Micah Brening <micah.brening gmail.com> writes:
So my request:
Please, anyone who knows how to accomplish what I’m attempting, please post
code to initialize OpenGL, convert an SDL_Surface to an OpenGL Texture, or
even
the drawing functions used. Or what ever might be involved in getting rid of
the boxes around the textures. I’m assuming I’m just forgetting to enable
some
option, or set some value. But I cannot find anywhere on the Internet that
just comes out and tells it all plain and simple. I guess I need something
from start to finish so that I’m not missing something so brain numbingly
obvious.
I added the code that Mr. Mart?nez had shown me. This is what I have now (the
current result is just a blue screen. So in other words, no I have no textures
showing at all.)
Also, I’d like to note, I structured this code to be a part of a SO/DLL But
this is all of the OpenGL commands I run. the GFX_* commands are the ones the
rest of my code runs directly.
Any ideas? Suggestions? Theories?
The Code:
#include “main.h”
#include “SDL_opengl.h”
#include “SDL_image.h”
typedef struct sprite{
GLuint img;
GLfloat texcoord[4];
} sprite;
static int power_of_two(int input)
{
int value = 1;
while ( value < input ) {
value <<= 1;
}
return value;
}
GLuint SDL_GL_LoadTexture(SDL_Surface *surface,GLfloat *texcoord)
{
GLuint texture;
int w, h;
SDL_Surface *image;
SDL_Rect area;
Uint32 saved_flags,colorkey;
Uint8 saved_alpha;
w = power_of_two(surface->w);
h = power_of_two(surface->h);
texcoord[0] = 0.0f;
texcoord[1] = 0.0f;
texcoord[2] = (GLfloat)surface->w / w;
texcoord[3] = (GLfloat)surface->h / h;
image = SDL_CreateRGBSurface(
SDL_SWSURFACE,
w, h,
32,
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
0x000000FF,
0x0000FF00,
0x00FF0000,
0xFF000000
#else
0xFF000000,
0x00FF0000,
0x0000FF00,
0x000000FF
#endif
);
if ( image == NULL ) {
return 0;
}
saved_flags = surface->flags&(SDL_SRCALPHA|SDL_RLEACCELOK);
saved_alpha = surface->format->alpha;
if ( (saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA ) {
SDL_SetAlpha(surface, 0, 0);
}
area.x = 0;
area.y = 0;
area.w = surface->w;
area.h = surface->h;
SDL_BlitSurface(surface, &area, image, &area);
if ( (saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA ) {
SDL_SetAlpha(surface, saved_flags, saved_alpha);
}
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexImage2D(GL_TEXTURE_2D,
0,
GL_RGBA,
w, h,
0,
GL_RGBA,
GL_UNSIGNED_BYTE,
image->pixels);
SDL_FreeSurface(image);
return texture;
}
int GFX_initgfx(kelset *rage)
{ rage->printd(rage,“Setting Video Mode”);
rage->screen = SDL_SetVideoMode(rage->width,rage->height,rage->bpp,rage-
flags);
if (!rage->screen)
{
rage->printd(rage,“Unable to initalize SDL”);
return -1;
}
else
{
rage->printd(rage,“Setting Window Title”);
SDL_WM_SetCaption(rage->wmtitle,NULL);
glClearColor(0,0,1,0);
glClear(GL_COLOR_BUFFER_BIT);
glEnable(GL_TEXTURE_2D);
glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_REPLACE);
glAlphaFunc(GL_GREATER,0);
glEnable(GL_ALPHA_TEST);
rage->printd(rage,"Returning Successful");
return 1;
}
}
void* GFX_loadsprite(char * filename,SDL_Rect *def)
{
SDL_Surface *img;
sprite *glimg = (sprite *)malloc(sizeof(sprite));
img = IMG_Load(filename);
def->w = img->w;
def->h = img->h;
SDL_SetColorKey(img,SDL_SRCCOLORKEY,SDL_MapRGB(img->format,0,0,0));
glimg->img = SDL_GL_LoadTexture(img,glimg->texcoord);
SDL_FreeSurface(img);
return glimg;
}
void GFX_drawsprite(void *vimg,int x,int y,int w,int h)
{
sprite *glimg = (sprite *)vimg;
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D,glimg->img);
glBegin(GL_QUADS);
glTexCoord2f(glimg->texcoord[0],glimg->texcoord[1]);
glVertex2i(x,y);
glTexCoord2f(glimg->texcoord[0],glimg->texcoord[3]);
glVertex2i(x+w,y);
glTexCoord2f(glimg->texcoord[2],glimg->texcoord[3]);
glVertex2i(x,y+h);
glTexCoord2f(glimg->texcoord[2],glimg->texcoord[1]);
glVertex2i(x+w,y+h);
glEnd();
}
void GFX_killsprite(void *vimg)
{
sprite *glimg = (sprite *)vimg;
glDeleteTextures(1,&glimg->img);
free(glimg);
}
void GFX_clearscreen(void)
{
glClear(GL_COLOR_BUFFER_BIT);
}
void GFX_flip(kelset *rage)
{
glFlush();
SDL_GL_SwapBuffers();
}
void GFX_killgfx(void)
{
SDL_Quit();
}
void GFX_drawline(int sx,int sy,int dx,int dy,SDL_Color color)
{
glDisable(GL_TEXTURE_2D);
glBegin(GL_LINE_STRIP);
glColor4ub(color.r, color.g, color.b,255);
glVertex2i(sx,sy);
glVertex2i(dx,dy);
glEnd();
glEnable(GL_TEXTURE_2D);
}
void GFX_drawgrline(int sx,int sy,SDL_Color scolor,int dx,int dy,SDL_Color
dcolor)
{
glDisable(GL_TEXTURE_2D);
glBegin(GL_LINE_STRIP);
glColor4ub(scolor.r, scolor.g, scolor.b,255);
glVertex2i(sx,sy);
glColor4ub(dcolor.r, dcolor.g, dcolor.b,255);
glVertex2i(dx,dy);
glEnd();
glEnable(GL_TEXTURE_2D);
}
void *GFX_totexture(SDL_Surface *img)
{
sprite *glimg = (sprite *)malloc(sizeof(sprite));
glimg->img = SDL_GL_LoadTexture(img,glimg->texcoord);
SDL_FreeSurface(img);
return glimg;
}
