[英]GLSL LWJGL woes/Shaders do nothing?
好的,因此,我試圖在此使用本教程: http : //lwjgl.org/wiki/index.php?title=GLSL_Shaders_with_LWJGL
我的問題是為什么在此示例中我的着色器不做任何事情? 我是GLSL的新手。
這是主類的代碼
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.util.glu.GLU;
/*
* Sets up the Display, the GL context, and runs the main game
loop.
*
* @author Stephen Jones
*/
public class GLSLTest{
Box box;
private boolean done=false; //game runs until done is set to true
public GLSLTest(){
init();
while(!done){
if(Display.isCloseRequested())
done=true;
render();
Display.update();
}
Display.destroy();
}
private void render(){
GL11.glClear(GL11.GL_COLOR_BUFFER_BIT |
GL11.GL_DEPTH_BUFFER_BIT);
GL11.glLoadIdentity();
box.draw();
}
private void init(){
int w=1024;
int h=768;
try{
Display.setDisplayMode(new DisplayMode(w, h));
Display.setVSyncEnabled(true);
Display.setTitle("Shader Setup");
Display.create();
}catch(Exception e){
System.out.println("Error setting up display");
System.exit(0);
}
GL11.glViewport(0,0,w,h);
GL11.glMatrixMode(GL11.GL_PROJECTION);
GL11.glLoadIdentity();
GLU.gluPerspective(45.0f, ((float)w/(float)h),0.1f,100.0f);
GL11.glMatrixMode(GL11.GL_MODELVIEW);
GL11.glLoadIdentity();
GL11.glShadeModel(GL11.GL_SMOOTH);
GL11.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
GL11.glClearDepth(1.0f);
GL11.glEnable(GL11.GL_DEPTH_TEST);
GL11.glDepthFunc(GL11.GL_LEQUAL);
GL11.glHint(GL11.GL_PERSPECTIVE_CORRECTION_HINT,
GL11.GL_NICEST);
box = new Box();
}
public static void main(String[] args){
new GLSLTest();
}
}
這是Box類的代碼:
import org.lwjgl.opengl.GL11;
import java.io.BufferedReader;
import java.io.FileReader;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.ARBShaderObjects;
import org.lwjgl.opengl.ARBVertexShader;
import org.lwjgl.opengl.ARBFragmentShader;
import org.lwjgl.opengl.Util;
/**
* The vertex and fragment shaders are setup when the box object is
* constructed. They are applied to the GL state prior to the box
* being drawn, and released from that state after drawing.
* @author Stephen Jones
*/
public class Box {
/*
* if the shaders are setup ok we can use shaders, otherwise we just
* use default settings
*/
private boolean useShader=true;
/*
* program shader, to which is attached a vertex and fragment shaders.
* They are set to 0 as a check because GL will assign unique int
* values to each
*/
private int shader=0;
private int vertShader=0;
private int fragShader=0;
public Box(){
/*
* create the shader program. If OK, create vertex
* and fragment shaders
*/
shader=ARBShaderObjects.glCreateProgramObjectARB();
if(shader!=0){
vertShader=createVertShader("screen.vert");
fragShader=createFragShader("screen.frag");
}
else useShader=false;
/*
* if the vertex and fragment shaders setup sucessfully,
* attach them to the shader program, link the sahder program
* (into the GL context I suppose), and validate
*/
if(vertShader !=0 && fragShader !=0){
ARBShaderObjects.glAttachObjectARB(shader, vertShader);
ARBShaderObjects.glAttachObjectARB(shader, fragShader);
ARBShaderObjects.glLinkProgramARB(shader);
ARBShaderObjects.glValidateProgramARB(shader);
useShader=printLogInfo(shader);
}else useShader=false;
}
/*
* If the shader was setup succesfully, we use the shader. Otherwise
* we run normal drawing code.
*/
public void draw(){
if(useShader) {
ARBShaderObjects.glUseProgramObjectARB(shader);
}
GL11.glLoadIdentity();
GL11.glTranslatef(0.0f, 0.0f, -10.0f);
GL11.glColor3f(1.0f, 1.0f, 1.0f);//white
GL11.glBegin(GL11.GL_QUADS);
GL11.glVertex3f(-1.0f, 1.0f, 0.0f);
GL11.glVertex3f(1.0f, 1.0f, 0.0f);
GL11.glVertex3f(1.0f, -1.0f, 0.0f);
GL11.glVertex3f(-1.0f, -1.0f, 0.0f);
GL11.glEnd();
//release the shader
ARBShaderObjects.glUseProgramObjectARB(0);
}
/*
* With the exception of syntax, setting up vertex and fragment shaders
* is the same.
* @param the name and path to the vertex shader
*/
private int createVertShader(String filename){
//vertShader will be non zero if succefully created
vertShader=ARBShaderObjects.glCreateShaderObjectARB(ARBVertexShader.GL_VERTEX_SHADER_ARB);
//if created, convert the vertex shader code to a String
if(vertShader==0){return 0;}
String vertexCode="";
String line;
try{
BufferedReader reader=new BufferedReader(new FileReader(filename));
while((line=reader.readLine())!=null){
vertexCode+=line + "\n";
}
}catch(Exception e){
System.out.println("Fail reading vertex shading code");
return 0;
}
/*
* associate the vertex code String with the created vertex shader
* and compile
*/
ARBShaderObjects.glShaderSourceARB(vertShader, vertexCode);
ARBShaderObjects.glCompileShaderARB(vertShader);
//if there was a problem compiling, reset vertShader to zero
if(!printLogInfo(vertShader)){
vertShader=0;
}
//if zero we won't be using the shader
return vertShader;
}
//same as per the vertex shader except for method syntax
private int createFragShader(String filename){
fragShader=ARBShaderObjects.glCreateShaderObjectARB(ARBFragmentShader.GL_FRAGMENT_SHADER_ARB);
if(fragShader==0){return 0;}
String fragCode="";
String line;
try{
BufferedReader reader=new BufferedReader(new FileReader(filename));
while((line=reader.readLine())!=null){
fragCode+=line + "\n";
}
}catch(Exception e){
System.out.println("Fail reading fragment shading code");
return 0;
}
ARBShaderObjects.glShaderSourceARB(fragShader, fragCode);
ARBShaderObjects.glCompileShaderARB(fragShader);
if(!printLogInfo(fragShader)){
fragShader=0;
}
return fragShader;
}
private static boolean printLogInfo(int obj){
IntBuffer iVal = BufferUtils.createIntBuffer(1);
ARBShaderObjects.glGetObjectParameterARB(obj,
ARBShaderObjects.GL_OBJECT_INFO_LOG_LENGTH_ARB, iVal);
int length = iVal.get();
if (length > 1) {
// We have some info we need to output.
ByteBuffer infoLog = BufferUtils.createByteBuffer(length);
iVal.flip();
ARBShaderObjects.glGetInfoLogARB(obj, iVal, infoLog);
byte[] infoBytes = new byte[length];
infoLog.get(infoBytes);
String out = new String(infoBytes);
System.out.println("Info log:\n"+out);
}
else return true;
return false;
}
}
這是片段着色器的代碼
varying vec4 vertColor;
void main(){
gl_FragColor = vertColor;
}
和頂點着色器:
varying vec4 vertColor;
void main(){
gl_Position = gl_ModelViewProjectionMatrix*gl_Vertex;
vertColor = vec4(0.6, 0.3, 0.4, 1.0);
}
這是我運行代碼時得到的輸出:
Info log:
Vertex shader was successfully compiled to run on hardware.
Info log:
Fragment shader was successfully compiled to run on hardware.
這是屏幕截圖: http : //dl.dropbox.com/u/28109593/glslss.png
該問題是由於您實際上在Info日志中看不到任何東西,即它在成功時產生一條消息,這是某些OpenGL驅動程序傾向於這樣做的方式。 printLogInfo還將作為驗證函數加倍,如果有任何日志信息,則返回false,這告訴createVertShader和createFragShader將完美的着色器ID歸零,並返回失敗。 出於這樣的原因,它實際上根本不是一個好的設計(而且我知道它是來自其他人的,所以我知道我不會親自給你排渣:)
此程序的一個快速解決方法是僅使printLogInfo始終返回true。 您最終要做的是使用glGetShader(id,param)檢查返回狀態,如下所示:
glCompileShader(obj)
if (glGetShader(obj, GL_COMPILE_STATUS) == GL_FALSE
... handle error here ...
然后進行鏈接和驗證:
glLinkProgram(obj)
if (glGetProgram(obj, GL_LINK_STATUS) == GL_FALSE
... handle error here ...
glValidateProgram(obj)
if (glGetProgram(obj, GL_VALIDATE_STATUS) == GL_FALSE
... handle error here ...
抱歉,我不知道這些的ARB_ *等效項,但是您可能應該使用OpenGL 2.0 API而不是ARB擴展來實現這一基本功能。 仍然僅支持着色器作為擴展的任何內容可能都不值得進行着色器。
着色器正在執行應做的工作。
不要像在視頻游戲中聽到的那樣考慮着色器,着色器只是直接訪問GPU的一種方式。
之所以沒有看到顏色差異,是因為沒有輸出顏色,請嘗試更改在片段着色器中為gl_fragColor
設置的gl_fragColor
。
如果您需要有關着色器驅動的opengl的更多信息,建議您看一下在線書
如果您搜索該標題,它應該是第一個結果。
希望這可以幫助!
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.