texture_2d.cpp

#include "texture.h"
 
using namespace sgltk;
 
Texture_2d::Texture_2d() : Texture() {
    target = GL_TEXTURE_2D;
}
 
Texture_2d::Texture_2d(unsigned int res_x, unsigned int res_y, GLenum internal_format, GLenum type, GLenum format) : Texture() {
    target = GL_TEXTURE_2D;
    create_empty(res_x, res_y, internal_format, type, format);
}
 
Texture_2d::Texture_2d(const Image& image) : Texture() {
    target = GL_TEXTURE_2D;
    load(image);
}
 
Texture_2d::Texture_2d(const std::string& path) : Texture() {
    target = GL_TEXTURE_2D;
    load(path);
}
 
Texture_2d::~Texture_2d() {
}
 
void Texture_2d::create_empty(unsigned int res_x, unsigned int res_y, GLenum internal_format, GLenum type, GLenum format) {
    width = res_x;
    height = res_y;
 
    bind();
    glTexImage2D(GL_TEXTURE_2D, 0, internal_format, res_x, res_y, 0,
        format, type, nullptr);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    unbind();
}
 
bool Texture_2d::load(const std::string& path) {
    Image img;
    if(!img.load(path))
        return false;
 
    width = img.width;
    height = img.height;
    return load(img);
}
 
bool Texture_2d::load(const Image& image) {
    if(!image.image)
        return false;
 
    SDL_Surface *tmp = SDL_ConvertSurfaceFormat(image.image,
        SDL_PIXELFORMAT_RGBA8888, 0);
    if(!tmp) {
        return false;
    }
 
    bind();
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width, image.height, 0,
        GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, tmp->pixels);
    glGenerateMipmap(GL_TEXTURE_2D);
    unbind();
    SDL_FreeSurface(tmp);
    return true;
}
 
void Texture_2d::bind(unsigned int texture_unit) {
    glActiveTexture(GL_TEXTURE0 + texture_unit);
    glBindTexture(GL_TEXTURE_2D, texture);
}
 
void Texture_2d::unbind(unsigned int texture_unit) {
    glActiveTexture(GL_TEXTURE0 + texture_unit);
    glBindTexture(GL_TEXTURE_2D, 0);
}