轮廓轮廓着色器
and*_*med 0 opengl shader glsl vertex-shader
我正在尝试实现GLSL着色器，该着色器将突出显示渲染的3D网格的外部边缘。问题是我无权访问OpenGL客户端代码，因此只能在GLSL着色器中完成。
我的第一个尝试是从Unity使用/采用此着色器，并在OpenGL GLSL中进行操作。这里看起来应该是这样：
这是我得到的：
我不确定我是否可以正确计算内容，但是如您所见，输出与我的期望值相差甚远。
这是食人魔的材料
material Chassis
{
technique
{
pass standard
{
cull_software back
scene_blend zero one
}
pass psssm
{
cull_software front
scene_blend src_alpha one_minus_src_alpha
vertex_program_ref reflection_cube_specularmap_normalmap_vs100
{
param_named_auto modelViewProjectionMatrix worldviewproj_matrix
param_named_auto normalMatrix inverse_transpose_world_matrix
param_named_auto modelView worldview_matrix
param_named_auto camera_world_position camera_position
param_named_auto inverse_projection_matrix inverse_projection_matrix
param_named_auto projection_matrix projection_matrix
param_named_auto p_InverseModelView inverse_worldview_matrix
}
fragment_program_ref reflection_cube_specularmap_normalmap_fs100
{
}
}
}
}
这是顶点着色器
material Chassis
{
technique
{
pass standard
{
cull_software back
scene_blend zero one
}
pass psssm
{
cull_software front
scene_blend src_alpha one_minus_src_alpha
vertex_program_ref reflection_cube_specularmap_normalmap_vs100
{
param_named_auto modelViewProjectionMatrix worldviewproj_matrix
param_named_auto normalMatrix inverse_transpose_world_matrix
param_named_auto modelView worldview_matrix
param_named_auto camera_world_position camera_position
param_named_auto inverse_projection_matrix inverse_projection_matrix
param_named_auto projection_matrix projection_matrix
param_named_auto p_InverseModelView inverse_worldview_matrix
}
fragment_program_ref reflection_cube_specularmap_normalmap_fs100
{
}
}
}
}
编辑：我添加了食人魔使用的材质脚本，并且添加了顶点着色器代码。
我假设使用单个复杂的3D网格。我会通过2次渲染来做到这一点：
清晰的画面
让我们使用它
(0,0,0)作为清晰的颜色。渲染网格
禁用深度输出，测试（或随后清除）。不要仅使用一些预定义的颜色作为阴影填充，例如，
(1,1,1)让我们对简单的多维数据集执行此操作：
读取帧缓冲区并将其用作纹理
因此，无论使用FBO和纹理渲染为＃1，＃2或使用
glReadPixels替代并加载一些质地回GPU（我知道它速度较慢，但也适用于英特尔）。有关更多信息，请参见此处的两个答案：清晰的背景色屏幕
渲染
因此，要么渲染
GL_QUAD覆盖整个屏幕，要么使用阴影以及所需的任何东西渲染网格。您还需要将上一步的纹理传递到GLSL中。像往常一样在片段渲染中...但最后还要添加以下内容：
扫描当前片段屏幕位置周围的所有纹理像素，直到距离上一步中纹理轮廓线的距离为止。如果在其中找到任何黑色像素，则用轮廓颜色覆盖输出的颜色。您甚至可以以最小的距离将其调制为黑色。
这非常类似于：
但要简单得多。结果如下：
分段：
// Fragment
#version 400 core
#extension GL_ARB_explicit_uniform_location : enable
layout(location =64) uniform vec3 lt_pnt_pos;// point light source position [GCS]
layout(location =67) uniform vec3 lt_pnt_col;// point light source color&strength
layout(location =70) uniform vec3 lt_amb_col;// ambient light source color&strength
in vec3 LCS_pos; // fragment position [LCS]
in vec3 pixel_pos; // fragment position [GCS]
in vec3 pixel_col; // fragment surface color
in vec3 pixel_nor; // fragment surface normal [GCS]
out vec4 col;
// outline
uniform sampler2D txr; // texture from previous pass
uniform int thickness; // [pixels] outline thickness
uniform float xs,ys; // [pixels] texture/screen resolution
void main()
{
// standard rendering
float li;
vec3 c,lt_dir;
lt_dir=normalize(lt_pnt_pos-pixel_pos); // vector from fragment to point light source in [GCS]
li=dot(pixel_nor,lt_dir);
if (li<0.0) li=0.0;
c=pixel_col*(lt_amb_col+(lt_pnt_col*li));
// outline effect
if (thickness>0) // thickness effect in second pass
{
int i,j,r=thickness;
float xx,yy,rr,x,y,dx,dy;
dx=1.0/xs; // texel size
dy=1.0/ys;
x=gl_FragCoord.x*dx;
y=gl_FragCoord.y*dy;
rr=thickness*thickness;
for (yy=y-(float(thickness)*dy),i=-r;i<=r;i++,yy+=dy)
for (xx=x-(float(thickness)*dx),j=-r;j<=r;j++,xx+=dx)
if ((i*i)+(j*j)<=rr)
if ((texture(txr,vec2(xx,yy)).r)<0.01)
{
c=vec3(1.0,0.0,0.0); // outline color
i=r+r+1;
j=r+r+1;
break;
}
}
else c=vec3(1.0,1.0,1.0); // render with white in first pass
// output color
col=vec4(c,1.0);
}
该顶点着色器是没有变化：
// Vertex
#version 400 core
#extension GL_ARB_explicit_uniform_location : enable
layout(location = 0) in vec3 pos;
layout(location = 2) in vec3 nor;
layout(location = 3) in vec3 col;
layout(location = 0) uniform mat4 m_model; // model matrix
layout(location =16) uniform mat4 m_normal; // model matrix with origin=(0,0,0)
layout(location =32) uniform mat4 m_view; // inverse of camera matrix
layout(location =48) uniform mat4 m_proj; // projection matrix
out vec3 LCS_pos; // fragment position [LCS]
out vec3 pixel_pos; // fragment position [GCS]
out vec3 pixel_col; // fragment surface color
out vec3 pixel_nor; // fragment surface normal [GCS]
void main()
{
LCS_pos=pos;
pixel_col=col;
pixel_pos=(m_model*vec4(pos,1)).xyz;
pixel_nor=(m_normal*vec4(nor,1)).xyz;
gl_Position=m_proj*m_view*m_model*vec4(pos,1);
}
和CPU端的代码如下所示：
//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop
#include "Unit1.h"
#include "gl_simple.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
GLfloat lt_pnt_pos[3]={+2.5,+2.5,+2.5};
GLfloat lt_pnt_col[3]={0.8,0.8,0.8};
GLfloat lt_amb_col[3]={0.2,0.2,0.2};
GLuint txrid=0;
GLfloat animt=0.0;
//---------------------------------------------------------------------------
// https://stackoverflow.com/q/46603878/2521214
//---------------------------------------------------------------------------
void gl_draw()
{
// load values into shader
GLint i,id;
GLfloat m[16];
glUseProgram(prog_id);
GLfloat x,y,z,d=0.25;
id=glGetUniformLocation(prog_id,"txr"); glUniform1i(id,0);
id=glGetUniformLocation(prog_id,"xs"); glUniform1f(id,xs);
id=glGetUniformLocation(prog_id,"ys"); glUniform1f(id,ys);
id=64; glUniform3fv(id,1,lt_pnt_pos);
id=67; glUniform3fv(id,1,lt_pnt_col);
id=70; glUniform3fv(id,1,lt_amb_col);
glGetFloatv(GL_MODELVIEW_MATRIX,m);
id=0; glUniformMatrix4fv(id,1,GL_FALSE,m);
m[12]=0.0; m[13]=0.0; m[14]=0.0;
id=16; glUniformMatrix4fv(id,1,GL_FALSE,m);
for (i=0;i<16;i++) m[i]=0.0; m[0]=1.0; m[5]=1.0; m[10]=1.0; m[15]=1.0;
id=32; glUniformMatrix4fv(id,1,GL_FALSE,m);
glGetFloatv(GL_PROJECTION_MATRIX,m);
id=48; glUniformMatrix4fv(id,1,GL_FALSE,m);
// draw VAO cube (no outline)
id=glGetUniformLocation(prog_id,"thickness"); glUniform1i(id,0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
vao_draw(); // render cube
// copy frame buffer to CPU memory and than back to GPU as Texture
BYTE *map=new BYTE[xs*ys*4];
glReadPixels(0,0,xs,ys,GL_RGB,GL_UNSIGNED_BYTE,map); // framebuffer -> map[]
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D,txrid);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, xs, ys, 0, GL_RGB, GL_UNSIGNED_BYTE, map); // map[] -> texture txrid
delete[] map;
// draw VAO cube (outline)
id=glGetUniformLocation(prog_id,"thickness"); glUniform1i(id,5);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
vao_draw(); // render cube
glDisable(GL_TEXTURE_2D);
// turn of shader
glUseProgram(0);
// rotate the cube to see animation
glMatrixMode(GL_MODELVIEW);
// glRotatef(1.0,0.0,1.0,0.0);
// glRotatef(1.0,1.0,0.0,0.0);
glFlush();
SwapBuffers(hdc);
}
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner):TForm(Owner)
{
gl_init(Handle);
glGenTextures(1,&txrid);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D,txrid);
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_NEAREST);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE,GL_COPY);
glDisable(GL_TEXTURE_2D);
int hnd,siz; char vertex[4096],fragment[4096];
hnd=FileOpen("normal_shading.glsl_vert",fmOpenRead); siz=FileSeek(hnd,0,2); FileSeek(hnd,0,0); FileRead(hnd,vertex ,siz); vertex [siz]=0; FileClose(hnd);
hnd=FileOpen("normal_shading.glsl_frag",fmOpenRead); siz=FileSeek(hnd,0,2); FileSeek(hnd,0,0); FileRead(hnd,fragment,siz); fragment[siz]=0; FileClose(hnd);
glsl_init(vertex,fragment);
// hnd=FileCreate("GLSL.txt"); FileWrite(hnd,glsl_log,glsl_logs); FileClose(hnd);
int i0,i;
mm_log->Lines->Clear();
for (i=i0=0;i<glsl_logs;i++)
if ((glsl_log[i]==13)||(glsl_log[i]==10))
{
glsl_log[i]=0;
mm_log->Lines->Add(glsl_log+i0);
glsl_log[i]=13;
for (;((glsl_log[i]==13)||(glsl_log[i]==10))&&(i<glsl_logs);i++);
i0=i;
}
if (i0<glsl_logs) mm_log->Lines->Add(glsl_log+i0);
vao_init();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormDestroy(TObject *Sender)
{
glDeleteTextures(1,&txrid);
gl_exit();
glsl_exit();
vao_exit();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormResize(TObject *Sender)
{
gl_resize(ClientWidth,ClientHeight-mm_log->Height);
glMatrixMode(GL_PROJECTION);
glTranslatef(0,0,-15.0);
glMatrixMode(GL_MODELVIEW);
glRotatef(-15.0,0.0,1.0,0.0);
glRotatef(-125.0,1.0,0.0,0.0);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormPaint(TObject *Sender)
{
gl_draw();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Timer1Timer(TObject *Sender)
{
gl_draw();
animt+=0.02; if (animt>1.5) animt=-0.5;
Caption=animt;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormMouseWheel(TObject *Sender, TShiftState Shift, int WheelDelta, TPoint &MousePos, bool &Handled)
{
GLfloat dz=2.0;
if (WheelDelta<0) dz=-dz;
glMatrixMode(GL_PROJECTION);
glTranslatef(0,0,dz);
gl_draw();
}
//---------------------------------------------------------------------------
和往常一样，代码使用/基于此：
[笔记]
如果您有多个对象，请在＃2中为每个对象使用不同的颜色。然后在＃5中扫描任何不同的颜色，然后扫描当前位置上纹理像素中的颜色，而不是扫描黑色。
同样，这可以在2D图像上完成，而不必使用网格。您只需要知道背景色即可。因此，您也可以为此使用预渲染/抓取/截屏的图像。
您可以添加discard 和/或更改最终if逻辑以更改行为（例如，您只需要轮廓而内部不包含网格等）。或者，您可以添加轮廓颜色来呈现颜色，而不是直接分配轮廓颜色以获得高亮效果...而不是着色
参见修改后的片段中的a），b），c）选项：
// Fragment
#version 400 core
#extension GL_ARB_explicit_uniform_location : enable
layout(location =64) uniform vec3 lt_pnt_pos;// point light source position [GCS]
layout(location =67) uniform vec3 lt_pnt_col;// point light source color&strength
layout(location =70) uniform vec3 lt_amb_col;// ambient light source color&strength
in vec3 LCS_pos; // fragment position [LCS]
in vec3 pixel_pos; // fragment position [GCS]
in vec3 pixel_col; // fragment surface color
in vec3 pixel_nor; // fragment surface normal [GCS]
out vec4 col;
// outline
uniform sampler2D txr; // texture from previous pass
uniform int thickness; // [pixels] outline thickness
uniform float xs,ys; // [pixels] texture/screen resolution
void main()
{
// standard rendering
float li;
vec3 c,lt_dir;
lt_dir=normalize(lt_pnt_pos-pixel_pos); // vector from fragment to point light source in [GCS]
li=dot(pixel_nor,lt_dir);
if (li<0.0) li=0.0;
c=pixel_col*(lt_amb_col+(lt_pnt_col*li));
// outline effect
if (thickness>0) // thickness effect in second pass
{
int i,j,r=thickness;
float xx,yy,rr,x,y,dx,dy;
dx=1.0/xs; // texel size
dy=1.0/ys;
x=gl_FragCoord.x*dx;
y=gl_FragCoord.y*dy;
rr=thickness*thickness;
for (yy=y-(float(thickness)*dy),i=-r;i<=r;i++,yy+=dy)
for (xx=x-(float(thickness)*dx),j=-r;j<=r;j++,xx+=dx)
if ((i*i)+(j*j)<=rr)
if ((texture(txr,vec2(xx,yy)).r)<0.01)
{
c =vec3(1.0,0.0,0.0); // a) assign outline color
// c+=vec3(1.0,0.0,0.0); // b) add outline color
i=r+r+1;
j=r+r+1;
r=0;
break;
}
// if (r!=0) discard; // c) do not render inside
}
else c=vec3(1.0,1.0,1.0); // render with white in first pass
// output color
col=vec4(c,1.0);
}
[Edit1]平滑边缘的单遍方法
由于您无法访问客户端代码，因此该方法仅在着色器中有效。对于平滑（弯曲）的边缘形状，表面法线接近垂直于相机视轴（z）的位置。因此dot它们之间几乎为零。可以直接利用此...着色器的更新：
顶点
// Vertex
#version 400 core
#extension GL_ARB_explicit_uniform_location : enable
layout(location = 0) in vec3 pos;
layout(location = 2) in vec3 nor;
layout(location = 3) in vec3 col;
layout(location = 0) uniform mat4 m_model; // model matrix
layout(location =16) uniform mat4 m_normal; // model matrix with origin=(0,0,0)
layout(location =32) uniform mat4 m_view; // inverse of camera matrix
layout(location =48) uniform mat4 m_proj; // projection matrix
out vec3 pixel_pos; // fragment position [GCS]
out vec3 pixel_col; // fragment surface color
out vec3 pixel_nor; // fragment surface normal [GCS]
out vec3 view_nor; // surface normal in camera [LCS]
void main()
{
pixel_col=col;
pixel_pos=(m_model*vec4(pos,1)).xyz;
pixel_nor=(m_normal*vec4(nor,1)).xyz;
mat4 m;
m=m_model*m_view; // model view matrix
m[3].xyz=vec3(0.0,0.0,0.0); // with origin set to (0,0,0)
view_nor=(m*vec4(nor,1.0)).xyz; // object local normal to camera local normal
gl_Position=m_proj*m_view*m_model*vec4(pos,1);
}
分段
// Fragment
#version 400 core
#extension GL_ARB_explicit_uniform_location : enable
layout(location =64) uniform vec3 lt_pnt_pos;// point light source position [GCS]
layout(location =67) uniform vec3 lt_pnt_col;// point light source color&strength
layout(location =70) uniform vec3 lt_amb_col;// ambient light source color&strength
in vec3 pixel_pos; // fragment position [GCS]
in vec3 pixel_col; // fragment surface color
in vec3 pixel_nor; // fragment surface normal [GCS]
out vec4 col;
// outline
in vec3 view_nor; // surface normal in camera [LCS]
void main()
{
// standard rendering
float li;
vec3 c,lt_dir;
lt_dir=normalize(lt_pnt_pos-pixel_pos); // vector from fragment to point light source in [GCS]
li=dot(pixel_nor,lt_dir);
if (li<0.0) li=0.0;
c=pixel_col*(lt_amb_col+(lt_pnt_col*li));
// outline effect
if (abs(dot(view_nor,vec3(0.0,0.0,1.0)))<=0.5) c=vec3(1.0,0.0,0.0);
// output color
col=vec4(c,1.0);
}
这里预览：
如您所见，它适用于光滑的对象，但对于像立方体这样的尖锐边缘根本不起作用...您可以使用与a,b,c先前方法相同的组合（）。
该m持有原产设置为模型视图矩阵(0,0,0)。这样就可以进行矢量转换（无需翻译）。有关更多信息，请参见了解4x4均匀变换矩阵。
的0.5在点积结果if是轮廓的厚度。0.0表示没有轮廓，1.0表示整个对象都是轮廓。
| 归档时间： |
|
| 查看次数： |
2832 次 |
| 最近记录： |