LIBGDX版NEHE OPENGL- 3. Adding Color

opengl在给图形加颜色时，需要为每一点指定比如：

glColor3f(1.0f,0.0f,0.0f);          // Set The Color To Red

glVertex3f( 0.0f, 1.0f, 0.0f);          // Move Up One Unit From Center (Top Point)

glColor3f(0.0f,1.0f,0.0f);          // Set The Color To Green

glVertex3f(-1.0f,-1.0f, 0.0f);          // Left And Down One Unit (Bottom Left)

glColor3f(0.0f,0.0f,1.0f);          // Set The Color To Blue

glVertex3f( 1.0f,-1.0f, 0.0f);          // Right And Down One Unit (Bottom Right)

在libgdx中，我们相应的给mesh添加上颜色的属性，全部代码如下：

package com.kyugao.screen;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Screen;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.GL10;
import com.badlogic.gdx.graphics.Mesh;
import com.badlogic.gdx.graphics.PerspectiveCamera;
import com.badlogic.gdx.graphics.VertexAttribute;
import com.badlogic.gdx.graphics.VertexAttributes.Usage;

public class AddingColor implements Screen {

	private Mesh triangleMesh, squareMesh;
	private PerspectiveCamera camera;

	@Override
	public void render(float delta) {

		camera.update();
		camera.apply(Gdx.graphics.getGL10());
		Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);

		drawGLScene();
	}

	private boolean drawGLScene() {
		triangleMesh.render(GL10.GL_TRIANGLES, 0, 3);
		squareMesh.render(GL10.GL_TRIANGLE_STRIP, 0, 4);
		return true;
	}

	@Override
	public void show() {
		triangleMesh = new Mesh(true, 3, 3, new VertexAttribute(Usage.Position,
				3, "a_position"), new VertexAttribute(Usage.ColorPacked, 4,
				"a_color"));
		squareMesh = new Mesh(true, 4, 4, new VertexAttribute(Usage.Position,
				3, "b_position"), new VertexAttribute(Usage.ColorPacked, 4,
				"b_color"));
		triangleMesh.setVertices(new float[] { //
				-1.5f, 1.0f, -6.0f, // point 1
						Color.toFloatBits(1f, 0f, 0f, 1f), // color 1
						-2.5f, -1.0f, -6.0f, // point 2
						Color.toFloatBits(0f, 1f, 0f, 1f), // color 2
						-0.5f, -1.0f, -6.0f,// point 3
						Color.toFloatBits(0f, 0f, 1f, 1f) // color 3
				});
		triangleMesh.setIndices(new short[] { 0, 1, 2 });

		squareMesh.setVertices(new float[] { 0.5f, -1.0f, -6.0f,// point BL
				Color.toFloatBits(0.5f, 0.5f, 1f, 1f), // color 1
				2.5f, -1.0f, -6.0f,// point BR
				Color.toFloatBits(0.5f, 0.5f, 1f, 1f), // color 1
				0.5f, 1.0f, -6.0f, // point TL
				Color.toFloatBits(0.5f, 0.5f, 1f, 1f), // color 1
				2.5f, 1.0f, -6.0f, // point TR
				Color.toFloatBits(0.5f, 0.5f, 1f, 1f) // color 1
				});
		squareMesh.setIndices(new short[] { 0, 1, 2, 3 });
	}

	@Override
	public void hide() {
	}

	@Override
	public void pause() {
	}

	@Override
	public void resume() {
	}

	@Override
	public void dispose() {
	}

	@Override
	public void resize(int width, int height) {
		float aspectRatio = (float) width / (float) height;
		camera = new PerspectiveCamera(45, 2f * aspectRatio, 2f);
	}

}

显示效果如下：