我该如何将一系列IOSurface绘制到另一个界面上并显示?我尝试使用苹果的MultiGPU示例项目中的源码进行实验,但最好的结果只能绘制出白屏或导致大量图像伪影并使应用程序崩溃。
我非常新手OpenGL,不太理解帧缓存和纹理的绑定以及它们如何与IOSurface交互。
以下是我用来从IOSurface创建纹理的代码(直接来自苹果的源代码)。
我非常新手OpenGL,不太理解帧缓存和纹理的绑定以及它们如何与IOSurface交互。
以下是我用来从IOSurface创建纹理的代码(直接来自苹果的源代码)。
// Create an IOSurface backed texture
// Create an FBO using the name of this texture and bind the texture to the color attachment of the FBO
- (GLuint)setupIOSurfaceTexture:(IOSurfaceRef)ioSurfaceBuffer {
GLuint name;
CGLContextObj cgl_ctx = (CGLContextObj)[[self openGLContext] CGLContextObj];
glGenTextures(1, &name);
glBindTexture(GL_TEXTURE_RECTANGLE_EXT, name);
CGLTexImageIOSurface2D(cgl_ctx, GL_TEXTURE_RECTANGLE_EXT, GL_RGBA, 512, 512, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV,
ioSurfaceBuffer, 0);
glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// Generate an FBO using the same name with the same texture bound to it as a render target.
glBindTexture(GL_TEXTURE_RECTANGLE_EXT, 0);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, name);
glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_RECTANGLE_EXT, name, 0);
if(!_depthBufferName) {
glGenRenderbuffersEXT(1, &_depthBufferName);
glRenderbufferStorageEXT(GL_TEXTURE_RECTANGLE_EXT, GL_DEPTH, 512, 512);
}
glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_TEXTURE_RECTANGLE_EXT, _depthBufferName);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
return name;
}
我有一段代码可以将表面绘制到屏幕上。(这也是来自苹果的源代码)
// Fill the view with the IOSurface backed texture
- (void)textureFromCurrentIOSurface {
NSRect bounds = [self bounds];
CGLContextObj cgl_ctx = (CGLContextObj)[[self openGLContext] CGLContextObj];
// Render quad from our iosurface texture
glViewport(0, 0, (GLint)bounds.size.width, (GLint)bounds.size.height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, (GLfloat)bounds.size.width, 0.0f, (GLfloat)bounds.size.height, -1.0f, 1.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
glBindTexture(GL_TEXTURE_RECTANGLE_EXT, [[NSApp delegate] currentTextureName]); // Grab the texture from the delegate
glEnable(GL_TEXTURE_RECTANGLE_EXT);
glTexEnvi(GL_TEXTURE_RECTANGLE_EXT, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glBegin(GL_QUADS);
glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
glTexCoord2f(0.0f, 0.0f);
glVertex2f(0.0f, 0.0f);
glTexCoord2f(512.0f, 0.0f);
glVertex2f((GLfloat)bounds.size.width, 0.0f);
glTexCoord2f(512.0f, 512.0f);
glVertex2f((GLfloat)bounds.size.width, (GLfloat)bounds.size.height);
glTexCoord2f(0.0f, 512.0f);
glVertex2f(0.0f, (GLfloat)bounds.size.height);
glEnd();
glDisable(GL_TEXTURE_RECTANGLE_EXT);
}
当单个IOSurface被绘制到屏幕上时,这是有效的。那么我缺少什么来将IOSurface绘制到另一个位置?
假设我有纹理A、B、C和D,我想要:
-在特定区域内将A绘制到C上,
-在不同的区域内(可能与A重叠)将B绘制到C上,
-将C绘制到屏幕上。