void run_main_loop(App &app) {
bool running = true;
app.running = true;
while (running) {
while (app.running) {
while (SDL_PollEvent(&app.event)) {
switch (app.event.type) {
case SDL_QUIT:
running = false;
app.running = false;
break;
}
}
@ -188,6 +193,9 @@ void run_main_loop(App &app) {
glDrawArrays(GL_TRIANGLES, 0, 3);
// End draw call
// Not necessary if we only have one shader program
glUseProgram(0);
SDL_GL_SwapWindow(app.window);
}
}
@ -207,8 +215,25 @@ GLuint create_shader_program(const std::string &vertex_shader_source, const std:
glAttachShader(shader_program, fragment_shader);
glLinkProgram (shader_program);
GLint link_status;
glGetProgramiv(shader_program, GL_LINK_STATUS, &link_status);
if (link_status != GL_TRUE) {
GLsizei log_length = 0;
GLchar message[1024];
glGetProgramInfoLog(shader_program, 1024, &log_length, message);
fprintf(stderr, "Failed to link program: %s\n", message);
}
// Validate the shader_program
glValidateProgram(shader_program);
GLint validation_status;
glGetProgramiv(shader_program, GL_VALIDATE_STATUS, &validation_status);
if (validation_status != GL_TRUE) {
GLsizei log_length = 0;
GLchar message[1024];
glGetProgramInfoLog(shader_program, 1024, &log_length, message);
fprintf(stderr, "Failed to validate program: %s\n", message);
}
return shader_program;
}
@ -226,7 +251,7 @@ GLuint compile_shader(GLuint type, const std::string &source) {
GLsizei log_length = 0;
GLchar message[1024];
glGetShaderInfoLog(shader, 1024, &log_length, message);
fprintf(stderr, "%s\n", message);
fprintf(stderr, "Failed to compile shader: %s\n", message);
}
return shader;