-#include <cmath>
-#include "meshbuilder.h"
-#include "oculusriftcombiner.h"
-#include "texture2d.h"
-
-using namespace std;
-
-namespace {
-
-const char vs_source[] =
- "uniform float offset;\n"
- "uniform vec2 lens_center;\n"
- "uniform vec3 scale;\n"
- "varying vec2 texcoord;\n"
- "void main()\n"
- "{\n"
- " gl_Position = vec4(gl_Vertex.x*0.5+offset, gl_Vertex.yzw);\n"
- " texcoord = (gl_Vertex.xy*0.5+0.5-lens_center)*scale.xy;\n"
- "}\n";
-
-const char fs_source[] =
- "uniform sampler2D texture;\n"
- "uniform vec4 distortion;\n"
- "uniform vec2 eye_center;\n"
- "uniform vec3 scale;\n"
- "varying vec2 texcoord;\n"
- "vec2 distort(vec2 coord)\n"
- "{\n"
- " float r_sq = dot(coord, coord);\n"
- " return coord*dot(distortion, vec4(1.0, r_sq, r_sq*r_sq, r_sq*r_sq*r_sq));\n"
- "}\n"
- "void main()\n"
- "{\n"
- " vec2 dtc = (distort(texcoord)-eye_center)/(scale.xy*scale.z)+0.5;\n"
- " if(dtc.x<0.0 || dtc.y<0.0 || dtc.x>1.0 || dtc.y>1.0)\n"
- " gl_FragColor = vec4(0.0);\n"
- " else\n"
- " gl_FragColor = texture2D(texture, dtc);\n"
- "}\n";
-
-}
-
-namespace Msp {
-namespace GL {
-
-OculusRiftCombiner::OculusRiftCombiner():
- mesh(VERTEX2),
- shprog(vs_source, fs_source),
- // Default values copied from the SDK
- view_distance(0.438f),
- lens_separation(0.424f),
- eye_separation(0.42735f),
- fill_factor(0.95f)
-{
- width_div = 2;
-
- left_shdata.uniform("texture", 0);
- left_shdata.uniform("offset", -0.5f);
- right_shdata.uniform("texture", 0);
- right_shdata.uniform("offset", 0.5f);
-
- // This will also call update_parameters
- set_distortion(1.0f, 0.22f, 0.24f);
-
- MeshBuilder bld(mesh);
- bld.begin(TRIANGLE_STRIP);
- bld.vertex(-1, 1);
- bld.vertex(-1, -1);
- bld.vertex(1, 1);
- bld.vertex(1, -1);
- bld.end();
-}
-
-void OculusRiftCombiner::set_view_distance(float d)
-{
- view_distance = d;
- update_parameters();
-}
-
-void OculusRiftCombiner::set_lens_separation(float s)
-{
- lens_separation = s;
- update_parameters();
-}
-
-void OculusRiftCombiner::set_eye_separation(float s)
-{
- eye_separation = s;
- update_parameters();
-}
-
-void OculusRiftCombiner::set_distortion(float d0, float d1, float d2, float d3)
-{
- distortion[0] = d0;
- distortion[1] = d1;
- distortion[2] = d2;
- distortion[3] = d3;
-
- update_parameters();
-}
-
-void OculusRiftCombiner::set_fill_factor(float f)
-{
- fill_factor = f;
- update_parameters();
-}
-
-void OculusRiftCombiner::update_parameters()
-{
- left_shdata.uniform4("distortion", distortion);
- right_shdata.uniform4("distortion", distortion);
-
- // Set lens center positions, in output texture coordinates
- left_shdata.uniform("lens_center", 1.0f-lens_separation, 0.5);
- right_shdata.uniform("lens_center", lens_separation, 0.5);
-
- /* Compute distance between eye and lens centers, in sampling texture
- coordinates. */
- float eye_offset = distort((eye_separation-lens_separation)*2);
- left_shdata.uniform("eye_center", -eye_offset, 0.0f);
- right_shdata.uniform("eye_center", eye_offset, 0.0f);
-
- /* Determine the necessary scaling factor to avoid quality degradation in
- the center of the screen. */
- float horiz_oversize = distort((fill_factor-lens_separation)*2)-eye_offset;
- float vert_oversize = distort(1.25f*fill_factor)/(1.25f*fill_factor);
- oversize = min(horiz_oversize, vert_oversize);
-
- left_shdata.uniform("scale", 2.0f, 2.5f, oversize);
- right_shdata.uniform("scale", 2.0f, 2.5f, oversize);
-
- fov = Geometry::atan(oversize*0.625f/view_distance)*2.0f;
-}
-
-float OculusRiftCombiner::distort(float r) const
-{
- float r_sq = r*r;
- return r*(distortion[0]+(distortion[1]+(distortion[2]+distortion[3]*r_sq)*r_sq)*r_sq);
-}
-
-float OculusRiftCombiner::undistort(float r) const
-{
- float x = r;
- while(1)
- {
- float y = distort(x);
- if(abs(r-y)<1e-5)
- return x;
-
- float x_sq = x*x;
- float d = distortion[0]+(3*distortion[1]+(5*distortion[2]+7*distortion[3]*x_sq)*x_sq)*x_sq;
- x -= (y-r)/d;
- }
-}
-
-void OculusRiftCombiner::render(const Texture2D &left, const Texture2D &right) const
-{
- Bind bind_shprog(shprog);
-
- Bind bind_tex(left);
- left_shdata.apply();
- mesh.draw();
-
- right.bind();
- right_shdata.apply();
- mesh.draw();
-}
-
-} // namespace GL
-} // namespace Msp