在GLSL中使用OpenGL卡通着色器

我对学习如何用OpenGL着色语言编写感兴趣。我找到了一个，但无法在我的计算机上运行演示。我遇到的麻烦是编写一个将使用此着色器的应用程序。有人能告诉我如何编写一个使用该着色器的简单应用程序吗？我正在Linux上使用GLSL 1.2（OpenGL 2.1）。

以下是主要示意图：

/*
* Use keys 1 - 8 to play with different GLUT Solids
* mouse affects light position
* Toon Shader by Philip Rideout:
* http://www.lighthouse3d.com/opengl/glsl/index.php?toon2
*/
import processing.opengl.*;
import javax.media.opengl.*;
import javax.media.opengl.glu.*;
import com.sun.opengl.util.*; 

PGraphicsOpenGL pgl;
GL gl;
GLSL toon;
GLU glu;
GLUT glut;
boolean glInit;
int glutSolidIndex = 7;

void setup()
{
  size(600, 500, OPENGL);

  glu = new GLU();
  glut = new GLUT();

  pgl = (PGraphicsOpenGL) g;
  gl = pgl.gl;
}

void draw()
{
  background(0);
  PGraphicsOpenGL pgl = (PGraphicsOpenGL) g;
  GL gl = pgl.beginGL();

  if(!glInit){
    toon=new GLSL();
    toon.loadVertexShader("toon.vs");
    toon.loadFragmentShader("toon.fs");
    toon.useShaders();

    glInit = true;
  }

  gl.glClear(gl.GL_COLOR_BUFFER_BIT | gl.GL_DEPTH_BUFFER_BIT);

 //TRS
  gl.glTranslatef(width * .5, height * .5,0.0f);
  gl.glRotatef(160,1,0,0);
  gl.glRotatef(frameCount * .5,0,1,0);
  gl.glRotatef(frameCount * .5,0,0,1);
  gl.glScalef(80,80,80);
  // draw 
  toon.startShader();
  toon.uniform3f(toon.getUniformLocation("LightPosition"), mouseX-width*.5, -(mouseY-height*.5), 20.0f);
    gl.glColor3f(1.0f, 0.5f, 0.0f);
    glutSolid();
  toon.endShader();

  pgl.endGL();
}

void glutSolid(){
 switch(glutSolidIndex){
   case 0:
     glut.glutSolidCube(1);
   break;
   case 1:
     glut.glutSolidTetrahedron();
   break;
   case 2:
     glut.glutSolidOctahedron();
   break;
   case 3:
     glut.glutSolidDodecahedron();
   break;
   case 4:
     glut.glutSolidIcosahedron();
   break;
   case 5:
     glut.glutSolidSphere(1,16,8);
   break;
   case 6:
     glut.glutSolidTorus(.5,1,32,24);
   break;
   case 7:
     glut.glutSolidTeapot(1);
   break;
 }
}
void keyPressed(){
  if((int)key >= 49 && (int)key <= 56) glutSolidIndex = (int)(key) - 49;
}

片段着色器：toon.fs

/* http://www.lighthouse3d.com/opengl/glsl/index.php?toon2 */

varying vec3 Normal;

uniform vec3 LightPosition;// = vec3(10.0, 10.0, 20.0);

void main()
{
    vec4 color1 = gl_FrontMaterial.diffuse;
    vec4 color2;

    float intensity = dot(normalize(LightPosition),Normal);

    if (intensity > 0.95)      color2 = vec4(1.0, 1.0, 1.0, 1.0);
    else if (intensity > 0.75) color2 = vec4(0.8, 0.8, 0.8, 1.0);
    else if (intensity > 0.50) color2 = vec4(0.6, 0.6, 0.6, 1.0);
    else if (intensity > 0.25) color2 = vec4(0.4, 0.4, 0.4, 1.0);
    else                       color2 = vec4(0.2, 0.2, 0.2, 1.0);

    gl_FragColor = color1 * color2;
}

如果有帮助的话，是压缩处理项目。安装Processing后，将文件解压缩到默认的Processing文件夹（~/Documents/Processing），然后运行Processing>file>Sketchbook下应该显示的文件

下面是一个屏幕截图：

嗯

更新

处理现在提供了一个很好的解决方案。 它包括一个卡通着色器：

PShader toon;

void setup() {
  size(640, 360, P3D);
  noStroke();
  fill(204);
  toon = loadShader("ToonFrag.glsl", "ToonVert.glsl");
  toon.set("fraction", 1.0);
}

void draw() {
  shader(toon);
  background(0); 
  float dirY = (mouseY / float(height) - 0.5) * 2;
  float dirX = (mouseX / float(width) - 0.5) * 2;
  directionalLight(204, 204, 204, -dirX, -dirY, -1);
  translate(width/2, height/2);
  sphere(120);
}

ToonVert.glsl：

uniform mat4 transform;
uniform mat3 normalMatrix;
uniform vec3 lightNormal;

attribute vec4 vertex;
attribute vec4 color;
attribute vec3 normal;

varying vec4 vertColor;
varying vec3 vertNormal;
varying vec3 vertLightDir;

void main() {
  gl_Position = transform * vertex;  
  vertColor = color;
  vertNormal = normalize(normalMatrix * normal);
  vertLightDir = -lightNormal;
}

ToonFrag.glsl：

#ifdef GL_ES
precision mediump float;
precision mediump int;
#endif

#define PROCESSING_LIGHT_SHADER

uniform float fraction;

varying vec4 vertColor;
varying vec3 vertNormal;
varying vec3 vertLightDir;

void main() {  
  float intensity;
  vec4 color;
  intensity = max(0.0, dot(vertLightDir, vertNormal));

  if (intensity > pow(0.95, fraction)) {
    color = vec4(vec3(1.0), 1.0);
  } else if (intensity > pow(0.5, fraction)) {
    color = vec4(vec3(0.6), 1.0);
  } else if (intensity > pow(0.25, fraction)) {
    color = vec4(vec3(0.4), 1.0);
  } else {
    color = vec4(vec3(0.2), 1.0);
  }

  gl_FragColor = color * vertColor;  
}

---

“无法在我的电脑上运行演示”，你做了什么？它是如何工作的？@Ben Anderson Oops！现在已修复：）

uniform mat4 transform;
uniform mat3 normalMatrix;
uniform vec3 lightNormal;

attribute vec4 vertex;
attribute vec4 color;
attribute vec3 normal;

varying vec4 vertColor;
varying vec3 vertNormal;
varying vec3 vertLightDir;

void main() {
  gl_Position = transform * vertex;  
  vertColor = color;
  vertNormal = normalize(normalMatrix * normal);
  vertLightDir = -lightNormal;
}

#ifdef GL_ES
precision mediump float;
precision mediump int;
#endif

#define PROCESSING_LIGHT_SHADER

uniform float fraction;

varying vec4 vertColor;
varying vec3 vertNormal;
varying vec3 vertLightDir;

void main() {  
  float intensity;
  vec4 color;
  intensity = max(0.0, dot(vertLightDir, vertNormal));

  if (intensity > pow(0.95, fraction)) {
    color = vec4(vec3(1.0), 1.0);
  } else if (intensity > pow(0.5, fraction)) {
    color = vec4(vec3(0.6), 1.0);
  } else if (intensity > pow(0.25, fraction)) {
    color = vec4(vec3(0.4), 1.0);
  } else {
    color = vec4(vec3(0.2), 1.0);
  }

  gl_FragColor = color * vertColor;  
}