网站建设与更新,恶意点击别人的网站,白银网站建设熊掌号,虚拟主机代理1 前言 使用Mesh绘制三角形 中介绍了绘制三角形的方法#xff0c;本文将介绍绘制正方形的方法。 libGDX 以点、线段、三角形为图元#xff0c;没有提供绘制矩形内部的接口。要绘制矩形内部#xff0c;必须通过三角形拼接而成#xff0c;如下图#xff0c;是通过GL_TRIANGL…1 前言 使用Mesh绘制三角形 中介绍了绘制三角形的方法本文将介绍绘制正方形的方法。 libGDX 以点、线段、三角形为图元没有提供绘制矩形内部的接口。要绘制矩形内部必须通过三角形拼接而成如下图是通过GL_TRIANGLE_FAN 模式绘制矩形。 绘制的坐标点如下屏幕中心为坐标原点向右和向上分别为 x 轴和 y 轴正方向。
float[] vertices {-0.5f, -0.5f, 0.0f, // 左下0.5f, -0.5f, 0.0f, // 右下0.5f, 0.5f, 0.0f, // 右上-0.5f, 0.5f, 0.0f // 左上
};
2 绘制矩形 DesktopLauncher.java
package com.zhyan8.game;import com.badlogic.gdx.backends.lwjgl3.Lwjgl3Application;
import com.badlogic.gdx.backends.lwjgl3.Lwjgl3ApplicationConfiguration;public class DesktopLauncher {public static void main (String[] arg) {Lwjgl3ApplicationConfiguration config new Lwjgl3ApplicationConfiguration();config.setForegroundFPS(60);config.setTitle(Square);new Lwjgl3Application(new Square(), config);}
} Square.java
package com.zhyan8.game;import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL30;
import com.badlogic.gdx.graphics.Mesh;
import com.badlogic.gdx.graphics.VertexAttribute;
import com.badlogic.gdx.graphics.VertexAttributes.Usage;
import com.badlogic.gdx.graphics.glutils.ShaderProgram;public class Square extends ApplicationAdapter {private ShaderProgram mShaderProgram;private Mesh mMesh;Overridepublic void create() {initShader();initMesh();}Overridepublic void render() {Gdx.gl.glClearColor(0.455f, 0.725f, 1.0f, 1.0f);Gdx.gl.glClear(GL30.GL_COLOR_BUFFER_BIT);mShaderProgram.bind();mMesh.render(mShaderProgram, GL30.GL_TRIANGLE_FAN);}Overridepublic void dispose() {mShaderProgram.dispose();mMesh.dispose();}private void initShader() { // 初始化着色器程序String vertex Gdx.files.internal(shaders/square_vertex.glsl).readString();String fragment Gdx.files.internal(shaders/square_fragment.glsl).readString();mShaderProgram new ShaderProgram(vertex, fragment);}private void initMesh() { // 初始化网格float[] vertices {-0.5f, -0.5f, 0.0f, // 左下0.5f, -0.5f, 0.0f, // 右下0.5f, 0.5f, 0.0f, // 右上-0.5f, 0.5f, 0.0f // 左上};short[] indices {0, 1, 2, 3};VertexAttribute vertexPosition new VertexAttribute(Usage.Position, 3, a_position);mMesh new Mesh(true, vertices.length / 3, indices.length, vertexPosition);mMesh.setVertices(vertices);mMesh.setIndices(indices);}
} square_vertex.glsl
#version 300 es
precision mediump float; // 声明float型变量的精度为mediumpout vec4 fragColor;void main() {fragColor vec4(1, 0, 0, 0);
} square_fragment.glsl
#version 300 esin vec3 a_position;void main() {gl_Position vec4(a_position, 1.0);
} 运行效果如下。 3 绘制正方形 Square.java
package com.zhyan8.game;import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL30;
import com.badlogic.gdx.graphics.Mesh;
import com.badlogic.gdx.graphics.VertexAttribute;
import com.badlogic.gdx.graphics.VertexAttributes.Usage;
import com.badlogic.gdx.graphics.glutils.ShaderProgram;public class Square extends ApplicationAdapter {private ShaderProgram mShaderProgram;private Mesh mMesh;private float mRatio;Overridepublic void create() {initShader();initMesh();}Overridepublic void render() {Gdx.gl.glClearColor(0.455f, 0.725f, 1.0f, 1.0f);Gdx.gl.glClear(GL30.GL_COLOR_BUFFER_BIT);mShaderProgram.bind();mShaderProgram.setUniformf(u_wh_ratio, mRatio);mMesh.render(mShaderProgram, GL30.GL_TRIANGLE_FAN);}Overridepublic void dispose() {mShaderProgram.dispose();mMesh.dispose();}private void initShader() { // 初始化着色器程序String vertex Gdx.files.internal(shaders/square_vertex.glsl).readString();String fragment Gdx.files.internal(shaders/square_fragment.glsl).readString();mShaderProgram new ShaderProgram(vertex, fragment);mRatio 1.0f * Gdx.graphics.getWidth() / Gdx.graphics.getHeight();}private void initMesh() { // 初始化网格float[] vertices {-0.5f, -0.5f, 0.0f, // 左下0.5f, -0.5f, 0.0f, // 右下0.5f, 0.5f, 0.0f, // 右上-0.5f, 0.5f, 0.0f // 左上};short[] indices {0, 1, 2, 3};VertexAttribute vertexPosition new VertexAttribute(Usage.Position, 3, a_position);mMesh new Mesh(true, vertices.length / 3, indices.length, vertexPosition);mMesh.setVertices(vertices);mMesh.setIndices(indices);}
} square_vertex.glsl
#version 300 esin vec3 a_position;uniform float u_wh_ratio; // 屏幕宽高比void main() {gl_Position vec4(a_position, 1.0);if (u_wh_ratio 1.0) {gl_Position.x / u_wh_ratio;} else {gl_Position.y * u_wh_ratio;}
} square_fragment.glsl
#version 300 es
precision mediump float; // 声明float型变量的精度为mediumpout vec4 fragColor;void main() {fragColor vec4(0, 1, 0, 0);
}
