所以我试图用 LibGDX 实现“多边形艺术/低多边形”风格。我首先构建一个由三角形组成的模型。
然后使用顶点着色器，我根据高度计算每个顶点的颜色。
问题是，当我希望地形像这样平坦阴影时，地形是 Gouraud 阴影：
我知道对于更高版本的 OpenGL，在 glsl 中有一个“flat”关键字，它将禁用顶点之间的颜色插值。根据我在网上和这篇文章中阅读的内容：http: //i.stack.imgur.com/DrNx9.jpg，我认为我需要让地形中的每个三角形彼此分开？我还需要计算每个三角形的法线？我无法理解其他 StackOverflow 中的代码，但这是我试图做的：
原来的
public Model getWorld(){
returnWorld = new Model();
modelBuilder = new ModelBuilder();
modelBuilder.begin();
worldMeshBuilder = modelBuilder.part("worldPart", GL20.GL_TRIANGLES, Usage.Position | Usage.Normal, new Material());
pieceMeshBuilder = new MeshBuilder();
meshPiece = new Mesh(false, 3, 3,
new VertexAttribute(Usage.Position, 3, "a_position"),
new VertexAttribute(Usage.Normal, 3, "a_normal"),
new VertexAttribute(Usage.ColorPacked, 4, "a_color"));
Vector3 vectorCopy = new Vector3();
for(int i = 0; i < world.length - 1; i++){
for(int j = 0; j < world[0].length - 1; j++){
if((i + j) % 2 == 0){
pieceMeshBuilder.begin(Usage.Position | Usage.Normal, renderType);
pieceMeshBuilder.triangle(
vectorCopy = verticies[i][j],
vectorCopy = verticies[i][j + 1],
vectorCopy = verticies[i + 1][j + 1]
);
worldMeshBuilder.addMesh(pieceMeshBuilder.end());
pieceMeshBuilder.begin(Usage.Position | Usage.Normal, renderType);
pieceMeshBuilder.triangle(
vectorCopy = verticies[i + 1][j + 1],
vectorCopy = verticies[i + 1][j],
vectorCopy = verticies[i][j]
);
worldMeshBuilder.addMesh(pieceMeshBuilder.end());
} else {
pieceMeshBuilder.begin(Usage.Position | Usage.Normal, renderType);
pieceMeshBuilder.triangle(
vectorCopy = verticies[i][j],
vectorCopy = verticies[i][j + 1],
vectorCopy = verticies[i + 1][j]
);
worldMeshBuilder.addMesh(pieceMeshBuilder.end());
pieceMeshBuilder.begin(Usage.Position | Usage.Normal, renderType);
pieceMeshBuilder.triangle(
vectorCopy = verticies[i + 1][j + 1],
vectorCopy = verticies[i + 1][j],
vectorCopy = verticies[i][j + 1]
);
worldMeshBuilder.addMesh(pieceMeshBuilder.end());
}
}
}
returnWorld = modelBuilder.end();
return returnWorld;
}
现在：
public Model getWorld(){
returnWorld = new Model();
modelBuilder = new ModelBuilder();
modelBuilder.begin();
worldMeshBuilder = modelBuilder.part("worldPart", GL20.GL_LINES, Usage.Position | Usage.Normal, new Material());
for(int i = 0; i < world.length - 1; i++){
for(int j = 0; j < world[0].length - 1; j++){
Vector3 normal1 = calcNormal(verticies[i][j], verticies[i + 1][j], verticies[i + 1][j + 1]);
Vector3 normal2 = calcNormal(verticies[i][j], verticies[i + 1][j + 1], verticies[i][j + 1]);
if((i + j) % 2 == 0){
meshPiece = new Mesh(false, 18, 3,
new VertexAttribute(Usage.Position, 3, "a_position"),
new VertexAttribute(Usage.Normal, 3, "a_normal")//,
//new VertexAttribute(Usage.ColorPacked, 4, "a_color")
);
worldMeshBuilder.addMesh(meshPiece.setVertices(new float[] {
verticies[i][j].x, verticies[i][j].y, verticies[i][j].z, normal1.x, normal1.y, normal1.z,
verticies[i + 1][j].x, verticies[i + 1][j].y, verticies[i + 1][j].z, normal1.x, normal1.y, normal1.z,
verticies[i + 1][j + 1].x, verticies[i + 1][j + 1].y, verticies[i + 1][j + 1].z, normal1.x, normal1.y, normal1.z,
}));
meshPiece = new Mesh(false, 18, 3,
new VertexAttribute(Usage.Position, 3, "a_position"),
new VertexAttribute(Usage.Normal, 3, "a_normal")//,
//new VertexAttribute(Usage.ColorPacked, 4, "a_color")
);
worldMeshBuilder.addMesh(meshPiece.setVertices(new float[] {
verticies[i][j].x, verticies[i][j].y, verticies[i][j].z, normal2.x, normal2.y, normal2.z,
verticies[i + 1][j + 1].x, verticies[i + 1][j + 1].y, verticies[i + 1][j + 1].z, normal2.x, normal2.y, normal2.z,
verticies[i][j + 1].x, verticies[i][j + 1].y, verticies[i][j + 1].z, normal2.x, normal2.y, normal2.z,
}));
} else {
meshPiece = new Mesh(false, 18, 3,
new VertexAttribute(Usage.Position, 3, "a_position"),
new VertexAttribute(Usage.Normal, 3, "a_normal")//,
//new VertexAttribute(Usage.ColorPacked, 4, "a_color")
);
worldMeshBuilder.addMesh(meshPiece.setVertices(new float[] {
verticies[i][j].x, verticies[i][j].y, verticies[i][j].z, normal1.x, normal1.y, normal1.z,
verticies[i + 1][j].x, verticies[i + 1][j].y, verticies[i + 1][j].z, normal1.x, normal1.y, normal1.z,
verticies[i][j + 1].x, verticies[i][j + 1].y, verticies[i][j + 1].z, normal1.x, normal1.y, normal1.z,
}));
meshPiece = new Mesh(false, 18, 3,
new VertexAttribute(Usage.Position, 3, "a_position"),
new VertexAttribute(Usage.Normal, 3, "a_normal")//,
//new VertexAttribute(Usage.ColorPacked, 4, "a_color")
);
worldMeshBuilder.addMesh(meshPiece.setVertices(new float[] {
verticies[i + 1][j].x, verticies[i + 1][j].y, verticies[i + 1][j].z, normal2.x, normal2.y, normal2.z,
verticies[i + 1][j + 1].x, verticies[i + 1][j + 1].y, verticies[i + 1][j + 1].z, normal2.x, normal2.y, normal2.z,
verticies[i][j + 1].x, verticies[i][j + 1].y, verticies[i][j + 1].z, normal2.x, normal2.y, normal2.z,
}));
}
}
}
returnWorld = modelBuilder.end();
return returnWorld;
}
问题是新代码没有渲染任何东西……我查看了 ModelBuilder、MeshBuilder、Mesh 和 VertexAttribute/s 的 API，但我不知道为什么它不起作用。任何帮助都会很棒，因为这是非常令人沮丧的一天。非常感谢！
