Changeset 33a9664 in opengl-game

Timestamp:

Dec 16, 2017, 4:45:49 AM (7 years ago)

Author:

Dmitry Portnoy <dmitry.portnoy@…>

Branches:

feature/imgui-sdl, master, points-test

Children:

1099b95

Parents:

c62eee6

Message:

Debug object detection for mouse clicks

Files:

• new-game.cpp (modified) (13 diffs)
• opengl-notes.txt (added)

new-game.cpp

@@ -31 +31 @@
 vec3 face_point1, face_point2, face_point3;
 
+bool clicked = false;
+int colors_i = 0;
+
 mat4 view_mat;
 mat4 proj_mat;
+
+bool insideTriangle(vec3 p, vec3 v1, vec3 v2, vec3 v3);
 
 GLuint loadShader(GLenum type, string file);
@@ -51 +56 @@
       float x = (2.0f*mouse_x) / width - 1.0f;
       float y = 1.0f - (2.0f*mouse_y) / height;
-
-      vec4 ray_clip = vec4(x, y, -1.0f, 1.0f);
+      cout << "x: " << x << ", y: " << y << endl;
+
+      // Since the projection matrix gets applied before the view matrix,
+      // treat the initial camera position (aka origin of the ray) as (0, 0, 0)
+
+      // When getting the ray direction, you can use near and fov to get the
+      // coordinates
+
+      vec4 ray_clip = vec4(x, y, -1.0f, 1.0f); // this should have a z equal to the near clipping plane
       vec4 ray_eye = inverse(proj_mat) * ray_clip;
       ray_eye = vec4(ray_eye.xy(), -1.0f, 0.0f);
       vec3 ray_world = normalize((inverse(view_mat) * ray_eye).xyz());
+
+      /* LATEST NOTES:
+       *
+       * Normalizing the world ray caused issues, although it should make sense with the projection
+       * matrix, since the z coordinate has meaning there.
+       *
+       * Now, I need to figure out the correct intersection test in 2D space
+       * Also, need to check that the global triangle points are correct
+       */
+
+      // since ray_world is the end result we want anyway, we probably don't need to add cam_pos to
+      // it, only to subtract it later
 
       vec3 click_point = cam_pos + ray_world;
@@ -67 +91 @@
        */
 
+      // upper right corner is 1, 1 in opengl
+
       cout << "Converted -> (" << ray_world.x << "," << ray_world.y << "," << ray_world.z << ")" << endl << endl;;
       cout << "Camera -> (" << cam_pos.x << "," << cam_pos.y << "," << cam_pos.z << ")" << endl;
@@ -84 +110 @@
        */
 
+      vec3 fp1 = face_point1;
+      vec3 fp2 = face_point2;
+      vec3 fp3 = face_point3;
+
       cout << "Points on the plane" << endl;
-      cout << "(" << face_point1.x << "," << face_point1.y << "," << face_point1.z << ")" << endl;
-      cout << "(" << face_point2.x << "," << face_point2.y << "," << face_point2.z << ")" << endl;
-      cout << "(" << face_point3.x << "," << face_point3.y << "," << face_point3.z << ")" << endl;
+      cout << "(" << fp1.x << ", " << fp1.y << ", " << fp1.z << ")" << endl;
+      cout << "(" << fp2.x << ", " << fp2.y << ", " << fp2.z << ")" << endl;
+      cout << "(" << fp3.x << ", " << fp3.y << ", " << fp3.z << ")" << endl;
+
+      float pa = (fp2.y-fp1.y)*(fp3.z-fp1.z) - (fp3.y-fp1.y)*(fp2.z-fp1.z);
+      float pb = (fp2.z-fp1.z)*(fp3.x-fp1.x) - (fp3.z-fp1.z)*(fp2.x-fp1.x);
+      float pc = (fp2.x-fp1.x)*(fp3.y-fp1.y) - (fp3.x-fp1.x)*(fp2.y-fp1.y);
+      float pd = -(pa*fp1.x+pb*fp1.y+pc*fp1.z);
+
+      cout << pa << "x+" << pb << "y+" << pc << "z+" << pd << "=0" << endl;
 
       // get intersection
+
+      // the intersection this computes is incorrect
+      // it doesn't match the equation of the plane
+      vec3 i;
+      i.z = -cam_pos.z - pc*pd/(pa*a+pb*b);
+      i.x = cam_pos.x + a * (i.z-cam_pos.z) / c;
+      i.y = cam_pos.y + b * (i.z-cam_pos.z) / c;
+
+      cout << "The holy grail?" << endl;
+      cout << "(" << i.x << "," << i.y << "," << i.z << ")" << endl;
+
+      bool hit = insideTriangle(i, fp1, fp2, fp3);
+      cout << (hit ? "true" : "false")  << endl;
+
+      if (hit) {
+         clicked = true;
+      }
+   }
+}
+
+void mouse_button_callback_new(GLFWwindow* window, int button, int action, int mods) {
+   double mouse_x, mouse_y;
+   glfwGetCursorPos(window, &mouse_x, &mouse_y);
+
+   if (button == GLFW_MOUSE_BUTTON_LEFT && action == GLFW_PRESS) {
+      cout << "Mouse clicked (" << mouse_x << "," << mouse_y << ")" << endl;
+
+      float x = (2.0f*mouse_x) / width - 1.0f;
+      float y = 1.0f - (2.0f*mouse_y) / height;
+      cout << "x: " << x << ", y: " << y << endl;
+
+      // CHECK: Looks good up to here
+
+      // Since the projection matrix gets applied before the view matrix,
+      // treat the initial camera position (aka origin of the ray) as (0, 0, 0)
+
+      // When getting the ray direction, you can use near and fov to get the
+      // coordinates
+
+      // vec4 ray_clip = vec4(x, y, -1.0f, 1.0f); // this should have a z equal to the near clipping plane
+      // vec4 ray_eye = inverse(proj_mat) * ray_clip;
+      // ray_eye = vec4(ray_eye.xy(), -1.0f, 0.0f);
+      // vec3 ray_world = normalize((inverse(view_mat) * ray_eye).xyz());
+
+      vec4 ray_clip = vec4(x, y, 1.0f, 1.0f); // this should have a z equal to the near clipping plane
+      vec3 ray_world = (inverse(view_mat) * ray_clip).xyz();
+
+      /* LATEST NOTES:
+       *
+       * Normalizing the world ray caused issues, although it should make sense with the projection
+       * matrix, since the z coordinate has meaning there.
+       *
+       * Now, I need to figure out the correct intersection test in 2D space
+       * Also, need to check that the global triangle points are correct
+       */
+
+      // since ray_world is the end result we want anyway, we probably don't need to add cam_pos to
+      // it, only to subtract it later
+
+      vec3 click_point = cam_pos + ray_world;
+
+      /* Now, we need to generate the constants for the equations describing
+       * a 3D line:
+       *   (x - x0) / a = (y - y0) / b = (z - z0) / c
+       *
+       * The line goes through the camera position, so
+       * cam_pos = <x0, y0, z0>
+       */
+
+      // upper right corner is 1, 1 in opengl
+
+      cout << "Converted -> (" << ray_world.x << "," << ray_world.y << "," << ray_world.z << ")" << endl << endl;;
+      cout << "Camera -> (" << cam_pos.x << "," << cam_pos.y << "," << cam_pos.z << ")" << endl;
+      cout << "Click point -> (" << click_point.x << "," << click_point.y << "," << click_point.z << ")" << endl;
+
+      float a = 1.0f;
+      float b = a * (click_point.y - cam_pos.y) / (click_point.x - cam_pos.x);
+      float c = a * (click_point.z - cam_pos.z) / (click_point.x - cam_pos.x);
+
+      cout << "(x - " << cam_pos.x << ") / " << a << " = ";
+      cout << "(y - " << cam_pos.y << ") / " << b << " = ";
+      cout << "(z - " << cam_pos.z << ") / " << c << endl;;
+
+      /* Now, we need to generate the constants for the equations describing
+       * a 3D plane:
+       * dx + ey +fz +g = 0
+       */
+
+      vec3 fp1 = face_point1;
+      vec3 fp2 = face_point2;
+      vec3 fp3 = face_point3;
+
+      cout << "Points on the plane" << endl;
+      cout << "(" << fp1.x << ", " << fp1.y << ", " << fp1.z << ")" << endl;
+      cout << "(" << fp2.x << ", " << fp2.y << ", " << fp2.z << ")" << endl;
+      cout << "(" << fp3.x << ", " << fp3.y << ", " << fp3.z << ")" << endl;
+
+      float pa = (fp2.y-fp1.y)*(fp3.z-fp1.z) - (fp3.y-fp1.y)*(fp2.z-fp1.z);
+      float pb = (fp2.z-fp1.z)*(fp3.x-fp1.x) - (fp3.z-fp1.z)*(fp2.x-fp1.x);
+      float pc = (fp2.x-fp1.x)*(fp3.y-fp1.y) - (fp3.x-fp1.x)*(fp2.y-fp1.y);
+      float pd = -(pa*fp1.x+pb*fp1.y+pc*fp1.z);
+
+      cout << pa << "x+" << pb << "y+" << pc << "z+" << pd << "=0" << endl;
+
+      // get intersection
+
+      // the intersection this computes is incorrect
+      // it doesn't match the equation of the plane
+      vec3 i;
+      i.z = -cam_pos.z - pc*pd/(pa*a+pb*b);
+      i.x = cam_pos.x + a * (i.z-cam_pos.z) / c;
+      i.y = cam_pos.y + b * (i.z-cam_pos.z) / c;
+
+      cout << "The holy grail?" << endl;
+      cout << "(" << i.x << "," << i.y << "," << i.z << ")" << endl;
+
+      bool hit = insideTriangle(i, fp1, fp2, fp3);
+      cout << (hit ? "true" : "false")  << endl;
+
+      if (hit) {
+         clicked = true;
+      }
    }
 }
@@ -176 +335 @@
 
    GLfloat points[] = {
-      0.0f,  0.5f,  0.0f,
+      0.0f,  0.5f, -0.001f,
      -0.5f, -0.5f,  0.0f,
       0.5f, -0.5f,  0.0f,
       0.5f, -0.5f,  0.0f,
      -0.5f, -0.5f,  0.0f,
-      0.0f,  0.5f,  0.0f,
-   };
+      0.0f,  0.5f, -0.001f,
+   };
+   /*
+   GLfloat points[] = {
+      0.0f,  1.0f,  0.0f,
+     -1.0f,  0.0f,  0.0f,
+      1.0f,  0.0f,  0.0f,
+      1.0f,  0.0f,  0.0f,
+     -1.0f,  0.0f,  0.0f,
+      0.0f,  1.0f,  0.0f,
+   };
+   */
 
    // initialize global variables for click intersection test
@@ -196 +365 @@
      0.0, 0.0, 1.0,
      1.0, 0.0, 0.0,
+   };
+
+   GLfloat colors_new[] = {
+     0.0, 1.0, 0.0,
+     0.0, 1.0, 0.0,
+     0.0, 1.0, 0.0,
+     0.0, 1.0, 0.0,
+     0.0, 1.0, 0.0,
+     0.0, 1.0, 0.0,
    };
 
@@ -242 +420 @@
 
    mat4 T_model2 = translate(mat4(), vec3(-1.0f, 0.0f, 0.0f));
+   // mat4 T_model2 = translate(mat4(), vec3(0.0f, 0.0f, 0.0f));
    mat4 R_model2 = rotate(mat4(), 0.0f, vec3(0.0f, 1.0f, 0.0f));
    mat4 model_mat2 = T_model2*R_model2;
@@ -306 +485 @@
 
    cam_pos = vec3(0.0f, 0.0f, 2.0f);
+   //cam_pos = vec3(0.0f, 0.0f, 0.0f);
    float cam_yaw = 0.0f;
 
    mat4 T = translate(mat4(), vec3(-cam_pos.x, -cam_pos.y, -cam_pos.z));
    mat4 R = rotate(mat4(), -cam_yaw, vec3(0.0f, 1.0f, 0.0f));
+   /*
+   mat4 T = translate(mat4(), vec3(0.0f, 0.0f, 0.0f));
+   mat4 R = rotate(mat4(), 0.0f, vec3(0.0f, 1.0f, 0.0f));
+   */
    view_mat = R*T;
 
@@ -329 +513 @@
      0.0f, 0.0f, Pz, 0.0f,
    };
+   /*
+   float proj_arr[] = {
+     1.0f, 0.0f, 0.0f, 0.0f,
+     0.0f, 1.0f, 0.0f, 0.0f,
+     0.0f, 0.0f, 1.0f, 0.0f,
+     0.0f, 0.0f, 0.0f, 1.0f,
+   };
+   */
    proj_mat = make_mat4(proj_arr);
 
@@ -361 +553 @@
       }
 
+     if (clicked) {
+        glBindBuffer(GL_ARRAY_BUFFER, colors_vbo);
+
+        if (colors_i == 0) {
+           glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors_new, GL_STATIC_DRAW);
+           colors_i = 1;
+        } else {
+           glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors, GL_STATIC_DRAW);
+           colors_i = 0;
+        }
+
+        clicked = false;
+     }
+
       /*
       model[12] = last_position + speed*elapsed_seconds;
@@ -380 +586 @@
       glBindVertexArray(vao2);
 
-      glDrawArrays(GL_TRIANGLES, 0, numPoints2);
+      int numPoints3 = numPoints2;
+      numPoints2 = numPoints3;
+      // glDrawArrays(GL_TRIANGLES, 0, numPoints2);
 
       glfwPollEvents();
@@ -421 +629 @@
          T = translate(mat4(), vec3(-cam_pos.x, -cam_pos.y, -cam_pos.z));
          R = rotate(mat4(), -cam_yaw, vec3(0.0f, 1.0f, 0.0f));
-         view_mat = R*T;
+         // view_mat = R*T;
 
          glUniformMatrix4fv(view_mat_loc, 1, GL_FALSE, value_ptr(view_mat));
@@ -481 +689 @@
   return image_data;
 }
+
+bool insideTriangle(vec3 p, vec3 v1, vec3 v2, vec3 v3) {
+   vec3 v21 = v2-v1;
+   vec3 v31 = v3-v1;
+   vec3 pv1 = p-v1;
+
+   float y = (pv1.y*v21.x - pv1.x*v21.y) / (v31.y*v21.x - v31.x*v21.y);
+   float x = (pv1.x-y*v31.x) / v21.x;
+
+   cout << "(" << x << ", " << y << ")" << endl;
+
+   return x > 0.0f && y > 0.0f && x+y < 1.0f;
+}