FrameBuffer.java

package org.saintandreas.gl;

import static org.lwjgl.opengl.GL11.GL_INT;
import static org.lwjgl.opengl.GL11.GL_LINEAR;
import static org.lwjgl.opengl.GL11.GL_RGBA;
import static org.lwjgl.opengl.GL11.GL_RGBA8;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_2D;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_MAG_FILTER;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_MIN_FILTER;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_WRAP_S;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_WRAP_T;
import static org.lwjgl.opengl.GL11.glBindTexture;
import static org.lwjgl.opengl.GL11.glTexImage2D;
import static org.lwjgl.opengl.GL11.glTexParameteri;
import static org.lwjgl.opengl.GL11.glViewport;
import static org.lwjgl.opengl.GL12.GL_CLAMP_TO_EDGE;
import static org.lwjgl.opengl.GL14.GL_DEPTH_COMPONENT24;
import static org.lwjgl.opengl.GL30.GL_COLOR_ATTACHMENT0;
import static org.lwjgl.opengl.GL30.GL_DEPTH_ATTACHMENT;
import static org.lwjgl.opengl.GL30.GL_FRAMEBUFFER;
import static org.lwjgl.opengl.GL30.GL_RENDERBUFFER;
import static org.lwjgl.opengl.GL30.glBindFramebuffer;
import static org.lwjgl.opengl.GL30.glBindRenderbuffer;
import static org.lwjgl.opengl.GL30.glFramebufferRenderbuffer;
import static org.lwjgl.opengl.GL30.glFramebufferTexture2D;
import static org.lwjgl.opengl.GL30.glGenFramebuffers;
import static org.lwjgl.opengl.GL30.glGenRenderbuffers;
import static org.lwjgl.opengl.GL30.glRenderbufferStorage;

import org.saintandreas.gl.textures.Texture;

public class FrameBuffer {
  int frameBuffer;
  Texture texture;
  int depthBuffer;
  int width, height;

  public FrameBuffer(int width, int height) {
    this.width = width;
    this.height = height;

    frameBuffer = glGenFramebuffers();
    glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer);

    texture = new Texture();
    texture.bind();
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height, 0, GL_RGBA, GL_INT, (java.nio.ByteBuffer) null);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture.id, 0);

    depthBuffer = glGenRenderbuffers();
    glBindRenderbuffer(GL_RENDERBUFFER, depthBuffer);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, width, height);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthBuffer);

    glBindFramebuffer(GL_FRAMEBUFFER, 0);
  }

  public void activate() {
    glViewport(0, 0, width, height);
    glBindTexture(GL_TEXTURE_2D, 0);
    glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer);
  }

  public void deactivate() {
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
  }

  public Texture getTexture() {
    return texture;
  }
}