source/shadowmap.cpp

   1 #include <cmath>
   2 #include <cstdlib>
   3 #include "camera.h"
   4 #include "light.h"
   5 #include "matrix.h"
   6 #include "misc.h"
   7 #include "renderer.h"
   8 #include "scene.h"
   9 #include "shadowmap.h"
  10 #include "tests.h"
  11 #include "texunit.h"
  12
  13 using namespace std;
  14
  15 namespace Msp {
  16 namespace GL {
  17
  18 ShadowMap::ShadowMap(unsigned s, const Renderable &r, const Light &l):
  19         Effect(r),
  20         size(s),
  21         light(l),
  22         radius(1),
  23         depth_bias(4),
  24         rendered(false)
  25 {
  26         depth_buf.set_min_filter(LINEAR);
  27         depth_buf.set_compare_enabled(true);
  28         depth_buf.set_compare_func(LEQUAL);
  29         depth_buf.set_wrap(CLAMP_TO_EDGE);
  30         depth_buf.storage(DEPTH_COMPONENT, size, size);
  31         fbo.attach(DEPTH_ATTACHMENT, depth_buf, 0);
  32         fbo.require_complete();
  33
  34         set_darkness(0.7);
  35 }
  36
  37 void ShadowMap::set_target(const Vector3 &t, float r)
  38 {
  39         target = t;
  40         radius = r;
  41 }
  42
  43 void ShadowMap::set_darkness(float d)
  44 {
  45         if(d<0.0f || d>1.0f)
  46                 throw invalid_argument("ShadowMap::set_darkness");
  47
  48         shdata.uniform("shadow_darkness", d);
  49 }
  50
  51 void ShadowMap::set_depth_bias(float b)
  52 {
  53         if(b<0.0f)
  54                 throw invalid_argument("ShadowMap::set_depth_bias");
  55
  56         depth_bias = b;
  57 }
  58
  59 void ShadowMap::setup_frame() const
  60 {
  61         if(rendered)
  62                 return;
  63
  64         renderable.setup_frame();
  65         rendered = true;
  66
  67         const Vector4 &lpos = light.get_position();
  68         Vector3 back;
  69         if(lpos.w)
  70         {
  71                 /* XXX Not really proper way to support positional lights, but good
  72                 enough when the light source is far away */
  73                 back = Vector3(lpos)-target;
  74         }
  75         else
  76                 back = Vector3(lpos);
  77         back.normalize();
  78
  79         Vector3 up;
  80         if(abs(back.z)<0.99)
  81                 up = Vector3(0, 0, 1);
  82         else
  83                 up = Vector3(0, 1, 0);
  84
  85         Vector3 right = normalize(cross(up, back));
  86
  87         Vector4 columns[4];
  88         columns[0] = Vector4(right, 0.0f);
  89         columns[1] = Vector4(normalize(cross(back, right)), 0.0f);
  90         columns[2] = Vector4(back, 0.0f);
  91         columns[3] = Vector4(target, 1.0f);
  92         light_matrix = Matrix::from_columns(columns);
  93         view_matrix = invert(light_matrix);
  94
  95         MatrixStack::Push push_mv(MatrixStack::modelview());
  96         MatrixStack::Push push_proj(MatrixStack::projection());
  97
  98         MatrixStack::projection() = Matrix::ortho(-radius, radius, -radius, radius, -radius, radius);
  99         MatrixStack::modelview() = view_matrix;
 100
 101         shadow_matrix = light_matrix;
 102         shadow_matrix.scale(radius*2, radius*2, -radius*2);
 103         shadow_matrix.translate(-0.5, -0.5, depth_bias/size-0.5);
 104         shadow_matrix.invert();
 105
 106         BindRestore bind_fbo(fbo);
 107         Bind bind_depth(DepthTest::lequal());
 108         fbo.clear(DEPTH_BUFFER_BIT);
 109         renderable.render("shadow");
 110 }
 111
 112 void ShadowMap::finish_frame() const
 113 {
 114         renderable.finish_frame();
 115         rendered = false;
 116 }
 117
 118 void ShadowMap::render(Renderer &renderer, const Tag &tag) const
 119 {
 120         if(!enabled_passes.count(tag))
 121                 return renderer.render(renderable, tag);
 122
 123         Renderer::Push _push_rend(renderer);
 124
 125         unsigned unit = renderer.allocate_effect_texunit();
 126         int iunit = unit;
 127         shdata.uniform("shadow", iunit);
 128
 129         Bind _bind_depth(depth_buf, unit);
 130
 131         if(const Camera *camera = renderer.get_camera())
 132                 /* Multiply by camera's object matrix to form a matrix that transforms
 133                 from eye space to shadow space. */
 134                 shdata.uniform("shd_eye_matrix", shadow_matrix*camera->get_object_matrix());
 135         else
 136                 shdata.uniform("shd_eye_matrix", shadow_matrix);
 137
 138         renderer.add_shader_data(shdata);
 139         renderer.render(renderable, tag);
 140 }
 141
 142 } // namespace GL
 143 } // namespace Msp