我一直在编写程序来可视化分形的点云，到目前为止，一切都已经进行了，相机移动使用的是以原点为中心的弧光球移动，并且正在渲染点。但是，我需要将场景输出到UI内的集成窗口中，因此我一直在尝试使帧缓冲区起作用。
到目前为止，我已经将纹理成功渲染到四边形上，然后将其输出到屏幕上，用于测试目的与我不使用fbo时基本相同。我的问题是试图使摄像机移动以使用渲染纹理进行显示时出现。我知道这绝对是可能的，因为有很多这样的例子，但是我还无法使用我的代码。我相当确定我的着色器存在问题，但是我已经搜索了许多网站，YouTube教程，openGL示例，但没有发现任何可行的方法。据我所知，我必须正常渲染场景，因此我一直使用与以前为初始渲染步骤工作的着色器相同的着色器，但我使用的是fbo而不是默认的fbo
为了简单起见，我刚渲染了一个点立方体，因为它比每次生成分形都要快。
这里是fbo，texture和rbo的主要设置：
GLuint fbo;
GLuint texturebuffer;
GLuint rbo;
void initFBO(){
glGenFramebuffers(1, &fbo);
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glGenTextures(1, &texturebuffer);
glBindTexture(GL_TEXTURE_2D, texturebuffer);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, WINDOW_WIDTH, WINDOW_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, texturebuffer, 0);
glGenRenderbuffers(1, &rbo);
glBindRenderbuffer(GL_RENDERBUFFER, rbo);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, WINDOW_WIDTH, WINDOW_HEIGHT);
glBindRenderbuffer(GL_RENDERBUFFER, 0); // once rbo memory allocated unbind
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rbo);
}
这里是主循环和绘制循环：
int main(){
if(!setup())
return -1;
// // white background
glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
GLuint VertexArrayID;
glGenVertexArrays(1, &VertexArrayID);
glBindVertexArray(VertexArrayID);
// GLuint programID = LoadShaders( "new_vertex_shader", "new_fragment_shader" ); // custom shader
GLuint programID = LoadShaders("new_vertex_shader", "new_fragment_shader");
GLuint modelMatrixID = glGetUniformLocation(programID, "model");
GLuint viewMatrixID = glGetUniformLocation(programID, "view");
GLuint matrixID = glGetUniformLocation(programID, "MVP");
GLuint quad_programID = LoadShaders( "screen_vertex_shader", "screen_fragment_shader" );
GLuint textureID = glGetUniformLocation(quad_programID, "screenTexture");
// initialise mvp matrices
glm::mat4 ProjectionMatrix = perspective(radians(45.0f), 4.0f / 3.0f, 0.1f, 100.0f);
glm::mat4 ViewMatrix = translate(mat4(1.0f), vec3(0,0,-RADIUS));
glm::mat4 ModelMatrix = mat4(1.0f);
glm::mat4 MVP;
GLuint vertexbuffer;
glGenBuffers(1, &vertexbuffer);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
GLfloat cube[24] = {
0.5,0.5,0.5,
0.5,-0.5,0.5,
-0.5,0.5,0.5,
-0.5,-0.5,0.5,
0.5,0.5,-0.5,
0.5,-0.5,-0.5,
-0.5,-0.5,-0.5,
-0.5,0.5,-0.5
};
glBufferData(GL_ARRAY_BUFFER, sizeof(cube),cube, GL_STATIC_DRAW);
glfwSetMouseButtonCallback(window, mouseCallback);
// ################# main draw loop #######################
while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS && glfwWindowShouldClose(window) == 0 ){
// render to fbo first
glBindFramebuffer(GL_FRAMEBUFFER, fbo);
glEnable(GL_DEPTH_TEST);
glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
computeMatricesFromInputs();
ProjectionMatrix = getProjectionMatrix();
ViewMatrix = getViewMatrix();
ModelMatrix = getModelMatrix();
MVP = ProjectionMatrix * ViewMatrix * ModelMatrix;
// Use our shader
glUseProgram(programID);
// Send our transformation to the currently bound shader in the "MVP" uniform
glUniformMatrix4fv(matrixID, 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(modelMatrixID, 1, GL_FALSE, &ModelMatrix[0][0]);
glUniformMatrix4fv(viewMatrixID, 1, GL_FALSE, &ViewMatrix[0][0]);
// render scene as normal
glEnableVertexAttribArray(0);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); // index buffer
glVertexAttribPointer(
0, // attribute 0. No particular reason for 0, but must match the layout in the shader.
3, // size
GL_FLOAT, // type
GL_FALSE, // normalized?
0, // stride
(void*)0 // array buffer offset
);
glPointSize(POINT_SIZE);
glDrawArrays(GL_POINTS, 0, sizeof(cube));
glDisableVertexAttribArray(0);
// bind back to default frame buffer to show on screen
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glDisable(GL_DEPTH_TEST);
glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(quad_programID);
glEnableVertexAttribArray(0);
glBindVertexArray(quad_vertex_buffer);
glVertexAttribPointer(
0, // attribute 0. No particular reason for 0, but must match the layout in the shader.
3, // size
GL_FLOAT, // type
GL_FALSE, // normalized?
0, // stride
(void*)0 // array buffer offset
);
glDrawArrays(GL_POINTS, 0, sizeof(cube));
glDisableVertexAttribArray(0);
// Swap buffers
glfwSwapBuffers(window);
glfwPollEvents();
}
顶点着色器：
#version 330 core
// Input vertex data, different for all executions of this shader.
layout(location = 0) in vec3 vertexPosition_modelspace;
// Values that stay constant for the whole mesh.
uniform mat4 MVP;
uniform mat4 view;
uniform mat4 model;
void main(){
// Output position of the vertex, in clip space : MVP * position
gl_Position = MVP * vec4(vertexPosition_modelspace,1.0);
}
片段着色器：
#version 330 core
// Output data
out vec3 color;
void main(){
// Output color = black
color = vec3(0,0,0);
}
屏幕四边形顶点着色器：
#version 330 core
layout (location = 0) in vec2 aPos;
layout (location = 1) in vec2 aTexCoords;
out vec2 TexCoords;
void main()
{
TexCoords = aTexCoords;
gl_Position = vec4(aPos.x, aPos.y, 0.0, 1.0);
}
屏幕四片段着色器：
#version 330 core
out vec4 FragColour;
in vec2 TexCoords;
uniform sampler2D screenTexture;
void main()
{
FragColour = texture(screenTexture, TexCoords);
}
很抱歉，如果这是一个很大的代码块，我不能完全确定错误将在哪里，并且对于使用openGL来说有点新。非常感谢您的任何帮助。
glBindVertexArray当绘制屏幕空间四边形（第二遍）时，必须使用quad_vertex_buffer类型生成（填充的）多边形（可能是glBindVertexArray(quad_vertex_buffer);
glEnableVertexAttribArray(0);
或primitive），而不是点图元类型[C0 ]：
GL_TRIANGLES
GL_TRIANGLE_STRIP