我在移植一些已成功实现的代码时遇到问题着色玩具 https://www.shadertoy.com/view/XdyfWK对于桌面 OpenGL,问题是我需要创建一个 FrameBufferObject FBO,以便我可以进行离屏计算,稍后将其传递到主 glsl 片段着色器,问题是该缓冲区需要将自身引用为纹理以获得它能够运行模拟的先前值。
我已经成功创建了 FBO:
// Framebuffer configuration.
unsigned int frameBufferOne;
glGenFramebuffers(1, &frameBufferOne);
glBindFramebuffer(GL_FRAMEBUFFER, frameBufferOne);
// Create a colour attachment texture.
unsigned int textureColourBufferOne;
glGenTextures(1, &textureColourBufferOne);
glBindTexture(GL_TEXTURE_2D, textureColourBufferOne);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, WIDTH, HEIGHT, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textureColourBufferOne, 0);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
std::cout << "ERROR::FRAMEBUFFER:: Framebuffer is not complete!" << std::endl;
glBindFramebuffer(GL_FRAMEBUFFER, 0);
并设法在我的渲染循环中调用它,以便我可以渲染到 FBO,然后将这些值传递到默认帧缓冲区:
// Render Loop.
while( !glfwWindowShouldClose( window ) )
{
// Input.
processInput( window );
// Render.
// Bind to frameBuffer and draw scene as normally would to colour texture.
glBindFramebuffer( GL_FRAMEBUFFER, frameBufferOne );
glClearColor( 0.2f, 0.3f, 0.1f, 1.0f );
glClear( GL_COLOR_BUFFER_BIT );
bufferShader.use();
float currentFrame = glfwGetTime();
//Set the iTimeDelta uniform.
float deltaTime = currentFrame - lastFrame;
lastFrame = currentFrame;
bufferShader.setFloat( "iTimeDelta", deltaTime );
// Set the iTime uniform.
float timeValue = currentFrame;
bufferShader.setFloat( "iTime", timeValue );
// Set the iResolution uniform.
bufferShader.setVec2( "iResolution", WIDTH, HEIGHT );
// Input iMouse.
double xPos, yPos;
glfwGetCursorPos( window, &xPos, &yPos );
yPos = HEIGHT - yPos;
bufferShader.setVec2( "iMouse", xPos, yPos );
glBindVertexArray( VAO );
glBindTexture( GL_TEXTURE_2D, textureColourBufferOne );
glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0 );
glBindVertexArray( 0 );
glBindFramebuffer( GL_FRAMEBUFFER, 0 );
glDisable( GL_DEPTH_TEST );
glClearColor( 1.0f, 1.0f, 1.0f, 1.0f );
glClear( GL_COLOR_BUFFER_BIT );
ourShader.use();
ourShader.setVec2( "iResolution", WIDTH, HEIGHT );
// Set the iTime uniform.
ourShader.setFloat( "iTime", timeValue );
glBindVertexArray(VAO);
glBindTexture( GL_TEXTURE_2D, textureColourBufferOne );
glDrawElements( GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0 );
glfwSwapBuffers( window );
glfwPollEvents();
frameCount++;
finalTime = time( NULL );
if( finalTime - initialTime > 0 )
{
std::cout << "FPS : " << frameCount / (finalTime - initialTime) << std::endl;
frameCount = 0;
initialTime = finalTime;
}
但我无法将缓冲区渲染为纹理本身,我知道它输出未定义的行为,并且我应该使用乒乓球技术。
有人能指出我正确的方向吗?