add util for copying a texture

includes/utils.h

@@ -1,6 +1,7 @@
 #ifndef DEMO_UTILS_H
 #define DEMO_UTILS_H 1
 
+#include <GL4D/gl4dh.h>
 #include <GL4D/gl4duw_SDL2.h>
 #include <SDL_image.h>
 #include <string.h>
@@ -32,4 +33,7 @@ void rotate_vec(GLfloat *, GLfloat);
 // Load an image into a GL texture
 void load_img(const char *filename, GLuint texture);
 
+// Copy a texture
+void copy_texture(GLuint, GLuint);
+
 #endif

src/tag.c

@@ -37,7 +37,7 @@ static void init(void) {
 
   glGenTextures(2, _texId);
   load_img("images/wall.png", _texId[0]);
-  load_img("images/wall.png", _texId[1]);
+  copy_texture(_texId[0], _texId[1]);
 
   TTF_Font *font = NULL;
   if (initFont(&font, "fonts/Instrument.ttf", 100)) {

src/utils.c

@@ -50,3 +50,39 @@ void load_img(const char *filename, GLuint texture) {
 
   glBindTexture(GL_TEXTURE_2D, 0);
 }
+
+void copy_texture(GLuint src, GLuint dst) {
+  if (!(src || dst)) {
+    fprintf(stderr,
+            "Erreur copie texture: Source/Destination pas initalisée\n");
+    exit(4);
+  }
+
+  glBindTexture(GL_TEXTURE_2D, src);
+  GLint w, h;
+  glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &w);
+  glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &h);
+
+  SDL_Surface *s;
+  if (!(s = SDL_CreateRGBSurface(0, w, h, 32, R_MASK, G_MASK, B_MASK,
+                                 A_MASK))) {
+    fprintf(stderr, "Erreur copie texture : %s\n", SDL_GetError());
+    exit(4);
+  }
+
+  // Copie des données
+  glGetTexImage(GL_TEXTURE_2D, 0, GL_RGBA, GL_UNSIGNED_BYTE, s->pixels);
+
+  // Copy data
+  glBindTexture(GL_TEXTURE_2D, dst);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+
+  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, s->w, s->h, 0, GL_RGBA,
+               GL_UNSIGNED_BYTE, s->pixels);
+
+  SDL_FreeSurface(s);
+  glBindTexture(GL_TEXTURE_2D, 0);
+}