-1

我需要能够渲染到纹理,然后将该纹理绘制到全屏四边形。通过公然复制 lwjgl 教程,我能够制作一个带纹理的移动四边形,但我不能让它渲染到纹理:

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;

import org.lwjgl.BufferUtils;
import org.lwjgl.LWJGLException;
import org.lwjgl.input.Keyboard;
import org.lwjgl.opengl.ContextAttribs;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL12;
import org.lwjgl.opengl.GL13;
import org.lwjgl.opengl.GL15;
import org.lwjgl.opengl.GL20;
import org.lwjgl.opengl.GL30;
import org.lwjgl.opengl.GL32;
import org.lwjgl.opengl.PixelFormat;
import org.lwjgl.util.glu.GLU;
import org.lwjgl.util.vector.Matrix4f;
import org.lwjgl.util.vector.Vector3f;


import de.matthiasmann.twl.utils.PNGDecoder;
import de.matthiasmann.twl.utils.PNGDecoder.Format;

public class TheQuadExampleMovingFBO {
    // Entry point for the application
    public static void main(String[] args) {
        new TheQuadExampleMovingFBO();
    }

    // Setup variables
    private final String WINDOW_TITLE = "The Quad: Moving";
    private final int WIDTH = 320;
    private final int HEIGHT = 240;
    private final double PI = 3.14159265358979323846;
    // Frame Buffer variables
    private int fboID = 0;
    private int colID = 0;
    private int depID = 0;
    private IntBuffer drawBuffs;
    // Quad variables
    private int vaoId = 0;
    private int vboId = 0;
    private int vboiId = 0;
    private int indicesCount = 0;
    private VertexData[] vertices = null;
    private ByteBuffer verticesByteBuffer = null;
    // Shader variables
    private int vsId = 0;
    private int fsId = 0;
    private int pId = 0;
    // Texture variables
    private int[] texIds = new int[] {0, 0};
    private int textureSelector = 0;
    // Moving variables
    private int projectionMatrixLocation = 0;
    private int viewMatrixLocation = 0;
    private int modelMatrixLocation = 0;
    private Matrix4f projectionMatrix = null;
    private Matrix4f viewMatrix = null;
    private Matrix4f modelMatrix = null;
    private Vector3f modelPos = null;
    private Vector3f modelAngle = null;
    private Vector3f modelScale = null;
    private Vector3f cameraPos = null;
    private FloatBuffer matrix44Buffer = null;

    public TheQuadExampleMovingFBO() {
        // Initialize OpenGL (Display)
        this.setupOpenGL();

        this.setupQuad();
        this.setupShaders();
        this.setupTextures();
        this.setupMatrices();

        while (!Display.isCloseRequested()) {
            // Do a single loop (logic/render)
            this.loopCycle();

            // Force a maximum FPS of about 60
            Display.sync(60);
            // Let the CPU synchronize with the GPU if GPU is tagging behind
            Display.update();
        }

        // Destroy OpenGL (Display)
        this.destroyOpenGL();
    }

    private void setupMatrices() {
        // Setup projection matrix
        projectionMatrix = new Matrix4f();
        float fieldOfView = 60f;
        float aspectRatio = (float)WIDTH / (float)HEIGHT;
        float near_plane = 0.1f;
        float far_plane = 100f;

        float y_scale = this.coTangent(this.degreesToRadians(fieldOfView / 2f));
        float x_scale = y_scale / aspectRatio;
        float frustum_length = far_plane - near_plane;

        projectionMatrix.m00 = x_scale;
        projectionMatrix.m11 = y_scale;
        projectionMatrix.m22 = -((far_plane + near_plane) / frustum_length);
        projectionMatrix.m23 = -1;
        projectionMatrix.m32 = -((2 * near_plane * far_plane) / frustum_length);

        // Setup view matrix
        viewMatrix = new Matrix4f();

        // Setup model matrix
        modelMatrix = new Matrix4f();

        // Create a FloatBuffer with the proper size to store our matrices later
        matrix44Buffer = BufferUtils.createFloatBuffer(16);
    }

    private void setupTextures() {
        texIds[0] = this.loadPNGTexture("assets/images/stGrid1.png", GL13.GL_TEXTURE0);
        texIds[1] = this.loadPNGTexture("assets/images/stGrid2.png", GL13.GL_TEXTURE0);

        this.exitOnGLError("setupTexture");
    }

    private void setupOpenGL() {
        // Setup an OpenGL context with API version 3.2
        try {
            PixelFormat pixelFormat = new PixelFormat();
            ContextAttribs contextAtrributes = new ContextAttribs(3, 2);
            contextAtrributes.withForwardCompatible(true);
            contextAtrributes.withProfileCore(true);

            Display.setDisplayMode(new DisplayMode(WIDTH, HEIGHT));
            Display.setTitle(WINDOW_TITLE);
            Display.create(pixelFormat, contextAtrributes);

            GL11.glViewport(0, 0, WIDTH, HEIGHT);
        } catch (LWJGLException e) {
            e.printStackTrace();
            System.exit(-1);
        }

        // Setup an XNA like background color
        GL11.glClearColor(0.4f, 0.6f, 0.9f, 0f);

        // Map the internal OpenGL coordinate system to the entire screen
        GL11.glViewport(0, 0, WIDTH, HEIGHT);
        System.out.println(GL11.glGetString(GL11.GL_VERSION));
        this.exitOnGLError("setupOpenGL");
    }

    private void setupQuad() {
        // We'll define our quad using 4 vertices of the custom 'TexturedVertex' class
        VertexData v0 = new VertexData(); 
        v0.setXYZ(-0.5f, 0.5f, 0); v0.setRGB(1, 0, 0); v0.setST(0, 0);
        VertexData v1 = new VertexData(); 
        v1.setXYZ(-0.5f, -0.5f, 0); v1.setRGB(0, 1, 0); v1.setST(0, 1);
        VertexData v2 = new VertexData(); 
        v2.setXYZ(0.5f, -0.5f, 0); v2.setRGB(0, 0, 1); v2.setST(1, 1);
        VertexData v3 = new VertexData(); 
        v3.setXYZ(0.5f, 0.5f, 0); v3.setRGB(1, 1, 1); v3.setST(1, 0);

        vertices = new VertexData[] {v0, v1, v2, v3};

        // Put each 'Vertex' in one FloatBuffer
        verticesByteBuffer = BufferUtils.createByteBuffer(vertices.length * 
                VertexData.stride);             
        FloatBuffer verticesFloatBuffer = verticesByteBuffer.asFloatBuffer();
        for (int i = 0; i < vertices.length; i++) {
            // Add position, color and texture floats to the buffer
            verticesFloatBuffer.put(vertices[i].getElements());
        }
        verticesFloatBuffer.flip();


        // OpenGL expects to draw vertices in counter clockwise order by default
        byte[] indices = {
                0, 1, 2,
                2, 3, 0
        };
        indicesCount = indices.length;
        ByteBuffer indicesBuffer = BufferUtils.createByteBuffer(indicesCount);
        indicesBuffer.put(indices);
        indicesBuffer.flip();

        // Create a new Vertex Array Object in memory and select it (bind)
        vaoId = GL30.glGenVertexArrays();
        GL30.glBindVertexArray(vaoId);

        // Create a new Vertex Buffer Object in memory and select it (bind)
        vboId = GL15.glGenBuffers();
        GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vboId);
        GL15.glBufferData(GL15.GL_ARRAY_BUFFER, verticesFloatBuffer, GL15.GL_STREAM_DRAW);

        // Put the position coordinates in attribute list 0
        GL20.glVertexAttribPointer(0, VertexData.positionElementCount, GL11.GL_FLOAT, 
                false, VertexData.stride, VertexData.positionByteOffset);
        // Put the color components in attribute list 1
        GL20.glVertexAttribPointer(1, VertexData.colorElementCount, GL11.GL_FLOAT, 
                false, VertexData.stride, VertexData.colorByteOffset);
        // Put the texture coordinates in attribute list 2
        GL20.glVertexAttribPointer(2, VertexData.textureElementCount, GL11.GL_FLOAT, 
                false, VertexData.stride, VertexData.textureByteOffset);

        GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);

        // Deselect (bind to 0) the VAO
        GL30.glBindVertexArray(0);

        // Create a new VBO for the indices and select it (bind) - INDICES
        vboiId = GL15.glGenBuffers();
        GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, vboiId);
        GL15.glBufferData(GL15.GL_ELEMENT_ARRAY_BUFFER, indicesBuffer, 
                GL15.GL_STATIC_DRAW);
        GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);

        // Set the default quad rotation, scale and position values
        modelPos = new Vector3f(0, 0, 0);
        modelAngle = new Vector3f(0, 0, 0);
        modelScale = new Vector3f(1, 1, 1);
        cameraPos = new Vector3f(0, 0, 0);

        ////////// THIS IS WHERE I ADDED CODE FOR THE FRAMEBUFFER STUFF  //////////////

        //render to texture attempt
        fboID = GL30.glGenFramebuffers();
        GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, fboID);
        colID = GL11.glGenTextures();
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, colID);
        GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGB, WIDTH, HEIGHT, 0, GL11.GL_RGB, GL11.GL_UNSIGNED_BYTE, (ByteBuffer)null);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_NEAREST);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_NEAREST);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL12.GL_CLAMP_TO_EDGE);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_T, GL12.GL_CLAMP_TO_EDGE);
        depID = GL30.glGenRenderbuffers();
        GL30.glBindRenderbuffer(GL30.GL_RENDERBUFFER, depID);
        GL30.glRenderbufferStorage(GL30.GL_RENDERBUFFER, GL11.GL_DEPTH_COMPONENT, WIDTH, HEIGHT);
        GL30.glFramebufferRenderbuffer(GL30.GL_FRAMEBUFFER, GL30.GL_DEPTH_ATTACHMENT, GL30.GL_RENDERBUFFER, depID);
        GL32.glFramebufferTexture(GL30.GL_FRAMEBUFFER, GL30.GL_COLOR_ATTACHMENT0, colID, 0);
        drawBuffs = BufferUtils.createIntBuffer(1);
        drawBuffs.put(0, GL30.GL_COLOR_ATTACHMENT0);
        GL20.glDrawBuffers(drawBuffs);
        if(GL30.glCheckFramebufferStatus(GL30.GL_FRAMEBUFFER) != GL30.GL_FRAMEBUFFER_COMPLETE){
            System.out.println("Framebuffer not complete!");
        }else{ System.out.println("Framebuffer is complete!");}


        //////// END OF NEW CODE HERE, LOOK IN RENDER CYCLE FOR MORE NEW CODE ///////////

        this.exitOnGLError("setupQuad");
    }

    private void setupShaders() {       
        // Load the vertex shader
        vsId = this.loadShader("assets/shaders/moving/vertex.glsl", 
                GL20.GL_VERTEX_SHADER);
        // Load the fragment shader
        fsId = this.loadShader("assets/shaders/moving/fragment.glsl", 
                GL20.GL_FRAGMENT_SHADER);

        // Create a new shader program that links both shaders
        pId = GL20.glCreateProgram();
        GL20.glAttachShader(pId, vsId);
        GL20.glAttachShader(pId, fsId);
        GL20.glLinkProgram(pId);

        // Position information will be attribute 0
        GL20.glBindAttribLocation(pId, 0, "in_Position");
        // Color information will be attribute 1
        GL20.glBindAttribLocation(pId, 1, "in_Color");
        // Textute information will be attribute 2
        GL20.glBindAttribLocation(pId, 2, "in_TextureCoord");

        // Get matrices uniform locations
        projectionMatrixLocation = GL20.glGetUniformLocation(pId, "projectionMatrix");
        viewMatrixLocation = GL20.glGetUniformLocation(pId, "viewMatrix");
        modelMatrixLocation = GL20.glGetUniformLocation(pId, "modelMatrix");

        GL20.glValidateProgram(pId);

        this.exitOnGLError("setupShaders");
    }

    private void logicCycle() {
        //-- Input processing
        float rotationDelta = 15f;
        float scaleDelta = 0.1f;
        float posDelta = 0.1f;
        Vector3f scaleAddResolution = new Vector3f(scaleDelta, scaleDelta, scaleDelta);
        Vector3f scaleMinusResolution = new Vector3f(-scaleDelta, -scaleDelta, 
                -scaleDelta);

        while(Keyboard.next()) {            
            // Only listen to events where the key was pressed (down event)
            if (!Keyboard.getEventKeyState()) continue;

            // Switch textures depending on the key released
            switch (Keyboard.getEventKey()) {
            case Keyboard.KEY_1:
                textureSelector = 0;
                break;
            case Keyboard.KEY_2:
                textureSelector = 1;
                break;
            }

            // Change model scale, rotation and translation values
            switch (Keyboard.getEventKey()) {
            // Move
            case Keyboard.KEY_UP:
                modelPos.y += posDelta;
                break;
            case Keyboard.KEY_DOWN:
                modelPos.y -= posDelta;
                break;
            // Scale
            case Keyboard.KEY_P:
                Vector3f.add(modelScale, scaleAddResolution, modelScale);
                break;
            case Keyboard.KEY_M:
                Vector3f.add(modelScale, scaleMinusResolution, modelScale);
                break;
            // Rotation
            case Keyboard.KEY_LEFT:
                modelAngle.z += rotationDelta;
                break;
            case Keyboard.KEY_RIGHT:
                modelAngle.z -= rotationDelta;
                break;
            }
        }

        //-- Update matrices
        // Reset view and model matrices
        viewMatrix = new Matrix4f();
        modelMatrix = new Matrix4f();

        // Translate camera
        Matrix4f.translate(cameraPos, viewMatrix, viewMatrix);

        // Scale, translate and rotate model
        Matrix4f.scale(modelScale, modelMatrix, modelMatrix);
        Matrix4f.translate(modelPos, modelMatrix, modelMatrix);
        Matrix4f.rotate(this.degreesToRadians(modelAngle.z), new Vector3f(0, 0, 1), 
                modelMatrix, modelMatrix);
        Matrix4f.rotate(this.degreesToRadians(modelAngle.y), new Vector3f(0, 1, 0), 
                modelMatrix, modelMatrix);
        Matrix4f.rotate(this.degreesToRadians(modelAngle.x), new Vector3f(1, 0, 0), 
                modelMatrix, modelMatrix);

        // Upload matrices to the uniform variables
        GL20.glUseProgram(pId);

        projectionMatrix.store(matrix44Buffer); matrix44Buffer.flip();
        GL20.glUniformMatrix4(projectionMatrixLocation, false, matrix44Buffer);
        viewMatrix.store(matrix44Buffer); matrix44Buffer.flip();
        GL20.glUniformMatrix4(viewMatrixLocation, false, matrix44Buffer);
        modelMatrix.store(matrix44Buffer); matrix44Buffer.flip();
        GL20.glUniformMatrix4(modelMatrixLocation, false, matrix44Buffer);

        GL20.glUseProgram(0);

        this.exitOnGLError("logicCycle");
    }

    private void renderCycle() {
        ////////// THESE LINES ARE NEW, ADDED TO RENDER TO THE FRAME BUFFER /////////
        GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, fboID);
        GL11.glViewport(0, 0, WIDTH, HEIGHT);
        ///////// THIS IS THE ORIGINAL RENDER CYCLE CODE, I WANT THIS TO GO TO THE FBO ///////
        GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);

        GL20.glUseProgram(pId);

        // Bind the texture
        GL13.glActiveTexture(GL13.GL_TEXTURE0);
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, texIds[textureSelector]);

        // Bind to the VAO that has all the information about the vertices
        GL30.glBindVertexArray(vaoId);
        GL20.glEnableVertexAttribArray(0);
        GL20.glEnableVertexAttribArray(1);
        GL20.glEnableVertexAttribArray(2);

        // Bind to the index VBO that has all the information about the order of the vertices
        GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, vboiId);

        // Draw the vertices
        GL11.glDrawElements(GL11.GL_TRIANGLES, indicesCount, GL11.GL_UNSIGNED_BYTE, 0);

        // Put everything back to default (deselect)
        GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);
        GL20.glDisableVertexAttribArray(0);
        GL20.glDisableVertexAttribArray(1);
        GL20.glDisableVertexAttribArray(2);
        GL30.glBindVertexArray(0);

        GL20.glUseProgram(0);


        //////// NEW CODE, I WANT TO DRAW A FULL SCREEN QUAD WITH THE TEXTURE FROM THE FBO ///////
        // draw the texture from the FBO
        GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, 0);
        GL11.glViewport(0, 0, WIDTH, HEIGHT);
        GL11.glBegin(GL11.GL_QUADS);
            GL11.glTexCoord2f(0.0f, 0.0f); GL11.glVertex3f(0.0f, 0.0f, 0.0f);
            GL11.glTexCoord2f(1.0f, 0.0f); GL11.glVertex3f((float)WIDTH, 0.0f, 0.0f);
            GL11.glTexCoord2f(1.0f, 1.0f); GL11.glVertex3f((float)WIDTH, (float)HEIGHT, 0.0f);
            GL11.glTexCoord2f(0.0f, 1.0f); GL11.glVertex3f(0.0f, (float)HEIGHT, 0.0f);
        GL11.glEnd();
        ///////// END OF NEW CODE ///////////
        this.exitOnGLError("renderCycle");
    }

    private void loopCycle() {
        // Update logic
        this.logicCycle();
        // Update rendered frame
        this.renderCycle();

        this.exitOnGLError("loopCycle");
    }

    private void destroyOpenGL() {  
        // Delete the texture
        GL11.glDeleteTextures(texIds[0]);
        GL11.glDeleteTextures(texIds[1]);

        // Delete the shaders
        GL20.glUseProgram(0);
        GL20.glDetachShader(pId, vsId);
        GL20.glDetachShader(pId, fsId);

        GL20.glDeleteShader(vsId);
        GL20.glDeleteShader(fsId);
        GL20.glDeleteProgram(pId);

        // Select the VAO
        GL30.glBindVertexArray(vaoId);

        // Disable the VBO index from the VAO attributes list
        GL20.glDisableVertexAttribArray(0);
        GL20.glDisableVertexAttribArray(1);

        // Delete the vertex VBO
        GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);
        GL15.glDeleteBuffers(vboId);

        // Delete the index VBO
        GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);
        GL15.glDeleteBuffers(vboiId);

        // Delete the VAO
        GL30.glBindVertexArray(0);
        GL30.glDeleteVertexArrays(vaoId);

        this.exitOnGLError("destroyOpenGL");

        Display.destroy();
    }

    private int loadShader(String filename, int type) {
        StringBuilder shaderSource = new StringBuilder();
        int shaderID = 0;

        try {
            BufferedReader reader = new BufferedReader(new FileReader(filename));
            String line;
            while ((line = reader.readLine()) != null) {
                shaderSource.append(line).append("\n");
            }
            reader.close();
        } catch (IOException e) {
            System.err.println("Could not read file.");
            e.printStackTrace();
            System.exit(-1);
        }

        shaderID = GL20.glCreateShader(type);
        GL20.glShaderSource(shaderID, shaderSource);
        GL20.glCompileShader(shaderID);

        if (GL20.glGetShader(shaderID, GL20.GL_COMPILE_STATUS) == GL11.GL_FALSE) {
            System.err.println("Could not compile shader.");
            System.exit(-1);
        }

        this.exitOnGLError("loadShader");

        return shaderID;
    }

    private int loadPNGTexture(String filename, int textureUnit) {
        ByteBuffer buf = null;
        int tWidth = 0;
        int tHeight = 0;

        try {
            // Open the PNG file as an InputStream
            InputStream in = new FileInputStream(filename);
            // Link the PNG decoder to this stream
            PNGDecoder decoder = new PNGDecoder(in);

            // Get the width and height of the texture
            tWidth = decoder.getWidth();
            tHeight = decoder.getHeight();


            // Decode the PNG file in a ByteBuffer
            buf = ByteBuffer.allocateDirect(
                    4 * decoder.getWidth() * decoder.getHeight());
            decoder.decode(buf, decoder.getWidth() * 4, Format.RGBA);
            buf.flip();

            in.close();
        } catch (IOException e) {
            e.printStackTrace();
            System.exit(-1);
        }

        // Create a new texture object in memory and bind it
        int texId = GL11.glGenTextures();
        GL13.glActiveTexture(textureUnit);
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, texId);

        // All RGB bytes are aligned to each other and each component is 1 byte
        GL11.glPixelStorei(GL11.GL_UNPACK_ALIGNMENT, 1);

        // Upload the texture data and generate mip maps (for scaling)
        GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGB, tWidth, tHeight, 0, 
                GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, buf);
        GL30.glGenerateMipmap(GL11.GL_TEXTURE_2D);

        // Setup the ST coordinate system
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL11.GL_REPEAT);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_T, GL11.GL_REPEAT);

        // Setup what to do when the texture has to be scaled
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, 
                GL11.GL_LINEAR);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, 
                GL11.GL_LINEAR_MIPMAP_LINEAR);

        this.exitOnGLError("loadPNGTexture");

        return texId;
    }

    private float coTangent(float angle) {
        return (float)(1f / Math.tan(angle));
    }

    private float degreesToRadians(float degrees) {
        return degrees * (float)(PI / 180d);
    }

    private void exitOnGLError(String errorMessage) {
        int errorValue = GL11.glGetError();

        if (errorValue != GL11.GL_NO_ERROR) {
            String errorString = GLU.gluErrorString(errorValue);
            System.err.println("ERROR - " + errorMessage + ": " + errorString);

            if (Display.isCreated()) Display.destroy();
            System.exit(-1);
        }
    }
}

以下是我添加行以渲染到纹理的代码部分:

设置 FBO ////////// 这是我为帧缓冲区添加代码的地方 /////////////

    //render to texture attempt
    fboID = GL30.glGenFramebuffers();
    GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, fboID);
    colID = GL11.glGenTextures();
    GL11.glBindTexture(GL11.GL_TEXTURE_2D, colID);
    GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGB, WIDTH, HEIGHT, 0, GL11.GL_RGB, GL11.GL_UNSIGNED_BYTE, (ByteBuffer)null);
    GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_NEAREST);
    GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_NEAREST);
    GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL12.GL_CLAMP_TO_EDGE);
    GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_T, GL12.GL_CLAMP_TO_EDGE);
    depID = GL30.glGenRenderbuffers();
    GL30.glBindRenderbuffer(GL30.GL_RENDERBUFFER, depID);
    GL30.glRenderbufferStorage(GL30.GL_RENDERBUFFER, GL11.GL_DEPTH_COMPONENT, WIDTH, HEIGHT);
    GL30.glFramebufferRenderbuffer(GL30.GL_FRAMEBUFFER, GL30.GL_DEPTH_ATTACHMENT, GL30.GL_RENDERBUFFER, depID);
    GL32.glFramebufferTexture(GL30.GL_FRAMEBUFFER, GL30.GL_COLOR_ATTACHMENT0, colID, 0);
    drawBuffs = BufferUtils.createIntBuffer(1);
    drawBuffs.put(0, GL30.GL_COLOR_ATTACHMENT0);
    GL20.glDrawBuffers(drawBuffs);
    if(GL30.glCheckFramebufferStatus(GL30.GL_FRAMEBUFFER) != GL30.GL_FRAMEBUFFER_COMPLETE){
        System.out.println("Framebuffer not complete!");
    }else{ System.out.println("Framebuffer is complete!");}


    //////// END OF NEW CODE HERE, LOOK IN RENDER CYCLE FOR MORE NEW CODE ///////////

这是渲染代码: ////////// 这些行是新的,添加到渲染到帧缓冲区 ///////// GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, fboID); GL11.glViewport(0, 0, WIDTH, HEIGHT); ///////// 这是原始的渲染周期代码,我想把它放到 FBO /////// GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);

    GL20.glUseProgram(pId);

    // Bind the texture
    GL13.glActiveTexture(GL13.GL_TEXTURE0);
    GL11.glBindTexture(GL11.GL_TEXTURE_2D, texIds[textureSelector]);

    // Bind to the VAO that has all the information about the vertices
    GL30.glBindVertexArray(vaoId);
    GL20.glEnableVertexAttribArray(0);
    GL20.glEnableVertexAttribArray(1);
    GL20.glEnableVertexAttribArray(2);

    // Bind to the index VBO that has all the information about the order of the vertices
    GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, vboiId);

    // Draw the vertices
    GL11.glDrawElements(GL11.GL_TRIANGLES, indicesCount, GL11.GL_UNSIGNED_BYTE, 0);

    // Put everything back to default (deselect)
    GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);
    GL20.glDisableVertexAttribArray(0);
    GL20.glDisableVertexAttribArray(1);
    GL20.glDisableVertexAttribArray(2);
    GL30.glBindVertexArray(0);

    GL20.glUseProgram(0);


    //////// NEW CODE, I WANT TO DRAW A FULL SCREEN QUAD WITH THE TEXTURE FROM THE FBO ///////
    // draw the texture from the FBO
    GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, 0);
    GL11.glViewport(0, 0, WIDTH, HEIGHT);
    GL11.glBegin(GL11.GL_QUADS);
        GL11.glTexCoord2f(0.0f, 0.0f); GL11.glVertex3f(0.0f, 0.0f, 0.0f);
        GL11.glTexCoord2f(1.0f, 0.0f); GL11.glVertex3f((float)WIDTH, 0.0f, 0.0f);
        GL11.glTexCoord2f(1.0f, 1.0f); GL11.glVertex3f((float)WIDTH, (float)HEIGHT, 0.0f);
        GL11.glTexCoord2f(0.0f, 1.0f); GL11.glVertex3f(0.0f, (float)HEIGHT, 0.0f);
    GL11.glEnd();
    ///////// END OF NEW CODE ///////////

当我运行此代码时,我得到一个黑色矩形大约一秒钟,控制台告诉我帧缓冲区已完成,然后我得到一个关于渲染周期中无效操作的 openGL 错误,它崩溃了。我认为问题出在我的全屏四码代码中,但我不知道如何正确处理。我是否需要为渲染到屏幕创建新的着色器程序?我是否需要删除 glBegin(GL_QUADS) 并使用顶点缓冲区?

4

1 回答 1

2

在绑定 FBO 以进行绘图之前,您必须取消绑定 colID 纹理(否则您可能会同时读取和写入它)。

于 2012-10-07T09:44:42.847 回答