Infrastructure to implement a vertex-baesd lighting model for GLTensors.

fsl/fsleyes/displaycontext/tensoropts.py

@@ -24,7 +24,7 @@ class TensorOpts(vectoropts.VectorOpts):
 
 
     # Enable/disable lighting effects
-    lighting = props.Boolean(default=False)
+    lighting = props.Boolean(default=True)
 
 
     # Tensor ellipsoid resolution

fsl/fsleyes/gl/gl21/gllinevector_vert.glsl

@@ -52,7 +52,7 @@ attribute float vertexID;
 
 varying vec3 fragVoxCoord;
 varying vec3 fragTexCoord;
-
+varying vec4 fragColourFactor;
 
 void main(void) {
 
@@ -127,6 +127,7 @@ void main(void) {
                 voxToDisplayMat              *
                 vec4(vertVoxCoord + vector, 1);
 
-  fragVoxCoord = voxCoord;
-  fragTexCoord = texCoord;
+  fragVoxCoord     = voxCoord;
+  fragTexCoord     = texCoord;
+  fragColourFactor = vec4(1, 1, 1, 1);
 }

fsl/fsleyes/gl/gl21/glrgbvector_vert.glsl

+/*
+ * OpenGL vertex shader used for rendering GLRGBVector instances.
+ * All this shader does is set the vertex position, and pass the
+ * voxel and texture coordinates through to the fragment shader.
+ *
+ * Author: Paul McCarthy <pauldmccarthy@gmail.com>
+ */
+#version 120
+
+attribute vec3 vertex;
+attribute vec3 voxCoord;
+attribute vec3 texCoord;
+
+varying vec3 fragVoxCoord;
+varying vec3 fragTexCoord;
+varying vec4 fragColourFactor;
+
+void main(void) {
+
+  fragVoxCoord     = voxCoord;
+  fragTexCoord     = texCoord;
+  fragColourFactor = vec4(1, 1, 1, 1);
+
+  gl_Position = gl_ModelViewProjectionMatrix * vec4(vertex, 1);
+}

fsl/fsleyes/gl/gl21/gltensor_funcs.py

@@ -103,7 +103,8 @@ def compileShaders(self):
                     'l1Texture',       'l2Texture',  'l3Texture',
                     'v1ValXform',      'v2ValXform', 'v3ValXform',
                     'l1ValXform',      'l2ValXform', 'l3ValXform',
-                    'voxToDisplayMat', 'imageShape', 'resolution']
+                    'voxToDisplayMat', 'imageShape', 'resolution',
+                    'lighting']
 
     vertAtts     = ['voxel', 'vertex']
 
@@ -181,10 +182,12 @@ def updateShaderState(self):
     imageShape   = np.array(self.image.shape[:3], dtype=np.float32)
     resolution   = opts.tensorResolution
     modThreshold = opts.modThreshold / 100.0
+    lighting     = 1 if opts.lighting else 0
     useSpline    = 0
 
     gl.glUniform3fv(self.imageShapePos, 1, imageShape)
     gl.glUniform1f( self.resolutionPos,    resolution)
+    gl.glUniform1f( self.lightingPos,      lighting)
     gl.glUniform1f( self.modThresholdPos,  modThreshold)
     gl.glUniform1f( self.useSplinePos,     useSpline)
     
@@ -215,13 +218,21 @@ def preDraw(self):
     """Must be called before :func:`draw`. Loads the shader programs, binds
     textures, and enables vertex arrays.
     """
-    gl.glUseProgram(self.shaders) 
+    gl.glUseProgram(self.shaders)
+
+    if self.displayOpts.lighting:
+        gl.glEnable(gl.GL_LIGHTING)
+        gl.glEnable(gl.GL_LIGHT0)
+    
+        # gl.glLight(gl.GL_LIGHT0, gl.GL_)
+    
     self.v1Texture.bindTexture(gl.GL_TEXTURE5)
     self.v2Texture.bindTexture(gl.GL_TEXTURE6)
     self.v3Texture.bindTexture(gl.GL_TEXTURE7)
     self.l1Texture.bindTexture(gl.GL_TEXTURE8)
     self.l2Texture.bindTexture(gl.GL_TEXTURE9)
     self.l3Texture.bindTexture(gl.GL_TEXTURE10)
+    
     gl.glEnableVertexAttribArray(self.voxelPos)
     gl.glEnableVertexAttribArray(self.vertexPos)
 
@@ -284,13 +295,20 @@ def draw(self, zpos, xform=None):
 
 def postDraw(self):
     gl.glUseProgram(0)
+
+    if self.displayOpts.lighting: 
+        gl.glDisable(gl.GL_LIGHT0)
+        gl.glDisable(gl.GL_LIGHTING)
+        
     gl.glBindBuffer(gl.GL_ARRAY_BUFFER,         0)
     gl.glBindBuffer(gl.GL_ELEMENT_ARRAY_BUFFER, 0)
+    
     self.v1Texture.unbindTexture()
     self.v2Texture.unbindTexture()
     self.v3Texture.unbindTexture()
     self.l1Texture.unbindTexture()
     self.l2Texture.unbindTexture()
     self.l3Texture.unbindTexture()
+    
     gl.glDisableVertexAttribArray(self.voxelPos)
     gl.glDisableVertexAttribArray(self.vertexPos)

fsl/fsleyes/gl/gl21/gltensor_vert.glsl

@@ -25,17 +25,22 @@ uniform vec3 imageShape;
 
 uniform float resolution;
 
+uniform bool lighting;
+
 attribute vec3  voxel;
 attribute vec3  vertex;
 
 varying vec3 fragVoxCoord;
 varying vec3 fragTexCoord;
 
+varying vec4 fragColourFactor;
+
 
 void main(void) {
 
   // Lookup the tensor parameters from the textures
   vec3 texCoord = (voxel + 0.5) / imageShape;
+  vec3 light;
 
   vec3  v1 = texture3D(v1Texture, texCoord).xyz;
   vec3  v2 = texture3D(v2Texture, texCoord).xyz;
@@ -58,7 +63,9 @@ void main(void) {
   // shift it by the voxel coordinates
   // to transform it in to the image
   // voxel coordinate system.
-  vec3 pos = vertex;
+  vec3 pos  = vertex;
+
+  // TODO scale by the range of l1/l2/l3
   pos.x *= l1 * 150;
   pos.y *= l2 * 150;
   pos.z *= l3 * 150;
@@ -66,11 +73,26 @@ void main(void) {
   pos  = mat3(v1, v2, v3) * pos;
   pos += voxel;
 
+  if (lighting) {
+    
+    vec3 norm = vertex;
+    norm.x   /= l2;
+    norm.y   /= l2;
+    norm.z   /= l3;
+    norm      = mat3(v1, v2, v3) * pos;
+    
+    light     = vec3(1, 1, 1);
+  }
+  
+  else
+    light     = vec3(1, 1, 1);
+
   // Transform from voxels into display
   gl_Position = gl_ModelViewProjectionMatrix *
                 voxToDisplayMat              *
                 vec4(pos, 1);
 
-  fragVoxCoord = voxel;
-  fragTexCoord = texCoord;
+  fragVoxCoord     = voxel;
+  fragTexCoord     = texCoord;
+  fragColourFactor = vec4(light, 1);
 }

fsl/fsleyes/gl/gl21/glvector_frag.glsl

@@ -75,6 +75,13 @@ varying vec3 fragVoxCoord;
  */
 varying vec3 fragTexCoord;
 
+/*
+ * The final fragment colour is multiplied by this 
+ * scaling factor - this may be used for vertex-based
+ * lighting.
+ */
+varying vec4 fragColourFactor;
+
 
 void main(void) {
 
@@ -137,5 +144,5 @@ void main(void) {
   if (modValue < modThreshold)
       voxColour.a = 0.0;
 
-  gl_FragColor = voxColour;
+  gl_FragColor = voxColour * fragColourFactor;
 }

fsl/fsleyes/gl/shaders.py

@@ -243,12 +243,10 @@ _shaderTypePrefixMap = td.TypeDict({
     ('GLLabel',      'vert') : 'glvolume',
     ('GLLabel',      'frag') : 'gllabel',
     
-    ('GLRGBVector',  'vert') : 'glvolume',
-    
+    ('GLRGBVector',  'vert') : 'glrgbvector',
     ('GLRGBVector',  'frag') : 'glvector',
 
     ('GLLineVector', 'vert') : 'gllinevector',
-    
     ('GLLineVector', 'frag') : 'glvector',
 
     ('GLModel',      'vert') : 'glmodel',