libgdx-使用着色器(OpenGL ES 2.0)创建复杂的纹理对象

Question

我正在尝试创建3D场景。有云层的质地。我认为我将能够通过透明的球体和上面的云纹理来创建云（如果我错了，请纠正我）。因此，我以下有一些代码：

ShaderProgram shader;
Mesh mesh, cloudMesh;
Texture texture, cloudTexture;
Matrix4 matrix = new Matrix4();
 public void create() {
String vertexShader = "attribute vec4 a_position;    n"
    + "attribute vec4 a_color;n" 
    + "attribute vec2 a_texCoords;n"
    + "uniform mat4 u_worldView;n" 
    + "varying vec4 v_color;"
    + "varying vec2 v_texCoords;"
    + "void main()                  n"
    + "{                            n"
    + "   v_color = vec4(1, 1, 1, 1); n"
    + "   v_texCoords = a_texCoords; n"
    + "   gl_Position =  u_worldView * a_position;  n"
    + "}                            n";
String fragmentShader = "#ifdef GL_ESn"
    + "precision mediump float;n"
    + "#endifn"
    + "varying vec4 v_color;n"
    + "varying vec2 v_texCoords;n"
    + "uniform sampler2D u_texture;n"
    + "void main()                                  n"
    + "{                                            n"      
     + "  gl_FragColor = v_color * texture2D(u_texture, v_texCoords);n"
    + "}";
shader = new ShaderProgram(vertexShader, fragmentShader);
if (shader.isCompiled() == false) {     
  System.exit(0);
}
mesh = ObjLoader.loadObj(Gdx.files.internal("objects/earth.obj").read()); 
cloudMesh = ObjLoader.loadObj(Gdx.files.internal("objects/cloud_sphere.obj").read()); 
texture = new Texture(Gdx.files.internal("images/earthmap.jpg"));
cloudTexture = new Texture(Gdx.files.internal("images/earth_clouds_map.jpg"));
}
public void render() {
angle += Gdx.graphics.getDeltaTime() * 30;
matrix.setToRotation(axis, angle);
Gdx.graphics.getGL20().glViewport(-10, 10, Gdx.graphics.getWidth(),
    Gdx.graphics.getHeight());
Gdx.graphics.getGL20().glClearColor(0.2f, 0.2f, 0.2f, 1);
Gdx.graphics.getGL20().glClear(GL20.GL_COLOR_BUFFER_BIT);
Gdx.graphics.getGL20().glEnable(GL20.GL_TEXTURE_2D);
Gdx.graphics.getGL20().glEnable(GL20.GL_BLEND);
Gdx.graphics.getGL20().glBlendFunc(GL20.GL_SRC_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA);
texture.bind();
shader.begin();
shader.setUniformMatrix("u_worldView", matrix);
shader.setUniformi("u_texture", 0);
mesh.render(shader, GL20.GL_TRIANGLE_STRIP);
shader.end();    
//SHOULD I USE SHADER PROGRAM LIKE BELOW?
cloudTexture .bind();
shader.begin();
shader.setUniformMatrix("u_worldView", matrix);
shader.setUniformi("u_texture", 0);
cloudMesh.render(shader, GL20.GL_TRIANGLE_STRIP);
shader.end();  
}    

所以我看不到球体上的任何纹理。错误在哪里？如果有人有任何想法，链接或示例，将不胜感激！

Answer 1

在加载纹理之前，必须定义一个"插槽"，在其中存储纹理：

Gdx.graphics.getGL20().glActiveTexture(GL20.GL_TEXTURE0);
texture = new Texture(Gdx.files.internal("images/earthmap.jpg"));
texture.bind();
Gdx.graphics.getGL20().glActiveTexture(GL20.GL_TEXTURE1);
cloudTexture = new Texture(Gdx.files.internal("images/earth_clouds_map.jpg"));
cloudTexture.bind();

在您的渲染方法中，您然后将纹理绑定并使用这些"插槽"

将其分配给着色器

shader.setUniformi("u_texture", 0);
...
...
shader.setUniformi("u_texture", 1);

应该全部...