我想将 JPEG 纹理贴图放置在球体上。它对我有用,但我想将纹理旋转 180 度。即我希望图像不是从零 UV 坐标开始,而是更早开始。
更新
我尝试重新分配球体的纹理坐标。纹理坐标是 float ,我希望它们不被限制在 [0..1] 的范围内。否则它应该将我的图像放入 [0..1 x 0..1] 区域。
它做了类似后者的事情,但不精确:
即整个图像被放入球体的一小块区域中。但是,它所在的这个确切区域与 U
的负值相对应,即在相同的经度上,即先前实验中图像边缘的位置(顶部球体)。
为什么?
图片在这里:https://en.wikipedia.org/wiki/File:Equirectangular_projection_SW.jpg
代码如下:
package tests.com.jme3;
import java.nio.FloatBuffer;
import com.jme3.app.SimpleApplication;
import com.jme3.font.BitmapText;
import com.jme3.light.DirectionalLight;
import com.jme3.material.Material;
import com.jme3.math.ColorRGBA;
import com.jme3.math.Quaternion;
import com.jme3.math.Vector2f;
import com.jme3.math.Vector3f;
import com.jme3.scene.Geometry;
import com.jme3.scene.VertexBuffer;
import com.jme3.scene.VertexBuffer.Type;
import com.jme3.scene.VertexBuffer.Usage;
import com.jme3.scene.shape.Sphere;
import com.jme3.util.BufferUtils;
public class Try_TextureTransform extends SimpleApplication {
public static void main(String[] args) {
Try_TextureTransform app = new Try_TextureTransform();
app.setShowSettings(false);
app.start(); // start the game
}
final float speed = 0.01f;
BitmapText hudText;
Sphere sphere1Mesh, sphere2Mesh;
Material sphere1Mat, sphere2Mat;
Geometry sphere1Geo, sphere2Geo;
Quaternion orientation;
DirectionalLight sun;
@Override
public void simpleInitApp() {
flyCam.setEnabled(false);
setDisplayStatView(false);
setDisplayFps(false);
hudText = new BitmapText(guiFont, false);
hudText.setSize(guiFont.getCharSet().getRenderedSize()); // font size
hudText.setColor(ColorRGBA.Blue); // font color
hudText.setText(""); // the text
hudText.setLocalTranslation(300, hudText.getLineHeight()*2, 0); // position
guiNode.attachChild(hudText);
sphere1Mesh = new Sphere(50, 50, 2);
sphere1Mesh.setTextureMode(Sphere.TextureMode.Projected); // matrc
sphere1Mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
sphere1Mat.setTexture("ColorMap", assetManager.loadTexture("textures/Equirectangular_projection_SW.jpg"));
sphere1Geo = new Geometry("Sphere2", sphere1Mesh);
sphere1Geo.setMaterial(sphere1Mat);
sphere1Geo.setLocalTranslation(0, 0, 2);
sphere2Mesh = new Sphere(50, 50, 2);
VertexBuffer vb = sphere2Mesh.getBuffer(Type.Position);
FloatBuffer fb = (FloatBuffer) vb.getData();
float[] vertexCoordinates = BufferUtils.getFloatArray(fb);
VertexBuffer vb2 = sphere2Mesh.getBuffer(Type.TexCoord);
FloatBuffer fb2 = (FloatBuffer) vb2.getData();
float[] uvCoordinates = BufferUtils.getFloatArray(fb2);
double rho;
for (int i = 0; i < vertexCoordinates.length/3; ++i) {
uvCoordinates[i*2] = (float) Math.atan2(vertexCoordinates[i*3+1], vertexCoordinates[i*3]);
rho = Math.sqrt(Math.pow( vertexCoordinates[i*3], 2) + Math.pow( vertexCoordinates[i*3+1], 2));
uvCoordinates[i*2+1] = (float) Math.atan2(vertexCoordinates[i*3+2], rho);
}
//apply new texture coordinates
VertexBuffer uvCoordsBuffer = new VertexBuffer(Type.TexCoord);
uvCoordsBuffer.setupData(Usage.Static, 2, com.jme3.scene.VertexBuffer.Format.Float, BufferUtils.createFloatBuffer(uvCoordinates));
sphere2Mesh.clearBuffer(Type.TexCoord);
sphere2Mesh.setBuffer(uvCoordsBuffer);
//sphere2Mesh.setTextureMode(Sphere.TextureMode.Projected); // better quality on spheres
sphere2Mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
sphere2Mat.setTexture("ColorMap", assetManager.loadTexture("textures/Equirectangular_projection_SW.jpg"));
sphere2Geo = new Geometry("Sphere2", sphere2Mesh);
sphere2Geo.setMaterial(sphere2Mat);
sphere2Geo.setLocalTranslation(0, 0, -2);
cam.setLocation(new Vector3f(-10, 0, 0));
cam.lookAt(Vector3f.ZERO, Vector3f.UNIT_Z);
rootNode.attachChild(sphere1Geo);
rootNode.attachChild(sphere2Geo);
}
@Override
public void simpleUpdate(float tpf) {
Vector2f cursorPosition = inputManager.getCursorPosition();
Vector3f cursorPositionWorld = cam.getWorldCoordinates(cursorPosition, 1);
orientation = new Quaternion().fromAngleAxis(cursorPositionWorld.z*speed, Vector3f.UNIT_Y);
orientation.multLocal(new Quaternion().fromAngleAxis(-cursorPositionWorld.y*speed, Vector3f.UNIT_Z));
rootNode.setLocalRotation(orientation);
}
}
最佳答案
正确的方法是按照您认为合适的方式旋转几何体或编辑纹理(技术 1 和 2),但因为您谈论的是修改纹理坐标本身,所以我包括技术 3 和 4,以防您使用这个例子是为了在合适的时候学习更大的技术。
技术 1 - 旋转几何图形
旋转几何体,使其按照您想要的方式定向。这是迄今为止最简单、最合适、最容易理解的技术,也是我推荐的
//Add this
Quaternion quat=new Quaternion();
quat.fromAngles(0 ,0 , FastMath.PI);
sphere1Geo.setLocalRotation(quat);
完整的程序
public class Main extends SimpleApplication {
public static void main(String[] args) {
Main app = new Main();
app.setShowSettings(false);
app.start(); // start the game
}
final float speed = 0.01f;
BitmapText hudText;
Quaternion orientation;
DirectionalLight sun;
@Override
public void simpleInitApp() {
flyCam.setEnabled(false);
setDisplayStatView(false);
setDisplayFps(false);
hudText = new BitmapText(guiFont, false);
hudText.setSize(guiFont.getCharSet().getRenderedSize()); // font size
hudText.setColor(ColorRGBA.Blue); // font color
hudText.setText(""); // the text
hudText.setLocalTranslation(300, hudText.getLineHeight()*2, 0); // position
guiNode.attachChild(hudText);
cam.setLocation(new Vector3f(10, 0, 0));
cam.lookAt(Vector3f.ZERO, Vector3f.UNIT_Z);
addOriginalSphere();
addRotatedSphere();
}
public void addOriginalSphere(){
Sphere sphere1Mesh = new Sphere(50, 50, 2);
sphere1Mesh.setTextureMode(Sphere.TextureMode.Projected); // matrc
Material sphere1Mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
sphere1Mat.setTexture("ColorMap", assetManager.loadTexture("Textures/world.png"));
Geometry sphere1Geo = new Geometry("Original Sphere", sphere1Mesh);
sphere1Geo.setMaterial(sphere1Mat);
sphere1Geo.setLocalTranslation(0, -2, 0);
rootNode.attachChild(sphere1Geo);
}
public void addRotatedSphere(){
Sphere sphere1Mesh = new Sphere(50, 50, 2);
sphere1Mesh.setTextureMode(Sphere.TextureMode.Projected); // matrc
Material sphere1Mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
sphere1Mat.setTexture("ColorMap", assetManager.loadTexture("Textures/world.png"));
Geometry sphere1Geo = new Geometry("Rotated Sphere", sphere1Mesh);
sphere1Geo.setMaterial(sphere1Mat);
sphere1Geo.setLocalTranslation(0, 2, 0);
//Add this
Quaternion quat=new Quaternion();
quat.fromAngles(0 ,0 , FastMath.PI);
sphere1Geo.setLocalRotation(quat);
rootNode.attachChild(sphere1Geo);
}
@Override
public void simpleUpdate(float tpf) {
}
}
技术 2 - 编辑纹理以符合您想要的方式
存在许多图像编辑程序,我使用的是 Paint.Net,并且(像大多数编辑软件一样)提供精确的像素鼠标坐标。只需剪切并粘贴图像,使格林威治位于最左侧。在你的情况下,你无论如何都需要编辑图像,因为它上面有可怕的白色边框。
技术 3 - 弄乱顶点纹理坐标
这对于这个来说太过分了,不是我推荐的。但如果这是学习创建自己的练习custom mesh然后继续阅读
public void addRotatedSphere_ByMessingWithMesh(){
Sphere sphere1Mesh = new Sphere(50, 50, 2);
sphere1Mesh.setTextureMode(Sphere.TextureMode.Projected); // matrc
FloatBuffer textureBuffer=sphere1Mesh.getFloatBuffer(Type.TexCoord);
float[] newTextureCoordinates=new float[textureBuffer.capacity()];
for(int i=0;i<newTextureCoordinates.length;i++){
//texture buffer goes x co-ordinate, y coordinate, x coordinate, y coordinate
if (i%2!=1){
newTextureCoordinates[i]=(float)((textureBuffer.get(i)+0.5)%1);
}else{
newTextureCoordinates[i]=textureBuffer.get(i);
}
}
sphere1Mesh.setBuffer(Type.TexCoord, 2,newTextureCoordinates);
Material sphere1Mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
sphere1Mat.setTexture("ColorMap", assetManager.loadTexture("Textures/world.png"));
Geometry sphere1Geo = new Geometry("Rotated Sphere", sphere1Mesh);
sphere1Geo.setMaterial(sphere1Mat);
sphere1Geo.setLocalTranslation(0, 2, 0);
rootNode.attachChild(sphere1Geo);
}
这个有问题,因为后面的接缝没有做好;因为真实的纹理坐标为 0,0.2,0.4,0.8,1。而新的则在远端进行环绕。在这个具体示例中,您可以手动处理接缝,但您已经可以看到这很痛苦。
技术 4 - 编写自己的着色器
这接近于限制,但你可以写一个 custom shader这将采用真实的纹理坐标并应用类似于技术 3 中执行的转换,但这将在图形卡上完成,并且对于调试来说是一场噩梦。
不用说,这将使用小型核武器杀死一只苍蝇,我不会明确解释所有步骤(但它很大程度上基于 unshaded.j3md 和 unshaded.vert
- 创建以下文件来定义我们的新 Material
Material 定义
唯一的变化是提及我们的自定义顶点着色器,而不是使用自定义顶点着色器
MaterialDef Unshaded {
MaterialParameters {
Texture2D ColorMap
Texture2D LightMap
Color Color (Color)
Boolean VertexColor (UseVertexColor)
Boolean SeparateTexCoord
// Texture of the glowing parts of the material
Texture2D GlowMap
// The glow color of the object
Color GlowColor
// For hardware skinning
Int NumberOfBones
Matrix4Array BoneMatrices
// Alpha threshold for fragment discarding
Float AlphaDiscardThreshold (AlphaTestFallOff)
//Shadows
Int FilterMode
Boolean HardwareShadows
Texture2D ShadowMap0
Texture2D ShadowMap1
Texture2D ShadowMap2
Texture2D ShadowMap3
//pointLights
Texture2D ShadowMap4
Texture2D ShadowMap5
Float ShadowIntensity
Vector4 Splits
Vector2 FadeInfo
Matrix4 LightViewProjectionMatrix0
Matrix4 LightViewProjectionMatrix1
Matrix4 LightViewProjectionMatrix2
Matrix4 LightViewProjectionMatrix3
//pointLight
Matrix4 LightViewProjectionMatrix4
Matrix4 LightViewProjectionMatrix5
Vector3 LightPos
Vector3 LightDir
Float PCFEdge
Float ShadowMapSize
}
Technique {
VertexShader GLSL100: MatDefs/TextureSplitting.vert
FragmentShader GLSL100: Common/MatDefs/Misc/Unshaded.frag
WorldParameters {
WorldViewProjectionMatrix
}
Defines {
SEPARATE_TEXCOORD : SeparateTexCoord
HAS_COLORMAP : ColorMap
HAS_LIGHTMAP : LightMap
HAS_VERTEXCOLOR : VertexColor
HAS_COLOR : Color
NUM_BONES : NumberOfBones
DISCARD_ALPHA : AlphaDiscardThreshold
}
}
Technique {
}
Technique PreNormalPass {
VertexShader GLSL100 : Common/MatDefs/SSAO/normal.vert
FragmentShader GLSL100 : Common/MatDefs/SSAO/normal.frag
WorldParameters {
WorldViewProjectionMatrix
WorldViewMatrix
NormalMatrix
}
Defines {
NUM_BONES : NumberOfBones
}
}
Technique PreShadow {
VertexShader GLSL100 : Common/MatDefs/Shadow/PreShadow.vert
FragmentShader GLSL100 : Common/MatDefs/Shadow/PreShadow.frag
WorldParameters {
WorldViewProjectionMatrix
WorldViewMatrix
}
Defines {
COLOR_MAP : ColorMap
DISCARD_ALPHA : AlphaDiscardThreshold
NUM_BONES : NumberOfBones
}
ForcedRenderState {
FaceCull Off
DepthTest On
DepthWrite On
PolyOffset 5 3
ColorWrite Off
}
}
Technique PostShadow15{
VertexShader GLSL150: Common/MatDefs/Shadow/PostShadow15.vert
FragmentShader GLSL150: Common/MatDefs/Shadow/PostShadow15.frag
WorldParameters {
WorldViewProjectionMatrix
WorldMatrix
}
Defines {
HARDWARE_SHADOWS : HardwareShadows
FILTER_MODE : FilterMode
PCFEDGE : PCFEdge
DISCARD_ALPHA : AlphaDiscardThreshold
COLOR_MAP : ColorMap
SHADOWMAP_SIZE : ShadowMapSize
FADE : FadeInfo
PSSM : Splits
POINTLIGHT : LightViewProjectionMatrix5
NUM_BONES : NumberOfBones
}
ForcedRenderState {
Blend Modulate
DepthWrite Off
PolyOffset -0.1 0
}
}
Technique PostShadow{
VertexShader GLSL100: Common/MatDefs/Shadow/PostShadow.vert
FragmentShader GLSL100: Common/MatDefs/Shadow/PostShadow.frag
WorldParameters {
WorldViewProjectionMatrix
WorldMatrix
}
Defines {
HARDWARE_SHADOWS : HardwareShadows
FILTER_MODE : FilterMode
PCFEDGE : PCFEdge
DISCARD_ALPHA : AlphaDiscardThreshold
COLOR_MAP : ColorMap
SHADOWMAP_SIZE : ShadowMapSize
FADE : FadeInfo
PSSM : Splits
POINTLIGHT : LightViewProjectionMatrix5
NUM_BONES : NumberOfBones
}
ForcedRenderState {
Blend Modulate
DepthWrite Off
PolyOffset -0.1 0
}
}
Technique Glow {
VertexShader GLSL100: Common/MatDefs/Misc/TextureSplitting.vert
FragmentShader GLSL100: Common/MatDefs/Light/Glow.frag
WorldParameters {
WorldViewProjectionMatrix
}
Defines {
NEED_TEXCOORD1
HAS_GLOWMAP : GlowMap
HAS_GLOWCOLOR : GlowColor
NUM_BONES : NumberOfBones
}
}
}
顶点着色器
使用平移将真实纹理坐标映射到移位后的坐标。顺便说一下,如果你认为这不是java;事实并非如此。它的 OpenGL 着色器语言。
#import "Common/ShaderLib/Skinning.glsllib"
uniform mat4 g_WorldViewProjectionMatrix;
attribute vec3 inPosition;
#if defined(HAS_COLORMAP) || (defined(HAS_LIGHTMAP) && !defined(SEPARATE_TEXCOORD))
#define NEED_TEXCOORD1
#endif
attribute vec2 inTexCoord;
attribute vec2 inTexCoord2;
attribute vec4 inColor;
varying vec2 texCoord1;
varying vec2 texCoord2;
varying vec4 vertColor;
void main(){
#ifdef NEED_TEXCOORD1
texCoord1 = inTexCoord;
texCoord1.x=texCoord1.x+0.5;
if (texCoord1.x>1){
texCoord1.x=texCoord1.x-1;
}
#endif
#ifdef SEPARATE_TEXCOORD
texCoord2 = inTexCoord2;
#endif
#ifdef HAS_VERTEXCOLOR
vertColor = inColor;
#endif
vec4 modelSpacePos = vec4(inPosition, 1.0);
#ifdef NUM_BONES
Skinning_Compute(modelSpacePos);
#endif
gl_Position = g_WorldViewProjectionMatrix * modelSpacePos;
}
然后使用它作为 Material 而不是unshaded.j3md
Material sphere1Mat = new Material(assetManager, "Materials/TextureSplitting.j3md");
背面再次出现令人讨厌的中断,真实纹理在 0 和 1 之间变化,如果我们想要的话,我们可以明确处理但是我们必须确保有 2 个顶点分割点一个纹理坐标为0,一个纹理坐标为1。
结论
技术 1 或 2 是您应该使用的技术。我包含技术 3 和 4 只是为了表明您可以使用实际纹理坐标来执行此操作,但您不应该这样做。
关于java - 如何在jME3中定位球体上的纹理?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23722599/