TexturedQuad.java

// Copyright 2008 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.android.stardroid.renderer.util;

import javax.microedition.khronos.opengles.GL10;

/**
 * A simple class for rendering a textured quad.
 *
 * @author James Powell
 *
 */
public class TexturedQuad {
  private TexCoordBuffer mTexCoords = null;
  private VertexBuffer mPosition = null;
  private TextureReference mTexture = null;

  /**
   * Constructs the textured quad.
   * p is the point at the center of the quad.
   * u is the vector from the center of quad, pointing right.
   * v is the vector from the center of the quad, pointing up.
   * The four vertices of the quad are: by p +/- u +/- v
   * @param tex The texture to apply to the quad
   * @param px
   * @param py
   * @param pz
   * @param ux
   * @param uy
   * @param uz
   * @param vx
   * @param vy
   * @param vz
   */
  public TexturedQuad(TextureReference tex,
                      float px, float py, float pz,
                      float ux, float uy, float uz,
                      float vx, float vy, float vz) {
    mPosition = new VertexBuffer(12);
    mTexCoords = new TexCoordBuffer(12);

    VertexBuffer vertexBuffer = mPosition;
    TexCoordBuffer texCoordBuffer = mTexCoords;

    // Upper left
    vertexBuffer.addPoint(px - ux - vx, py - uy - vy, pz - uz - vz);
    texCoordBuffer.addTexCoords(0, 1);

    // upper left
    vertexBuffer.addPoint(px - ux + vx, py - uy + vy, pz - uz + vz);
    texCoordBuffer.addTexCoords(0, 0);

    // lower right
    vertexBuffer.addPoint(px + ux - vx, py + uy - vy, pz + uz - vz);
    texCoordBuffer.addTexCoords(1, 1);

    // upper right
    vertexBuffer.addPoint(px + ux + vx, py + uy + vy, pz + uz + vz);
    texCoordBuffer.addTexCoords(1, 0);

    mTexture = tex;
  }

  public void draw(GL10 gl) {
    gl.glEnable(GL10.GL_TEXTURE_2D);
    mTexture.bind(gl);

    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
    gl.glDisableClientState(GL10.GL_COLOR_ARRAY);

    mPosition.set(gl);
    mTexCoords.set(gl);

    gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);

    gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
    gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
    gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

    gl.glDisable(GL10.GL_TEXTURE_2D);
  }
}