Qt OpenGL 纹理贴图

两张图片贴到一个正方形上。


混合之后的效果：

#pragma once

#include <QOpenGLWindow>
#include <QOpenGLShader>
#include <QOpenGLShaderProgram>
class QOpenGLFunctions_3_3_Core;

class TextureWnd : public QOpenGLWindow {
    
	Q_OBJECT

public:
	TextureWnd();
	~TextureWnd();

protected:
	virtual void initializeGL();
	virtual void paintGL();

private:
	QOpenGLFunctions_3_3_Core* _openGLCore;
	GLuint _VBO;//顶点位置VBO
	GLuint _VAO;
	GLuint _EBO;
	QOpenGLShaderProgram _shaderProgram;//着色器程序，所里系统所有的着色器
	class QOpenGLTexture* _texture;
	class QOpenGLTexture* _texture2;
};

#include <QOpenGLFunctions_3_3_Core>
#include <QVector4D>
#include <QOpenGLTexture>
#include "TextureWnd.h"

TextureWnd::TextureWnd() {
    
}

TextureWnd::~TextureWnd() {
    
}

void TextureWnd::initializeGL() {
    
	_openGLCore = QOpenGLContext::currentContext()->versionFunctions<QOpenGLFunctions_3_3_Core>();

	//定义数据-位置：颜色：纹理坐标
	GLfloat vert[] =	{
    
		//位置 颜色 纹理坐标
		0.5f,  0.5f, 0.0f,      1.0f, 0.0f, 0.0f,       1.0f, 1.0f,
		0.5f, -0.5f, 0.0f,      0.0f, 1.0f, 0.0f,       1.0f, 0.0f,
	   -0.5f, -0.5f, 0.0f,      0.0f, 0.0f, 1.0f,       0.0f, 0.0f,
	   -0.5f,  0.5f, 0.0f,      1.0f, 1.0f, 0.0f,       0.0f, 1.0f
	};

	//定义索引数据
	unsigned int indices[] ={
    
		0, 1, 3,
		1, 2, 3
	};


	_openGLCore->glGenVertexArrays(1, &_VAO);
	_openGLCore->glGenBuffers(1, &_VBO);

	//使用VAO开始记录数据属性操作
	_openGLCore->glBindVertexArray(_VAO);

	_openGLCore->glBindBuffer(GL_ARRAY_BUFFER, _VBO);
	_openGLCore->glBufferData(GL_ARRAY_BUFFER, sizeof(vert), vert, GL_STATIC_DRAW);

	//定义数据属性 - 位置属性（最大取8个浮点数（第5个参数），从0位置开始（第6个参数），取3个浮点数数据（第2个参数））
	_openGLCore->glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), 0);
	_openGLCore->glEnableVertexAttribArray(0);

	//定义数据属性 - 颜色属性（最大取8个浮点数（第5个参数），从3个浮点数开始（第6个参数），取3个浮点数数据（第2个参数））
	_openGLCore->glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void*)(3 * sizeof(GLfloat)));
	_openGLCore->glEnableVertexAttribArray(1);

	//定义数据属性 - 纹理坐标属性（最大取8个浮点数（第5个参数），从6个浮点数开始（第6个参数），取2个浮点数数据（第2个参数））
	_openGLCore->glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void*)(6 * sizeof(GLfloat)));
	_openGLCore->glEnableVertexAttribArray(2);

	//解除绑定缓存区
	_openGLCore->glBindBuffer(GL_ARRAY_BUFFER, 0);

	//索引缓存对象
	_openGLCore->glGenBuffers(1, &_EBO);
	_openGLCore->glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _EBO);
	_openGLCore->glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

	//结束记录数据属性的操作
	_openGLCore->glBindVertexArray(0);


	_shaderProgram.addShaderFromSourceFile(QOpenGLShader::Vertex, "E:/Projects/QtGuiTest/OPenGLApp/shader/Texture.vert");
	_shaderProgram.addShaderFromSourceFile(QOpenGLShader::Fragment, "E:/Projects/QtGuiTest/OPenGLApp/shader/Texture.frag");

	_shaderProgram.link();

	_texture = new QOpenGLTexture(QImage("E:/Projects/QtGuiTest/OPenGLApp/shader/1.jpg").mirrored());
	_texture2 = new QOpenGLTexture(QImage("E:/Projects/QtGuiTest/OPenGLApp/shader/2.png").mirrored());
	//如果是一张图片就不用绑定，默认绑定。如果是多于1张就需要主动绑定，
	_shaderProgram.bind();
	/* ** textureImg：对应的片元着色器的 uniform sampler2D textureImg; ** textureCpp：对应的片元着色器的 uniform sampler2D textureCpp; */
	_shaderProgram.setUniformValue("textureImg", 0);
	_shaderProgram.setUniformValue("textureCpp", 1);
}

void TextureWnd::paintGL() {
    
	_openGLCore->glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
	_openGLCore->glClear(GL_COLOR_BUFFER_BIT);

	_shaderProgram.bind();
	_openGLCore->glBindVertexArray(_VAO);

	_texture->bind(0);
	_texture2->bind(1);

	_openGLCore->glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, nullptr);
}

顶点着色器：

#version 330 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec2 aTextureCoord;
out vec3 outColor;
out vec2 textureCoord;
void main(){
    
	gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
	outColor = aColor;
	textureCoord = aTextureCoord;
}

片段着色器：

#version 330 core
out vec4 fragColor;
in vec3 outColor;//从顶点着色器中传过来的颜色
in vec2 textureCoord;
uniform sampler2D textureImg;
uniform sampler2D textureCpp;
void main(){
    
	//fragColor = texture(textureImg, textureCoord);
	 fragColor = mix(texture(textureImg,textureCoord), texture(textureCpp,textureCoord), 0.5);
}

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