/******************************************************************* * * * Using SDL With OpenGL * * * * Tutorial by Kyle Foley (sdw) * * * * http://gpwiki.org/index.php/SDL:Tutorials:Using_SDL_with_OpenGL * * * *******************************************************************/ /* THIS WORK, INCLUDING THE SOURCE CODE, DOCUMENTATION AND RELATED MEDIA AND DATA, IS PLACED INTO THE PUBLIC DOMAIN. THE ORIGINAL AUTHOR IS KYLE FOLEY. THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND, NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR REDISTRIBUTION OF THIS SOFTWARE. */ #include "SDL/SDL.h" #include "SDL/SDL_image.h" #include "SDL/SDL_opengl.h" #include #include #include #include #define MAX(x, y) ((x) > (y) ? (x) : (y)) int hasext(const char *exts, const char *ext) // from cube2, zlib licensed { int len = strlen(ext); if(len) for(const char *cur = exts; (cur = strstr(cur, ext)); cur += len) { if((cur == exts || cur[-1] == ' ') && (cur[len] == ' ' || !cur[len])) return 1; } return 0; } int main(int argc, char *argv[]) { SDL_Surface *screen; // Slightly different SDL initialization if ( SDL_Init(SDL_INIT_VIDEO) != 0 ) { printf("Unable to initialize SDL: %s\n", SDL_GetError()); return 1; } SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 ); // *new* screen = SDL_SetVideoMode( 600, 600, 16, SDL_OPENGL ); // *changed* if ( !screen ) { printf("Unable to set video mode: %s\n", SDL_GetError()); return 1; } // Check extensions const char *exts = (const char *)glGetString(GL_EXTENSIONS); assert(hasext(exts, "GL_EXT_texture_filter_anisotropic")); const char *vendor = (const char *)glGetString(GL_VENDOR); printf("vendor: %s\n", vendor); GLint aniso; glGetIntegerv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &aniso); printf("Max anisotropy: %d (using that)\n", aniso); assert(aniso >= 4); // Set the OpenGL state after creating the context with SDL_SetVideoMode glClearColor( 0, 0, 0, 0 ); glEnable( GL_TEXTURE_2D ); // Needed when we're using the fixed-function pipeline. glViewport( 0, 0, 600, 600 ); glMatrixMode( GL_PROJECTION ); GLfloat matrixData[] = { 2.0/600, 0, 0, 0, 0, -2.0/600, 0, 0, 0, 0, -2.0/600, 0, -1, 1, 0, 1 }; glLoadMatrixf(matrixData); // test loadmatrix glMatrixMode( GL_MODELVIEW ); glLoadIdentity(); // Load the OpenGL texture GLuint texture, texture2; const int DDS_SIZE = 43920; FILE *dds = fopen("water.dds", "rb"); assert(dds); char *ddsdata = (char*)malloc(DDS_SIZE); assert(fread(ddsdata, 1, DDS_SIZE, dds) == DDS_SIZE); fclose(dds); { glGenTextures( 1, &texture ); glBindTexture( GL_TEXTURE_2D, texture ); char *curr = ddsdata + 128; int level = 0; int w = 512; int h = 64; while (level < 5) { printf("uploading level %d: %d, %d\n", level, w, h); assert(!glGetError()); glCompressedTexImage2D(GL_TEXTURE_2D, level, GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, w, h, 0, w*h, curr); assert(!glGetError()); curr += MAX(w, 4)*MAX(h, 4); w /= 2; h /= 2; level++; } glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR ); } { glGenTextures( 1, &texture2 ); glBindTexture( GL_TEXTURE_2D, texture2 ); char *curr = ddsdata + 128; int level = 0; int w = 512; int h = 64; while (level < 5) { printf("uploading level %d: %d, %d\n", level, w, h); assert(!glGetError()); glCompressedTexImage2D(GL_TEXTURE_2D, level, GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, w, h, 0, w*h, curr); assert(!glGetError()); curr += MAX(w, 4)*MAX(h, 4); w /= 2; h /= 2; level++; } glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, aniso); } { assert(!glGetError()); glBindFramebuffer(GL_RENDERBUFFER, 0); assert(glGetError()); GLint out = 321; assert(!glGetError()); glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE, &out); // invalid, just test output assert(out == 0); } // Prepare and Render // Clear the screen before drawing glClear( GL_COLOR_BUFFER_BIT ); // Bind the texture to which subsequent calls refer to int w = 10; int n = 15; glBindTexture( GL_TEXTURE_2D, texture ); for (int x = 0; x < n; x++) { int start = x*w*2; glBegin( GL_TRIANGLES ); glTexCoord2i( 1, 0 ); glVertex2i( start , 0 ); glTexCoord2i( 0, 0 ); glVertex3f( start+w, 300, 0 ); glTexCoord2i( 1, 1 ); glVertex3f( start-w, 300, 0 ); glEnd(); } glBindTexture( GL_TEXTURE_2D, texture2 ); for (int x = 0; x < n; x++) { int start = n*w*2 + x*w*2; glBegin( GL_TRIANGLES ); glTexCoord2i( 1, 0 ); glVertex3f( start , 0, 0 ); glTexCoord2i( 0, 0 ); glVertex3f( start+w, 300, 0 ); glTexCoord2i( 1, 1 ); glVertex3f( start-w, 300, 0 ); glEnd(); } /* int w = 8; int n = 20; for (int x = 0; x < n; x++) { for (int y = 0; y < n*2; y++) { glBindTexture( GL_TEXTURE_2D, texture ); glBegin( GL_TRIANGLE_STRIP ); glTexCoord2i( 0, 0 ); glVertex3f( x*w, y*(w), 0 ); glTexCoord2i( 1, 0 ); glVertex3f( (x+1)*(w-2*y/n), y*(w), 0 ); glTexCoord2i( 1, 1 ); glVertex3f( (x+1)*(w-2*y/n), (y+1)*(w), 0 ); glTexCoord2i( 0, 1 ); glVertex3f( x*w, (y+1)*(w), 0 ); glEnd(); glBindTexture( GL_TEXTURE_2D, texture2 ); glBegin( GL_TRIANGLE_STRIP ); glTexCoord2i( 0, 0 ); glVertex3f( n*w + x*w, y*(w), 0 ); glTexCoord2i( 1, 0 ); glVertex3f( n*w + (x+1)*(w-2*y/n), y*(w), 0 ); glTexCoord2i( 1, 1 ); glVertex3f( n*w + (x+1)*(w-2*y/n), (y+1)*(w), 0 ); glTexCoord2i( 0, 1 ); glVertex3f( n*w + x*w, (y+1)*(w), 0 ); glEnd(); } } */ SDL_GL_SwapBuffers(); #ifndef __EMSCRIPTEN__ // Wait for 3 seconds to give us a chance to see the image SDL_Delay(2000); #endif // Now we can delete the OpenGL texture and close down SDL glDeleteTextures( 1, &texture ); SDL_Quit(); // check for asm compilation bug with aliased functions with different sigs void (*f)(int, int) = glVertex2i; if ((int)f % 16 == 4) f(5, 7); void (*g)(int, int) = glVertex3f; if ((int)g % 16 == 4) g(5, 7); return (int)f + (int)g; }