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Diffstat (limited to 'tests/sdl_fog_linear.c')
| -rw-r--r-- | tests/sdl_fog_linear.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/tests/sdl_fog_linear.c b/tests/sdl_fog_linear.c new file mode 100644 index 00000000..8fc18b7c --- /dev/null +++ b/tests/sdl_fog_linear.c @@ -0,0 +1,185 @@ +/******************************************************************* + * * + * 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 <stdio.h> +#include <string.h> +#include <assert.h> + +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( 640, 480, 16, SDL_OPENGL ); // *changed* + if ( !screen ) { + printf("Unable to set video mode: %s\n", SDL_GetError()); + return 1; + } + + // Set the OpenGL state after creating the context with SDL_SetVideoMode + + glClearColor( 0, 0, 0, 0 ); + +#if !EMSCRIPTEN + glEnable( GL_TEXTURE_2D ); // Need this to display a texture XXX unnecessary in OpenGL ES 2.0/WebGL +#endif + + glViewport( 0, 0, 640, 480 ); + + glMatrixMode( GL_PROJECTION ); + glPushMatrix(); // just for testing + glLoadIdentity(); + + glOrtho( 0, 640, 480, 0, -1000, 1000 ); + + glMatrixMode( GL_MODELVIEW ); + glLoadIdentity(); + + // Load the OpenGL texture + + GLuint texture; // Texture object handle + SDL_Surface *surface; // Gives us the information to make the texture + + if ( (surface = IMG_Load("screenshot.png")) ) { + + // Check that the image's width is a power of 2 + if ( (surface->w & (surface->w - 1)) != 0 ) { + printf("warning: image.bmp's width is not a power of 2\n"); + } + + // Also check if the height is a power of 2 + if ( (surface->h & (surface->h - 1)) != 0 ) { + printf("warning: image.bmp's height is not a power of 2\n"); + } + + // Have OpenGL generate a texture object handle for us + glGenTextures( 1, &texture ); + + // Bind the texture object + glBindTexture( GL_TEXTURE_2D, texture ); + + // Set the texture's stretching properties + glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR ); + glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR ); + + //SDL_LockSurface(surface); + + // Add some greyness + memset(surface->pixels, 0x66, surface->w*surface->h); + + // Edit the texture object's image data using the information SDL_Surface gives us + glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, surface->w, surface->h, 0, + GL_RGBA, GL_UNSIGNED_BYTE, surface->pixels ); + + //SDL_UnlockSurface(surface); + } + else { + printf("SDL could not load image.bmp: %s\n", SDL_GetError()); + SDL_Quit(); + return 1; + } + + // Free the SDL_Surface only if it was successfully created + if ( surface ) { + SDL_FreeSurface( surface ); + } + + // Clear the screen before drawing + glClear( GL_COLOR_BUFFER_BIT ); + + // Bind the texture to which subsequent calls refer to + glBindTexture( GL_TEXTURE_2D, texture ); + + glEnable(GL_FOG); + GLfloat fogColor[] = { 1.0, 0.5, 0.5, 0.05 }; + glFogfv(GL_FOG_COLOR, fogColor); + glFogi(GL_FOG_START, 8); + glFogi(GL_FOG_END, 13); + glFogi(GL_FOG_MODE, GL_LINEAR); + + assert(glIsEnabled(GL_FOG)); + + glBegin( GL_QUADS ); + glTexCoord2i( 0, 0 ); glVertex3f( 10, 10, 10 ); + glTexCoord2i( 1, 0 ); glVertex3f( 300, 10, 10 ); + glTexCoord2i( 1, 1 ); glVertex3f( 300, 128, 10 ); + glTexCoord2i( 0, 1 ); glVertex3f( 10, 128, 10 ); + + glTexCoord2f( 0, 0.5 ); glVertex3f( 410, 10, 5 ); + glTexCoord2f( 1, 0.5 ); glVertex3f( 600, 10, 6 ); + glTexCoord2f( 1, 1 ); glVertex3f( 630, 200, 7 ); + glTexCoord2f( 0.5, 1 ); glVertex3f( 310, 250, 8 ); + glEnd(); + + glBegin( GL_TRIANGLE_STRIP ); + glTexCoord2i( 0, 0 ); glVertex3f( 100, 300, 1 ); + glTexCoord2i( 1, 0 ); glVertex3f( 300, 300, 1 ); + glTexCoord2i( 1, 1 ); glVertex3f( 300, 400, 1 ); + glTexCoord2i( 0, 1 ); glVertex3f( 500, 410, 1 ); + glEnd(); + +#if !EMSCRIPTEN + glDisable(GL_TEXTURE_2D); +#endif + + glColor3ub(90, 255, 255); + glBegin( GL_QUADS ); + glVertex3f( 10, 410, 5 ); + glVertex3f( 300, 410, 50 ); + glVertex3f( 300, 480, 100 ); + glVertex3f( 10, 470, 5 ); + glEnd(); + + glBegin( GL_QUADS ); + glColor3f(1.0, 0, 1.0); glVertex3f( 410, 410, 10 ); + glColor3f(0, 1.0, 0); glVertex3f( 600, 410, 10 ); + glColor3f(0, 0, 1.0); glVertex3f( 600, 480, 10 ); + glColor3f(1.0, 1.0, 1.0); glVertex3f( 410, 470, 10 ); + glEnd(); + + SDL_GL_SwapBuffers(); + +#if !EMSCRIPTEN + // Wait for 3 seconds to give us a chance to see the image + SDL_Delay(30000); +#endif + + // Now we can delete the OpenGL texture and close down SDL + glDeleteTextures( 1, &texture ); + + SDL_Quit(); + + return 0; +} |