关于OpenGL ES的glTexImage2D API的问题
关于OpenGL ES的glTexImage2D API的问题
目前我在做一个iphone上的wmv播放器，采用OpenGL ES画屏。在decoder之后得到RGBA数据，调用glTexImage2D画屏。正常情况下，这个API花费4 ms，但是每隔30－40帧左右，就会有一次调用的时间在12ms左右，远远大于平均时间，此时CPU load只有60%,造成播放的时候会感觉到停顿。glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, textureWidth, textureHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, frameData);
使用OpenGL ES 1.0, RGBA格式，代码片段如下,有懂的朋友请指教.
context = [[EAGLContext alloc] initWithAPI: kEAGLRenderingAPIOpenGLES1];
。。。
glDisable(GL_DEPTH_TEST);
glDisable(GL_ALPHA_TEST);
glDisable(GL_LIGHTING);
glDisable(GL_BLEND);
glDisable(GL_DITHER);
glEnable(GL_TEXTURE_2D);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
。。。
eaglLayer.drawableProperties = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithBool: NO], kEAGLDrawablePropertyRetainedBacking,
kEAGLColorFormatRGBA8,
kEAGLDrawablePropertyColorFormat,
nil];
。。。
glGenFramebuffersOES(1, &frameBuffer);
glGenRenderbuffersOES(1, &renderBuffer);
glBindFramebufferOES(GL_FRAMEBUFFER_OES, frameBuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, renderBuffer);
[context renderbufferStorage: GL_RENDERBUFFER_OES fromDrawable: (CAEAGLLayer *)_view.layer];
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, renderBuffer);
if (glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES) {
return NO;
｝
。。。
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
/* Set viewport size to match the renderbuffer size */
int glX = 0;
int glY = 0;
glViewport(glX, glY, backingWidth, backingHeight);
/* Setup orthographic projection mode */
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrthof(0, backingWidth, 0, backingHeight, -1.0, 0);
/* Reset the matrix mode to model/view */
glMatrixMode(GL_MODELVIEW);
最后画屏
[EAGLContext setCurrentContext: context];
glClear(GL_COLOR_BUFFER_BIT);
//这里速度每隔30－40帧变慢
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, textureWidth, textureHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, frameData);
glTexCoordPointer(2, GL_FLOAT, 0, coordinates);
glVertexPointer(2, GL_FLOAT, 0, vertices);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
/* All rendered, so make render buffer appear on the screen */
[context presentRenderbuffer: GL_RENDERBUFFER_OES];