cpu_anim.h

#include <gl/freeglut.h>

class CPUAnimBitmap {
private:
	unsigned char* pixels;
	int width, height;
	void* dataBlock;
	void (*fAnim)(void*, int);
	void (*animExit)(void*);
	void (*clickDrag)(void*, int, int, int, int);
	int dragStartX, dragStartY;
public:
	CPUAnimBitmap(int w, int h, void* d = NULL) {
		width = w;
		height = h;
		pixels = new unsigned char[width * height * 4];
		dataBlock = d;
		clickDrag = NULL;
	}
	~CPUAnimBitmap() {
		delete[] pixels;
	}
	unsigned char* get_ptr() const { return pixels; }
	long image_size() const { return width * height * 4; }
	void click_drag(void(*f)(void*, int, int, int, int)) {
		clickDrag = f;
	}
	static CPUAnimBitmap** get_bitmap_ptr() {
		static CPUAnimBitmap* gBitmap;
		return &gBitmap;
	}
	static void mouse_func(int button, int state, int mx, int my) {
		if (button == GLUT_LEFT_BUTTON) {
			CPUAnimBitmap* bitmap = *(get_bitmap_ptr());
			if (state == GLUT_DOWN) {
				bitmap->dragStartX = mx;
				bitmap->dragStartY = my;
			}
			else if(state==GLUT_UP){
				bitmap->clickDrag(bitmap->dataBlock,
					bitmap->dragStartX,
					bitmap->dragStartY,
					mx, my);
			}
		}
	}
	static void idle_func(void) {
		static int ticks = 1;
		CPUAnimBitmap* bitmap = *(get_bitmap_ptr());
		bitmap->fAnim(bitmap->dataBlock, ticks++);
		glutPostRedisplay();
	}
	static void Key(unsigned char key, int x, int y) {
		switch (key) {
		case 27:
			CPUAnimBitmap * bitmap = *(get_bitmap_ptr());
			bitmap->animExit(bitmap->dataBlock);
			exit(0);
		}
	}
	static void Draw() {
		CPUAnimBitmap* bitmap = *(get_bitmap_ptr());
		glClearColor(0.0, 0.0, 0.0, 0.0);
		glClear(GL_COLOR_BUFFER_BIT);
		glDrawPixels(bitmap->width, bitmap->height, GL_RGBA, GL_UNSIGNED_BYTE, bitmap->pixels);
		glutSwapBuffers();
	}
	void anim_and_exit(void(*f)(void*, int), void(*e)(void*)) {
		CPUAnimBitmap** bitmap = get_bitmap_ptr();
		*bitmap = this;
		fAnim = f;
		animExit = e;
		int c = 1;
		char* dummy = "";
		glutInit(&c, &dummy);
		glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);
		glutInitWindowSize(width + 20,height+20);
		glutCreateWindow("bitmap");
		glutKeyboardFunc(Key);
		glutDisplayFunc(Draw);
		if (clickDrag != NULL)
			glutMouseFunc(mouse_func);
		glutIdleFunc(idle_func);
		glutMainLoop();
	}
};