我编写了一个粗略的阴影贴图实现,它使用 6 个不同的 View 矩阵渲染场景 6 次以创建立方体贴图。
作为一种优化,我尝试使用几何着色器升级到单 channel 方法,但很难从着色器获得任何输出。
我的问题是在绑定(bind)立方体贴图纹理时开始的。使用多 channel 时,我只需一次绑定(bind) 6 个 FBO 中的 1 个,但是使用单 channel 时,我需要一次绑定(bind)所有 6 个立方体贴图面,但我没有相应的句柄。在这些情况下,文档建议使用包含所有 6 个面的 FrameBufferTexture 创建单个 FBO。我这样做正确吗?
或者,问题可以在几何着色器中解决,但由于我没有得到任何输出,因此很难在那里进行调试。
单次通过(无输出)
固定基地台创建
// Create the FBO
GL.GenFramebuffers(1, out FBO_handle);
// Create and bind the cubemap Texture
GL.GenTextures(1, out cubeMapTexture);
GL.BindTexture(TextureTarget.TextureCubeMap, cubeMapTexture);
// Generate each of the single cubemap faces as 2D texture
GL.TexImage2D(TextureTarget.TextureCubeMapPositiveX, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapNegativeX, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapPositiveY, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapNegativeY, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapPositiveZ, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapNegativeZ, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
// Set the suitable texture parameters
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureWrapS, (int)TextureWrapMode.ClampToEdge);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureWrapT, (int)TextureWrapMode.ClampToEdge);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureWrapR, (int)TextureWrapMode.ClampToEdge);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureBaseLevel, 0);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureMaxLevel, 0);
// Attach cubemap texture as the FBO's color buffer
GL.BindFramebuffer(FramebufferTarget.Framebuffer, FBO_handle);
GL.FramebufferTexture(FramebufferTarget.Framebuffer, FramebufferAttachment.ColorAttachment0, cubeMapTexture, 0);
几何着色器
#version 330
layout(triangles) in;
layout (triangle_strip, max_vertices=18) out;
uniform mat4 projectionMatrix;
uniform mat4 shadowTransforms[6];
out vec4 frag_position;
void main()
{
for(int face = 0; face < 6; face++)
{
gl_Layer = face;
for(int i=0; i<3; i++)
{
frag_position = shadowTransforms[face] * gl_in[i].gl_Position;
gl_Position = projectionMatrix * shadowTransforms[shadowTransforms] * gl_in[i].gl_Position;
EmitVertex();
}
EndPrimitive();
}
}
渲染
for (int j = 0; j < lights.Count; j++)
{
// GL setup
GL.BindFramebuffer(FramebufferTarget.Framebuffer, shadowBuffers[j].FBO_handle);
GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
Matrix4 viewMatrix = Matrix4.Identity;
// Create the light's view matrices
List<Matrix4> shadowTransforms = new List<Matrix4>();
shadowTransforms.Add(Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(1, 0, 0), new Vector3(0, -1, 0)));
shadowTransforms.Add(Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(-1, 0, 0), new Vector3(0, -1, 0)));
shadowTransforms.Add(Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(0, 1, 0), new Vector3(0, 0, -1)));
shadowTransforms.Add(Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(0, -1, 0), new Vector3(0, 0, -1)));
shadowTransforms.Add(Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(0, 0, 1), new Vector3(0, -1, 0)));
shadowTransforms.Add(Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(0, 0, -1), new Vector3(0, -1, 0)));
// Send them to the shader
for (int i = 0; i < 6; ++i)
{
Matrix4 shadowTransform = shadowTransforms[i];
GL.UniformMatrix4(shader.getUniformID("shadowTransforms[" + i + "]"), false, ref shadowTransform);
}
// Draw Scene
for (int r = 0; r < renderables.Count; r++)
renderables[r].draw(shader);
}
对于大量的代码转储,我深表歉意,FBO 有点长,我相信你知道。对于那些不熟悉 OpenTK c# 包装器的人来说,我认为如果我还提供有效的多遍代码,可能会有所帮助。
多次通过(工作正常)
固定基地台创建
// Create cubemap texture
GL.GenTextures(1, out cubeTex);
GL.BindTexture(TextureTarget.TextureCubeMap, cubeTex);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureBaseLevel, 0);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureMaxLevel, 0);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
GL.TexParameter(TextureTarget.TextureCubeMap, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
GL.TexImage2D(TextureTarget.TextureCubeMapPositiveX, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapNegativeX, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapPositiveY, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapNegativeY, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapPositiveZ, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
GL.TexImage2D(TextureTarget.TextureCubeMapNegativeZ, 0, PixelInternalFormat.R16f, size, size, 0, PixelFormat.Red, PixelType.Float, IntPtr.Zero);
// Create cubemap FBOs
GL.GenFramebuffers(6, cubeFBOs);
for (int i = 0; i < 6; i++)
{
GL.BindFramebuffer(FramebufferTarget.Framebuffer, cubeFBOs[i]);
GL.FramebufferTexture2D(FramebufferTarget.Framebuffer, FramebufferAttachment.ColorAttachment0, TextureTarget.TextureCubeMapPositiveX + i, cubeTex, 0);
}
几何着色器
#version 330
layout(triangles) in;
layout(triangle_strip, max_vertices=3) out;
uniform mat4 viewMatrix;
uniform mat4 projectionMatrix;
out vec4 frag_position;
void main()
{
for(int i=0; i<3; i++)
{
frag_position = viewMatrix * gl_in[i].gl_Position;
gl_Position = projectionMatrix * viewMatrix * gl_in[i].gl_Position;
EmitVertex();
}
EndPrimitive();
}
渲染
for (int j = 0; j < lights.Count; j++)
{
for (int i = 0; i < 6; ++i)
{
GL.BindFramebuffer(FramebufferTarget.Framebuffer, shadowBuffers[j].cubeFBOs[i]);
GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
Matrix4 viewMatrix = Matrix4.Identity;
if (i == 0) viewMatrix = Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(1, 0, 0), new Vector3(0, -1, 0));
if (i == 1) viewMatrix = Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(-1, 0, 0), new Vector3(0, -1, 0));
if (i == 2) viewMatrix = Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(0, 1, 0), new Vector3(0, 0, -1));
if (i == 3) viewMatrix = Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(0, -1, 0), new Vector3(0, 0, -1));
if (i == 4) viewMatrix = Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(0, 0, 1), new Vector3(0, -1, 0));
if (i == 5) viewMatrix = Matrix4.LookAt(lights[j].position, lights[j].position + new Vector3(0, 0, -1), new Vector3(0, -1, 0));
GL.UniformMatrix4(shader.getUniformID("viewMatrix"), false, ref viewMatrix);
// Draw Scene
for (int r = 0; r < renderables.Count; r++)
renderables[r].draw(shader);
}
}
片段着色器
#version 330
precision lowp float;
in vec4 frag_position;
layout (location = 0) out vec4 outColor;
void main() {
float depth = length( vec3(frag_position) ) / 20;
float moment1 = depth;
float moment2 = depth * depth;
float dx = dFdx(depth);
float dy = dFdy(depth);
moment2 += 0.25*(dx*dx+dy*dy);
outColor = vec4( moment1, moment2, 0.0, 0.0);
}
如有任何见解,我们将不胜感激,谢谢!
最佳答案
令人尴尬的是,原因是几何着色器中的拼写错误组合。
shadowTransforms[shadowTransforms]
需要是 shadowTransforms[face]
和
uniform mat4shadowTransforms[6]
需要是uniform mat4shadowTransforms[]
。
这对我来说标志着一个巨大的突破。 60 fps 的多个阴影转换点光源。感谢一路以来帮助过我的所有人。
关于c# - OpenGL - 单 channel 立方体贴图不产生输出,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40222125/