学步园

demo功能：flowcover 效果，正反无限循环滚动，每个cover都有单独的倒影

demo说明：项目中FlowCover Classes文件夹是存放核心类。

demo接图：

demo主要代码：绘制部分

- (void)drawTile:(int)index atOffset:(double)off
{
	FlowCoverRecord *fcr = [self getTileAtIndex:index];
	GLfloat m[16];
	memset(m,0,sizeof(m));
	m[10] = 1;
	m[15] = 1;
	m[0] = 1;
	m[5] = 1;
	double trans = off * SPREADIMAGE;
	
	double f = off * FLANKSPREAD;
	if (f < -FLANKSPREAD) {
		f = -FLANKSPREAD;
	} else if (f > FLANKSPREAD) {
		f = FLANKSPREAD;
	}
	m[3] = -f;
	m[0] = 1-fabs(f);
	double sc = 0.45 * (1 - fabs(f));
	trans += f * 1;
	
	glPushMatrix();
	glBindTexture(GL_TEXTURE_2D,fcr.texture);
	glTranslatef(trans, 0, 0);
	glScalef(sc,sc,1.0);
	glMultMatrixf(m);
	glDrawArrays(GL_TRIANGLE_STRIP,0,4);
	
	// reflect
	glTranslatef(0,-2,0);
	glScalef(1,-1,1);
	glColor4f(0.5,0.5,0.5,0.5);
	glDrawArrays(GL_TRIANGLE_STRIP,0,4);
	glColor4f(1,1,1,1);
	
	glPopMatrix();
}

- (void)draw
{
	/*
	 *	Get the current aspect ratio and initialize the viewport
	 */
	
	double aspect = ((double)backingWidth)/backingHeight;
	
	glViewport(0,0,backingWidth,backingHeight);
	glDisable(GL_DEPTH_TEST);				// using painters algorithm
	
	glClearColor(0,0,0,0);
	glVertexPointer(3,GL_FLOAT,0,GVertices);
	glEnableClientState(GL_VERTEX_ARRAY);
	glTexCoordPointer(2, GL_SHORT, 0, GTextures);
	glEnableClientState(GL_TEXTURE_COORD_ARRAY);
	
	glEnable(GL_TEXTURE_2D);
	glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
	glEnable(GL_BLEND);
	
	/*
	 *	Setup for clear
	 */
	
	[EAGLContext setCurrentContext:context];
	
    glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
    glClear(GL_COLOR_BUFFER_BIT);
	
	/*
	 *	Set up the basic coordinate system
	 */
	
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glScalef(1,aspect,1);
    glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	
	//modify by chenwh 2010-01-06 for round view begin
	/*
	 *	Change from Alesandro Tagliati <alessandro.tagliati@gmail.com>:
	 *	We don't need to draw all the tiles, just the visible ones. We guess
	 *	there are 6 tiles visible; that can be adjusted by altering the 
	 *	constant
	 */
	/*
	int i,len = [self numTiles];
	int mid = (int)floor(offset + 0.5);
	int iStartPos = mid - VISTILES;
	if (iStartPos<0) {
		iStartPos=0;
	}
	for (i = iStartPos; i < mid; ++i) {
		[self drawTile:i atOffset:i-offset];
	}
	
	int iEndPos=mid + VISTILES;
	if (iEndPos >= len) {
		iEndPos = len-1;
	}
	for (i = iEndPos; i >= mid; --i) {
		[self drawTile:i atOffset:i-offset];
	}
	*/
	
	int len = [self numTiles];
	int iStartPos = -VISTILES;
	int iEndPos = VISTILES;
	int mid = 0;
	
	int pageCount = (int)offset;
	double moveOffset;
	if (offset < 0) {
		moveOffset = offset - ceil(offset);
	} else {
		moveOffset = offset - floor(offset);
	}
	
	int index, position;
	//NSLog(@"offset=%.2f, pageCount=%d, moveOffset=%.2f", offset, pageCount, moveOffset);
	for (position = iStartPos; position < mid; ++position) {
		index = (len + position + pageCount) % len;
		if (index < 0) {
			index = len + index;
		}
		//NSLog(@"index=%d, position=%d", index, position);
		[self drawTile:index atOffset:position - moveOffset];
	}
	for (position = iEndPos; position >= mid; --position) {
		index = (position + pageCount) % len;
		if (index < 0) {
			index = len + index;
		}
		//NSLog(@"index=%d, position=%d", index, position);
		[self drawTile:index atOffset:position - moveOffset];
	}
	//modify by chenwh 2010-01-06 for round view end
	
	glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
	[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

demo下载地址：http://download.csdn.net/detail/donny_zhang/5544499