--- /dev/null
+/* $Id$
+
+This file is part of libmspgl
+Copyright © 2010 Mikko Rasa, Mikkosoft Productions
+Distributed under the LGPL
+*/
+
+#include <cmath>
+#include "ambientocclusion.h"
+#include "blend.h"
+#include "meshbuilder.h"
+#include "tests.h"
+
+namespace {
+
+const char vertex_shader[] =
+ "varying vec2 texcoord;\n"
+ "void main()\n"
+ "{\n"
+ " gl_Position = gl_Vertex;\n"
+ " texcoord = gl_Vertex.xy*0.5+0.5;\n"
+ "}\n";
+
+const char occlude_fs[] =
+ "uniform sampler2D depth;\n"
+ "uniform sampler2D rotate;\n"
+ "uniform vec2 screen_size;\n"
+ "uniform vec2 depth_ratio;\n"
+ "uniform float darkness;\n"
+ "varying vec2 texcoord;\n"
+ "void main()\n"
+ "{\n"
+ " mat2 transform = mat2(texture2D(rotate, texcoord*screen_size/4.0)*2.0-1.0)\n"
+ " *mat2(screen_size.y/screen_size.x, 0.0, 0.0, 1.0)*0.02;\n"
+ " float depth_avg = 0.0;\n"
+ " for(int i=0; i<=3; ++i)\n"
+ " for(int j=0; j<=3; ++j)\n"
+ " {\n"
+ " vec2 offs = transform*vec2(float(i)-1.5, float(j)-1.5);\n"
+ " depth_avg += depth_ratio.x/(texture2D(depth, texcoord+offs).r-depth_ratio.y);\n"
+ " }\n"
+ " depth_avg /= 16;\n"
+ " float sample = depth_ratio.x/(texture2D(depth, texcoord).r-depth_ratio.y);\n"
+ " float diff = sample-depth_avg;\n"
+ " float shade = min(diff*darkness, 0.0)+1.0;\n"
+ " gl_FragColor = vec4(shade, 0.0, 0.0, 1.0);\n"
+ "}\n";
+
+const char combine_fs[] =
+ "uniform sampler2D color;\n"
+ "uniform sampler2D depth;\n"
+ "uniform sampler2D occlusion;\n"
+ "uniform vec2 screen_size;\n"
+ "uniform vec2 depth_ratio;\n"
+ "uniform float edge_threshold;\n"
+ "varying vec2 texcoord;\n"
+ "void main()\n"
+ "{\n"
+ " float sample = depth_ratio.x/(texture2D(depth, texcoord).r-depth_ratio.y);\n"
+ " float sum = 1.0;\n"
+ " float count = 1.0;\n"
+ " for(int i=0; i<=3; ++i)\n"
+ " for(int j=0; j<=3; ++j)\n"
+ " {\n"
+ " vec2 offs = vec2(float(i)-1.5, float(j)-1.5)/screen_size;\n"
+ " float depth = depth_ratio.x/(texture2D(depth, texcoord+offs).r-depth_ratio.y);\n"
+ " if(abs(depth-sample)<edge_threshold)\n"
+ " {\n"
+ " sum += texture2D(occlusion, texcoord+offs).r;\n"
+ " count += 1.0;\n"
+ " }\n"
+ " }\n"
+ " gl_FragColor = texture2D(color, texcoord)*sum/count;\n"
+ "}\n";
+
+}
+
+namespace Msp {
+namespace GL {
+
+AmbientOcclusion::AmbientOcclusion(unsigned w, unsigned h, float depth_ratio):
+ occlude_shader(vertex_shader, occlude_fs),
+ combine_shader(vertex_shader, combine_fs),
+ quad(VERTEX2)
+{
+ occlusion.storage(GL::RGB, w, h);
+ occlusion.set_min_filter(GL::NEAREST);
+ occlusion.set_mag_filter(GL::NEAREST);
+ fbo.attach(COLOR_ATTACHMENT0, occlusion, 0);
+
+ combine_texturing.attach(2, occlusion);
+
+ rotate_lookup.storage(GL::RGBA, 4, 4);
+ rotate_lookup.set_min_filter(GL::NEAREST);
+ rotate_lookup.set_mag_filter(GL::NEAREST);
+ unsigned char data[64];
+ for(unsigned i=0; i<16; ++i)
+ {
+ float a = ((i*541)%16)*M_PI/32;
+ float c = cos(a);
+ float s = sin(a);
+ data[i*3 ] = static_cast<unsigned char>(127+c*127);
+ data[i*3+1] = static_cast<unsigned char>(127+s*127);
+ data[i*3+2] = static_cast<unsigned char>(127-s*127);
+ data[i*3+4] = static_cast<unsigned char>(127+c*127);
+ }
+ rotate_lookup.image(0, GL::RGBA, GL::UNSIGNED_BYTE, data);
+
+ occlude_texturing.attach(1, rotate_lookup);
+
+ depth_ratio = 1/depth_ratio;
+
+ occlude_shdata.uniform(occlude_shader.get_uniform_location("depth"), 0);
+ occlude_shdata.uniform(occlude_shader.get_uniform_location("rotate"), 1);
+ occlude_shdata.uniform(occlude_shader.get_uniform_location("screen_size"), w, h);
+ occlude_shdata.uniform(occlude_shader.get_uniform_location("depth_ratio"), depth_ratio, 1+depth_ratio);
+
+ combine_shdata.uniform(combine_shader.get_uniform_location("color"), 1);
+ combine_shdata.uniform(combine_shader.get_uniform_location("depth"), 0);
+ combine_shdata.uniform(combine_shader.get_uniform_location("occlusion"), 2);
+ combine_shdata.uniform(combine_shader.get_uniform_location("screen_size"), w, h);
+ combine_shdata.uniform(combine_shader.get_uniform_location("depth_ratio"), depth_ratio, 1+depth_ratio);
+ combine_shdata.uniform(combine_shader.get_uniform_location("edge_threshold"), 0.05f);
+
+ set_darkness(15);
+
+ MeshBuilder bld(quad);
+ bld.begin(TRIANGLE_STRIP);
+ bld.vertex(-1, -1);
+ bld.vertex(-1, 1);
+ bld.vertex(1, -1);
+ bld.vertex(1, 1);
+ bld.end();
+}
+
+void AmbientOcclusion::set_darkness(float d)
+{
+ darkness = d;
+ occlude_shdata.uniform(occlude_shader.get_uniform_location("darkness"), darkness);
+}
+
+void AmbientOcclusion::render(const Texture2D &color, const Texture2D &depth)
+{
+ occlude_texturing.attach(0, depth);
+ combine_texturing.attach(0, depth);
+ combine_texturing.attach(1, color);
+
+ Bind unbind_dtest(static_cast<DepthTest *>(0), true);
+ Bind unbind_blend(static_cast<Blend *>(0), true);
+
+ {
+ GL::Bind bind_fbo(fbo, true);
+ GL::Bind bind_tex(occlude_texturing);
+ GL::Bind bind_shader(occlude_shader);
+ occlude_shdata.apply();
+ quad.draw();
+ }
+
+ GL::Bind bind_tex(combine_texturing);
+ GL::Bind bind_shader(combine_shader);
+ combine_shdata.apply();
+ quad.draw();
+}
+
+} // namespace GL
+} // namespace Msp
--- /dev/null
+/* $Id$
+
+This file is part of libmspgl
+Copyright © 2010 Mikko Rasa, Mikkosoft Productions
+Distributed under the LGPL
+*/
+
+#ifndef MSP_GL_AMBIENTOCCLUSION_H_
+#define MSP_GL_AMBIENTOCCLUSION_H_
+
+#include "framebuffer.h"
+#include "mesh.h"
+#include "postprocessor.h"
+#include "program.h"
+#include "programdata.h"
+#include "texture2d.h"
+#include "texturing.h"
+
+namespace Msp {
+namespace GL {
+
+/**
+Implements screen-space ambient occlusion.
+
+http://en.wikipedia.org/wiki/Screen_Space_Ambient_Occlusion
+*/
+class AmbientOcclusion: public PostProcessor
+{
+private:
+ Texture2D occlusion;
+ Texture2D rotate_lookup;
+ Framebuffer fbo;
+ Texturing occlude_texturing;
+ Program occlude_shader;
+ ProgramData occlude_shdata;
+ Texturing combine_texturing;
+ Program combine_shader;
+ ProgramData combine_shdata;
+ Mesh quad;
+ float darkness;
+
+public:
+ AmbientOcclusion(unsigned, unsigned, float);
+
+ void set_darkness(float);
+
+ virtual void render(const Texture2D &, const Texture2D &);
+};
+
+} // namespace GL
+} // namespace Msp
+
+#endif