OpenGL之路（七）为立方体加入丰富色彩

在立方体的六个面贴上不同的颜色，假设想达到混合颜色的效果，能够參照立方体的前面代码在每一行前都加上颜色

代码例如以下

#include <gl/glut.h>
#pragma comment(lib, "opengl32.lib")
#pragma comment(lib, "glut32.lib")
#pragma comment(lib, "glu32.lib")
#pragma comment(lib, "glut.lib")

void Box(float x, float y, float z) //长方体
{
	glPushMatrix();
	glScalef(x, y, z);
	glBegin(GL_QUADS);
	glColor3f(1, 0, 0);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);// 前
	glColor3f(0, 1, 0);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(1.0f, -1.0f, 1.0f);
	glColor3f(0, 0, 1);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(1.0f, 1.0f, 1.0f);
	glColor3f(0, 1, 1);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 1.0f);

	glColor3f(1, 0, 0);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);// 后
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, 1.0f, -1.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(1.0f, 1.0f, -1.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(1.0f, -1.0f, -1.0f);
	glColor3f(0, 1, 0);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, -1.0f);// 上
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, 1.0f, 1.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(1.0f, 1.0f, 1.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(1.0f, 1.0f, -1.0f);
	glColor3f(0, 0, 1);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f);// 下
	glTexCoord2f(0.0f, 1.0f); glVertex3f(1.0f, -1.0f, -1.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(1.0f, -1.0f, 1.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);
	glColor3f(1, 1, 0);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(1.0f, -1.0f, -1.0f);// 左
	glTexCoord2f(1.0f, 1.0f); glVertex3f(1.0f, 1.0f, -1.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(1.0f, 1.0f, 1.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(1.0f, -1.0f, 1.0f);
	glColor3f(0, 1, 1);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);// 右
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 1.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, -1.0f);
	glEnd();
	glPopMatrix();
}

void renderScene(void)
{
	static float i = 0;
	i += 0.01f;
	if (i > 360) i = 0;
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glLoadIdentity();

	glTranslatef(0, 0, -1.5);
	glRotatef(i, 1, 1, 1);
	Box(0.3f, 0.3f, 0.3f);

	glutSwapBuffers();
}
void changeSize(int w, int h)
{
	if (h == 0) h = 1;
	float ratio = 1.0* w / h;
	glMatrixMode(GL_PROJECTION);// 单位化投影矩阵。
	glLoadIdentity();
	glViewport(0, 0, w, h);// 设置视口大小为整个窗体大小
	gluPerspective(45, ratio, 1, 1000);// 设置正确的投影矩阵
	glMatrixMode(GL_MODELVIEW);//以下是设置模型视图矩阵
	glLoadIdentity();
	gluLookAt(0.0, 0.0, 5.0, 0.0, 0.0, -1.0, 0.0f, 1.0f, 0.0f);//设置观測点
}

int main(int argc, char * argv[])
{
	glutInit(&argc, argv);
	
	glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
	glutInitWindowPosition(100, 100);
	glutInitWindowSize(320, 320);
	glutCreateWindow("Hello OpenGL");
	glutDisplayFunc(renderScene);
	glutIdleFunc(renderScene); //指定程序空暇时调用函数
	glutReshapeFunc(changeSize); //指定窗体形状变化时的回调函数
	glEnable(GL_DEPTH_TEST);

	glutMainLoop();
	return 0;
}