181 строка
5.6 KiB
C
181 строка
5.6 KiB
C
/*******************************************************************
|
|
* *
|
|
* 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>
|
|
|
|
void (*true_glGenTextures)(GLsizei, GLuint*) = NULL;
|
|
|
|
void glGenTextures(GLsizei n, GLuint *textures) {
|
|
printf("num? %d\n", n);
|
|
true_glGenTextures(n + 1, textures); // correct the error, ensures we are gone through
|
|
}
|
|
|
|
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 );
|
|
|
|
glEnable( GL_TEXTURE_2D ); // Needed when we're using the fixed-function pipeline.
|
|
|
|
glViewport( 0, 0, 640, 480 );
|
|
|
|
glMatrixMode( GL_PROJECTION );
|
|
glPushMatrix(); // just for testing
|
|
glLoadIdentity();
|
|
|
|
glOrtho( 0, 640, 480, 0, -1, 1 );
|
|
|
|
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");
|
|
}
|
|
|
|
true_glGenTextures = SDL_GL_GetProcAddress("glGenTextures");
|
|
|
|
// Have OpenGL generate a texture object handle for us
|
|
glGenTextures( 0, &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 );
|
|
|
|
glBegin( GL_QUADS );
|
|
glTexCoord2i( 0, 0 ); glVertex3f( 10, 10, 0 );
|
|
glTexCoord2i( 1, 0 ); glVertex3f( 300, 10, 0 );
|
|
glTexCoord2i( 1, 1 ); glVertex3f( 300, 128, 0 );
|
|
glTexCoord2i( 0, 1 ); glVertex3f( 10, 128, 0 );
|
|
|
|
glTexCoord2f( 0, 0.5 ); glVertex3f( 410, 10, 0 );
|
|
glTexCoord2f( 1, 0.5 ); glVertex3f( 600, 10, 0 );
|
|
glTexCoord2f( 1, 1 ); glVertex3f( 630, 200, 0 );
|
|
glTexCoord2f( 0.5, 1 ); glVertex3f( 310, 250, 0 );
|
|
glEnd();
|
|
|
|
glBegin( GL_TRIANGLE_STRIP );
|
|
glTexCoord2i( 0, 0 ); glVertex3f( 100, 300, 0 );
|
|
glTexCoord2i( 1, 0 ); glVertex3f( 300, 300, 0 );
|
|
glTexCoord2i( 1, 1 ); glVertex3f( 300, 400, 0 );
|
|
glTexCoord2i( 0, 1 ); glVertex3f( 500, 410, 0 );
|
|
glEnd();
|
|
|
|
glDisable(GL_TEXTURE_2D);
|
|
|
|
glColor3ub(90, 255, 255);
|
|
glBegin( GL_QUADS );
|
|
glVertex3f( 10, 410, 0 );
|
|
glVertex3f( 300, 410, 0 );
|
|
glVertex3f( 300, 480, 0 );
|
|
glVertex3f( 10, 470, 0 );
|
|
glEnd();
|
|
|
|
glBegin( GL_QUADS );
|
|
glColor3f(1.0, 0, 1.0); glVertex3f( 410, 410, 0 );
|
|
glColor3f(0, 1.0, 0); glVertex3f( 600, 410, 0 );
|
|
glColor3f(0, 0, 1.0); glVertex3f( 600, 480, 0 );
|
|
glColor3f(1.0, 1.0, 1.0); glVertex3f( 410, 470, 0 );
|
|
glEnd();
|
|
|
|
SDL_GL_SwapBuffers();
|
|
|
|
#if !EMSCRIPTEN
|
|
// Wait for 3 seconds to give us a chance to see the image
|
|
SDL_Delay(3000);
|
|
#endif
|
|
|
|
// Now we can delete the OpenGL texture and close down SDL
|
|
glDeleteTextures( 1, &texture );
|
|
|
|
SDL_Quit();
|
|
|
|
return 0;
|
|
}
|