SDL_Surface to OpenGL texture problem.

Kain5056 · 2013-05-24T17:36:53

Hello. I have a bit of a problem, so a little help from someone more experienced would be appreciated. :-) I've been using SDL for a few months, and have gotten quite good at it and started making my first game. But now I want my game to use hardware accelerated rendering because software rendering won't cut it any more, so I started looking into OpenGL. Since I have some experience in SDL and kind of know what I'm doing with it, but know nothing about OpenGL, I tried to find the simplest way possible to convert my SDL surfaces to OpenGL textures and render them with OpenGL. So I found THIS and THIS from sdltutorials.com Following these instructions, I altered my Initialization and rendering functions from this: bool init() { if( SDL_Init( SDL_INIT_EVERYTHING ) == -1 ) return false; screen = SDL_SetVideoMode( SCREEN_WIDTH , SCREEN_HEIGHT , BITS_PER_PIXEL , SDL_HWSURFACE | SDL_DOUBLEBUF ); if( screen == NULL ) return false; if( Mix_OpenAudio( 44100 , MIX_DEFAULT_FORMAT , 2 , 512 ) < 0 ) return false; SDL_WM_SetCaption( "Test!" , NULL ); return true; } SDL_Surface * load( std::string file ) { SDL_Surface * loaded = NULL; SDL_Surface * optimized = NULL; loaded = IMG_Load( file.c_str() ); if( loaded != NULL ) { optimized = SDL_DisplayFormatAlpha( loaded ); SDL_FreeSurface( loaded ); } return optimized; } void apply_surface( int x , int y , SDL_Surface * get = NULL , SDL_Surface * give = NULL , SDL_Rect * clips = NULL ) { SDL_Rect offsets; offsets.x = x; offsets.y = y; SDL_BlitSurface( get , clips , give , &offsets ); } void apply_surface( int x , int y , SDL_Surface * get , SDL_Surface * give , int clips_x , int clips_y , int w , int h ) { SDL_Rect offsets; offsets.x = x; offsets.y = y; SDL_Rect clips; clips.x = clips_x; clips.y = clips_y; clips.w = w; clips.h = h; SDL_BlitSurface( get , &clips , give , &offsets ); } ...To this: bool init() { if( SDL_Init( SDL_INIT_EVERYTHING ) == -1 ) return false; 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,16); SDL_GL_SetAttribute(SDL_GL_BUFFER_SIZE,32); SDL_GL_SetAttribute(SDL_GL_ACCUM_RED_SIZE,8); SDL_GL_SetAttribute(SDL_GL_ACCUM_GREEN_SIZE,8); SDL_GL_SetAttribute(SDL_GL_ACCUM_BLUE_SIZE,8); SDL_GL_SetAttribute(SDL_GL_ACCUM_ALPHA_SIZE,8); SDL_GL_SetAttribute(SDL_GL_MULTISAMPLEBUFFERS,1); SDL_GL_SetAttribute(SDL_GL_MULTISAMPLESAMPLES,2); screen = SDL_SetVideoMode( SCREEN_WIDTH , SCREEN_HEIGHT , BITS_PER_PIXEL , SDL_HWSURFACE | SDL_GL_DOUBLEBUFFER | SDL_OPENGL ); glClearColor(0, 0, 0, 0); glClearDepth(1.0f); glViewport(0, 0, SCREEN_WIDTH , SCREEN_HEIGHT); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0, SCREEN_WIDTH , SCREEN_HEIGHT, 0, 1, -1); glMatrixMode(GL_MODELVIEW); glEnable(GL_TEXTURE_2D); glLoadIdentity(); if( screen == NULL ) return false; if( Mix_OpenAudio( 44100 , MIX_DEFAULT_FORMAT , 2 , 512 ) < 0 ) return false; SDL_WM_SetCaption( "OpenGL Test!" , NULL ); return true; } SDL_Surface * load( std::string file ) { SDL_Surface * loaded = NULL; loaded = IMG_Load( file.c_str() ); return loaded; } void apply_surface( int x , int y , SDL_Surface * get = NULL ) { GLuint textureID = 0; glGenTextures(1, &textureID); glBindTexture(GL_TEXTURE_2D, textureID); int Mode = GL_RGBA; glTexImage2D(GL_TEXTURE_2D, 0, Mode, get->w, get->h, 0, Mode, GL_UNSIGNED_BYTE, get->pixels); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glBindTexture(GL_TEXTURE_2D, textureID); glBegin(GL_QUADS); glTexCoord2f(0, 0); glVertex2f(x, y); glTexCoord2f(1, 0); glVertex2f(x+get->w, y); glTexCoord2f(1, 1); glVertex2f(x+get->w, y+get->h); glTexCoord2f(0, 1); glVertex2f(x, y+get->h); glEnd(); glDeleteTextures(1, &textureID); glDisable(GL_TEXTURE_2D); SDL_GL_SwapBuffers(); } void apply_surface( int x , int y , SDL_Surface * get , int clips_x , int clips_y , int w , int h ) { GLuint textureID = 0; glGenTextures(1, &textureID); glBindTexture(GL_TEXTURE_2D, textureID); int Mode = GL_RGBA; glTexImage2D(GL_TEXTURE_2D, 0, Mode, get->w, get->h, 0, Mode, GL_UNSIGNED_BYTE, get->pixels); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glBindTexture(GL_TEXTURE_2D, textureID); int cx = clips_x / get->w; int cy = clips_y / get->h; int cw = clips_x+w / get->w; int ch = clips_y+h / get->h; glBegin(GL_QUADS); glTexCoord2f(cx, cy); glVertex2f(x, y); glTexCoord2f(cx+cw, cy); glVertex2f(x+get->w, y); glTexCoord2f(cx+cw, cy+ch); glVertex2f(x+get->w, y+get->h); glTexCoord2f(cx, cy+ch); glVertex2f(x, y+get->h); glEnd(); glDeleteTextures(1, &textureID); glDisable(GL_TEXTURE_2D); SDL_GL_SwapBuffers(); } ...But all I see when I run it is a black screen with a few glitchy rectangles flying by diagonally, and the program runs at 4 frames per second. I will not lie, I have absolutely no idea what I'm actually doing, I just want an easy and fast way to have hardware acceleration without having to change too much of my code. I do want to learn how to properly use OpenGL eventually, but not before I at least finish my first game. If someone can offer some advice on what I'm doing wrong, I would really appreciate it. :-) Thank you in advance. :-)

For Beginners

Started by Kain5056 May 22, 2013 08:56 AM

9 comments, last by Kain5056 10 years, 10 months ago

Kain5056

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May 24, 2013 05:36 PM

I have actually been following THIS Tutorial, It says it does it this way for everything to move at the same speed no matter how fast or slow the computer is.

I might have missed something though. I will try out your code to see what happens, and I will look into variable and fixed time steps (THIS article seems promising on that subject, but I'll look into it some more).

Parallel to that I have already started learnig the basics of SFML, just to be sure.

SDL_Surface to OpenGL texture problem.

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SDL_Surface to OpenGL texture problem.

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