Question

首先，我要说我很抱歉今天提出这么多问题。所以，我有一个圆圈课。我有一个带有3个圆形实例的arraylist，每个实例都有一个不同的x坐标来绘制。无论出于何种原因，OpenGL ES 2.0只绘制其中一个，即使我将所有这些都称为绘制。我查看了我的代码几个小时并尝试了很多不同的东西，但无济于事。所以，我的问题是：为了让OpenGL ES 2.0绘制多个对象，我有什么特别之处吗？这是我的代码（我知道它是一团糟。我稍后会修复:)）：这是我的GLCircle课程：

package com.background.gl.objects;
import static android.opengl.GLES20.GL_TRIANGLE_FAN;
import static android.opengl.GLES20.glDrawArrays;
import static android.opengl.Matrix.multiplyMM;
import static android.opengl.Matrix.setIdentityM;
import static android.opengl.Matrix.translateM;
import static com.background.gl.glcirclebackgroundanimation.Constants.BYTES_PER_FLOAT;

import java.util.Random;

import android.opengl.Matrix;

import com.background.gl.data.VertexArray;
import com.background.gl.helper.TextureShaderProgram;

public class GLCircle {
    private static final int POSITION_COMPONENT_COUNT = 2;
    private static final int TEXTURE_COORDINATES_COMPONENT_COUNT = 2;
    private static final int STRIDE = (POSITION_COMPONENT_COUNT
    + TEXTURE_COORDINATES_COMPONENT_COUNT) * BYTES_PER_FLOAT;

    public  float x;
    public  float y;
    protected  float[] wallBounds;
    protected  boolean positiveX, positiveY;
    public  boolean nullify;
    protected  float xCounter = 0f;
    protected  float yCounter = 0f;
    public  float[] bounds;
    protected Random ran;

    private float[] VERTEX_DATA = {
        // Order of coordinates: X, Y, S, T
        // Triangle Fan
        0f, 0f, 0.5f, 0.5f,
        -0.25f, -0.25f, 0f, 0.9f,
        0.25f, -0.25f, 1f, 0.9f,
        0.25f, 0.25f, 1f, 0.1f,
        -0.25f, 0.25f, 0f, 0.1f,
        -0.25f, -0.25f, 0f, 0.9f };

    private final VertexArray vertexArray;

    public GLCircle(float x, float y) {
        vertexArray = new VertexArray(VERTEX_DATA);
        ran = new Random();
        wallBounds = new float[4];
        nullify = false;
        this.x = x;
        this.y = y;
    }

    public void bindData(TextureShaderProgram textureProgram) {
        //Bind the position data to the shader attribute
        vertexArray.setVertexAttribPointer(
            0,
            textureProgram.getPositionAttributeLocation(),
            POSITION_COMPONENT_COUNT,
            STRIDE);
        //Bind the texture coordinate data to the shader attribute
        vertexArray.setVertexAttribPointer(
                POSITION_COMPONENT_COUNT,
                textureProgram.getTextureCoordinatesAttributeLocation(),
                TEXTURE_COORDINATES_COMPONENT_COUNT,
                STRIDE);
        }

    public void drawCircle() {
        glDrawArrays(GL_TRIANGLE_FAN, 0, 6);
    }


    public float getX() {
        return this.x;
    }

    public float getY() {
        return this.y;
    }



    public  boolean isPositiveX() {
        return positiveX;
    }



    public  boolean isPositiveY() {
        return positiveY;
    }


    public float[] getBounds(float ranX, float ranY) {
        if(!positiveX) {
            /*if(ranX >= 0f) {
                wallBounds[0] = 1.05f + ranX;
            } else {*/
                this.wallBounds[0] = 1.05f + ranX;
            //}
        } else {
            /*
            if(ranX >= 0f) {
                wallBounds[0] = 1.05f - ranX;
            } else {*/
                this.wallBounds[1] = 1.05f - ranX;
            //}
        }
        if(!positiveY) {
            this.wallBounds[2] = 1.75f + ranY;
        } else {
            this.wallBounds[3] = 1.75f - ranY;
        }

        return this.wallBounds;
    }

    public void setPos(float[] modelMatrix, 
            float[] projectionMatrix, TextureShaderProgram textureProgram,
            int texture, float x, float y) {
        setIdentityM(modelMatrix, 0);
        translateM(modelMatrix, 0, 0f, 0.01f, 0f);
        final float[] temp = new float[16];
        multiplyMM(temp, 0, projectionMatrix, 0, modelMatrix, 0);
        System.arraycopy(temp, 0, projectionMatrix, 0, temp.length);

        textureProgram.useProgram();
        textureProgram.setUniforms(projectionMatrix, texture);
        bindData(textureProgram);

        drawCircle();
    }

public void scaleCircle(float[] modelMatrix, float x, float y, float z) {
        Matrix.scaleM(modelMatrix, 0, x, y, z);
    }


    public void translateCircle(float x, float[] modelMatrix) {
        translateM(modelMatrix, 0, /*-0.001f*/ x, -3f, -2f);
    }

}

所以在我的渲染器类中，这就是我在onSurfaceCreated（）中实例化这些对象（我知道我会调用generateRanFloats两次并通过这样做浪费内存）：

for(int i = 0; i < 3; i++) {
            GLCircle circle = new GLCircle(generateRanFloats()[0], generateRanFloats()[1]);
            circles.add(circle);
}

所以我创建了三个对象。现在，我将每个圆圈转换为onSurfaceChanged方法中的x位置：

for(int i = 0; i < circles.size(); i++) {
            circles.get(i).translateCircle(circles.get(i).x, modelMatrix);
}

然后我在onDrawFrame（）方法中更新它们：

circles.get(i).setPos(modelMatrix, projectionMatrix, textureProgram, texture, circles.get(i).x, circles.get(i).y);

现在，问题是我只看到我的一个圈子在屏幕上翻译，当我应该有三个。据我所知，我应该能够在屏幕上绘制多个对象。那么为什么只有一个被吸引？我还尝试添加一个名为circle2的单独的GLCircle对象，并对此做了同样的事情，但它也没有显示出来。我需要做些什么才能在屏幕上绘制多个对象？任何帮助表示赞赏，如果您需要查看更多代码，请告诉我们。 :)

编辑：整个渲染器类

package com.background.gl.glcirclebackgroundanimation;

import static android.opengl.GLES20.GL_COLOR_BUFFER_BIT;
import static android.opengl.GLES20.glClear;
import static android.opengl.GLES20.glClearColor;
import static android.opengl.GLES20.glViewport;
import static android.opengl.Matrix.multiplyMM;
import static android.opengl.Matrix.setIdentityM;
import static android.opengl.Matrix.translateM;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import android.content.Context;
import android.opengl.GLSurfaceView.Renderer;
import android.util.Log;

import com.background.gl.helper.TextureShaderProgram;
import com.background.gl.objects.GLCircle;
import com.background.gl.objects.Mallet;
import com.background.gl.objects.Table;
import com.background.gl.util.MatrixHelper;
import com.background.gl.util.TextureHelper;

public class CircleDynamicBackgroundRenderer implements Renderer {
private final Context context;

    private final float[] projectionMatrix = new float[16];
    private final float[] modelMatrix = new float[16];
    protected static float ranX, ranY, ranSignX, ranSignY, ranSignVeloX, ranSignVeloY;

    private Table table;
    private Mallet mallet;
    private List<GLCircle> circles;
    private GLCircle circle2;
    float xPos, yPos;
    int x = 1;
    float[] bounds;
    Random ran;

    private TextureShaderProgram textureProgram;

    private int texture;


    public CircleDynamicBackgroundRenderer(Context context) {
        this.context = context;
        circles = new ArrayList<GLCircle>();
        xPos = 0.1f;
        ran = new Random();
    }

    @Override
    public void onSurfaceChanged(GL10 glUnused, int width, int height) {
        glViewport(0, 0, width, height);
        Log.w("Width and height", Integer.toString(width) + ", " + Integer.toString(height));
        MatrixHelper.perspectiveM(projectionMatrix, 90, (float) width
                / (float) height, 1f, 10f);

        setIdentityM(modelMatrix, 0);
        for(int i = 0; i < circles.size(); i++) {
            circles.get(i).translateCircle(circles.get(i).x, modelMatrix);
        }
        circle2.translateCircle(circle2.x, modelMatrix);
        final float[] temp = new float[16];
        multiplyMM(temp, 0, projectionMatrix, 0, modelMatrix, 0);
        System.arraycopy(temp, 0, projectionMatrix, 0, temp.length);
    }

    @Override
    public void onSurfaceCreated(GL10 glUnused, EGLConfig config) {
        glClearColor(0.0f, 0.0f, 1.0f, 0.0f);

        table = new Table();
        mallet = new Mallet();

        textureProgram = new TextureShaderProgram(context);

        texture = TextureHelper.loadTexture(context, R.drawable.air_hockey_surface);
        //texture2 = TextureHelper.loadTexture(context, R.drawable.air_hockey_surface_2);
        for(int i = 0; i < 3; i++) {
            GLCircle circle = new GLCircle(generateRanFloats()[0], generateRanFloats()[1]);
            circles.add(circle);
            /*circle[i].x = circle[i].getX();
            circle[i].y = circle[i].getY();
            circle[i].bounds = circle[i].getBounds();*/
        }
            circle2 = new GLCircle(generateRanFloats()[0], generateRanFloats()[1]);
        Log.d("Circles size", Integer.toString(circles.size()));
        Log.d("circles", Float.toString(circles.get(1).getX()) + " " + Float.toString(circles.get(2).getX()));
    }

    @Override
    public void onDrawFrame(GL10 glUnused) {
        //Clear the rendering surface
        glClear(GL_COLOR_BUFFER_BIT);
        for(int i = 0; i < circles.size(); i++) {
        circles.get(i).setPos(modelMatrix, projectionMatrix, textureProgram, texture, circles.get(i).x, circles.get(i).y);
        Log.d("Circles", Float.toString(circles.get(i).x));
        }

        circle2.setPos(modelMatrix, projectionMatrix, textureProgram, texture, ranSignVeloX, circle2.x);
        Log.d("Circle2", Float.toString(circle2.x));


        //Pass data into our shaders(u_matrix) and enable/bind the texture
        //textureProgram.setUniforms2(projectionMatrix, texture, texture2);
        //Bind our [vertex array] data to our shaders(attribute data)
        //Draw it
        /*
        // Draw the mallets.
        colorProgram.useProgram();
        colorProgram.setUniforms(projectionMatrix);
        mallet.bindData(colorProgram);
        mallet.draw();*/
    }

    public float[] generateRanFloats() {
        ranSignX = ran.nextFloat();
        ranSignY = ran.nextFloat();
        ranSignX = ranSignX > 0.5f? -1:1;
        ranSignY = ranSignY > 0.5f? -1:1;
        ranSignVeloX = ran.nextFloat();
        ranSignVeloY = ran.nextFloat();
        ranX = ran.nextFloat() * 1.05f;
        ranY = ran.nextFloat() * 1.75f;  
        ranX = ranSignX > 0.5? -ranX:ranX;
        ranY = ranSignY > 0.5? -ranY:ranY;
        Log.d("Generated", Float.toString(ranX));
        return new float[] {ranX, ranY};
    }

}

Answer 1

public void drawCircle（）{             glDrawArrays（GL_TRIANGLE_FAN，0,6）;         }

以上代码吸引了一位粉丝。其余的代码在哪里？

如果你在循环中调用它，setPos()中发生的翻译在哪里 - 因为x，y似乎没有在任何地方使用，translateM(modelMatrix, 0, 0f, 0.01f, 0f)总是转换相同的偏移。

Answer 2

可能有点晚了，但是......

对我而言，似乎所有的圆圈都被绘制了，但它们是相互叠加的，因为translateM没有被应用。

您正在从onSurfaceChanged调用translateCircle。

但是在OnDrawFrame中，您通过调用setIdentityM来恢复模型矩阵。

setIdentityM(modelMatrix, 0);
translateM(modelMatrix, 0, 0f, 0.01f, 0f);
final float[] temp = new float[16];
multiplyMM(temp, 0, projectionMatrix, 0, modelMatrix, 0);
...

删除translateCircle并修改

translateM(modelMatrix, 0, 0f, 0.01f, 0f);

到

translateM(modelMatrix, 0, x, 0.01f, 0f);

应该有用。

OpenGL ES 2.0只绘制一次对象

2 个答案: