/*
 *  ofxFBOTexture.cpp
 *  openFrameworks
 *
 *  Created by Zach Gage on 3/28/08.
 *  Copyright 2008 STFJ.NET. All rights reserved.
 *
 */

#include "ofxFBOTexture.h"

void ofxFBOTexture::allocate(int w, int h, bool autoClear) {
        _isActive = false;

    texData.width = w;
        texData.height = h;

        imageSaver.setUseTexture(false);
        imageSaver.allocate(texData.width, texData.height, OF_IMAGE_COLOR_ALPHA);

    if (GLEE_ARB_texture_rectangle){
        texData.tex_w = w;
        texData.tex_h = h;
        texData.textureTarget = GL_TEXTURE_RECTANGLE_ARB;
    } else {
        texData.tex_w = ofNextPow2(w);
        texData.tex_h = ofNextPow2(h);
    }

        if (GLEE_ARB_texture_rectangle){
                texData.tex_t = w;
                texData.tex_u = h;
        } else {
                texData.tex_t = 1.0f;
                texData.tex_u = 1.0f;
        }

        // attempt to free the previous bound texture, if we can:
        clean();

        texData.width = w;
        texData.height = h;
        texData.bFlipTexture = true;
        texData.glType = GL_RGBA;

        this->autoClear = autoClear;
        // create & setup FBO
        glGenFramebuffersEXT(1, &fbo);
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);

        // Create the render buffer for depth
        glGenRenderbuffersEXT(1, &depthBuffer);
        glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depthBuffer);
        glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT, texData.tex_w, texData.tex_h);

        // create & setup texture
        glGenTextures(1, (GLuint *)texData.textureName);   // could be more then one, but for now, just one
        glBindTexture(texData.textureTarget, (GLuint)texData.textureName[0]);
        glTexParameterf(texData.textureTarget, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
        glTexParameterf(texData.textureTarget, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
        glTexParameterf(texData.textureTarget, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        glTexParameterf(texData.textureTarget, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexImage2D(texData.textureTarget, 0, texData.glType, texData.tex_w, texData.tex_h, 0, texData.glType, GL_UNSIGNED_BYTE, 0);
        glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

        // attach it to the FBO so we can render to it
        glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, texData.textureTarget, (GLuint)texData.textureName[0], 0);


        // Attach the depth render buffer to the FBO as it's depth attachment
        glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, depthBuffer);


        GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
        if(status != GL_FRAMEBUFFER_COMPLETE_EXT) {
                cout<<"glBufferTexture failed to initialize. Perhaps your graphics card doesnt support the framebuffer extension? If you are running osx prior to system 10.5, that could be the cause"<<endl;
                std::exit(1);
        }
        clear(0, 0, 0, 0);

        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

        texData.bAllocated = true;

}

void ofxFBOTexture::setupScreenForMe(){

        int w = texData.width;
        int h = texData.height;

        float halfFov, theTan, screenFov, aspect;
        screenFov               = 60.0f;

        float eyeX              = (float)w / 2.0;
        float eyeY              = (float)h / 2.0;
        halfFov                 = PI * screenFov / 360.0;
        theTan                  = tanf(halfFov);
        float dist              = eyeY / theTan;
        float nearDist  = dist / 10.0;  // near / far clip plane
        float farDist   = dist * 10.0;
        aspect                  = (float)w/(float)h;

        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluPerspective(screenFov, aspect, nearDist, farDist);
        gluLookAt(eyeX, eyeY, dist, eyeX, eyeY, 0.0, 0.0, 1.0, 0.0);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();


        glScalef(1, -1, 1);           // invert Y axis so increasing Y goes down.
        glTranslatef(0, -h, 0);       // shift origin up to upper-left corner.

    glViewport(0,0,texData.width, texData.height);

}

void ofxFBOTexture::setupScreenForThem(){
//      glPopAttrib();
//      return;

    int w, h;

        w = glutGet(GLUT_WINDOW_WIDTH);
        h = glutGet(GLUT_WINDOW_HEIGHT);

        float halfFov, theTan, screenFov, aspect;
        screenFov               = 60.0f;

        float eyeX              = (float)w / 2.0;
        float eyeY              = (float)h / 2.0;
        halfFov                 = PI * screenFov / 360.0;
        theTan                  = tanf(halfFov);
        float dist              = eyeY / theTan;
        float nearDist  = dist / 10.0;  // near / far clip plane
        float farDist   = dist * 10.0;
        aspect                  = (float)w/(float)h;

        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        gluPerspective(screenFov, aspect, nearDist, farDist);
        gluLookAt(eyeX, eyeY, dist, eyeX, eyeY, 0.0, 0.0, 1.0, 0.0);
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();


        glScalef(1, -1, 1);           // invert Y axis so increasing Y goes down.
        glTranslatef(0, -h, 0);       // shift origin up to upper-left corner.


    glViewport(0,0,w, h);
}

void ofxFBOTexture::swapIn() {
        _isActive = true;

        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo); // bind the FBO to the screen so we can draw to it

        if(autoClear) clear();
}

void ofxFBOTexture::swapOut() {
        _isActive = false;
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); //unbind the FBO
}

void ofxFBOTexture::clean()
{
        // try to free up the texture memory so we don't reallocate
        // http://www.opengl.org/documentation/specs/man_pages/hardcopy/GL/html/gl/deletetextures.html
        if (texData.textureName[0] != 0){
                glDeleteTextures(1, (GLuint *)texData.textureName);
        }
        texData.width = 0;
        texData.height = 0;
        texData.bFlipTexture = false;
}

void ofxFBOTexture::clear() {
        bool alreadyIn = _isActive;
        if(!alreadyIn) begin();         // MEMO
        glClearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);     // Clear Screen data of the texture to write on
        if(!alreadyIn) end();           // MEMO
}

void ofxFBOTexture::clear(float r, float g, float b, float a) {
    clearColor[0] = r;
    clearColor[1] = g;
    clearColor[2] = b;
    clearColor[3] = a;
    clear();
}

void ofxFBOTexture::bindAsTexture(){
	glBindTexture(GL_TEXTURE_2D, (GLuint *)texData.textureName);
}