Opengl SharpGL和RenderBuffers

我正在尝试将pathtracer移植到GLSL，为此，我需要修改着色器示例程序，以使用纹理作为帧缓冲区，而不是backbuffer

这是顶点片段

#version 130

out vec2 texCoord;

// https://rauwendaal.net/2014/06/14/rendering-a-screen-covering-triangle-in-opengl/
void main()
{
 float x = -1.0 + float((gl_VertexID & 1) << 2);
 float y = -1.0 + float((gl_VertexID & 2) << 1);
 texCoord.x = x;
 texCoord.y = y;
 gl_Position = vec4(x, y, 0, 1);
}

这是运行时代码

//  Get a reference to the raytracer shader.
var shader = shaderRayMarch;

// setup first framebuffer (RGB32F)
gl.BindFramebufferEXT(OpenGL.GL_FRAMEBUFFER_EXT, _FrameBuffer[0]);
gl.Viewport((int)viewport[0], (int)viewport[1], (int)viewport[2], (int)viewport[3]); //0,0,width,height)
gl.FramebufferRenderbufferEXT(OpenGL.GL_FRAMEBUFFER_EXT, OpenGL.GL_COLOR_ATTACHMENT0_EXT, OpenGL.GL_RENDERBUFFER_EXT, _RaytracerBuffer[0]);
gl.FramebufferRenderbufferEXT(OpenGL.GL_FRAMEBUFFER_EXT, OpenGL.GL_DEPTH_ATTACHMENT_EXT, OpenGL.GL_RENDERBUFFER_EXT, 0);
uint [] DrawBuffers = new uint[1];
DrawBuffers[0] = OpenGL.GL_COLOR_ATTACHMENT0_EXT;
gl.DrawBuffers(1, DrawBuffers);

shader.Bind(gl);
shader.SetUniform1(gl, "screenWidth", viewport[2]);
shader.SetUniform1(gl, "screenHeight", viewport[3]);
shader.SetUniform1(gl, "fov", 40.0f);
gl.DrawArrays(OpenGL.GL_TRIANGLES, 0, 3);
shader.Unbind(gl);

int[] pixels = new int[(int)viewport[2]*(int)viewport[3]*4];
gl.GetTexImage(_RaytracerBuffer[0], 0, OpenGL.GL_RGBA32F, OpenGL.GL_INT, pixels);

但是当我检查从GetEximage返回的像素时，它们是黑色的。当我在另一个transfer着色器中绑定此纹理时，它们将保持黑色。我怀疑我在renderbuffer的设置代码中遗漏了什么，如果您有任何建议，我将不胜感激

不是。因此，当您在renderbuffer上执行

glGetTexImage

时，可能会出现OpenGL错误。当您尝试使用

glBindTexture

将其绑定为纹理时，可能会遇到OpenGL错误

如果要渲染到纹理，则应渲染到纹理。如

glGenTextures/glTexImage2D/glFramebufferTexture2D

中所示

---

另外，请停止使用EXT\u framebuffer\u对象。您应该使用核心FBO功能，它不需要“EXT”后缀。除非您使用的是非常古老的OpenGL版本。

谢谢。FramebufferTexture2D就是我想要的。终于有了基础知识并开始运行。：）

//  Get a reference to the raytracer shader.
var shader = shaderRayMarch;

// setup first framebuffer (RGB32F)
gl.BindFramebufferEXT(OpenGL.GL_FRAMEBUFFER_EXT, _FrameBuffer[0]);
gl.Viewport((int)viewport[0], (int)viewport[1], (int)viewport[2], (int)viewport[3]); //0,0,width,height)
gl.FramebufferRenderbufferEXT(OpenGL.GL_FRAMEBUFFER_EXT, OpenGL.GL_COLOR_ATTACHMENT0_EXT, OpenGL.GL_RENDERBUFFER_EXT, _RaytracerBuffer[0]);
gl.FramebufferRenderbufferEXT(OpenGL.GL_FRAMEBUFFER_EXT, OpenGL.GL_DEPTH_ATTACHMENT_EXT, OpenGL.GL_RENDERBUFFER_EXT, 0);
uint [] DrawBuffers = new uint[1];
DrawBuffers[0] = OpenGL.GL_COLOR_ATTACHMENT0_EXT;
gl.DrawBuffers(1, DrawBuffers);

shader.Bind(gl);
shader.SetUniform1(gl, "screenWidth", viewport[2]);
shader.SetUniform1(gl, "screenHeight", viewport[3]);
shader.SetUniform1(gl, "fov", 40.0f);
gl.DrawArrays(OpenGL.GL_TRIANGLES, 0, 3);
shader.Unbind(gl);

int[] pixels = new int[(int)viewport[2]*(int)viewport[3]*4];
gl.GetTexImage(_RaytracerBuffer[0], 0, OpenGL.GL_RGBA32F, OpenGL.GL_INT, pixels);