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authorJessie Speert <speer034@umn.edu>2021-04-12 15:41:35 -0700
committerJessie Speert <speer034@umn.edu>2021-04-12 15:41:35 -0700
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Added assignment 6 directory and worksheet
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+/** CSci-4611 Assignment 6: Harold
+ */
+
+#include "ground.h"
+
+
+Ground::Ground() : diffuse_ramp_(GL_CLAMP_TO_EDGE),
+ specular_ramp_(GL_CLAMP_TO_EDGE), light_pos_(30,30,30)
+{
+
+}
+
+Ground::~Ground() {
+
+}
+
+Mesh* Ground::mesh_ptr() { return &ground_mesh_; }
+
+
+void Ground::Init(const std::vector<std::string> &search_path) {
+ // init ground geometry, a simple grid is used. if it is running too slow,
+ // you can turn down the resolution by decreasing nx and ny, but this will
+ // make the hills look more jaggy.
+ const int nx = 150;
+ const int ny = 150;
+ const float size = 100.0;
+ std::vector<Point3> verts;
+ std::vector<Vector3> norms;
+ for (int j = 0; j <= ny; j++) {
+ for (int i = 0; i <= nx; i++) {
+ float x = size*(float)j/nx - size/2.0f;
+ float y = size*(float)i/ny - size/2.0f;
+ verts.push_back(Point3(x, 0, y));
+ norms.push_back(Vector3(0,1,0));
+ }
+ }
+ std::vector<unsigned int> indices;
+ for (int j = 0; j < ny; j++) {
+ for (int i = 0; i < nx; i++) {
+ // L\ triangle
+ indices.push_back((i+0)+(j+0)*(nx+1));
+ indices.push_back((i+1)+(j+0)*(nx+1));
+ indices.push_back((i+0)+(j+1)*(nx+1));
+ // \7 triangle
+ indices.push_back((i+1)+(j+0)*(nx+1));
+ indices.push_back((i+1)+(j+1)*(nx+1));
+ indices.push_back((i+0)+(j+1)*(nx+1));
+ }
+ }
+ ground_mesh_.SetIndices(indices);
+ ground_mesh_.SetVertices(verts);
+ ground_mesh_.SetNormals(norms);
+ ground_mesh_.UpdateGPUMemory();
+ ground_edge_mesh_.CreateFromMesh(ground_mesh_);
+
+
+ // load textures and shaders
+ diffuse_ramp_.InitFromFile(Platform::FindFile("toonDiffuse.png", search_path));
+ specular_ramp_.InitFromFile(Platform::FindFile("toonSpecular.png", search_path));
+
+ artsy_shaderprog_.AddVertexShaderFromFile(Platform::FindFile("artsy.vert", search_path));
+ artsy_shaderprog_.AddFragmentShaderFromFile(Platform::FindFile("artsy.frag", search_path));
+ artsy_shaderprog_.LinkProgram();
+
+ outline_shaderprog_.AddVertexShaderFromFile(Platform::FindFile("outline.vert", search_path));
+ outline_shaderprog_.AddFragmentShaderFromFile(Platform::FindFile("outline.frag", search_path));
+ outline_shaderprog_.LinkProgram();
+}
+
+
+
+
+// Projects a 2D normalized screen point (e.g., the mouse position in normalized
+// device coordinates) to a 3D point on the ground. Returns true and sets ground_point
+// to be equal to the result if the conversion is successful. Returns false if
+// the screen point does not project onto the ground.
+bool Ground::ScreenPtHitsGround(const Matrix4 &view_matrix, const Matrix4 &proj_matrix,
+ const Point2 &normalized_screen_pt, Point3 *ground_point)
+{
+ Matrix4 camera_matrix = view_matrix.Inverse();
+ Point3 eye = camera_matrix.ColumnToPoint3(3);
+
+ Point3 pt3d = GfxMath::ScreenToNearPlane(view_matrix, proj_matrix, normalized_screen_pt);
+ Ray ray(eye, (pt3d - eye).ToUnit());
+ float i_time;
+ int i_tri;
+ return ray.FastIntersectMesh(&ground_mesh_, &i_time, ground_point, &i_tri);
+}
+
+
+
+
+/** This implements the "h" term used in the equations described in section 4.5 of the
+ paper. Three arguments are needed:
+ 1. projection_plane_normal: We need to know where the projection plane is in 3-space
+ Since a plane can be defined by a point within the plane and a normal, we use
+ this normal together with the 3rd argument to the function to define the projection
+ plane described in the paper.
+ 2. silhouette_curve: As described in the paper, the silhouette curve is a 3D version
+ of the curve the user draws with the mouse. It is formed by projecting the
+ original 2D screen-space curve onto the 3D projection plane.
+ 3. closest_pt_in_plane: As described in the paper, this is the closest point within
+ the projection plane to the vertex of the mesh that we want to modify. In other
+ words, it is the perpendicular projection of the vertex we want to modify onto
+ the projection plane.
+ */
+float hfunc(const Vector3 projection_plane_normal, const std::vector<Point3> &silhouette_curve, const Point3 &closest_pt_in_plane) {
+ // define the y axis for a "plane space" coordinate system as a world space vector
+ Vector3 plane_y = Vector3(0,1,0);
+ // define the x axis for a "plane space" coordinate system as a world space vector
+ Vector3 plane_x = plane_y.Cross(projection_plane_normal).ToUnit();
+ // define the origin for a "plane space" coordinate system as the first point in the curve
+ Point3 origin = silhouette_curve[0];
+
+ // loop over line segments in the curve, find the one that lies over the point by
+ // comparing the "plane space" x value for the start and end of the line segment
+ // to the "plane space" x value for the closest point to the vertex that lies
+ // in the projection plane.
+ float x_target = (closest_pt_in_plane - origin).Dot(plane_x);
+ for (int i=1; i<silhouette_curve.size(); i++) {
+ float x_start = (silhouette_curve[(size_t)i-1] - origin).Dot(plane_x);
+ float x_end = (silhouette_curve[i] - origin).Dot(plane_x);
+ if ((x_start <= x_target) && (x_target <= x_end)) {
+ float alpha = (x_target - x_start) / (x_end - x_start);
+ float y_curve = silhouette_curve[(size_t)i-1][1] + alpha*(silhouette_curve[i][1] - silhouette_curve[(size_t)i-1][1]);
+ return y_curve - closest_pt_in_plane[1];
+ }
+ else if ((x_end <= x_target) && (x_target <= x_start)) {
+ float alpha = (x_target - x_end) / (x_start - x_end);
+ float y_curve = silhouette_curve[i][1] + alpha*(silhouette_curve[(size_t)i-1][1] - silhouette_curve[i][1]);
+ return y_curve - closest_pt_in_plane[1];
+ }
+ }
+
+ // here return 0 because the point does not lie under the curve.
+ return 0.0;
+}
+
+
+
+
+/// Modifies the vertices of the ground mesh to create a hill or valley based
+/// on the input stroke. The 2D path of the stroke on the screen is passed
+/// in, this is the centerline of the stroke mesh that is actually drawn on
+/// the screen while the user is drawing.
+void Ground::ReshapeGround(const Matrix4 &view_matrix, const Matrix4 &proj_matrix,
+ const std::vector<Point2> &stroke2d)
+{
+ // TODO: Deform the 3D ground mesh according to the algorithm described in the
+ // Cohen et al. Harold paper.
+
+ // You might need the eye point and the look vector, these can be determined
+ // from the view matrix as follows:
+ Matrix4 camera_matrix = view_matrix.Inverse();
+ Point3 eye = camera_matrix.ColumnToPoint3(3);
+ Vector3 look = -camera_matrix.ColumnToVector3(2);
+
+
+
+ // There are 3 major steps to the algorithm, outlined here:
+
+ // 1. Define a plane to project the stroke onto. The first and last points
+ // of the stroke are guaranteed to project onto the ground plane. The plane
+ // should pass through these two points on the ground. The plane should also
+ // have a normal vector that points toward the camera and is parallel to the
+ // ground plane.
+
+
+
+
+
+ // 2. Project the 2D stroke into 3D so that it lies on the "projection plane"
+ // defined in step 1.
+
+
+
+
+
+ // 3. Loop through all of the vertices of the ground mesh, and adjust the
+ // height of each based on the equations in section 4.5 of the paper, also
+ // repeated in the assignment handout. The equations rely upon a function
+ // h(), and we have implemented that for you as hfunc() defined above in
+ // this file. The basic structure of the loop you will need is here:
+ std::vector<Point3> new_verts;
+ for (int i=0; i<ground_mesh_.num_vertices(); i++) {
+ Point3 P = ground_mesh_.read_vertex_data(i); // original vertex
+
+ // adjust P according to equations...
+
+
+
+
+
+ new_verts.push_back(P);
+ }
+ ground_mesh_.SetVertices(new_verts);
+ ground_mesh_.CalcPerVertexNormals();
+ ground_mesh_.UpdateGPUMemory();
+ ground_edge_mesh_.CreateFromMesh(ground_mesh_);
+}
+
+
+
+
+/// Draws the ground mesh with toon shading
+void Ground::Draw(const Matrix4 &view_matrix, const Matrix4 &proj_matrix, const Color &ground_color) {
+ // Lighting parameters
+ Color Ia(1.0f, 1.0f, 1.0f, 1.0f);
+ Color Id(1.0f, 1.0f, 1.0f, 1.0f);
+ Color Is(1.0f, 1.0f, 1.0f, 1.0f);
+
+ // Material parameters
+ Color ka = ground_color;
+ Color kd(0.4f, 0.4f, 0.4f, 1.0f);
+ Color ks(0.6f, 0.6f, 0.6f, 1.0f);
+ float s = 50.0f;
+
+ // Precompute matrices needed in the shader
+ Matrix4 model_matrix; // identity
+ Matrix4 modelview_matrix = view_matrix * model_matrix;
+ Matrix4 normal_matrix = modelview_matrix.Inverse().Transpose();
+ Point3 light_in_eye_space = view_matrix * light_pos_;
+
+ // Make sure the default option to only draw front facing triangles is set
+ glEnable(GL_CULL_FACE);
+
+
+ // Draw the ground using the artsy shader
+ artsy_shaderprog_.UseProgram();
+ artsy_shaderprog_.SetUniform("modelViewMatrix", modelview_matrix);
+ artsy_shaderprog_.SetUniform("normalMatrix", normal_matrix);
+ artsy_shaderprog_.SetUniform("projectionMatrix", proj_matrix);
+ artsy_shaderprog_.SetUniform("ka", ka);
+ artsy_shaderprog_.SetUniform("kd", kd);
+ artsy_shaderprog_.SetUniform("ks", ks);
+ artsy_shaderprog_.SetUniform("s", s);
+ artsy_shaderprog_.SetUniform("lightPosition", light_in_eye_space);
+ artsy_shaderprog_.SetUniform("Ia", Ia);
+ artsy_shaderprog_.SetUniform("Id", Id);
+ artsy_shaderprog_.SetUniform("Is", Is);
+ artsy_shaderprog_.BindTexture("diffuseRamp", diffuse_ramp_);
+ artsy_shaderprog_.BindTexture("specularRamp", specular_ramp_);
+ ground_mesh_.Draw();
+ artsy_shaderprog_.StopProgram();
+
+ // And, draw silhouette edges for the ground using the outline shader
+ glDisable(GL_CULL_FACE);
+ glEnable(GL_POLYGON_OFFSET_FILL);
+ glPolygonOffset(1,1);
+ static const float thickness = 0.2f;
+ outline_shaderprog_.UseProgram();
+ outline_shaderprog_.SetUniform("modelViewMatrix", modelview_matrix);
+ outline_shaderprog_.SetUniform("normalMatrix", normal_matrix);
+ outline_shaderprog_.SetUniform("projectionMatrix", proj_matrix);
+ outline_shaderprog_.SetUniform("thickness", thickness);
+ ground_edge_mesh_.Draw();
+ outline_shaderprog_.StopProgram();
+
+
+
+ // This can be useful for debugging, but it is extremely slow to draw.
+ // Before uncommenting this, it's recommended to turn down the resolution
+ // of the ground mesh by adjusting the nx and ny constants inside Init().
+ /**
+ // draw lines around each triangle
+ for (int t=0; t<ground_mesh_.num_triangles(); t++) {
+ std::vector<unsigned int> indices = ground_mesh_.triangle_vertices(t);
+ std::vector<Point3> loop;
+ loop.push_back(ground_mesh_.vertex(indices[0]));
+ loop.push_back(ground_mesh_.vertex(indices[1]));
+ loop.push_back(ground_mesh_.vertex(indices[2]));
+ qs_.DrawLines(model_matrix, view_matrix, proj_matrix, Color(0.7,0.7,0.7), loop, QuickShapes::LinesType::LINE_LOOP, 0.01);
+ }
+
+ // draw normals
+ for (int i=0; i<ground_mesh_.num_vertices(); i++) {
+ Point3 p1 = ground_mesh_.vertex(i);
+ Point3 p2 = p1 + 0.5*ground_mesh_.normal(i);
+ qs_.DrawLineSegment(model_matrix, view_matrix, proj_matrix, Color(0.7,0.7,0.7), p1, p2, 0.01);
+ }
+ **/
+}
+