Upgrading from SDL 1.2 to 1.3
Author
Hi,
I've upgraded the version of SDL I'm been using for my project from 1.2 to 1.3(built from SVN head) and I've been having very strange problems with OpenGL textures: I'm using SDL_Image(also built from head) to load my textures itno SDL_surfaces and am then uploading them manually, but whatever I do they just appear white. I've been using gDEbugger to investigate this problem and it's showing that the textures are uploaded correctly and the opengl state is more or less identical to that of the previous working SDL 1.2 version. Has anyone else experienced anything similar with SDL 1.3?
Cheers
Jamie
I have messed around with SDL 1.3, but I haven't started using it seriously. If you want you could post a small example demonstrating this behaviour I could see if I can reproduce it on my machine.
Author
Good idea! The following very rapid hack of my game's main.cpp does the same - gDEbugger shows the image fine, but the quad is entirely white:
// System includes#include <SDL.h>#include <SDL_opengl.h> #include <SDL_video.h>void CalculateOrthoMatrix(){ // Set up orthographic 2D matrices glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho( 0.0f, 480, 320, 0.0f, -1.0f, 1.0f); glMatrixMode(GL_MODELVIEW); glLoadIdentity();}void InitSDL(){ // Initialise SDL SDL_Init(SDL_INIT_EVERYTHING); // Enable key repeats SDL_EnableKeyRepeat(SDL_DEFAULT_REPEAT_DELAY, SDL_DEFAULT_REPEAT_INTERVAL); // Set opengl parameters - double buffered 32 bit colour SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8); SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8); SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8); SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8); SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0); SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1); SDL_GL_SetAttribute(SDL_GL_RETAINED_BACKING, 0); SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, 1); // Create window SDL_WindowID windowID = SDL_CreateWindow(NULL, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 480, 320, SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN); // Loop through all renderers found int rendererIndex = 0; int numRenderers = SDL_GetNumRenderDrivers(); for(int r = 0; r < numRenderers; r++) { // Get driver info SDL_RendererInfo rendererInfo; SDL_GetRenderDriverInfo(r, &rendererInfo); // If this is the opengl driver use this if(strcmp(rendererInfo.name, "opengl") == 0) { rendererIndex = r; } } // Create renderer SDL_CreateRenderer(windowID, rendererIndex, 0); // Immediately pump events(this seems to be // Required for messageboxes to ever work SDL_PumpEvents(); glClearColor(0.0, 0.0, 0.0, 0.0); // Enable normal alpha blending glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glShadeModel(GL_FLAT); glHint(GL_LINE_SMOOTH_HINT, GL_DONT_CARE); // Get initial viewing matrices CalculateOrthoMatrix();}int main(int argc, char* argv[]){ // Initialise SDL InitSDL(); SDL_Surface *pImageFormatSurface = SDL_LoadBMP("test.bmp"); GLuint textureHandle; glEnable(GL_TEXTURE_2D); glGenTextures(1, &textureHandle); glBindTexture(GL_TEXTURE_2D, textureHandle); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, pImageFormatSurface->w, pImageFormatSurface->h, 0, GL_RGB, GL_UNSIGNED_BYTE, pImageFormatSurface->pixels); SDL_FreeSurface(pImageFormatSurface); // Main SDL event loop bool shouldQuit = false; while(!shouldQuit) { SDL_Event sdlEvent; while(SDL_PollEvent(&sdlEvent) && !shouldQuit) { // Select what type of event's occured switch(sdlEvent.type) { // Quit event case SDL_QUIT: { shouldQuit = true; // Sets quitting flag }break; } } // Clear depth and colour buffers glClear(GL_COLOR_BUFFER_BIT); glBegin(GL_QUADS); glTexCoord2f(0.0f, 0.0f); glVertex2f(0.0f, 0.0f); glTexCoord2f(1.0f, 0.0f); glVertex2f(480.0f, 0.0f); glTexCoord2f(1.0f, 1.0f); glVertex2f(480.0f, 320.0f); glTexCoord2f(0.0f, 1.0f); glVertex2f(0.0f, 320.0f); glEnd(); SDL_RenderPresent(); } // Quit SDL SDL_Quit(); return 0;}
I don't have much time, but I can give you some hints.
Firstly, you are mixing SDL's new *Render* functions with raw OpenGL. I don't think this is really supported, I think if you want to use raw OpenGL you should use the SDL_GL_*() functions.
Take a look at the SDL test files for inspiration though, testgl2.c is particularly applicable I think. You can cut down that to the minimal code required to create and run an OpenGL program with the new API.
Firstly, you are mixing SDL's new *Render* functions with raw OpenGL. I don't think this is really supported, I think if you want to use raw OpenGL you should use the SDL_GL_*() functions.
Take a look at the SDL test files for inspiration though, testgl2.c is particularly applicable I think. You can cut down that to the minimal code required to create and run an OpenGL program with the new API.
Author
Hmm, that does make sense as the only thing that I can see which would explain the problem is that SDL's messing with the OpenGL state....I'll try switching to those functions and see what happens. Will they also work with OpenGL ES? I'm also targetting the iphone and that code basically came from the fireworks sample.
Quote:Original post by BigJim
Hmm, that does make sense as the only thing that I can see which would explain the problem is that SDL's messing with the OpenGL state....I'll try switching to those functions and see what happens. Will they also work with OpenGL ES? I'm also targetting the iphone and that code basically came from the fireworks sample.
I'm using SDL 1.3 on the iPhone and Windows without problems, instead of using glBegin/glEnd you can use VB= for instance. Basically is the same.
One question: Can SDL_Window window_id variable be local instead of class variable or global?
Thanks.
Author
Well, as SDL's written in C, SDL_Window won't have a destructor or anything so presumably you can do what you like with it :) How are you setting up your window/opengl context ricardo?
Author
Hi,
I've taken test2.c and added texture loading to it and exactly the same thing seems to be happening...Did anyone try compiling my demo program?
Cheers
Jamie
I've taken test2.c and added texture loading to it and exactly the same thing seems to be happening...Did anyone try compiling my demo program?
Cheers
Jamie
Author
Hi,
I've taken test2.c and added texture loading to it and exactly the same thing seems to be happening...Did anyone try compiling my demo program?
Cheers
Jamie
I've taken test2.c and added texture loading to it and exactly the same thing seems to be happening...Did anyone try compiling my demo program?
Cheers
Jamie
Author
Hi,
I've taken test2.c and added texture loading to it and exactly the same thing seems to be happening...Did anyone try compiling my demo program?
Cheers
Jamie
I've taken test2.c and added texture loading to it and exactly the same thing seems to be happening...Did anyone try compiling my demo program?
Cheers
Jamie
This topic is closed to new replies.
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