I'm trying to make a method to save a texture by converting the texture to a surface, but if the texture size is less than 100 (or so), it throws an error and the file is not saved.
void Graphics::saveTexture(SDL_Texture* texture, const std::string& file_path, Uint32* pixels) {
int width, height;
uint32_t format;
SDL_QueryTexture(texture, &format, NULL, &width, &height);
SDL_Texture* rendered_texture = SDL_CreateTexture(renderer_, format, SDL_TEXTUREACCESS_STREAMING, width, height);
SDL_SetRenderTarget(renderer_, rendered_texture);
SDL_SetRenderDrawColor(renderer_, kClearColor[0], kClearColor[1], kClearColor[2], SDL_ALPHA_OPAQUE);
SDL_RenderClear(renderer_);
SDL_RenderCopy(renderer_, texture, NULL, NULL);
SDL_Surface* surface = SDL_CreateRGBSurfaceWithFormat(0, width, height, SDL_BYTESPERPIXEL(format), format); // here
SDL_RenderReadPixels(renderer_, NULL, surface->format->format, surface->pixels_, surface->pitch);
SDL_SaveBMP(surface, file_path.c_str());
SDL_SetRenderTarget(renderer_, NULL);
SDL_DestroyTexture(rendered_texture);
SDL_FreeSurface(surface);
}
Related
I'm making a retro pixel game so I want to make my window a very low resolution (256x256). However when I try to make it fullscreen, the whole window was just rendered top left, while leaving all other areas black.
I want to know a way of globally setting the size of each pixel in a window, in order to let it fit the fullscreen, or, a way of stretching the whole window (or a renderer?) to a specified size(and full screen) while having the (w, h) unchanged in parameter 2 and 3 in SDL_CreateWindow, and also whilst having the sizes proportional (so, if it was a square window, it should be a square window after stretched, not a rect after stretched into a rect displayer).
First, render your game to a 256x256 texture. This gist has an example, I will inline it below.
Next, figure out the correct size and position of your game texture on your actual window, and render the texture there. That will require modifications to the SDL_RenderCopyEx call, as the gist simply renders it stretched to the screen.
#include <iostream>
#ifdef __linux__
#include <SDL2/SDL.h>
#elif defined(_WIN32)
#include <SDL.h>
#endif
const int WIN_WIDTH = 640;
const int WIN_HEIGHT = 480;
int main(int argc, char **argv){
if (SDL_Init(SDL_INIT_EVERYTHING) != 0){
std::cerr << "SDL_Init failed: " << SDL_GetError() << "\n";
return 1;
}
SDL_Window *win = SDL_CreateWindow("Rendering to a texture!", SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, WIN_WIDTH, WIN_HEIGHT, 0);
SDL_Renderer *renderer = SDL_CreateRenderer(win, -1,
SDL_RENDERER_ACCELERATED | SDL_RENDERER_TARGETTEXTURE);
//Put your own bmp image here
SDL_Surface *bmpSurf = SDL_LoadBMP("../res/image.bmp");
SDL_Texture *bmpTex = SDL_CreateTextureFromSurface(renderer, bmpSurf);
SDL_FreeSurface(bmpSurf);
//Make a target texture to render too
SDL_Texture *texTarget = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888,
SDL_TEXTUREACCESS_TARGET, WIN_WIDTH, WIN_HEIGHT);
//Now render to the texture
SDL_SetRenderTarget(renderer, texTarget);
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, bmpTex, NULL, NULL);
//Detach the texture
SDL_SetRenderTarget(renderer, NULL);
//Now render the texture target to our screen, but upside down
SDL_RenderClear(renderer);
SDL_RenderCopyEx(renderer, texTarget, NULL, NULL, 0, NULL, SDL_FLIP_VERTICAL);
SDL_RenderPresent(renderer);
SDL_Delay(1000);
SDL_DestroyTexture(texTarget);
SDL_DestroyTexture(bmpTex);
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(win);
SDL_Quit();
return 0;
}
I'm trying to create a .PNG image from a larger .PNG image.
Basically clip a rect area of the original and save the result as another .PNG
Sort of like a texture unpacker, if you will.
My issue is that the portions that were transparent in the original image are colored in the clipped image.
Initially I used hardware acceleration and the background was white with speckles, switching to software renderer just changed the background to Black.
I would like to maintain the transparency of the original image.
#include <SDL2/SDL.h>
#include <SDL2_image/SDL_image.h>
void save_texture(const char* file_name, SDL_Renderer* renderer, SDL_Texture* texture); //
save png to disk
SDL_Texture* clipTexture(SDL_Rect rect, SDL_Renderer* renderer, SDL_Texture* source); // get
a new texture that is clipped from the original
int main(int argc, const char * argv[])
{
SDL_Init(SDL_INIT_VIDEO);
IMG_Init(IMG_INIT_PNG);
SDL_Surface* surface = IMG_Load("LevelItems.png");
SDL_Renderer* renderer = SDL_CreateSoftwareRenderer(surface);
SDL_Texture *texture = SDL_CreateTextureFromSurface(renderer, surface);
SDL_Rect frame_rect = { 189, 243,115, 50 };
SDL_Texture* tex_clip = clipTexture( frame_rect, renderer, texture );
save_texture("test1.png", renderer, tex_clip);
SDL_FreeSurface(surface);
return 0;
}
// return a new texture that is a part of the original texture.
SDL_Texture* clipTexture(SDL_Rect rect, SDL_Renderer* renderer, SDL_Texture* source)
{
SDL_Texture* result = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888,
SDL_TEXTUREACCESS_TARGET, rect.w, rect.h);
SDL_SetRenderTarget(renderer, result);
SDL_RenderCopy(renderer, source, &rect, NULL);
return result;
}
// save png to disk
void save_texture(const char* file_name, SDL_Renderer* renderer, SDL_Texture* texture)
{
int width, height;
SDL_QueryTexture(texture, NULL, NULL, &width, &height);
SDL_Surface* surface = SDL_CreateRGBSurface(0, width, height, 32, 0, 0, 0, 0);
SDL_RenderReadPixels(renderer, NULL, surface->format->format, surface->pixels, surface-
>pitch);
IMG_SavePNG(surface, file_name);
SDL_FreeSurface(surface);
}
There are two problems:
Disable blending. Use SDL_SetTextureBlendMode(source, SDL_BLENDMODE_NONE); before RenderCopy, otherwise you'll get wrong colour (blended with default black - result would be darker than it shound be). Blending tied to texture so if you want to use this texture later you probably should reset blending mode right away. See SDL_SetTextureBlendMode doc for formulas used in different blend modes.
Your resulting surface don't have alpha channel so there is nowhere to copy result. Check documentation for SDL_CreateRGBSurface: while it allows to use 0 for colour masks to deduce default values, it explicitly don't allow it for alpha channel, so 0 in place of amask results in "I don't want alpha channel, just RGB". Your resulting format is RGB888 packed to 32bit. You want alpha, so you should use correct colour masks - get one from docs, in your case you don't even need to check for endianess, but it never hurts.
To sum it up:
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
void save_texture(const char* file_name, SDL_Renderer* renderer, SDL_Texture* texture);
SDL_Texture* clipTexture(SDL_Rect rect, SDL_Renderer* renderer, SDL_Texture* source);
int main(int argc, const char * argv[])
{
SDL_Init(SDL_INIT_VIDEO);
IMG_Init(IMG_INIT_PNG);
SDL_Surface* surface = IMG_Load("test.png");
SDL_Renderer* renderer = SDL_CreateSoftwareRenderer(surface);
SDL_Texture *texture = SDL_CreateTextureFromSurface(renderer, surface);
SDL_Rect frame_rect = { 189, 243,115, 50 };
SDL_Texture* tex_clip = clipTexture( frame_rect, renderer, texture );
save_texture("test1.png", renderer, tex_clip);
SDL_FreeSurface(surface);
return 0;
}
// return a new texture that is a part of the original texture.
SDL_Texture* clipTexture(SDL_Rect rect, SDL_Renderer* renderer, SDL_Texture* source)
{
SDL_Texture* result = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888,
SDL_TEXTUREACCESS_TARGET, rect.w, rect.h);
SDL_SetRenderTarget(renderer, result);
SDL_SetTextureBlendMode(source, SDL_BLENDMODE_NONE);
SDL_RenderCopy(renderer, source, &rect, NULL);
return result;
}
// save png to disk
void save_texture(const char* file_name, SDL_Renderer* renderer, SDL_Texture* texture)
{
int width, height;
SDL_QueryTexture(texture, NULL, NULL, &width, &height);
Uint32 rmask, gmask, bmask, amask;
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
rmask = 0xff000000;
gmask = 0x00ff0000;
bmask = 0x0000ff00;
amask = 0x000000ff;
#else
rmask = 0x000000ff;
gmask = 0x0000ff00;
bmask = 0x00ff0000;
amask = 0xff000000;
#endif
SDL_Surface* surface = SDL_CreateRGBSurface(0, width, height, 32, rmask, gmask, bmask, amask);
SDL_RenderReadPixels(renderer, NULL, surface->format->format, surface->pixels, surface->pitch);
IMG_SavePNG(surface, file_name);
SDL_FreeSurface(surface);
}
I'm trying to save a texture in tiff file from an other thread. But the only result i get is a white picture, I think it come from the glcontext ( because it's not possible to have one glcontext for several thread). That's why i've tried to create two glcontext and share the display context. But still i don't have the gl texture. I can't get the texture from the second opengl context
. I'm tring to do that because at the end the texture will be a video stream from a camera .
Here is my context creation :
static PIXELFORMATDESCRIPTOR pfd =
{
sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor
1, // Version Number
PFD_DRAW_TO_WINDOW | // Format Must Support Window
PFD_SUPPORT_OPENGL | // Format Must Support OpenGL
PFD_DOUBLEBUFFER, // Must Support Double Buffering
PFD_TYPE_RGBA, // Request An RGBA Format
8, // Select Our Color Depth
0, 0, 0, 0, 0, 0, // Color Bits Ignored
0, // No Alpha Buffer
0, // Shift Bit Ignored
0, // No Accumulation Buffer
0, 0, 0, 0, // Accumulation Bits Ignored
16, // 16Bit Z-Buffer (Depth Buffer)
0, // No Stencil Buffer
0, // No Auxiliary Buffer
PFD_MAIN_PLANE, // Main Drawing Layer
0, // Reserved
0, 0, 0 // Layer Masks Ignored
};
GLuint PixelFormat;
// create the pixel pixel format descriptor
PixelFormat = ChoosePixelFormat(dc, &pfd);
// set the pixel format descriptor
SetPixelFormat(dc, PixelFormat, &pfd);
gl = wglCreateContext(dc);
gl2 = wglCreateContext(dc);
wglShareLists(gl, gl2);
wglMakeCurrent(dc, gl);
GLenum g= glewInit();
wglewInit();
loadImage();
rec = new Recorder(dc,gl2);
rec->Start_StopRecord(text, true);
Here is the code to save to tiff file :
Recorder::Recorder(HDC &hdc, HGLRC &_gl)
{
isStarted = false;
dc = hdc;
gl = _gl;
}
Recorder::~Recorder()
{
if (isStarted) {
isStarted = false;
recordThread.join();
CloseTifFile();
delete mp_fileTifIn;
}
}
void Recorder::Start_StopRecord(GLuint Texture, bool launched){
if (launched) {
if (isStarted) {
wglMakeCurrent(dc, gl);
isStarted = false;
recordThread.join();
CloseTifFile();
pixels.release();
}
else {
isStarted = true;
//wglMakeCurrent(NULL, NULL);
//RecordShot(&Texture);
recordThread = std::thread(&Recorder::RecordShot, this,&Texture);
}
}
}
void Recorder::RecordShot(GLuint* texture){
wglMakeCurrent(dc, gl);
OpenTifFile(*texture);
pixels = std::unique_ptr<int>(new int[width*height]);
//while (isStarted) {
WriteTif8Bits(*texture);
WriteDirectory();
//Sleep(16);
//}
pixels.release();
}
void Recorder::OpenTifFile(GLuint &Texture){
char* filename="../test3.tiff";
glGetTexLevelParameteriv(GL_TEXTURE_2D,0,GL_TEXTURE_HEIGHT,&height);
glGetTexLevelParameteriv(GL_TEXTURE_2D,0,GL_TEXTURE_WIDTH,&width);
mp_fileTifIn = TIFFOpen(filename,"w");
}
void Recorder::CloseTifFile(){
TIFFClose(mp_fileTifIn);
}
/*
* Open Sub data for a Tiff file (allow multiple picture in one tif file)
*/
void Recorder::WriteDirectory(){
TIFFWriteDirectory(mp_fileTifIn);
}
void Recorder::WriteTif8Bits(GLuint &Texture){
//Setup Tiff Configuration
TIFFSetField(mp_fileTifIn,TIFFTAG_IMAGEWIDTH,width);
TIFFSetField(mp_fileTifIn,TIFFTAG_IMAGELENGTH,height);
TIFFSetField(mp_fileTifIn,TIFFTAG_SAMPLESPERPIXEL,4);
TIFFSetField(mp_fileTifIn,TIFFTAG_BITSPERSAMPLE,8);
TIFFSetField(mp_fileTifIn,TIFFTAG_ROWSPERSTRIP,TIFFDefaultStripSize(mp_fileTifIn,width));
TIFFSetField(mp_fileTifIn,TIFFTAG_ORIENTATION,ORIENTATION_TOPLEFT);
TIFFSetField(mp_fileTifIn,TIFFTAG_PLANARCONFIG,PLANARCONFIG_CONTIG);
TIFFSetField(mp_fileTifIn, TIFFTAG_COMPRESSION, COMPRESSION_NONE);
TIFFSetField(mp_fileTifIn, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_RGB);
glBindTexture(GL_TEXTURE_2D,Texture);
assert(glGetError() == GL_NO_ERROR);
glGetTexImage(GL_TEXTURE_2D,0,GL_RGBA,GL_UNSIGNED_BYTE,pixels.get());
assert(glGetError() == GL_NO_ERROR);
//Image Reversal
Reverse(pixels.get(), height, width);
//Write one picture
/*for (int row = 0; row < height; row++) {
TIFFWriteScanline(mp_fileTifIn, pixels.get(), row, 0);
lineChange(pixels.get(), width);
}*/
TIFFWriteEncodedStrip(mp_fileTifIn, 0, pixels.get(), height*width * sizeof(int));
}
void Recorder::lineChange(int* pointer, int width) {
pointer -= width;
}
void Recorder::Reverse(int* pointer, int height, int width) {
pointer += (height - 1) * width;
}
And here is the loadImages function
int loadImage() {
wglMakeCurrent(dc, gl);
cv::Mat image;
image = cv::imread(std::string("C:/Users/Public/Pictures/Sample Pictures/Desert.jpg"), CV_LOAD_IMAGE_COLOR);
if (!image.data)
return -1;
cvNamedWindow("try", cv::WINDOW_AUTOSIZE);
cv::imshow("try", image);
cv::flip(image, image, 0);
glGenTextures(1, &text);
GLenum g=glGetError();
glBindTexture(GL_TEXTURE_2D, text);
assert(glGetError() == GL_NO_ERROR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, image.cols, image.rows, 0, GL_BGR, GL_UNSIGNED_BYTE, image.ptr());
return 0;
}
Here is a test project where i'm loading a picture with opencv and i try to save it in an other thread : https://mega.nz/#!SBMUnJRI!dLC_l9hmCkhIDDUaygHuq4Kw2SKIuxRE7m19md74p0k
To run the project you need Opencv and glew, libtiff is already packaged inside
If you think somethink is missing for this post, i invite you to comment it before downgrade as i'm following my subject
I finally solved my problem by doing all opengl action in one thread ( i retrieve the image and display it in one thread, and i save it in another, which doesn't need an openglcontext)
An other thing that were confusing me is a bad configuration of
glGetTexImage(GL_TEXTURE_2D,0,GL_RGBA,GL_UNSIGNED_BYTE,this->rec[0].pixels.get());
But my textures are GL_TEXTURE_RECTANGLE_NV, that's why i had only a white picture sometimes.
This is probably rather simple problem, but after an hour of searching and trying I still didn't manage to solve it.
I have two png files. One is a background image and second is foreground. The foreground has an alpha channel. I want to display foreground on top of background.
I'm loading foreground using:
SDL_Surface *clip = SDL_CreateRGBSurface(0, SCREEN_WIDTH, SCREEN_HEIGHT, 32, 0, 0, 0, 0xff);
SDL_Rect rect = { x, 0, SCREEN_WIDTH, SCREEN_HEIGHT };
SDL_BlitSurface(map, &rect, clip, NULL);
*block = SDL_CreateTextureFromSurface(gRenderer, clip);
Where map is some SDL_Surface.
I'm loadin backgroun using:
SDL_Surface* loadedSurface = IMG_Load(path);
//Create texture from surface pixels
SDL_Texture* newTexture = SDL_CreateTextureFromSurface(gRenderer, loadedSurface);
SDL_FreeSurface(loadedSurface);
Then I trying to connect them:
SDL_RenderCopy(gRenderer, background, NULL, &cur);
SDL_RenderCopy(gRenderer, map, NULL, &cur);
But it results in foreground image with black background. What am i doing wrong?
You should add these 2 lines,
Uint32 colorkey = SDL_MapRGB(loadedSurface->format, 0, 0, 0);
SDL_SetColorKey(loadedSurface, SDL_TRUE, colorkey);
before this line in your code
SDL_Texture* newTexture = SDL_CreateTextureFromSurface(gRenderer, loadedSurface);
So, after fooling around with the width and height numbers on the SDL_CreateRGBSurface() function, i am really confused on how they work. According to SDL Wiki the width and height refer to the width and height of the surface, however when I say SCREENWIDTH / 2, or SCREENHEIGHT / 2, it shows bigger than without the division. This is the code I was messing around with:
#include <iostream>
#include <SDL.h>
const int WIN_WIDTH = 640;
const int WIN_HEIGHT = 480;
int main(int argc, char **argv){
if (SDL_Init(SDL_INIT_EVERYTHING) != 0){
std::cerr << "SDL_Init failed: " << SDL_GetError() << "\n";
return 1;
}
SDL_Window *win = SDL_CreateWindow("Rendering to a texture!", SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, WIN_WIDTH, WIN_HEIGHT, 0);
SDL_Renderer *renderer = SDL_CreateRenderer(win, -1,
SDL_RENDERER_ACCELERATED | SDL_RENDERER_TARGETTEXTURE);
SDL_Surface* s;
SDL_Color c = { 155, 0, 0 };
SDL_Rect r = { 0, 0, 100, 100 };
s = SDL_CreateRGBSurface(0, WIN_WIDTH / 2, WIN_HEIGHT, 32, 0, 0, 0, 0);
SDL_FillRect(s, &r, SDL_MapRGB(s->format, c.r, c.g, c.b));
SDL_Texture* t;
t = SDL_CreateTextureFromSurface(renderer, s);
SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xFF, 0xFF);
SDL_RenderClear(renderer);
SDL_RenderCopy(renderer, t, NULL, NULL);
SDL_RenderPresent(renderer);
SDL_Delay(2000);
SDL_FreeSurface(s);
SDL_DestroyTexture(t);
SDL_DestroyRenderer(renderer);
SDL_DestroyWindow(win);
SDL_Quit();
return 0;
}
All I really want is a rect with a width of 100 and height of 100, but to have it appear correctly on the screen, the width and height must be specified to the width and height of the window. Why is that?
SDL_RenderCopy will stretch the source texture to fit into the destination renderer. So it will stretch your surface over the entire window. If you want to draw a 100x100 pixel rectangle, your SDL surface should be the same size as the window you're copying it to; that way no stretching will take place and the surface will be presented 1:1.