Changes between Version 30 and Version 31 of tutorial

Timestamp:

Jun 29, 2013, 10:47:38 PM (11 years ago)

Author:

leon

Comment:

Point cloud vertex shader

tutorial

@@ -591 +591 @@
 [[Image(point-cloud.png,right)]]
 === Exercises #3 ===
- 1.Insert {{{teapot.c}}} interactivity example into {{{wavefront.c}}} above and save it as {{{motorbike.c}}}.
-   Verify that there is no compile problems ant that the {{{main()}}} contains {{{read_wavefront("motorBike.obj");}}}. 
-   Disable lengthy saving in {{{main()}}}.
+ 1. Insert {{{teapot.c}}} interactivity example into {{{wavefront.c}}} above and save it as {{{motorbike.c}}}.
+   Verify that there are no compile problems and that the {{{main()}}} contains {{{read_wavefront("motorBike.obj");}}}. 
+   Disable lengthy wavefront saving in {{{main()}}}.
  2. Instead of drawing of the teapot in {{{display()}}} we will draw single vertex array object as a point cloud with 
   {{{
   #!c
+   //glutSolidTeapot(0.6);
    glDrawArrays(GL_POINTS, 0, vertices);
   }}}
-  To be able to draw this, we need to prepare Vertex Array Object and buffer with {{{init();}}} that is called from {{{main()}} just before {{{glutMainLoop();}}}
+  To be able to draw this, we need to prepare Vertex Array Object and buffer with {{{init();}}} that is called from {{{main()}}} just before {{{glutMainLoop();}}}
   {{{
   #!c
@@ -616 +617 @@
 }
 }}}
+ 3. We see that rotation of the motorbike around front wheel is not really nice. 
+   To compensate we translate all points in {{{vertex_shader[]}}} by adding {{{vec3(-0.75, 0, -0.7);}}}
+   to every vertex in world coordinates and thus moving motor bike to origin. 
+   Last part of the {{{vertex_shader[]}}}now reads:
+   {{{
+  #!c
+  vec3 position = gl_Vertex.xyz + vec3(-0.75, 0, -0.7); \
+  gl_Position = gl_ProjectionMatrix * RotationMatrix \
+   * gl_ModelViewMatrix*vec4(Zoom*position, 1.0); \
+  }}}