terravisor/source/load_texture.cpp

#include "load_texture.h"
#include <FreeImage.h>


GLuint LoadTexture(const std::string& fname)
{
   GLuint tex_id;

   FREE_IMAGE_FORMAT format = FreeImage_GetFileType(fname.c_str(), 0);
   FIBITMAP* tempImg = FreeImage_Load(format, fname.c_str());
   FIBITMAP* img;

   if(format == FIF_EXR)
       img = FreeImage_ConvertToRGBF(tempImg);
   else
       img = FreeImage_ConvertTo32Bits(tempImg);

   FreeImage_Unload(tempImg);

   GLuint w = FreeImage_GetWidth(img);
   GLuint h = FreeImage_GetHeight(img);
   GLuint scanW = FreeImage_GetPitch(img);

   GLubyte* byteImg = new GLubyte[h * scanW];;
   GLfloat* floatImg = new GLfloat[h * scanW];;
   if (format == FIF_EXR)
       FreeImage_ConvertToRawBits((BYTE*)floatImg, img, scanW, 96, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK, TRUE);
   else
       FreeImage_ConvertToRawBits(byteImg, img, scanW, 32, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK, FALSE);

   FreeImage_Unload(img);

   glGenTextures(1, &tex_id);
   glBindTexture(GL_TEXTURE_2D, tex_id);
   if (format == FIF_EXR)
       glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F, w, h, 0, GL_RGB, GL_FLOAT, floatImg);
   else
       glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_BGRA, GL_UNSIGNED_BYTE, byteImg);
   glGenerateMipmap(GL_TEXTURE_2D);
   if (format == FIF_EXR)
   {
       glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
       glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   }
   else
   {
       glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
       glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
   }
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
   glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

   delete[] byteImg;
   delete[] floatImg;

   return tex_id;
}

GLuint LoadSkybox(const std::vector<std::string>& faces)
{
    GLuint tex_id;
    glGenTextures(1, &tex_id);
    glBindTexture(GL_TEXTURE_CUBE_MAP, tex_id);

    for (GLuint i = 0; i < faces.size(); i++)
    {
        FREE_IMAGE_FORMAT format = FreeImage_GetFileType(faces[i].c_str(), 0);
        FIBITMAP* tempImg = FreeImage_Load(format, faces[i].c_str());
        FIBITMAP* img = (format == FIF_EXR) ? FreeImage_ConvertToRGBF(tempImg) : FreeImage_ConvertTo32Bits(tempImg);
        FreeImage_Unload(tempImg);

        GLuint w = FreeImage_GetWidth(img);
        GLuint h = FreeImage_GetHeight(img);
        GLuint scanW = FreeImage_GetPitch(img);

        if (format == FIF_EXR)
        {
            GLfloat* floatImg = new GLfloat[h * scanW];
            FreeImage_ConvertToRawBits((BYTE*)floatImg, img, scanW, 96, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK, TRUE);
            glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGB32F, w, h, 0, GL_RGB, GL_FLOAT, floatImg);
            delete[] floatImg;
        }
        else
        {
            GLubyte* byteImg = new GLubyte[h * scanW];
            FreeImage_ConvertToRawBits(byteImg, img, scanW, 32, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK, FALSE);
            glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGBA, w, h, 0, GL_BGRA, GL_UNSIGNED_BYTE, byteImg);
            delete[] byteImg;
        }

        FreeImage_Unload(img);
    }

    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

    return tex_id;
}