KDE Rendering Experimental Program

docs/experimental/framebuffer_example.py

@@ -0,0 +1,195 @@
+import numpy as np
+from fury import window, actor, lib, shaders
+import vtk
+
+
+def shader_custom_uniforms(actor : actor.Actor, shader_type : str):
+    """Eases the passing of uniform values to the shaders by returning ``actor.GetShaderProperty().GetVertexCustomUniforms()``, 
+    that give access to the ``SetUniform`` methods.
+    Parameters
+    ----------
+    actor : actor.Actor
+          Actor which the uniform values will be passed to.
+    shader_type : str
+          Shader type of the uniform values to be passed. It can be: 
+          * "vertex"
+          * "fragment"
+          * "geometry"
+          """
+    if shader_type == "vertex":
+        return actor.GetShaderProperty().GetVertexCustomUniforms()
+    elif shader_type == "fragment":
+        return actor.GetShaderProperty().GetFragmentCustomUniforms()
+    elif shader_type == "geometry":
+        return actor.GetShaderProperty().GetGeometryCustomUniforms()
+    else: raise ValueError("Shader type unknown.")
+
+
+
+# Don't mind these shaders, I just set them up to focus first on the framebuffer, then after on the shaders themselves
+billboard_vert_decl =  """/* Billboard  vertex shader declaration */
+in vec3 center;
+in vec2 in_tex;
+
+out vec3 centerVertexMCVSOutput;
+out vec3 normalizedVertexMCVSOutput;
+varying vec2 out_tex;"""
+
+billboard_vert_impl =  """/* Billboard  vertex shader implementation */
+centerVertexMCVSOutput = center;
+normalizedVertexMCVSOutput = vertexMC.xyz - center; // 1st Norm. [-scale, scale]
+float scalingFactor = 1. / abs(normalizedVertexMCVSOutput.x);
+float size = abs(normalizedVertexMCVSOutput.x) * 2;
+normalizedVertexMCVSOutput *= scalingFactor; // 2nd Norm. [-1, 1]
+vec2 billboardSize = vec2(size, size); // Fixes the scaling issue
+vec3 cameraRightMC = vec3(MCVCMatrix[0][0], MCVCMatrix[1][0], MCVCMatrix[2][0]);
+vec3 cameraUpMC = vec3(MCVCMatrix[0][1], MCVCMatrix[1][1], MCVCMatrix[2][1]);
+vec3 vertexPositionMC = center +
+    cameraRightMC * billboardSize.x * normalizedVertexMCVSOutput.x +
+    cameraUpMC * billboardSize.y * normalizedVertexMCVSOutput.y;
+out_tex = in_tex;
+gl_Position = MCDCMatrix * vec4(vertexPositionMC, 1.);"""
+
+
+frag_decl = """in vec3 normalizedVertexMCVSOutput;
+"""
+
+kde_func = """float kde(vec3 point, vec3 coord, float sigma){ 
+    return exp(-pow(length(abs(point - coord)), 2.0)/(2.0*sigma*sigma)); 
+}; """
+
+frag_impl = """
+vec3 k = vec3(kde(point0, vec3(gl_FragCoord.xy/res0, 0.0), 10.0)); 
+fragOutput0 = vec4(k, 0.5);"""
+
+
+frag = """
+
+varying vec2 out_tex;
+void main(){ 
+    gl_FragColor = vec4(1.0, 0.0, 1.0, 1.0); 
+}"""
+
+
+frag_2 = """
+
+varying vec2 out_tex;
+
+uniform sampler2D screenTexture;
+
+void main(){ 
+    vec4 texture = texture(screenTexture, out_tex);
+    gl_FragColor = texture; 
+    //gl_FragColor = vec4(0.0, 0.0, 1.0, 1.0); 
+}"""
+
+
+width, height = (1920, 1080)
+
+scene = window.Scene()
+
+scene.set_camera(position=(-6, 5, -10),
+                 focal_point=(0.0,
+                              0.0,
+                              0.0),
+                 view_up=(0.0, 0.0, 0.0))
+
+
+
+scene.DebugOn()
+scene.GlobalWarningDisplayOn()
+
+manager = window.ShowManager(
+    scene,
+    "trees demo",
+    (1920,
+     1080),
+    reset_camera=True,
+    order_transparent=True)
+
+
+scale = np.array([[width, height, 0.0]])
+
+# Actor setup
+billboard = actor.billboard(np.array([[0.0, 0.0, 0.0]]), (1.0, 0.0, 0.0), scales=scale)
+
+# Adding first the kde rendering shaders
+actor.shader_to_actor(billboard, "vertex", billboard_vert_impl, billboard_vert_decl)
+actor.replace_shader_in_actor(billboard, "fragment", frag)
+billboard_tex = np.array([[0.0, 0.0], [0.0, 1.0], [1.0, 1.0], [1.0, 0.0]])
+actor.attribute_to_actor(billboard, billboard_tex, "in_tex")
+
+
+
+# Actor adding
+scene.add(billboard)
+
+
+
+scene.GetRenderWindow().DebugOn()
+scene.GetRenderWindow().GlobalWarningDisplayOn()
+
+
+
+# FBO setup
+
+# Useful links
+# https://vtk.org/doc/nightly/html/classvtkOpenGLFramebufferObject.html#details
+# https://gitlab.kitware.com/vtk/vtk/-/blob/v9.2.0/Rendering/OpenGL2/Testing/Cxx/TestWindowBlits.cxx
+# https://vtk.org/doc/nightly/html/classvtkTextureObject.html
+# https://vtk.org/doc/nightly/html/classvtkOpenGLRenderWindow.html
+# https://learnopengl.com/Advanced-OpenGL/Framebuffers
+# https://github.com/JoaoDell/Comp-Grafica/blob/main/shadow3d.c
+# https://github.com/Kitware/VTK/blob/8f88edb91d2efea2d9cef1a1399d7a856c47f3be/Rendering/OpenGL2/vtkOpenGLFramebufferObject.cxx 
+# https://fury.gl/latest/auto_examples/04_demos/viz_fine_tuning_gl_context.html#sphx-glr-auto-examples-04-demos-viz-fine-tuning-gl-context-py
+
+FBO = vtk.vtkOpenGLFramebufferObject()
+
+manager.window.SetOffScreenRendering(True)
+manager.initialize() # sets everything for rendering
+
+FBO.DebugOn()
+FBO.GlobalWarningDisplayOn()
+
+FBO.SetContext(manager.window) # Sets the context for the FBO. 
+FBO.SaveCurrentBindingsAndBuffers()
+FBO.PopulateFramebuffer(width, height, True, 1, vtk.VTK_UNSIGNED_CHAR, False, 24, 0)
+
+# Checking FBO status
+print("FBO of index:", FBO.GetFBOIndex()) 
+print("Number of color attachments:", FBO.GetNumberOfColorAttachments())
+FBO.RestorePreviousBindingsAndBuffers()
+
+
+
+# RENDER TIME
+# shaders.shader_apply_effects(manager.window, billboard, window.gl_disable_depth)
+# shaders.shader_apply_effects(manager.window, billboard, window.gl_set_normal_blending)
+
+FBO.SaveCurrentBindingsAndBuffers()
+FBO.Bind()
+FBO.ActivateBuffer(0)
+
+manager.render()
+
+FBO.RestorePreviousBindingsAndBuffers()
+
+
+
+color_texture = FBO.GetColorAttachmentAsTextureObject(0) # Gets the color texture for further rendering
+
+
+
+# WIP below
+manager.window.SetOffScreenRendering(False) # Then, after rendering everything in the offscreen FBO, time to render it to a simple billboard
+actor.replace_shader_in_actor(billboard, "fragment", frag_2)
+shaders.shader_apply_effects(manager.window, billboard, window.gl_disable_blend)
+
+color_texture.Activate()
+
+
+
+interactive = True
+
+if interactive:
+    manager.start()