openGL es2.0 创建无盖颜色圆柱

绝地灬酷狼 2022-08-06 12:16 149阅读 0赞

一、Java代码：

package com.gzdxid.utils;
    
    import java.nio.ByteBuffer;
    import java.nio.ByteOrder;
    import java.nio.FloatBuffer;
    
    import android.opengl.GLES20;
    
    public class DrawCylinderSideColor {
    
    	int mProgram;
    	int muMVPMatrixHandle;
    	int maPositionHandle;
    	
    	int muColorRHandle;
    	int muColorGHandle;
    	int muColorBHandle;
    	int muColorAHandle;
    	
    	FloatBuffer mVertexBuffer;
    	int vCount = 0;
    	
    	final float UNIT_SIZE=0.5f;
    	final int n=24;
    	
    	public DrawCylinderSideColor(float r,float length,int mProgram) {
    		// TODO Auto-generated constructor stub
    		initVertex(r,length);
    		initShader(mProgram);
    	}
    
    	private void initVertex(float r, float h) {
    		// TODO Auto-generated method stub
    		vCount=6*n;
    		r=r*UNIT_SIZE;
    		h=h*UNIT_SIZE;
    		int count=0;
    		float angleSpan=360f/n;
    		float[] vertices=new float[vCount*3];
    		for(float angle=0;Math.ceil(angle)<360;angle+=angleSpan){
    			double a0=Math.toRadians(angle);
    			double a1=Math.toRadians(angle+angleSpan);
    			vertices[count++]=(float) (-r*Math.sin(a0));
    			vertices[count++]=0;
    			vertices[count++]=(float) (-r*Math.cos(a0));
    			
    			vertices[count++]=(float) (-r*Math.sin(a1));
    			vertices[count++]=h;
    			vertices[count++]=(float) (-r*Math.cos(a1));
    			
    			vertices[count++]=(float) (-r*Math.sin(a0));
    			vertices[count++]=h;
    			vertices[count++]=(float) (-r*Math.cos(a0));
    			
    			vertices[count++]=(float) (-r*Math.sin(a0));
    			vertices[count++]=0;
    			vertices[count++]=(float) (-r*Math.cos(a0));
    			
    			vertices[count++]=(float) (-r*Math.sin(a1));
    			vertices[count++]=0;
    			vertices[count++]=(float) (-r*Math.cos(a1));
    			
    			vertices[count++]=(float) (-r*Math.sin(a1));
    			vertices[count++]=h;
    			vertices[count++]=(float) (-r*Math.cos(a1));
    		}
    		ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length*4);
            vbb.order(ByteOrder.nativeOrder());
            mVertexBuffer = vbb.asFloatBuffer();
            mVertexBuffer.put(vertices);
            mVertexBuffer.position(0);
            
    	}
    
    	private void initShader(int mProgram) {
    		// TODO Auto-generated method stub
    		this.mProgram=mProgram;
    		muMVPMatrixHandle=GLES20.glGetUniformLocation(mProgram, "uMVPMatrix");
    		maPositionHandle=GLES20.glGetAttribLocation(mProgram, "aPosition");
    		muColorRHandle=GLES20.glGetUniformLocation(mProgram, "uColorR");
    		muColorGHandle=GLES20.glGetUniformLocation(mProgram, "uColorG");
    		muColorBHandle=GLES20.glGetUniformLocation(mProgram, "uColorB");
    		muColorAHandle=GLES20.glGetUniformLocation(mProgram, "uColorA");
    	}
    	
    	public void drawSelf(float r,float g,float b,float a){
    		GLES20.glUseProgram(mProgram);
    		GLES20.glUniformMatrix4fv(muMVPMatrixHandle, 1, false, MatrixState.getFinalMatrix(), 0);
    		GLES20.glUniform1f(muColorRHandle, r);
    		GLES20.glUniform1f(muColorGHandle, g);
    		GLES20.glUniform1f(muColorBHandle, b);
    		GLES20.glUniform1f(muColorAHandle, a);
    		GLES20.glVertexAttribPointer(maPositionHandle, 3, GLES20.GL_FLOAT, false, 3*4, mVertexBuffer);
    		GLES20.glEnableVertexAttribArray(maPositionHandle);
    		GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vCount);
    	}
    }

二、定点着色器：

uniform mat4 uMVPMatrix;
    attribute vec3 aPosition;
    
    void main(){
        gl_Position=uMVPMatrix*vec4(aPosition,1); 
    }

三、片源着色器：

precision mediump float;
    
    uniform float uColorR;
    uniform float uColorG;
    uniform float uColorB;
    uniform float uColorA;
    
    void main(){
        vec4 finalColor;
        finalColor=vec4(uColorR,uColorG,uColorB,uColorA);
        gl_FragColor=finalColor;
    }