Question

基本上当我渲染到纹理时，看起来纹理的某些部分丢失了。

package org.yourorghere;

import com.jogamp.opengl.util.GLBuffers;
import java.awt.Component;
import java.nio.ByteBuffer;
import javax.media.opengl.*;
import javax.media.opengl.glu.GLU;


public class GLRenderer implements GLEventListener {

int[] textureID = new int[1];
private int floorWidth=48, floorHeight=48;
int[] frameBufferID = new int[1];
int[] depthRenderBufferID = new int[1];
ByteBuffer pixels;
GLU glu;

public void init(GLAutoDrawable drawable) {
    glu = new GLU();

    System.out.println("init");

    GL2 gl = drawable.getGL().getGL2();
    System.err.println("INIT GL IS: " + gl.getClass().getName());

    // Setup the drawing area and shading mode
    gl.glShadeModel(GL2.GL_SMOOTH); // try setting this to GL_FLAT and see what happens.

    renderShadowsToTexture(gl);

    gl.glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
}

public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
}

public void display(GLAutoDrawable drawable) {
    GL2 gl = drawable.getGL().getGL2();

    System.out.println("display");

    float a = 1.0f;

    gl.glMatrixMode(GL2.GL_PROJECTION);
    // Reset the current matrix to the "identity"
    gl.glLoadIdentity();
    glu.gluPerspective(60.0f, (((Component)drawable).getWidth()/
            ((Component)drawable).getHeight()), 1.0f, 50.0f);

    gl.glMatrixMode(GL2.GL_MODELVIEW);
    gl.glLoadIdentity();
    glu.gluLookAt(0.0f, 0.0f, 0.0f, 
                  0.0f, 0.0f, 1.0f, 
                  0.0f, 1.0f, 0.0f);

    // Clear the drawing area
    gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT);

    gl.glTranslatef(-2.5f, 0.0f, 0.0f);

    gl.glEnable(GL2.GL_TEXTURE_2D);

    gl.glBindTexture(GL2.GL_TEXTURE_2D, textureID[0]);

        gl.glColor3f(1.0f, 1.0f, 1.0f);
        gl.glBegin(GL2.GL_QUADS);
            gl.glTexCoord2f(0, 0);
            gl.glVertex3f(-1.0f,-1.0f, 0.0f);
            gl.glTexCoord2f(0, a);
            gl.glVertex3f(-1.0f, 1.0f, 0.0f);
            gl.glTexCoord2f(1.0f, 1.0f);
            gl.glVertex3f( 1.0f, 1.0f, 0.0f);
            gl.glTexCoord2f(a, 0);
            gl.glVertex3f( 1.0f,-1.0f, 0.0f);
        gl.glEnd();
    gl.glDisable(GL2.GL_TEXTURE_2D);

    gl.glRasterPos2d(3, -2);
    gl.glDrawPixels(floorWidth, floorHeight, GL2.GL_RGBA, GL2.GL_UNSIGNED_BYTE, pixels);

}

private void renderShadowsToTexture(GL2 gl) {
    gl.glGenTextures(1, textureID, 0);
    gl.glBindTexture(GL2.GL_TEXTURE_2D, textureID[0]);

    gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_MIN_FILTER, GL2.GL_NEAREST);
    gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_MAG_FILTER, GL2.GL_NEAREST);

    // null means reserve texture memory, but texels are undefined
    gl.glTexImage2D(GL2.GL_TEXTURE_2D, 0, GL2.GL_RGB, floorWidth, floorHeight,
                                                0, GL2.GL_RGB, GL2.GL_FLOAT, null);

    gl.glGenFramebuffers(1, frameBufferID, 0);
    gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, frameBufferID[0]);

    //Attach 2D texture to this FBO
    gl.glFramebufferTexture2D(GL2.GL_FRAMEBUFFER, GL2.GL_COLOR_ATTACHMENT0, 
                                    GL2.GL_TEXTURE_2D, textureID[0], 0);

    // depth buffer
    gl.glGenRenderbuffers(1, depthRenderBufferID, 0);
    gl.glBindRenderbuffer(GL2.GL_RENDERBUFFER, depthRenderBufferID[0]);
    gl.glRenderbufferStorage(GL2.GL_RENDERBUFFER, GL2.GL_DEPTH_COMPONENT, 
                                            floorWidth, floorHeight);
    gl.glFramebufferRenderbuffer(GL2.GL_FRAMEBUFFER, GL2.GL_DEPTH_ATTACHMENT,
                                        GL2.GL_RENDERBUFFER, depthRenderBufferID[0]);

    if(gl.glCheckFramebufferStatus(GL2.GL_FRAMEBUFFER) == GL2.GL_FRAMEBUFFER_COMPLETE)
        System.out.println("[Viewer] GL_FRAMEBUFFER_COMPLETE!!");
    else
        System.out.println("..cazzo ^^");

    gl.glMatrixMode(GL2.GL_MODELVIEW);
    gl.glPushMatrix();
    gl.glLoadIdentity();

    gl.glClearColor(0.9f, 0.9f, 0.9f, 1.0f);
    gl.glClear(GL2.GL_COLOR_BUFFER_BIT);

    gl.glPointSize(10.0f);
    gl.glBegin(GL2.GL_POINTS);
        gl.glColor3f(0.0f, 1.0f, 0.0f);
        gl.glVertex2d(1.0f, 1.0f);        // THIS IS NOT SHOWN
        gl.glColor3f(0.0f, 0.0f, 1.0f);
        gl.glVertex2d(-1.0f, -1.0f);
        gl.glVertex2d(-0.9f, -0.9f);
    gl.glEnd();

    gl.glPopMatrix();

    pixels = GLBuffers.newDirectByteBuffer(floorWidth*floorHeight*4);

    gl.glReadPixels(0, 0, floorWidth, floorHeight, GL2.GL_RGBA, 
                                                GL2.GL_UNSIGNED_BYTE, pixels);


    System.out.println("glIsTexture: "+gl.glIsTexture(textureID[0]));

    //  bind the back buffer for rendering
    gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, 0);
}

public void dispose(GLAutoDrawable glad) {
//        throw new UnsupportedOperationException("Not supported yet.");
        System.out.println("dispose");
    }

}

从左侧开始，使用display()正常渲染三角形和第一个四边形，而右侧的最后一个四边形和下面的四个分别是渲染的四边形，其上映射的纹理和四边形显示什么是纹理本身。

基本上我没有看到红点，只看到蓝点。为什么？

enter image description here

Answer 1

我不熟悉这个特定的OpenGL包装器，但我注意到你的代码是在renderShadowsToTexture中你没有配置两件事：视口和投影矩阵。这两个都会影响结果图像的缩放。

投影矩阵可能是单位矩阵（因为你还没有运行gluPerspective），这对你正在使用的坐标是合理的。但是为了清晰和稳健（可能还有pushMatrix / popMatrix），将它明确地设置为你想要的东西仍然是一个好习惯。

但我看不到你的代码在哪里配置视口？也许JOGL为你做到了这一点？如果是这样，它将是窗口的大小，而不是纹理的大小。这个太大的视口会导致场景的某些部分在高坐标末端被切断，这与您看到的纹理一致（请注意，第二个蓝点应该非常接近第一个蓝点但显示远处远）。因此，您需要添加到renderShadowsToTexture：

glViewport(0, 0, floorWidth, floorHeight)

可能会在之后恢复（或使用glPushAttrib的{{1}} / glPopAttrib。

此外，颜色组件为红绿蓝色，因此缺少的点将为绿色，而不是红色。

Answer 2

根据Kevin Reid的回答（感谢他），我修改了renderShadowsToTexture(GL2 gl)，这对我来说非常有用。我只想在下面与新人分享。

private void renderShadowsToTexture(GL2 gl) {

    gl.glGenTextures(1, textureID, 0);
    gl.glBindTexture(GL2.GL_TEXTURE_2D, textureID[0]);

    gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_MIN_FILTER,
            GL2.GL_NEAREST);
    gl.glTexParameteri(GL2.GL_TEXTURE_2D, GL2.GL_TEXTURE_MAG_FILTER,
            GL2.GL_NEAREST);

    // null means reserve texture memory, but texels are undefined
    gl.glTexImage2D(GL2.GL_TEXTURE_2D, 0, GL2.GL_RGB, floorWidth,
            floorHeight, 0, GL2.GL_RGB, GL2.GL_FLOAT, null);

    gl.glGenFramebuffers(1, frameBufferID, 0);
    gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, frameBufferID[0]);

    // Attach 2D texture to this FBO
    gl.glFramebufferTexture2D(GL2.GL_FRAMEBUFFER, GL2.GL_COLOR_ATTACHMENT0,
            GL2.GL_TEXTURE_2D, textureID[0], 0);

    // depth buffer
    gl.glGenRenderbuffers(1, depthRenderBufferID, 0);
    gl.glBindRenderbuffer(GL2.GL_RENDERBUFFER, depthRenderBufferID[0]);
    gl.glRenderbufferStorage(GL2.GL_RENDERBUFFER, GL2.GL_DEPTH_COMPONENT,
            floorWidth, floorHeight);
    gl.glFramebufferRenderbuffer(GL2.GL_FRAMEBUFFER,
            GL2.GL_DEPTH_ATTACHMENT, GL2.GL_RENDERBUFFER,
            depthRenderBufferID[0]);

    if (gl.glCheckFramebufferStatus(GL2.GL_FRAMEBUFFER) == GL2.GL_FRAMEBUFFER_COMPLETE)
        System.out.println("[Viewer] GL_FRAMEBUFFER_COMPLETE!!");
    else
        System.out.println("..cazzo ^^");

    gl.glViewport(0, 0, floorWidth, floorHeight);

    gl.glMatrixMode(GL2.GL_PROJECTION);
    gl.glLoadIdentity();
    gl.glOrthof(0, floorWidth, 0, floorHeight, -10, 10);

    gl.glMatrixMode(GL2.GL_MODELVIEW);
    gl.glPushMatrix();
    gl.glLoadIdentity();

    gl.glClearColor(0.9f, 0.9f, 0.9f, 1.0f);
    gl.glClear(GL2.GL_COLOR_BUFFER_BIT);

    gl.glPointSize(10.0f);
    gl.glBegin(GL2.GL_POINTS);
    gl.glColor3f(0.0f, 1.0f, 0.0f);
    gl.glVertex2d(20.0f, 32.0f); // THIS IS NOT SHOWN

    gl.glColor3f(0.0f, 0.0f, 1.0f);
    gl.glVertex2d(20.0f, 10.0f);
    gl.glVertex2d(0.9f, 0.9f);

    gl.glEnd();

    gl.glPopMatrix();

    pixels = GLBuffers.newDirectByteBuffer(floorWidth * floorHeight * 4);

    gl.glReadPixels(0, 0, floorWidth, floorHeight, GL2.GL_RGBA,
            GL2.GL_UNSIGNED_BYTE, pixels);

    System.out.println("glIsTexture: " + gl.glIsTexture(textureID[0]));

    // bind the back buffer for rendering
    gl.glBindFramebuffer(GL2.GL_FRAMEBUFFER, 0);

}

渲染到纹理，纹理未完全显示

2 个答案: