cubemap.cpp

#include "texture.h"
 
using namespace sgltk;
 
Cubemap::Cubemap() : Texture() {
    target = GL_TEXTURE_CUBE_MAP;
}
 
Cubemap::Cubemap(unsigned int res_x,
         unsigned int res_y,
         GLenum internal_format,
         GLenum type, GLenum format) : Texture() {
 
    target = GL_TEXTURE_CUBE_MAP;
    create_empty(res_x, res_y, internal_format, type, format);
}
 
Cubemap::Cubemap(const Image& pos_x, const Image& neg_x,
         const Image& pos_y, const Image& neg_y,
         const Image& pos_z, const Image& neg_z) : Texture() {
 
    target = GL_TEXTURE_CUBE_MAP;
    load(pos_x, neg_x, pos_y, neg_y, pos_z, neg_z);
}
 
Cubemap::~Cubemap() {
}
 
void Cubemap::create_empty(unsigned int res_x,
               unsigned int res_y,
               GLenum internal_format,
               GLenum type, GLenum format) {
 
    width = res_x;
    height = res_y;
    bind();
 
    for(unsigned int i = 0; i < 6; i++) {
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0,
            internal_format, res_x, res_y, 0, format,
            type, nullptr);
    }
    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);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    unbind();
}
 
bool Cubemap::load(const std::string& pos_x, const std::string& neg_x,
           const std::string& pos_y, const std::string& neg_y,
           const std::string& pos_z, const std::string& neg_z) {
 
    Image positive_x(pos_x);
    Image negative_x(neg_x);
    Image positive_y(pos_y);
    Image negative_y(neg_y);
    Image positive_z(pos_z);
    Image negative_z(neg_z);
 
    return load(positive_x, negative_x, positive_y, negative_y, positive_z, negative_z);
}
 
bool Cubemap::load(const Image& pos_x, const Image& neg_x,
           const Image& pos_y, const Image& neg_y,
           const Image& pos_z, const Image& neg_z) {
 
    SDL_Surface *tmp;
    std::vector<const Image *> sides =
    {&pos_x, &neg_x, &pos_y, &neg_y, &pos_z, &neg_z};
 
    bind();
    for(unsigned int i = 0; i < 6; i++) {
        tmp = SDL_ConvertSurfaceFormat(sides[i]->image,
            SDL_PIXELFORMAT_RGBA8888, 0);
 
        if(!tmp)
            return false;
 
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGBA,
            sides[i]->width, sides[i]->height,
            0, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, tmp->pixels);
        SDL_FreeSurface(tmp);
    }
    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);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    unbind();
    return true;
}
 
void Cubemap::bind(unsigned int texture_unit) {
    glActiveTexture(GL_TEXTURE0 + texture_unit);
    glBindTexture(GL_TEXTURE_CUBE_MAP, texture);
}
 
void Cubemap::unbind(unsigned int texture_unit) {
    glActiveTexture(GL_TEXTURE0 + texture_unit);
    glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
}