最后,我能够将自定义属性传递给顶点着色器!非常感谢@Xoppa为我指明了正确的方向。
这是我目前得到的有效解决方案(我愿意就如何以更优雅的方式实施它提供进一步的建议):
首先,正如Xoppa在评论中所说,需要在构建模型时创建一个提供自定义顶点结构的模型。因此,模型创建可能如下所示:
VertexAttribute posAttr = new VertexAttribute(VertexAttributes.Usage.Position, 3, ShaderProgram.POSITION_ATTRIBUTE);
...
VertexAttribute customVertexAttr = new VertexAttribute(512, 3, "a_custom");
VertexAttributes vertexAttributes = new VertexAttributes(
posAttr,
...
customVertexAttr);
ModelBuilder modelBuilder = new ModelBuilder();
modelBuilder.begin();
modelBuilder.
part("box", GL20.GL_TRIANGLES, vertexAttributes, new Material()).
box(1f, 1f, 1f);
model = modelBuilder.end();
或与
MeshBuilder
:
MeshBuilder meshBuilder = new MeshBuilder();
VertexAttributes vertexAttributes = new VertexAttributes(...);
meshBuilder.begin(vertexAttributes);
meshBuilder.part("box", GL20.GL_TRIANGLES);
meshBuilder.setColor(color);
meshBuilder.box(1f, 1f, 1f);
Mesh mesh = meshBuilder.end();
该代码将根据提供的属性创建包含附加数据的顶点的模型。是时候填充相应的顶点阵列了。为此,您需要一个网格-它存储顶点数组-一个一个顶点的压缩属性的平面数组。所以,您需要的是每个顶点的属性数量以及需要修改的属性的偏移量。Mesh存储所有数据:
Mesh mesh = model.meshes.get(0);
int numVertices = mesh.getNumVertices();
int vertexSize = mesh.getVertexAttributes().vertexSize / 4;
VertexAttribute customAttribute = mesh.getVertexAttribute(512)
int offset = customAttribute.offset / 4;
float[] vertices = new float[numVertices * vertexSize];
mesh.getVertices(vertices);
我们准备好传递数据:
List<Vector3> customData ...
for(int i = 0; i < numVertices; ++i){
int index = i * vertexSize + offset;
vertices[index + 0] = customData.get(i).x;
vertices[index + 1] = customData.get(i).y;
vertices[index + 2] = customData.get(i).z;
}
不要忘记将更新的顶点数组传递回网格:
mesh.updateVertices(0, vertices);
就是这样。
这里还有一个helper方法的实现,它使用
Usage
带有自定义属性的标志:
private VertexAttributes createMixedVertexAttribute(int defaultAtributes, List<VertexAttribute> customAttributes){
VertexAttributes defaultAttributes = MeshBuilder.createAttributes(defaultAtributes);
List<VertexAttribute> attributeList = new ArrayList<VertexAttribute>();
for(VertexAttribute attribute: defaultAttributes){
attributeList.add(attribute);
}
attributeList.addAll(customAttributes);
VertexAttribute[] typeArray = new VertexAttribute[0];
VertexAttributes mixedVertexAttributes = new VertexAttributes(attributeList.toArray(typeArray));
return mixedVertexAttributes;
}
完整的源
:
public class ProtoGame implements ApplicationListener {
private static final int CUSTOM_ATTRIBUTE_USAGE = 512;
public ProtoGame()
{
super();
}
public PerspectiveCamera cam;
public CameraInputController camController;
public Model model;
public Array<ModelInstance> instances = new Array<ModelInstance>();
public ModelBatch modelBatch;
@Override
public void create () {
cam = new PerspectiveCamera(67, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
cam.position.set(0f, 8f, 8f);
cam.lookAt(0, 0, 0);
cam.near = 1f;
cam.far = 300f;
cam.update();
camController = new CameraInputController(cam);
Gdx.input.setInputProcessor(camController);
Model model = createModelWithCustomAttributes();
Mesh mesh = model.meshes.get(0);
setCustomAttributeData(mesh);
Color colorU = new Color(), colorV = new Color();
for (int x = -5; x <= 5; x+=2) {
for (int z = -5; z<=5; z+=2) {
ModelInstance instance = new ModelInstance(model, x, 0, z);
TestShader.DoubleColorAttribute attr = new TestShader.DoubleColorAttribute(TestShader.DoubleColorAttribute.DiffuseUV,
colorU.set((x+5f)/10f, 1f - (z+5f)/10f, 0, 1),
colorV.set(1f - (x+5f)/10f, 0, (z+5f)/10f, 1));
instance.materials.get(0).set(attr);
instances.add(instance);
}
}
modelBatch = new ModelBatch(new BaseShaderProvider() {
@Override
protected Shader createShader(Renderable renderable) {
return new TestShader();
}
});
}
@Override
public void render () {
camController.update();
Gdx.gl.glViewport(0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight());
Gdx.gl.glClearColor(1, 1, 1, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);
modelBatch.begin(cam);
for (ModelInstance instance : instances)
modelBatch.render(instance);
modelBatch.end();
}
private Model createModelWithCustomAttributes() {
int defaultAttributes = VertexAttributes.Usage.Position | VertexAttributes.Usage.Normal | VertexAttributes.Usage.TextureCoordinates;
VertexAttribute customVertexAttr = new VertexAttribute(CUSTOM_ATTRIBUTE_USAGE, 3, "a_custom");
List<VertexAttribute> customAttributeList = new ArrayList<VertexAttribute>();
customAttributeList.add(customVertexAttr);
VertexAttributes vertexAttributes = createMixedVertexAttribute(defaultAttributes, customAttributeList);
ModelBuilder modelBuilder = new ModelBuilder();
modelBuilder.begin();
modelBuilder.
part("box", GL20.GL_TRIANGLES, vertexAttributes, new Material()).
box(1f, 1f, 1f);
return modelBuilder.end();
}
private void setCustomAttributeData(Mesh mesh) {
int numVertices = mesh.getNumVertices();
int vertexSize = mesh.getVertexAttributes().vertexSize / 4;
int offset = mesh.getVertexAttribute(CUSTOM_ATTRIBUTE_USAGE).offset / 4;
float[] vertices = new float[numVertices * vertexSize];
mesh.getVertices(vertices);
for(int i = 0; i < numVertices; ++i){
int index = i * vertexSize + offset;
vertices[index + 0] = i;
vertices[index + 1] = i;
vertices[index + 2] = i;
}
mesh.updateVertices(0, vertices);
}
@Override
public void dispose () {
model.dispose();
modelBatch.dispose();
}
private VertexAttributes createMixedVertexAttribute(int defaultAtributes, List<VertexAttribute> customAttributes){
VertexAttributes defaultAttributes = MeshBuilder.createAttributes(defaultAtributes);
List<VertexAttribute> attributeList = new ArrayList<VertexAttribute>();
for(VertexAttribute attribute: defaultAttributes){
attributeList.add(attribute);
}
attributeList.addAll(customAttributes);
VertexAttribute[] typeArray = new VertexAttribute[0];
VertexAttributes mixedVertexAttributes = new VertexAttributes(attributeList.toArray(typeArray));
return mixedVertexAttributes;
}
@Override
public void resize(int width, int height) {
}
@Override
public void pause() {
}
@Override
public void resume() {
}
}
顶点著色引擎
:
attribute vec3 a_position;
attribute vec3 a_normal;
attribute vec2 a_texCoord0;
uniform mat4 u_worldTrans;
uniform mat4 u_projTrans;
varying vec2 v_texCoord0;
attribute vec3 a_custom;
void main() {
v_texCoord0 = a_texCoord0;
float posX = a_position.x + a_custom.x;
float posY = a_position.y + a_custom.y;
float posZ = a_position.z + a_custom.z;
gl_Position = u_projTrans * u_worldTrans * vec4(posX, posY, posZ, 1.0);
}
片段着色器
precision mediump float;
uniform vec3 u_colorU;
uniform vec3 u_colorV;
varying vec2 v_texCoord0;
void main() {
gl_FragColor = vec4(v_texCoord0.x * u_colorU + v_texCoord0.y * u_colorV, 1.0);
}
