texture.cpp

#include "texture.h"

Texture::Texture(std::string path, bool loadNow) {
    //Initialize texture ID
    mTextureID = 0;

    //Initialize texture dimensions
    width = 0;
    height = 0;

    this->path = path;

    if(loadNow) {
        loadTexture(path);
    }
}

Texture::~Texture() {
    freeTexture();
}

bool Texture::loadTexture(std::string path) {
    //Texture loading success
    loaded = false;

    SDL_Surface *image = IMG_Load(path.c_str());

    //Image loaded successfully
    if(image != NULL) {
        if((image->w & (image->w - 1)) == 0) {
            printf("Warning: image width not power of 2 -> %s\n", path.c_str());
        }
        if((image->h & (image->h - 1)) == 0) {
            printf("Warning: image height not power of 2 -> %s\n", path.c_str());
        }
        loaded = loadTextureFromPixels32(image, (GLuint)image->w, (GLuint)image->h);
    }

    //Report error
    if(!loaded) {
        printf( "Unable to load %s\n", path.c_str() );
    }


    return loaded;
}

bool Texture::loadTextureFromPixels32(SDL_Surface *image, GLuint width, GLuint height ) {
    //Free texture if it exists
    freeTexture();

    //Get texture dimensions
    this->width = width;
    this->height = height;

    //Generate texture ID
    glGenTextures(1, &mTextureID);

    //Bind texture ID
    glBindTexture(GL_TEXTURE_RECTANGLE_ARB, mTextureID);

    //Generate texture
    glTexImage2D(GL_TEXTURE_RECTANGLE_ARB, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image->pixels);

    //Set texture parameters
    glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_RECTANGLE_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    //Unbind texture
    glBindTexture(GL_TEXTURE_2D, 0);

    //Check for error
    GLenum error = glGetError();
    if(error != GL_NO_ERROR) {
        printf("Error loading texture from %p pixels!\n", image->pixels);
        return false;
    }

    return true;
}

void Texture::render(GLfloat x, GLfloat y) {
    if(loaded) {
        //If the texture exists
        if(mTextureID != 0) {
            GLfloat realX = x;// - (this->width / 2);
            GLfloat realY = y;// - (this->height / 2);

            //Remove any previous transformations
            glLoadIdentity();

            //Move to rendering point
            glTranslatef(realX, realY, 0.f);
            glClearDepth(1.0f); 

            //Set texture ID
            glBindTexture(GL_TEXTURE_RECTANGLE_ARB, mTextureID);

            //Render textured quad
            glBegin(GL_QUADS);
                glTexCoord2f( 0.f, 0.f ); glVertex2f(0.f,   0.f);
                glTexCoord2f( 1.f, 0.f ); glVertex2f(width, 0.f);
                glTexCoord2f( 1.f, 1.f ); glVertex2f(width, height);
                glTexCoord2f( 0.f, 1.f ); glVertex2f(0.f,   height);
            glEnd();
        }
    } else {
        // do nothing
    }
}

GLuint Texture::getWidth() {
    return this->width;
}

GLuint Texture::getHeight() {
    return this->height;
}

void Texture::freeTexture() {
    //Delete texture
    if(mTextureID != 0) {
        glDeleteTextures(1, &mTextureID);
        mTextureID = 0;
    }

    width = 0;
    height = 0;
}