TessellationExample(void)
: shape_instr(make_shape.Instructions(PrimitiveType::Patches))
, shape_indices(make_shape.Indices())
, vs(ObjectDesc("Vertex"))
, cs(ObjectDesc("Tessellation Control"))
, es(ObjectDesc("Tessellation Evaluation"))
, gs(ObjectDesc("Geometry"))
, fs(ObjectDesc("Fragment"))
, projection_matrix(prog, "ProjectionMatrix")
, camera_matrix(prog, "CameraMatrix")
, model_matrix(prog, "ModelMatrix")
, offset(prog, "Offset")
, view_position(prog, "ViewPosition")
, viewport_dimensions(prog, "ViewportDimensions")
{
vs.Source(
"#version 330\n"
"uniform vec3 ViewPosition;"
"in vec3 Position;"
"out vec3 vertPosition;"
"out float vertDistance;"
"void main(void)"
"{"
" vertPosition = Position;"
" vertDistance = length(ViewPosition - vertPosition);"
"}"
);
vs.Compile();
cs.Source(
"#version 330\n"
"#extension ARB_tessellation_shader : enable\n"
"layout(vertices = 3) out;"
"in vec3 vertPosition[];"
"in float vertDistance[];"
"out vec3 tecoPosition[];"
"int tessLevel(float dist)"
"{"
" return int(9.0 / sqrt(dist+0.1));"
"}"
"void main(void)"
"{"
" tecoPosition[gl_InvocationID] ="
" vertPosition[gl_InvocationID];"
" if(gl_InvocationID == 0)"
" {"
" gl_TessLevelInner[0] = tessLevel(("
" vertDistance[0]+"
" vertDistance[1]+"
" vertDistance[2] "
" )*0.333);"
" gl_TessLevelOuter[0] = tessLevel(("
" vertDistance[1]+"
" vertDistance[2] "
" )*0.5);"
" gl_TessLevelOuter[1] = tessLevel(("
" vertDistance[2]+"
" vertDistance[0] "
" )*0.5);"
" gl_TessLevelOuter[2] = tessLevel(("
" vertDistance[0]+"
" vertDistance[1] "
" )*0.5);"
" }"
"}"
);
cs.Compile();
es.Source(
"#version 330\n"
"#extension ARB_tessellation_shader : enable\n"
"layout(triangles, equal_spacing, ccw) in;"
"const vec3 LightPosition = vec3(12.0, 10.0, 7.0);"
"uniform mat4 ProjectionMatrix, CameraMatrix, ModelMatrix;"
"in vec3 tecoPosition[];"
"out vec3 teevNormal;"
"out vec3 teevLightDir;"
"void main(void)"
"{"
" vec3 p0 = gl_TessCoord.x * tecoPosition[0];"
" vec3 p1 = gl_TessCoord.y * tecoPosition[1];"
" vec3 p2 = gl_TessCoord.z * tecoPosition[2];"
" vec4 tempPosition = vec4(normalize(p0+p1+p2), 0.0);"
" teevNormal = (ModelMatrix * tempPosition).xyz;"
" tempPosition.w = 1.0;"
" tempPosition = ModelMatrix * tempPosition;"
" teevLightDir = LightPosition - tempPosition.xyz;"
" gl_Position = "
" ProjectionMatrix *"
" CameraMatrix *"
" tempPosition;"
"}"
);
es.Compile();
gs.Source(
"#version 330\n"
"layout (triangles) in;"
"layout (triangle_strip, max_vertices = 3) out;"
"uniform vec3 Offset;"
"uniform vec2 ViewportDimensions;"
"in vec3 teevNormal[], teevLightDir[];"
"noperspective out vec3 geomDist;"
"flat out vec3 geomNormal;"
"out vec3 geomColor;"
"out vec3 geomLightDir;"
"void main(void)"
"{"
" geomNormal = normalize("
" teevNormal[0]+"
" teevNormal[1]+"
" teevNormal[2]"
" );"
" vec2 ScreenPos[3];"
" for(int i=0; i!=3; ++i)"
" {"
" ScreenPos[i] = "
" ViewportDimensions*"
" gl_in[i].gl_Position.xy/"
" gl_in[i].gl_Position.w;"
" }"
" vec2 TmpVect[3];"
" for(int i=0; i!=3; ++i)"
" {"
" TmpVect[i] = "
" ScreenPos[(i+2)%3]-"
" ScreenPos[(i+1)%3];"
" }"
" const vec3 EdgeMask[3] = vec3[3]("
" vec3(1.0, 0.0, 0.0),"
" vec3(0.0, 1.0, 0.0),"
" vec3(0.0, 0.0, 1.0) "
" );"
" for(int i=0; i!=3; ++i)"
" {"
" float Dist = abs("
" TmpVect[(i+1)%3].x*TmpVect[(i+2)%3].y-"
" TmpVect[(i+1)%3].y*TmpVect[(i+2)%3].x "
" ) / length(TmpVect[i]);"
" vec3 DistVect = vec3(Dist, Dist, Dist);"
" gl_Position = gl_in[i].gl_Position;"
" geomColor = normalize(abs("
" vec3(2.0, 2.0, 2.0)-"
" teevNormal[i]-"
" Offset"
" ));"
" geomLightDir = teevLightDir[i];"
" geomDist = EdgeMask[i] * DistVect;"
" EmitVertex();"
" }"
" EndPrimitive();"
"}"
);
gs.Compile();
fs.Source(
"#version 330\n"
"noperspective in vec3 geomDist;"
"flat in vec3 geomNormal;"
"in vec3 geomColor;"
"in vec3 geomLightDir;"
"out vec3 fragColor;"
"void main(void)"
"{"
" float MinDist = min(min(geomDist.x,geomDist.y),geomDist.z);"
" float EdgeAlpha = exp2(-pow(MinDist, 2.0));"
" const float Ambient = 0.8;"
" float Diffuse = max(dot("
" normalize(geomNormal),"
" normalize(geomLightDir)"
" ), 0.0);"
" vec3 FaceColor = geomColor * (Diffuse + Ambient);"
" const vec3 EdgeColor = vec3(0.0, 0.0, 0.0);"
" fragColor = mix(FaceColor, EdgeColor, EdgeAlpha);"
"}"
);
fs.Compile();
prog.AttachShader(vs);
prog.AttachShader(cs);
prog.AttachShader(es);
prog.AttachShader(gs);
prog.AttachShader(fs);
prog.Link();
prog.Use();
shape.Bind();
verts.Bind(Buffer::Target::Array);
{
std::vector<GLfloat> data;
GLuint n_per_vertex = make_shape.Positions(data);
Buffer::Data(Buffer::Target::Array, data);
VertexAttribArray attr(prog, "Position");
attr.Setup<GLfloat>(n_per_vertex);
attr.Enable();
indices.Bind(Buffer::Target::ElementArray);
Buffer::Data(Buffer::Target::ElementArray, shape_indices);
shape_indices.clear();
}
//
gl.ClearColor(0.8f, 0.8f, 0.8f, 0.0f);
gl.ClearDepth(1.0f);
gl.Enable(Capability::DepthTest);
prog.Use();
}
TessellationExample(void)
: shape_instr(make_shape.Instructions())
, shape_indices(make_shape.Indices())
, tess_level(prog)
, viewport_dimensions(prog)
, projection_matrix(prog)
, camera_matrix(prog)
, model_matrix(prog)
{
vs.Source(
"#version 330\n"
"in vec4 Position;"
"void main(void)"
"{"
" gl_Position = Position;"
"}"
);
vs.Compile();
gs.Source(
"#version 330\n"
"layout (triangles) in;"
"layout (triangle_strip, max_vertices = 48) out;"
"const vec3 LightPosition = vec3(12.0, 10.0, 7.0);"
"uniform mat4 ProjectionMatrix, CameraMatrix, ModelMatrix;"
"uniform vec2 ViewportDimensions;"
"uniform int TessLevel;"
"noperspective out vec3 geomDist;"
"flat out vec3 geomNormal;"
"out vec3 geomColor;"
"out vec3 geomLightDir;"
"void make_triangle(vec4 p0, vec4 p1, vec4 p2)"
"{"
" vec3 n0 = (ModelMatrix*vec4(p0.xyz, 0)).xyz;"
" vec3 n1 = (ModelMatrix*vec4(p1.xyz, 0)).xyz;"
" vec3 n2 = (ModelMatrix*vec4(p2.xyz, 0)).xyz;"
" vec4 m0 = ModelMatrix*p0;"
" vec4 m1 = ModelMatrix*p1;"
" vec4 m2 = ModelMatrix*p2;"
" vec4 c0 = ProjectionMatrix*CameraMatrix*m0;"
" vec4 c1 = ProjectionMatrix*CameraMatrix*m1;"
" vec4 c2 = ProjectionMatrix*CameraMatrix*m2;"
" vec2 s0 = ViewportDimensions * c0.xy/c0.w;"
" vec2 s1 = ViewportDimensions * c1.xy/c1.w;"
" vec2 s2 = ViewportDimensions * c2.xy/c2.w;"
" vec2 v0 = s2 - s1;"
" vec2 v1 = s0 - s2;"
" vec2 v2 = s1 - s0;"
" float d0 = abs(v1.x*v2.y-v1.y*v2.x)/length(v0);"
" float d1 = abs(v2.x*v0.y-v2.y*v0.x)/length(v1);"
" float d2 = abs(v0.x*v1.y-v0.y*v1.x)/length(v2);"
" geomNormal = normalize(n0+n1+n2);"
" gl_Position = c0;"
" geomColor = normalize(abs(vec3(1, 1, 1) - n0));"
" geomLightDir = LightPosition - m0.xyz;"
" geomDist = vec3(d0, 0.0, 0.0);"
" EmitVertex();"
" gl_Position = c1;"
" geomColor = normalize(abs(vec3(1, 1, 1) - n1));"
" geomLightDir = LightPosition - m1.xyz;"
" geomDist = vec3(0.0, d1, 0.0);"
" EmitVertex();"
" gl_Position = c2;"
" geomColor = normalize(abs(vec3(1, 1, 1) - n2));"
" geomLightDir = LightPosition - m2.xyz;"
" geomDist = vec3(0.0, 0.0, d2);"
" EmitVertex();"
" EndPrimitive();"
"}"
"void do_tess_1(vec4 p_0, vec4 p_1, vec4 p_2, int l)"
"{"
" if(l == 1) make_triangle(p_0, p_1, p_2);"
" else"
" {"
" vec4 p01 = vec4(normalize(p_0.xyz+p_1.xyz), 1.0);"
" vec4 p12 = vec4(normalize(p_1.xyz+p_2.xyz), 1.0);"
" vec4 p20 = vec4(normalize(p_2.xyz+p_0.xyz), 1.0);"
" make_triangle(p_0, p01, p20);"
" make_triangle(p01, p_1, p12);"
" make_triangle(p20, p12, p_2);"
" make_triangle(p01, p12, p20);"
" }"
"}"
"void do_tess_0(vec4 p_0, vec4 p_1, vec4 p_2, int l)"
"{"
" if(l == 0) make_triangle(p_0, p_1, p_2);"
" else"
" {"
" vec4 p01 = vec4(normalize(p_0.xyz+p_1.xyz), 1.0);"
" vec4 p12 = vec4(normalize(p_1.xyz+p_2.xyz), 1.0);"
" vec4 p20 = vec4(normalize(p_2.xyz+p_0.xyz), 1.0);"
" do_tess_1(p_0, p01, p20, l);"
" do_tess_1(p01, p_1, p12, l);"
" do_tess_1(p20, p12, p_2, l);"
" do_tess_1(p01, p12, p20, l);"
" }"
"}"
"void main(void)"
"{"
" do_tess_0("
" gl_in[0].gl_Position,"
" gl_in[1].gl_Position,"
" gl_in[2].gl_Position,"
" TessLevel"
" );"
"}"
);
gs.Compile();
fs.Source(
"#version 330\n"
"noperspective in vec3 geomDist;"
"flat in vec3 geomNormal;"
"in vec3 geomColor;"
"in vec3 geomLightDir;"
"out vec3 fragColor;"
"void main(void)"
"{"
" float MinDist = min(min(geomDist.x,geomDist.y),geomDist.z);"
" float EdgeAlpha = exp2(-pow(MinDist, 2.0));"
" const float Ambient = 0.7;"
" float Diffuse = max(dot("
" normalize(geomNormal),"
" normalize(geomLightDir)"
" )+0.1, 0.0)*1.4;"
" vec3 FaceColor = geomColor * (Diffuse + Ambient);"
" const vec3 EdgeColor = vec3(0.0, 0.0, 0.0);"
" fragColor = mix(FaceColor, EdgeColor, EdgeAlpha);"
"}"
);
fs.Compile();
prog.AttachShader(vs);
prog.AttachShader(gs);
prog.AttachShader(fs);
prog.Link();
prog.Use();
tess_level.BindTo("TessLevel");
viewport_dimensions.BindTo("ViewportDimensions");
projection_matrix.BindTo("ProjectionMatrix");
camera_matrix.BindTo("CameraMatrix");
model_matrix.BindTo("ModelMatrix");
shape.Bind();
verts.Bind(Buffer::Target::Array);
{
std::vector<GLfloat> data;
GLuint n_per_vertex = make_shape.Positions(data);
Buffer::Data(Buffer::Target::Array, data);
VertexArrayAttrib attr(prog, "Position");
attr.Setup<GLfloat>(n_per_vertex);
attr.Enable();
indices.Bind(Buffer::Target::ElementArray);
Buffer::Data(Buffer::Target::ElementArray, shape_indices);
shape_indices.clear();
}
//
gl.ClearColor(0.7f, 0.7f, 0.7f, 0.0f);
gl.ClearDepth(1.0f);
gl.Enable(Capability::DepthTest);
prog.Use();
}