All posts by kpark

Modern OpenGL

Texture Animation

Texture Animation
5974008442.zip
// init 중간생략..

 for (int i=0; i<7; i++)
 {
  char filename[255];
  sprintf(filename, “tacgun0%d.rgb”, i);
        texture[i] = InitTexture(filename);
 }


// draw 중간생략..

 glActiveTexture(GL_TEXTURE0);
 glBindTexture(GL_TEXTURE_2D, texture[currentTex]);
 drawSquare();
 glBindTexture(GL_TEXTURE_2D, 0);

// update

void update()
{
 static int currentTime, deltaTime, prevTime = 0;
 currentTime = glutGet(GLUT_ELAPSED_TIME);
 deltaTime = currentTime – prevTime;
 prevTime = currentTime;
 currentTex = (GLuint) ((float)currentTime * 0.01) % 7;
 glutPostRedisplay();
}

Modern OpenGL

ModernOpenGL Mipmap

Automatic mipmap generation


Mipmaps of a texture can be automatically generated with the glGenerateMipmap​ function. OpenGL 3.0 or greater is required for this function (or the extension GL_ARB_framebuffer_object). The function works quite simply; when you call it for a texture, mipmaps are generated for that texture:
http://www.opengl.org/wiki/Common_Mistakes#Automatic_mipmap_generation




  glTexImage2D(GL_TEXTURE_2D, 0, numComponents == 3 ? GL_RGB : GL_RGBA, imageWidth, imageHeight,  0, numComponents == 3 ? GL_RGB : GL_RGBA, GL_UNSIGNED_BYTE, imagePtr);
  glGenerateMipmap(GL_TEXTURE_2D); // Generate mipmaps now!!
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 4);