/* -*- mode: java; c-basic-offset: 2; indent-tabs-mode: nil -*- */

/*
  Part of the Processing project - http://processing.org

  Copyright (c) 2011-12 Ben Fry and Casey Reas

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General
  Public License along with this library; if not, write to the
  Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  Boston, MA  02111-1307  USA
*/

package processing.opengl;

import processing.core.PApplet;
import processing.core.PConstants;

import java.nio.IntBuffer;

/**
 * Encapsulates a Frame Buffer Object for offscreen rendering.
 * When created with onscreen == true, it represents the normal
 * framebuffer. Needed by the stack mechanism in OPENGL2 to return
 * to onscreen rendering after a sequence of pushFramebuffer calls.
 * It transparently handles the situations when the FBO extension is
 * not available.
 *
 * By Andres Colubri.
 */

public class FrameBuffer implements PConstants {
  protected PGL pgl;
  protected int context;   // The context that created this framebuffer.

  public int glFbo;
  public int glDepth;
  public int glStencil;
  public int glDepthStencil;
  public int glMultisample;
  public int width;
  public int height;

  protected int depthBits;
  protected int stencilBits;
  protected boolean packedDepthStencil;

  protected boolean multisample;
  protected int nsamples;

  protected int numColorBuffers;
  protected Texture[] colorBufferTex;

  protected boolean screenFb;
  protected boolean noDepth;

  protected IntBuffer pixelBuffer;


  FrameBuffer() {
    pgl = PGraphicsOpenGL.pgl;
    context = pgl.createEmptyContext();
  }


  FrameBuffer(int w, int h, int samples, int colorBuffers,
               int depthBits, int stencilBits, boolean packedDepthStencil,
               boolean screen) {
    this();

    glFbo = 0;
    glDepth = 0;
    glStencil = 0;
    glDepthStencil = 0;
    glMultisample = 0;

    if (screen) {
      // If this framebuffer is used to represent a on-screen buffer,
      // then it doesn't make it sense for it to have multisampling,
      // color, depth or stencil buffers.
      depthBits = stencilBits = samples = colorBuffers = 0;
    }

    width = w;
    height = h;

    if (1 < samples) {
      multisample = true;
      nsamples = samples;
    } else {
      multisample = false;
      nsamples = 1;
    }

    numColorBuffers = colorBuffers;
    colorBufferTex = new Texture[numColorBuffers];
    for (int i = 0; i < numColorBuffers; i++) {
      colorBufferTex[i] = null;
    }

    if (depthBits < 1 && stencilBits < 1) {
      this.depthBits = 0;
      this.stencilBits = 0;
      this.packedDepthStencil = false;
    } else {
      if (packedDepthStencil) {
        // When combined depth/stencil format is required, the depth and stencil
        // bits are overriden and the 24/8 combination for a 32 bits surface is
        // used.
        this.depthBits = 24;
        this.stencilBits = 8;
        this.packedDepthStencil = true;
      } else {
        this.depthBits = depthBits;
        this.stencilBits = stencilBits;
        this.packedDepthStencil = false;
      }
    }

    screenFb = screen;

    allocate();
    noDepth = false;

    pixelBuffer = null;
  }


  FrameBuffer(int w, int h) {
    this(w, h, 1, 1, 0, 0, false, false);
  }


  FrameBuffer(int w, int h, boolean screen) {
    this(w, h, 1, 1, 0, 0, false, screen);
  }


  @Override
  protected void finalize() throws Throwable {
    try {
      if (!screenFb) {
        if (glFbo != 0) {
          PGraphicsOpenGL.finalizeFrameBufferObject(glFbo, context);
        }
        if (glDepth != 0) {
          PGraphicsOpenGL.finalizeRenderBufferObject(glDepth, context);
        }
        if (glStencil != 0) {
          PGraphicsOpenGL.finalizeRenderBufferObject(glStencil, context);
        }
        if (glMultisample != 0) {
          PGraphicsOpenGL.finalizeRenderBufferObject(glMultisample, context);
        }
        if (glDepthStencil != 0) {
          PGraphicsOpenGL.finalizeRenderBufferObject(glDepthStencil, context);
        }
      }
    } finally {
      super.finalize();
    }
  }

  public void clear() {
    PGraphicsOpenGL.pushFramebuffer();
    PGraphicsOpenGL.setFramebuffer(this);
    pgl.clearDepth(1);
    pgl.clearStencil(0);
    pgl.clearColor(0, 0, 0, 0);
    pgl.clear(PGL.DEPTH_BUFFER_BIT |
              PGL.STENCIL_BUFFER_BIT |
              PGL.COLOR_BUFFER_BIT);
    PGraphicsOpenGL.popFramebuffer();
  }

  public void copy(FrameBuffer dest, FrameBuffer current) {
    pgl.bindFramebuffer(PGL.READ_FRAMEBUFFER, this.glFbo);
    pgl.bindFramebuffer(PGL.DRAW_FRAMEBUFFER, dest.glFbo);
    pgl.blitFramebuffer(0, 0, this.width, this.height,
                          0, 0, dest.width, dest.height,
                          PGL.COLOR_BUFFER_BIT, PGL.NEAREST);
    pgl.bindFramebuffer(PGL.READ_FRAMEBUFFER, current.glFbo);
    pgl.bindFramebuffer(PGL.DRAW_FRAMEBUFFER, current.glFbo);
  }

  public void bind() {
    pgl.bindFramebuffer(PGL.FRAMEBUFFER, glFbo);
  }

  public void disableDepthTest() {
    noDepth = true;
  }

  public void finish(PGraphicsOpenGL pg) {
    if (noDepth) {
      // No need to clear depth buffer because depth testing was disabled.
      if (pg.getHint(ENABLE_DEPTH_TEST)) {
        pgl.enable(PGL.DEPTH_TEST);
      } else {
        pgl.disable(PGL.DEPTH_TEST);
      }
    }
  }

  public void readPixels() {
    if (pixelBuffer == null) createPixelBuffer();
    pixelBuffer.rewind();
    pgl.readPixels(0, 0, width, height, PGL.RGBA, PGL.UNSIGNED_BYTE,
                   pixelBuffer);
  }

  public void getPixels(int[] pixels) {
    if (pixelBuffer != null) {
      pixelBuffer.get(pixels, 0, pixels.length);
      pixelBuffer.rewind();
    }
  }

  public IntBuffer getPixelBuffer() {
    return pixelBuffer;
  }

  public boolean hasDepthBuffer() {
    return 0 < depthBits;
  }

  public boolean hasStencilBuffer() {
    return 0 < stencilBits;
  }

  public void setFBO(int id) {
    if (screenFb) {
      glFbo = id;
    }
  }

  ///////////////////////////////////////////////////////////

  // Color buffer setters.


  public void setColorBuffer(Texture tex) {
    setColorBuffers(new Texture[] { tex }, 1);
  }


  public void setColorBuffers(Texture[] textures) {
    setColorBuffers(textures, textures.length);
  }


  public void setColorBuffers(Texture[] textures, int n) {
    if (screenFb) return;

    if (numColorBuffers != PApplet.min(n, textures.length)) {
      throw new RuntimeException("Wrong number of textures to set the color " +
                                 "buffers.");
    }

    for (int i = 0; i < numColorBuffers; i++) {
      colorBufferTex[i] = textures[i];
    }

    PGraphicsOpenGL.pushFramebuffer();
    PGraphicsOpenGL.setFramebuffer(this);

    // Making sure nothing is attached.
    for (int i = 0; i < numColorBuffers; i++) {
      pgl.framebufferTexture2D(PGL.FRAMEBUFFER, PGL.COLOR_ATTACHMENT0 + i,
                               PGL.TEXTURE_2D, 0, 0);
    }

    for (int i = 0; i < numColorBuffers; i++) {
      pgl.framebufferTexture2D(PGL.FRAMEBUFFER, PGL.COLOR_ATTACHMENT0 + i,
                               colorBufferTex[i].glTarget,
                               colorBufferTex[i].glName, 0);
    }

    pgl.validateFramebuffer();

    PGraphicsOpenGL.popFramebuffer();
  }


  public void swapColorBuffers() {
    for (int i = 0; i < numColorBuffers - 1; i++) {
      int i1 = (i + 1);
      Texture tmp = colorBufferTex[i];
      colorBufferTex[i] = colorBufferTex[i1];
      colorBufferTex[i1] = tmp;
    }

    PGraphicsOpenGL.pushFramebuffer();
    PGraphicsOpenGL.setFramebuffer(this);
    for (int i = 0; i < numColorBuffers; i++) {
      pgl.framebufferTexture2D(PGL.FRAMEBUFFER, PGL.COLOR_ATTACHMENT0 + i,
                               colorBufferTex[i].glTarget,
                               colorBufferTex[i].glName, 0);
    }
    pgl.validateFramebuffer();

    PGraphicsOpenGL.popFramebuffer();
  }


  public int getDefaultReadBuffer() {
    if (screenFb) {
      return pgl.getDefaultReadBuffer();
    } else {
      return PGL.COLOR_ATTACHMENT0;
    }
  }


  public int getDefaultDrawBuffer() {
    if (screenFb) {
      return pgl.getDefaultDrawBuffer();
    } else {
      return PGL.COLOR_ATTACHMENT0;
    }
  }


  ///////////////////////////////////////////////////////////

  // Allocate/release framebuffer.


  protected void allocate() {
    dispose(); // Just in the case this object is being re-allocated.

    context = pgl.getCurrentContext();

    if (screenFb) {
      glFbo = 0;
    } else {
      //create the FBO object...
      glFbo = PGraphicsOpenGL.createFrameBufferObject(context);

      // ... and then create the rest of the stuff.
      if (multisample) {
        createColorBufferMultisample();
      }

      if (packedDepthStencil) {
        createPackedDepthStencilBuffer();
      } else {
        if (0 < depthBits) {
          createDepthBuffer();
        }
        if (0 < stencilBits) {
          createStencilBuffer();
        }
      }
    }
  }


  protected void dispose() {
    if (screenFb) return;

    if (glFbo != 0) {
      PGraphicsOpenGL.finalizeFrameBufferObject(glFbo, context);
      glFbo = 0;
    }
    if (glDepth != 0) {
      PGraphicsOpenGL.finalizeRenderBufferObject(glDepth, context);
      glDepth = 0;
    }
    if (glStencil != 0) {
      PGraphicsOpenGL.finalizeRenderBufferObject(glStencil, context);
      glStencil = 0;
    }
    if (glMultisample != 0) {
      PGraphicsOpenGL.finalizeRenderBufferObject(glMultisample, context);
      glMultisample = 0;
    }
    if (glDepthStencil != 0) {
      PGraphicsOpenGL.finalizeRenderBufferObject(glDepthStencil, context);
      glDepthStencil = 0;
    }
  }


  protected boolean contextIsOutdated() {
    if (screenFb) return false;

    boolean outdated = !pgl.contextIsCurrent(context);
    if (outdated) {
      PGraphicsOpenGL.removeFrameBufferObject(glFbo, context);
      PGraphicsOpenGL.removeRenderBufferObject(glDepth, context);
      PGraphicsOpenGL.removeRenderBufferObject(glStencil, context);
      PGraphicsOpenGL.removeRenderBufferObject(glDepthStencil, context);
      PGraphicsOpenGL.removeRenderBufferObject(glMultisample, context);

      glFbo = 0;
      glDepth = 0;
      glStencil = 0;
      glDepthStencil = 0;
      glMultisample = 0;

      for (int i = 0; i < numColorBuffers; i++) {
        colorBufferTex[i] = null;
      }
    }
    return outdated;
  }


  protected void createColorBufferMultisample() {
    if (screenFb) return;

    PGraphicsOpenGL.pushFramebuffer();
    PGraphicsOpenGL.setFramebuffer(this);

    glMultisample = PGraphicsOpenGL.createRenderBufferObject(context);
    pgl.bindRenderbuffer(PGL.RENDERBUFFER, glMultisample);
    pgl.renderbufferStorageMultisample(PGL.RENDERBUFFER, nsamples,
                                       PGL.RGBA8, width, height);
    pgl.framebufferRenderbuffer(PGL.FRAMEBUFFER, PGL.COLOR_ATTACHMENT0,
                                PGL.RENDERBUFFER, glMultisample);

    PGraphicsOpenGL.popFramebuffer();
  }


  protected void createPackedDepthStencilBuffer() {
    if (screenFb) return;

    if (width == 0 || height == 0) {
      throw new RuntimeException("PFramebuffer: size undefined.");
    }

    PGraphicsOpenGL.pushFramebuffer();
    PGraphicsOpenGL.setFramebuffer(this);

    glDepthStencil = PGraphicsOpenGL.createRenderBufferObject(context);
    pgl.bindRenderbuffer(PGL.RENDERBUFFER, glDepthStencil);

    if (multisample) {
      pgl.renderbufferStorageMultisample(PGL.RENDERBUFFER, nsamples,
                                         PGL.DEPTH24_STENCIL8, width, height);
    } else {
      pgl.renderbufferStorage(PGL.RENDERBUFFER, PGL.DEPTH24_STENCIL8,
                              width, height);
    }

    pgl.framebufferRenderbuffer(PGL.FRAMEBUFFER, PGL.DEPTH_ATTACHMENT,
                                PGL.RENDERBUFFER, glDepthStencil);
    pgl.framebufferRenderbuffer(PGL.FRAMEBUFFER, PGL.STENCIL_ATTACHMENT,
                                PGL.RENDERBUFFER, glDepthStencil);

    PGraphicsOpenGL.popFramebuffer();
  }


  protected void createDepthBuffer() {
    if (screenFb) return;

    if (width == 0 || height == 0) {
      throw new RuntimeException("PFramebuffer: size undefined.");
    }

    PGraphicsOpenGL.pushFramebuffer();
    PGraphicsOpenGL.setFramebuffer(this);

    glDepth = PGraphicsOpenGL.createRenderBufferObject(context);
    pgl.bindRenderbuffer(PGL.RENDERBUFFER, glDepth);

    int glConst = PGL.DEPTH_COMPONENT16;
    if (depthBits == 16) {
      glConst = PGL.DEPTH_COMPONENT16;
    } else if (depthBits == 24) {
      glConst = PGL.DEPTH_COMPONENT24;
    } else if (depthBits == 32) {
      glConst = PGL.DEPTH_COMPONENT32;
    }

    if (multisample) {
      pgl.renderbufferStorageMultisample(PGL.RENDERBUFFER, nsamples, glConst,
                                         width, height);
    } else {
      pgl.renderbufferStorage(PGL.RENDERBUFFER, glConst, width, height);
    }

    pgl.framebufferRenderbuffer(PGL.FRAMEBUFFER, PGL.DEPTH_ATTACHMENT,
                                PGL.RENDERBUFFER, glDepth);

    PGraphicsOpenGL.popFramebuffer();
  }


  protected void createStencilBuffer() {
    if (screenFb) return;

    if (width == 0 || height == 0) {
      throw new RuntimeException("PFramebuffer: size undefined.");
    }

    PGraphicsOpenGL.pushFramebuffer();
    PGraphicsOpenGL.setFramebuffer(this);

    glStencil = PGraphicsOpenGL.createRenderBufferObject(context);
    pgl.bindRenderbuffer(PGL.RENDERBUFFER, glStencil);

    int glConst = PGL.STENCIL_INDEX1;
    if (stencilBits == 1) {
      glConst = PGL.STENCIL_INDEX1;
    } else if (stencilBits == 4) {
      glConst = PGL.STENCIL_INDEX4;
    } else if (stencilBits == 8) {
      glConst = PGL.STENCIL_INDEX8;
    }
    if (multisample) {
      pgl.renderbufferStorageMultisample(PGL.RENDERBUFFER, nsamples, glConst,
                                         width, height);
    } else {
      pgl.renderbufferStorage(PGL.RENDERBUFFER, glConst, width, height);
    }

    pgl.framebufferRenderbuffer(PGL.FRAMEBUFFER, PGL.STENCIL_ATTACHMENT,
                                PGL.RENDERBUFFER, glStencil);

    PGraphicsOpenGL.popFramebuffer();
  }


  protected void createPixelBuffer() {
    pixelBuffer = IntBuffer.allocate(width * height);
    pixelBuffer.rewind();
  }
}
