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 "texgen.h"
  12 #include "texunit.h"
  13
  14 using namespace std;
  15
  16 namespace Msp {
  17 namespace GL {
  18
  19 ShadowMap::ShadowMap(unsigned s, const Renderable &r, const Light &l):
  20         Effect(r),
  21         size(s),
  22         light(l),
  23         radius(1),
  24         depth_bias(4),
  25         rendered(false)
  26 {
  27         depth_buf.set_min_filter(LINEAR);
  28         depth_buf.set_compare_enabled(true);
  29         depth_buf.set_compare_func(LEQUAL);
  30         depth_buf.set_wrap(CLAMP_TO_EDGE);
  31         depth_buf.storage(DEPTH_COMPONENT, size, size);
  32         fbo.attach(DEPTH_ATTACHMENT, depth_buf, 0);
  33         fbo.require_complete();
  34
  35         set_darkness(0.7);
  36 }
  37
  38 void ShadowMap::set_target(const Vector3 &t, float r)
  39 {
  40         target = t;
  41         radius = r;
  42 }
  43
  44 void ShadowMap::set_darkness(float d)
  45 {
  46         if(d<0.0f || d>1.0f)
  47                 throw invalid_argument("ShadowMap::set_darkness");
  48
  49         shdata.uniform("shadow_darkness", d);
  50 }
  51
  52 void ShadowMap::set_depth_bias(float b)
  53 {
  54         if(b<0.0f)
  55                 throw invalid_argument("ShadowMap::set_depth_bias");
  56
  57         depth_bias = b;
  58 }
  59
  60 void ShadowMap::setup_frame() const
  61 {
  62         if(rendered)
  63                 return;
  64
  65         renderable.setup_frame();
  66         rendered = true;
  67
  68         const Vector4 &lpos = light.get_position();
  69         Vector3 back;
  70         if(lpos.w)
  71         {
  72                 /* XXX Not really proper way to support positional lights, but good
  73                 enough when the light source is far away */
  74                 back = Vector3(lpos)-target;
  75         }
  76         else
  77                 back = Vector3(lpos);
  78         back.normalize();
  79
  80         Vector3 up;
  81         if(abs(back.z)<0.99)
  82                 up = Vector3(0, 0, 1);
  83         else
  84                 up = Vector3(0, 1, 0);
  85
  86         Vector3 right = normalize(cross(up, back));
  87
  88         Vector4 columns[4];
  89         columns[0] = Vector4(right, 0.0f);
  90         columns[1] = Vector4(normalize(cross(back, right)), 0.0f);
  91         columns[2] = Vector4(back, 0.0f);
  92         columns[3] = Vector4(target, 1.0f);
  93         light_matrix = Matrix::from_columns(columns);
  94         view_matrix = invert(light_matrix);
  95
  96         MatrixStack::Push push_mv(MatrixStack::modelview());
  97         MatrixStack::Push push_proj(MatrixStack::projection());
  98
  99         MatrixStack::projection() = Matrix::ortho(-radius, radius, -radius, radius, -radius, radius);
 100         MatrixStack::modelview() = view_matrix;
 101
 102         shadow_matrix = light_matrix;
 103         shadow_matrix.scale(radius*2, radius*2, -radius*2);
 104         shadow_matrix.translate(-0.5, -0.5, depth_bias/size-0.5);
 105         shadow_matrix.invert();
 106
 107         Bind bind_fbo(fbo, true);
 108         Bind bind_depth(DepthTest::lequal());
 109         fbo.clear(DEPTH_BUFFER_BIT);
 110         renderable.render("shadow");
 111 }
 112
 113 void ShadowMap::finish_frame() const
 114 {
 115         renderable.finish_frame();
 116         rendered = false;
 117 }
 118
 119 void ShadowMap::render(Renderer &renderer, const Tag &tag) const
 120 {
 121         if(!enabled_passes.count(tag))
 122                 return renderer.render(renderable, tag);
 123
 124         Renderer::Push _push_rend(renderer);
 125
 126         unsigned unit = renderer.allocate_effect_texunit();
 127         int iunit = unit;
 128         shdata.uniform("shadow", iunit);
 129         shdata.uniform("shadow_unit", iunit);
 130
 131         depth_buf.bind_to(unit);
 132         TexGen tg_s, tg_t, tg_r;
 133         tg_s.set_plane(Vector4(shadow_matrix(0, 0), shadow_matrix(0, 1), shadow_matrix(0, 2), shadow_matrix(0, 3)));
 134         tg_t.set_plane(Vector4(shadow_matrix(1, 0), shadow_matrix(1, 1), shadow_matrix(1, 2), shadow_matrix(1, 3)));
 135         tg_r.set_plane(Vector4(shadow_matrix(2, 0), shadow_matrix(2, 1), shadow_matrix(2, 2), shadow_matrix(2, 3)));
 136         tg_s.bind_to(unit, SCOORD);
 137         tg_t.bind_to(unit, TCOORD);
 138         tg_r.bind_to(unit, RCOORD);
 139
 140         if(const Camera *camera = renderer.get_camera())
 141                 /* Multiply by camera's object matrix to form a matrix that transforms
 142                 from eye space to shadow space. */
 143                 shdata.uniform("shd_eye_matrix", shadow_matrix*camera->get_object_matrix());
 144         else
 145                 shdata.uniform("shd_eye_matrix", shadow_matrix);
 146
 147         renderer.add_shader_data(shdata);
 148         renderer.render(renderable, tag);
 149
 150         Texture::unbind_from(unit);
 151         TexGen::unbind_from(unit, SCOORD);
 152         TexGen::unbind_from(unit, TCOORD);
 153         TexGen::unbind_from(unit, RCOORD);
 154 }
 155
 156 } // namespace GL
 157 } // namespace Msp