C++ opengl 纹理过滤之GL_NEAREST

源码还是这个博文里的

https://blog.csdn.net/qq78442761/article/details/81228557

GL_LINEAR过滤：表示给多边形进行着色的时候，它的颜色需要通过他周围的一些点进行某一种线性的差值之后计算出来的颜色；

GL_NEAREST过滤：表示给多边形进行着色的时候，取离他当前最近的那个纹理坐标的颜色【纹理图片是离散的（如128*128的图片，他采集像素的时候是离散的，如，从1.1采或1.5采）】GL_NEAREST指离他最近的点。这会使得，画面比较平滑

采用GL_NEAREST的截图如下：

伪代码如下：

GLuint CreateTexture2D(unsigned char*pixelData, int width, int height, GLenum type) {
	GLuint texture;
	glGenTextures(1, &texture);
	glBindTexture(GL_TEXTURE_2D, texture);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
	glTexImage2D(GL_TEXTURE_2D, 0, type, width, height, 0, type, GL_UNSIGNED_BYTE, pixelData);
	glBindTexture(GL_TEXTURE_2D, 0);
	return texture;
}

void Draw() {
	glClearColor(0.1f, 0.4f, 0.6f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT);
	glEnable(GL_TEXTURE_2D);	//开启2D纹理
	glBindTexture(GL_TEXTURE_2D, texture);//将当前纹理设置为新创建的纹理对象
	glBegin(GL_QUADS);
	glColor4ub(255, 255, 255, 255);
	glTexCoord2f(0.0f, 0.0f);
	glVertex3f(-0.1f, -0.1f, -0.4f);
	glTexCoord2f(1.0f, 0.0f);
	glVertex3f(0.1f, -0.1f, -0.4f);
	glTexCoord2f(1.0f, 1.0f);
	glVertex3f(0.1f, 0.1f, -0.4f);
	glTexCoord2f(0.0f, 1.0f);
	glVertex3f(-0.1f, 0.1f, -0.4f);
	glEnd();
}