Click on rendering sets coordinates (#22)

MRIcroGL.app/Contents/Resources/shader/Depth.glsl

@@ -0,0 +1,70 @@
+//pref
+overlayClip|float|0|0|1|Does clipping also influence overlay layers?
+//frag
+//in theory, we could write to gl_FragDepth, but getting XYZ simpler than scalar depth
+uniform float overlayClip = 0.0;
+
+void main() {
+    vec3 start = TexCoord1.xyz;
+	vec3 backPosition = GetBackPosition(start);
+	vec3 dir = backPosition - start;
+	float len = length(dir);
+	dir = normalize(dir);
+	vec4 deltaDir = vec4(dir.xyz * stepSize, stepSize);
+	vec4 colorSample;
+	float bgNearest = len; //assume no hit
+	float overFarthest = len;
+	vec4 colAcc = vec4(0.0,0.0,0.0,0.0);
+	vec4 samplePos;
+	//background pass
+	float noClipLen = len;
+	samplePos = vec4(start.xyz +deltaDir.xyz* (fract(sin(gl_FragCoord.x * 12.9898 + gl_FragCoord.y * 78.233) * 43758.5453)), 0.0);
+	vec4 clipPos = applyClip(dir, samplePos, len);
+	float stepSizeX2 = samplePos.a + (stepSize * 2.0);
+	while (samplePos.a <= len) {
+		colorSample = texture3Df(intensityVol,samplePos.xyz);
+		if (colorSample.a > 0.0) {
+			colAcc = vec4(samplePos.xyz, 1.0);
+			bgNearest = samplePos.a;
+			break;
+		}
+		samplePos += deltaDir;
+	} //while samplePos.a < len
+	#if ( __VERSION__ > 300 )
+	if ( overlays < 1 ) {
+		FragColor = colAcc;
+		return;
+	}
+	#else
+	if ((textureSz.x < 1) || ( overlays < 1 )) {
+		gl_FragColor = colAcc;
+		return;
+	}
+	#endif
+
+	//overlay pass
+	vec4 overAcc = vec4(0.0,0.0,0.0,0.0);
+	if (overlayClip > 0)
+		samplePos = clipPos;
+	else {
+		len = noClipLen;
+		samplePos = vec4(start.xyz +deltaDir.xyz* (fract(sin(gl_FragCoord.x * 12.9898 + gl_FragCoord.y * 78.233) * 43758.5453)), 0.0);
+	}
+	while (samplePos.a <= len) {
+		colorSample = texture3Df(intensityOverlay,samplePos.xyz);
+		if (colorSample.a > 0.00) {
+			overAcc = vec4(samplePos.xyz, 1.0);
+			overFarthest = samplePos.a;
+			break;
+		}
+		samplePos += deltaDir;
+		if (samplePos.a > bgNearest) break;
+	} //while samplePos.a < len
+	if (overFarthest < bgNearest)
+		colAcc = overAcc;
+	#if ( __VERSION__ > 300 )
+	FragColor = colAcc;
+	#else
+	gl_FragColor = colAcc;
+	#endif
+}

MRIcroGL.lpr

@@ -10,6 +10,7 @@
   {$ENDIF}{$ENDIF}
   //{$IFDEF LCLGtk2}uscale,{$ENDIF}
   {$IFDEF Darwin}uscale,{$ENDIF}
+  {$IFDEF LCLGtk3}uscale,{$ENDIF}
   //{$ifdef windows},udark, {$endif}
   {$ifdef windows}Windows, {$endif}
   Interfaces, // this includes the LCL widgetset
@@ -31,7 +32,7 @@
   Application.CreateForm(TCropForm, CropForm);
   Application.CreateForm(TIntensityFilterForm, IntensityFilterForm);
   //{$ifdef windows} SetDarkTheme; {$endif}
-  //{$IFDEF LCLGtk2}ConstrainTrackBars();{$ENDIF}  //if unpatched, see https://bugs.freepascal.org/view.php?id=35861
+  {$IFDEF LCLGtk3}ConstrainTrackBars();{$ENDIF}  //if unpatched, see https://bugs.freepascal.org/view.php?id=35861
   {$IFDEF Darwin}ConstrainTrackBars();{$ENDIF}  //if unpatched, see https://bugs.freepascal.org/view.php?id=35861
   Application.Run;
   //Windows: if you get an error "Can't find object file" you can copy the 'static' folder from