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Source code and assets for the TwinklebearDev Tutorials

Home Page: http://www.willusher.io/pages/sdl2/

License: MIT License

CMake 46.38% C++ 53.62%

twinklebeardev-lessons's Introduction

TwinklebearDev-Lessons

Source code and assets for the TwinklebearDev SDL 2.0 Lessons. The full lesson text is available at my site.

Lesson Index:

Lesson 0: Setting up SDL:
- A simple program to make sure you've set up SDL correctly
Lesson 1: Hello World:
- The standard Hello World program, for SDL 2.0
Lesson 2: Don't Put Everything in Main
- An introduction to creating some functions to help us with writing better and reusable code.
Lesson 3: SDL Extension Libraries
- An introduction to the various extension libraries that are available for SDL in this lesson we cover usage of SDL_image to load non-BMP images
Lesson 4: Handling Events
- An introduction to using SDL's event system to get user input from the window, mouse and keyboard
Lesson 5: Clipping Sprite Sheets
- An introduction to selecting specific subsets of an image sheet, ie. sprite sheet, that we want to draw
Lesson 6: True Type Fonts with SDL_ttf
- An introduction to using the SDL_ttf extension library to render true type fonts

Other Language Bindings

Go: mbenkmann has SDL2 bindings for Go and ported these tutorials to Go.

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twinklebeardev-lessons's Issues

how to configure SDL_Image?

when i configured SDL_Image, i met a problom. i use dll of SDL_Image.

Plans for Tutorial 7 and 8?

Hi I found your tutorials for SDL 2.0 really informative and a great starting point for using SDL. I noticed however that you only have write-ups for tutorials 1-6 (7 and 8 are left out).

Do you have any plans to create tutorial write-ups for these two? If so, do you have an approximate timeframe of when you plan to write them?

"os << msg" in logSDLError does not work in Visual Studios

I was following lesson 2 where logSDLError() was to be implemented. The tutorial showed:

void logSDLError(std::ostream &os, const std::string &msg){
    os << msg << " error: " << SDL_GetError() << std::endl;
}

But on Visual Studios 2012 express edition, the << between os and msg gets underlined red and the compiler complains that << cannot take in msg. Here's what Visual Studios said:

error C2679: binary '<<' : no operator found which takes a right-hand operand 
of type 'const std::string' (or there is no acceptable conversion)

Fortunately I found a workaround. The string msg instance should call c_str() to get the string in C-String form, like:

os << msg.c_str() << " error: " << SDL_GetError() << std::endl;

Everything worked after that.

Copy resources if lessons not built in situ

I've run into situations where building a project in the same folder as the source is not practical. What I have found to be the best practice is to make a separate directory and invoke all necessary build commands in that folder. Clean up then becomes a matter of removing the created directory. This is especially useful when wanting to refresh/reset CMake's cache values.

However, current project do not allow for this practice. The resources folder res would have to be manually copied over. I only discovered that by accident and digging. Others may not be so savvy.

To allow for alternate build location, I would like to suggest the code below be appended to the end of the CMakeLists.txt file at directory root right after the line add_subdirectory(Lesson6):

if ( NOT ${PROJECT_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_BINARY_DIR})
    file(COPY "${PROJECT_SOURCE_DIR}/res" DESTINATION "${CMAKE_CURRENT_BINARY_DIR}")
endif()

CMake file(COPY...) command will do the heavy lifting to copy the directory from source to destination. The if statement is there to prevent overwriting the res directory if in-place build is being done.

Lesson 0 crashes on Visual Studio

After following the steps for setting up SDL in Visual Studio, I'm able to build the executable but when I run it fails with a message saying it can't find SDL2.dll

On Lesson 1, the window does not show up

I tried the tutorial Lesson 1. I successfully compiled the file, but when running, it did not show any window; all that happened was that the terminal stopped for exactly three seconds and then the program ended with exit code 0.

I googled and found a similar issue on StackOverflow: SDL Window Not Showing Up at all. According to the answer, it may be the problem that SDL_Delay prevents the window from opening. I tried two source code on the page, one from the question and the other from the answer, then the former does not show the window, while the latter did. So I guess the reason Lesson 1 did not work is the same to that? Maybe it needs to be rewritten.

Also, if you don't mind, please tell me why "SDL_Delay [blocks] the window gets a chance to show"? I'm completely new to SDL, and I want to understand how does it work, what is going on under the hood.

System Information:

$ sw_vers
ProductName:    Mac OS X
ProductVersion: 10.14.6
BuildVersion:   18G2022
$ g++ --version
Apple clang version 11.0.0 (clang-1100.0.33.17)
Target: x86_64-apple-darwin18.7.0
Thread model: posix
$ brew info sdl2
sdl2: stable 2.0.10 (bottled), HEAD
Low-level access to audio, keyboard, mouse, joystick, and graphics
https://www.libsdl.org/
/usr/local/Cellar/sdl2/2.0.10 (87 files, 4.6MB) *
  Poured from bottle on 2019-09-03 at 09:45:53
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/sdl2.rb
==> Options
--HEAD
        Install HEAD version
==> Analytics
install: 53,946 (30 days), 163,725 (90 days), 730,192 (365 days)
install-on-request: 6,346 (30 days), 19,145 (90 days), 82,627 (365 days)
build-error: 0 (30 days)

The source code I wrote, which did not show a window:

#include <iostream>
#include <SDL.h>

int main(int argc, const char **argv){

if (SDL_Init(SDL_INIT_VIDEO) != 0){
	std::cout << "SDL_Init Error: " << SDL_GetError() << std::endl;
	return 1;
}

SDL_Window *win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN);
if (win == nullptr){
	std::cout << "SDL_CreateWindow Error: " << SDL_GetError() << std::endl;
	SDL_Quit();
	return 1;
}

SDL_Renderer *ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
if (ren == nullptr){
	SDL_DestroyWindow(win);
	std::cout << "SDL_CreateRenderer Error: " << SDL_GetError() << std::endl;
	SDL_Quit();
	return 1;
}

std::string imagePath = "/path/to/hello.bmp";
SDL_Surface *bmp = SDL_LoadBMP(imagePath.c_str());
if (bmp == nullptr){
	SDL_DestroyRenderer(ren);
	SDL_DestroyWindow(win);
	std::cout << "SDL_LoadBMP Error: " << SDL_GetError() << std::endl;
	SDL_Quit();
	return 1;
}

SDL_Texture *tex = SDL_CreateTextureFromSurface(ren, bmp);
SDL_FreeSurface(bmp);
if (tex == nullptr){
	SDL_DestroyRenderer(ren);
	SDL_DestroyWindow(win);
	std::cout << "SDL_CreateTextureFromSurface Error: " << SDL_GetError() << std::endl;
	SDL_Quit();
	return 1;
}

//A sleepy rendering loop, wait for 3 seconds and render and present the screen each time
for (int i = 0; i < 10; ++i){
 	//First clear the renderer
 	SDL_RenderClear(ren);
 	//Draw the texture
 	SDL_RenderCopy(ren, tex, NULL, NULL);
 	//Update the screen
 	SDL_RenderPresent(ren);
	//Take a quick break after all that hard work
	SDL_Delay(1000);
}

SDL_DestroyTexture(tex);
SDL_DestroyRenderer(ren);
SDL_DestroyWindow(win);
SDL_Quit();

	return 0;
}

Your lessons in Go

Hi, just wanted to let you know that I'm converting your lesson example code to Go to serve as examples for my Go SDL bindings project:

https://github.com/mbenkmann/bindings

I know I'm pedantic, but I'm a programmer...

In the 1st paragraph of lesson 4, you wrote:

To read events SDL provides the SDL_Event structure

SDL_Event is actually a union, not a struct.
Would you like to fix it, 7 years later? haha

it made kwin crash

I run https://github.com/Twinklebear/TwinklebearDev-Lessons/blob/master/Lesson1/src/main.cpp,
and kwin crash:

QXcbConnection: XCB error: 3 (BadWindow), sequence: 49027, resource id: 115343374, major code: 18 (ChangeProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49028, resource id: 115343374, major code: 18 (ChangeProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49034, resource id: 115343374, major code: 18 (ChangeProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49035, resource id: 115343374, major code: 20 (GetProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49037, resource id: 115343374, major code: 18 (ChangeProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49038, resource id: 115343374, major code: 42 (SetInputFocus), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49039, resource id: 115343374, major code: 25 (SendEvent), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49044, resource id: 115343374, major code: 12 (ConfigureWindow), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49045, resource id: 115343374, major code: 25 (SendEvent), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49051, resource id: 115343374, major code: 18 (ChangeProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49052, resource id: 115343374, major code: 18 (ChangeProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49053, resource id: 115343374, major code: 20 (GetProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49113, resource id: 115343374, major code: 20 (GetProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49114, resource id: 115343374, major code: 18 (ChangeProperty), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49119, resource id: 115343374, major code: 15 (QueryTree), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49182, resource id: 113249506, major code: 3 (GetWindowAttributes), minor code: 0
QXcbConnection: XCB error: 9 (BadDrawable), sequence: 49183, resource id: 113249506, major code: 14 (GetGeometry), minor code: 0
QXcbConnection: XCB error: 3 (BadWindow), sequence: 49209, resource id: 113249504, major code: 15 (QueryTree), minor code: 0
QXcbConnection: XCB error: 9 (BadDrawable), sequence: 49212, resource id: 113249504, major code: 55 (CreateGC), minor code: 0
QXcbConnection: XCB error: 13 (BadGC), sequence: 49213, resource id: 113249509, major code: 59 (SetClipRectangles), minor code: 0
QXcbConnection: XCB error: 9 (BadDrawable), sequence: 49214, resource id: 113249504, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 13 (BadGC), sequence: 49215, resource id: 113249509, major code: 56 (ChangeGC), minor code: 0
QXcbConnection: XCB error: 13 (BadGC), sequence: 49216, resource id: 113249509, major code: 59 (SetClipRectangles), minor code: 0
QXcbConnection: XCB error: 9 (BadDrawable), sequence: 49217, resource id: 113249504, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 13 (BadGC), sequence: 49218, resource id: 113249509, major code: 56 (ChangeGC), minor code: 0
kwin_x11: Couldn't find current GLX or EGL context.

forgotten include in cleanup.h

i noticed u forgot to include .