Make shadow volumes visible

src/Game.cpp

@@ -30,27 +30,21 @@
 
 namespace Zoom {
 
-Game::Game(bool multisample) : playerPos(vmml::vec3f::ZERO), playerRotY(vmml::mat4f::IDENTITY), playerRotX(0),
+Game::Game() : playerPos(vmml::vec3f::ZERO), playerRotY(vmml::mat4f::IDENTITY), playerRotX(0),
     input(0), lightPos(0) {
-  glClearColor(0.0, 0.0, 0.0, 1.0);
-  glClearDepth(1.0);
   glEnable(GL_DEPTH_TEST);
+  glEnable(GL_STENCIL_TEST);
 
   glEnable(GL_BLEND);
 
-#ifndef _WIN32
+  glEnable(GL_MULTISAMPLE_ARB);
-  if(multisample)
-    glEnable(GL_MULTISAMPLE_ARB);
-#endif
 
   glLightModelfv(GL_LIGHT_MODEL_AMBIENT, vmml::vec4f(0.1, 0.1, 0.1, 1).array);
 
   glLightfv(GL_LIGHT0, GL_AMBIENT, vmml::vec4f::ZERO.array);
   glLightfv(GL_LIGHT0, GL_DIFFUSE, vmml::vec4f::ONE.array);
   glLightfv(GL_LIGHT0, GL_SPECULAR, vmml::vec4f::ONE.array);
-  glLightf(GL_LIGHT0, GL_CONSTANT_ATTENUATION, 0);
   glLightf(GL_LIGHT0, GL_QUADRATIC_ATTENUATION, 0.2);
-  glDisable(GL_LIGHT0);
 
   glEnable(GL_COLOR_MATERIAL);
   glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE);
@@ -72,6 +66,20 @@ bool Game::loadLevel(const std::string &name) {
   return level;
 }
 
+void Game::resize(int width, int height) {
+  if(height == 0) {
+    height = 1;
+  }
+
+
+  glMatrixMode(GL_PROJECTION);
+  glLoadMatrixf(MathUtil::perspective(50.0f, (float)width/(float)height, 0.1).array);
+
+  glMatrixMode(GL_MODELVIEW);
+
+  glViewport(0, 0, width, height);
+}
+
 void Game::turn(float x, float y) {
   playerRotY.rotate_y(-x*M_PI/180/10);
 
@@ -107,29 +115,29 @@ void Game::run(int delta) {
 
 void Game::render() {
   int i;
-  float light[] = {0, 0, 0, 1};
+  vmml::vec3f light(vmml::vec3f::ZERO);
 
   if(lightPos < 12000) i = lightPos;
   else i = 24000 - lightPos;
 
   if(i < 4000) {
-    light[0] = 0.0;
+    light.x() = 0.0;
-    light[2] = -i * 0.001;
+    light.z() = -i * 0.001;
   }
   else if(i < 8000) {
-    light[0] = (i-4000) * 0.001;
+    light.x() = (i-4000) * 0.001;
-    light[2] = -4.0;
+    light.z() = -4.0;
   }
   else if(i < 12000) {
-    light[0] = 4.0;
+    light.x() = 4.0;
-    light[2] = -4.0 - (i-8000) * 0.001;
+    light.z() = -4.0 - (i-8000) * 0.001;
   }
   else {
-    light[0] = 4.0;
+    light.x() = 4.0;
-    light[2] = -8.0;
+    light.z() = -8.0;
   }
 
-  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
 
   vmml::mat4f transform(playerRotY), inverse;
   transform.rotate_x(playerRotX);
@@ -138,28 +146,37 @@ void Game::render() {
 
   glLoadMatrixf(inverse.array);
 
-  glLightfv(GL_LIGHT0, GL_POSITION, light);
+  renderer.render(triangles, light);
-
-  renderer.render(triangles);
 
   Shader::disable();
-  glDepthFunc(GL_LEQUAL);
+  glDepthMask(GL_FALSE);
-  glBlendFunc(GL_ONE, GL_ZERO);
+  glBlendFunc(GL_ONE, GL_ONE);
-
+  glBlendEquation(GL_FUNC_ADD);
-  glBegin(GL_LINES);
+  glDepthFunc(GL_GREATER);
-
+  glColor3f(0.05, 0.05, 0.05);
-  glColor3f(1, 1, 0);
+  glFrontFace(GL_CCW);
 
+  glBegin(GL_TRIANGLES);
   for(std::vector<BSPTree::TriangleRecord>::iterator t = triangles.begin(); t != triangles.end(); ++t) {
     ShadowVolume v(t->triangle, light);
-
+    v.render();
-    for(int i = 0; i < 3; ++i) {
-      glVertex3fv(v.getVertex(i).array);
-      glVertex3fv((v.getVertex(i)+v.getDirection(i)).array);
-    }
   }
-
   glEnd();
+
+  glFrontFace(GL_CW);
+  glBlendEquation(GL_FUNC_REVERSE_SUBTRACT);
+
+  glBegin(GL_TRIANGLES);
+  for(std::vector<BSPTree::TriangleRecord>::iterator t = triangles.begin(); t != triangles.end(); ++t) {
+    ShadowVolume v(t->triangle, light);
+    v.render();
+  }
+  glEnd();
+
+  glFrontFace(GL_CCW);
+  glDepthMask(GL_TRUE);
+  glDepthFunc(GL_LEQUAL);
+  glBlendEquation(GL_FUNC_ADD);
 }
 
 }

src/Game.h

@@ -38,10 +38,12 @@ class Game {
       RIGHT = (1 << 3)
     };
 
-    Game(bool multisample);
+    Game();
 
     bool loadLevel(const std::string &name);
 
+    void resize(int width, int height);
+
     void setInput(unsigned input) {
       this->input = input;
     }

src/Renderer.cpp

@@ -27,7 +27,7 @@ Renderer::Renderer() : activeTexture(0), renderVisitor(this) {
   lightShader = boost::shared_ptr<Shader>(Shader::load("light.vert", "light.frag"));
 }
 
-void Renderer::render(const BSPTree &tree) {
+/*void Renderer::render(const BSPTree &tree) {
   vmml::mat4f transform, inverseTransform;
   glGetFloatv(GL_MODELVIEW_MATRIX, transform.array);
 
@@ -39,7 +39,7 @@ void Renderer::render(const BSPTree &tree) {
   tree.visit(renderVisitor, viewPoint);
   glEnd();
 
-}
+}*/
 
 void Renderer::renderTriangle(const Triangle &t) {
   glColor4fv(t.getColor().array);

src/Renderer.h

@@ -23,6 +23,7 @@
 #include "gl.h"
 #include "BSPTree.h"
 #include "Shader.h"
+#include <limits>
 
 
 namespace Zoom {
@@ -31,13 +32,17 @@ class Renderer {
   public:
     Renderer();
 
-    void render(const BSPTree &tree);
+    //void render(const BSPTree &tree);
 
     template <typename T>
-    void render(const T &triangles) {
+    void render(const T &triangles, const vmml::vec3f &lightPos) {
+      glLightfv(GL_LIGHT0, GL_POSITION, vmml::vec4f(lightPos, 1).array);
+
       Shader::enable(ambientShader);
       glBlendFunc(GL_ONE, GL_ZERO);
       glDepthFunc(GL_LEQUAL);
+      //glStencilFunc(GL_ALWAYS, 0, std::numeric_limits<GLuint>::max());
+      //glStencilOp(GL_KEEP, GL_INCR, GL_KEEP);
 
       typename T::const_iterator t = triangles.begin();
       if(t == triangles.end())
@@ -54,6 +59,8 @@ class Renderer {
       Shader::enable(lightShader);
       glBlendFunc(GL_ONE, GL_ONE);
       glDepthFunc(GL_EQUAL);
+      //glStencilFunc(GL_EQUAL, 0, std::numeric_limits<GLuint>::max());
+      //glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
 
       t = triangles.begin();
 

src/ShadowVolume.cpp

@@ -20,19 +20,19 @@
 #include "ShadowVolume.h"
 #include "MathUtil.h"
 
+#include "gl.h"
+
 namespace Zoom {
 
-ShadowVolume::ShadowVolume(const Triangle &t, const vmml::vec3f &lightPos) {
+ShadowVolume::ShadowVolume(const Triangle &t, const vmml::vec3f &lightPos) : visible(true) {
   MathUtil::Plane trianglePlane(t);
 
   for(int i = 0; i < 3; ++i) {
     rays[i].p = t.getVertex(i);
   }
 
-  if(trianglePlane.isBehind(lightPos)) {
+  if(trianglePlane.isInFront(lightPos)) {
-    for(int i = 0; i < 3; ++i) {
+    visible = false;
-      rays[i].dir = vmml::vec3f::ZERO;
-    }
 
     return;
   }
@@ -42,4 +42,30 @@ ShadowVolume::ShadowVolume(const Triangle &t, const vmml::vec3f &lightPos) {
   }
 }
 
+void ShadowVolume::render() const {
+  if(!visible)
+    return;
+
+  glVertex3fv(rays[0].p.array);
+  glVertex3fv(rays[1].p.array);
+  glVertex3fv(rays[2].p.array);
+
+  for(int i = 0; i < 3; ++i) {
+    const Ray &r1 = rays[i];
+    const Ray &r2 = rays[(i+1)%3];
+
+    glVertex3fv(r1.p.array);
+    glVertex4fv(vmml::vec4f(r1.dir, 0).array);
+    glVertex3fv(r2.p.array);
+
+    glVertex3fv(r2.p.array);
+    glVertex4fv(vmml::vec4f(r1.dir, 0).array);
+    glVertex4fv(vmml::vec4f(r2.dir, 0).array);
+  }
+
+  glVertex4fv(vmml::vec4f(rays[2].dir, 0).array);
+  glVertex4fv(vmml::vec4f(rays[1].dir, 0).array);
+  glVertex4fv(vmml::vec4f(rays[0].dir, 0).array);
+}
+
 }

src/ShadowVolume.h

@@ -21,6 +21,7 @@
 #define ZOOM_SHADOWVOLUME_H_
 
 #include <vmmlib/vector.hpp>
+#include <vmmlib/matrix.hpp>
 
 namespace Zoom {
 
@@ -39,7 +40,11 @@ class ShadowVolume {
       return rays[i].dir;
     }
 
+    void render() const;
+
   private:
+    bool visible;
+
     struct Ray {
         vmml::vec3f p;
         vmml::vec3f dir;

src/zoom.cpp

@@ -35,20 +35,6 @@
 #include <unistd.h>
 #endif
 
-void resize(int width, int height) {
-  if(height == 0) {
-    height = 1;
-  }
-
-
-  glMatrixMode(GL_PROJECTION);
-  glLoadMatrixf(Zoom::MathUtil::perspective(50.0f, (float)width/(float)height, 0.1).array);
-
-  glMatrixMode(GL_MODELVIEW);
-
-  glViewport(0, 0, width, height);
-}
-
 
 #ifdef _WIN32
 
@@ -250,12 +236,13 @@ bool XIInit(Display *disp, int *opcode) {
   return true;
 }
 
-bool GLXinit(Display *disp, Atom windele, Window *wnd, GLXContext *gc, bool *multisample, int *xi_opcode, int *pointer) {
+bool GLXinit(Display *disp, Atom windele, Window *wnd, GLXContext *gc, int *xi_opcode, int *pointer) {
   static const int msAttributeList[] = {GLX_RENDER_TYPE, GLX_RGBA_BIT,
                                         GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
                                         GLX_X_RENDERABLE, True,
                                         GLX_DOUBLEBUFFER, True,
                                         GLX_DEPTH_SIZE, 1,
+                                        GLX_STENCIL_SIZE, 1,
                                         GLX_SAMPLE_BUFFERS, 1,
                                         GLX_SAMPLES, 4,
                                         None};
@@ -265,13 +252,13 @@ bool GLXinit(Display *disp, Atom windele, Window *wnd, GLXContext *gc, bool *mul
                                       GLX_X_RENDERABLE, True,
                                       GLX_DOUBLEBUFFER, True,
                                       GLX_DEPTH_SIZE, 1,
+                                      GLX_STENCIL_SIZE, 1,
                                       None};
   
   if(!XIInit(disp, xi_opcode))
     return false;
 
   bool ok = false;
-  *multisample = true;
 
   int nElements;
   GLXFBConfig *fbConfig = glXChooseFBConfig(disp, DefaultScreen(disp), msAttributeList, &nElements);
@@ -280,7 +267,6 @@ bool GLXinit(Display *disp, Atom windele, Window *wnd, GLXContext *gc, bool *mul
       XFree(fbConfig);
     }
 
-    *multisample = false;
     fbConfig = glXChooseFBConfig(disp, DefaultScreen(disp), attributeList, &nElements);
   }
 
@@ -362,17 +348,15 @@ int main() {
   Window wnd;
   GLXContext gc;
 
-  bool multisample;
   int xi_opcode;
   int pointer;
-  if(!GLXinit(disp, windele, &wnd, &gc, &multisample, &xi_opcode, &pointer))
+  if(!GLXinit(disp, windele, &wnd, &gc, &xi_opcode, &pointer))
     return 1;
 
   glewInit();
 
-  resize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
+  Zoom::Game game;
-
+  game.resize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
-  Zoom::Game game(multisample);
 
   GLint samples;
   glGetIntegerv(GL_SAMPLES, &samples);
@@ -394,7 +378,7 @@ int main() {
       XNextEvent(disp, &event);
       switch(event.type) {
         case ConfigureNotify:
-          resize(event.xconfigure.width, event.xconfigure.height);
+          game.resize(event.xconfigure.width, event.xconfigure.height);
           break;
 
         case ClientMessage: