If (gTexture.Handle = 0) Then Begin
Assert (GL_EXT_texture3D, 'Graphic card does not support 3D textures.');
//Use PROXY to see if video card can support a texture...
//http://www.opengl.org/resources/faq/technical/texture.htm
//glTexImage3D(GL_PROXY_TEXTURE_2D, level, internalFormat, width, height, border, format, type, NULL);
//Note the pixels parameter is NULL, because OpenGL doesn't load texel data when the target parameter is GL_PROXY_TEXTURE_2D. Instead, OpenGL merely considers whether it can accommodate a texture of the specified size and description. If the specified texture can't be accommodated, the width and height texture values will be set to zero. After making a texture proxy call, you'll want to query these values as follows:
glTexImage3D (GL_PROXY_TEXTURE_3D, 0, GL_RGBA8, gTexture3D.FiltDim[1], gTexture3D.FiltDim[2], gTexture3D.FiltDim[3], 0, gTexture3D.DataType, GL_UNSIGNED_BYTE, nil);
glGetTexLevelParameteriv(GL_PROXY_TEXTURE_3D, 0, GL_TEXTURE_WIDTH, @i);
if i < 1 then begin
showmessage('Your video card is unable to load an image that is this large.');
exit;
end;
//end of PROXY
If (gTexture.Handle = 0) then
gTexture.AllocateHandle;
glBindTexture (GL_TEXTURE_3D, gTexture.Handle);
glTexParameterf (GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP);
glTexParameterf (GL_TEXTURE_3D, GL_TEXTURE_WRAP_T, GL_CLAMP);
glTexParameterf (GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP);
glTexParameteri (GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri (GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
//OSX glTexImage3D not glTexImage3DEXT
{$IFDEF Darwin}
glTexImage3D (GL_TEXTURE_3D, 0, GL_RGBA8, gTexture3D.FiltDim[1], gTexture3D.FiltDim[2], gTexture3D.FiltDim[3], 0, gTexture3D.DataType, GL_UNSIGNED_BYTE, PChar(gTexture3D.FiltImg));
{$ELSE}
glTexImage3DExt (GL_TEXTURE_3D, 0, GL_RGBA8, gTexture3D.FiltDim[1], gTexture3D.FiltDim[2], gTexture3D.FiltDim[3], 0, gTexture3D.DataType, GL_UNSIGNED_BYTE, PChar(gTexture3D.FiltImg));
{$ENDIF}
//glTexImage3DEXT (GL_TEXTURE_3D, 0, GL_RGBA8, gTexture3D.FiltDim[1], gTexture3D.FiltDim[2], gTexture3D.FiltDim[3], 0, gTexture3D.DataType, GL_UNSIGNED_BYTE, PChar(gTexture3D.FiltImg));
//glTexImage3DEXT (GL_TEXTURE_3D, 0, GL_RGBA8, gTexture3D.Dim[1], gTexture3D.Dim[2], gTexture3D.Dim[3], 0, gTexture3D.Data_Type, GL_UNSIGNED_BYTE, PChar (gTexture3D.OData));
End; //new texture
//exit;
If M_Refresh = TRUE Then Begin //if texture changed due to loading new image, adjusting surface threshold, changing cutout
M_Refresh := FALSE;
Calculate_Transfer_Function;
//glTexImage3D (GL_TEXTURE_3D, 0, GL_RGBA8, gTexture3D.Dim[1], gTexture3D.Dim[2], gTexture3D.Dim[3], 0, gTexture3D.Data_Type, GL_UNSIGNED_BYTE, PChar (gTexture3D.OData));
//glTexImage3DEXT (GL_TEXTURE_3D, 0, GL_RGBA8, gTexture3D.FiltDim[1], gTexture3D.FiltDim[2], gTexture3D.FiltDim[3], 0, gTexture3D.DataType, GL_UNSIGNED_BYTE, PChar(gTexture3D.FiltImg));
//OSX only supports glTexSubImage3D not glTexSubImage3DExt
//Intel cards on Windows only support glTexSubImage3D not glTexSubImage3DExt
{$IFDEF FPC}
{$IFDEF Darwin}
glTexSubImage3D (GL_TEXTURE_3D, 0, 0, 0, 0, gTexture3D.FiltDim[1], gTexture3D.FiltDim[2], gTexture3D.FiltDim[3], gTexture3D.DataType, GL_UNSIGNED_BYTE, PChar (gTexture3D.FiltImg));
{$ELSE} //The stable release of Lazarus GLScene for Windows only includes the Ext version...
glTexSubImage3DExt (GL_TEXTURE_3D, 0, 0, 0, 0, gTexture3D.FiltDim[1], gTexture3D.FiltDim[2], gTexture3D.FiltDim[3], gTexture3D.DataType, GL_UNSIGNED_BYTE, PChar (gTexture3D.FiltImg));
{$ENDIF}
{$ELSE} //not FPC - Intel cards on Windows prefer glTexSubImage3D over glTexSubImage3DExt
glTexSubImage3D (GL_TEXTURE_3D, 0, 0, 0, 0, gTexture3D.FiltDim[1], gTexture3D.FiltDim[2], gTexture3D.FiltDim[3], gTexture3D.DataType, GL_UNSIGNED_BYTE, PChar (gTexture3D.FiltImg));
{$ENDIF}
End; //if M_refresh
// reset matrix - glLoadIdentity();
glPushAttrib (GL_ENABLE_BIT);
glPushMatrix;
glEnable (GL_BLEND);
//glShadeModel(GL_SMOOTH);
//integration can select brightest voxel that the ray traverses [MIP]
// or the data can be integrated based on alpha level [trnanslucent slices]
if MIPMenu.checked then
glBlendEquationEXT(GL_MAX_EXT)
else
glBlendEquationEXT(GL_FUNC_ADD_EXT);
glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable (GL_CULL_FACE);
glDisable (GL_LIGHTING);
//glEnable (GL_LIGHTING);
glTexGenf (GL_S, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
glTexGenf (GL_T, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
glTexGenf (GL_R, GL_TEXTURE_GEN_MODE, GL_OBJECT_LINEAR);
SetVector (v, XVector, 0.5);
glTexGenfv (GL_S, GL_OBJECT_PLANE, @v);
SetVector (v, YVector, 0.5);
glTexGenfv (GL_T, GL_OBJECT_PLANE, @v);
SetVector (v, ZVector, 0.5);
glTexGenfv (GL_R, GL_OBJECT_PLANE, @v);
glEnable (GL_TEXTURE_GEN_S);
glEnable (GL_TEXTURE_GEN_T);
glEnable (GL_TEXTURE_GEN_R);
//without clip planes, voxels on the edges bleed into the periphery...
glClipPlane(GL_CLIP_PLANE0, @clip0);
glClipPlane(GL_CLIP_PLANE1, @clip1);
glClipPlane(GL_CLIP_PLANE2, @clip2);
glClipPlane(GL_CLIP_PLANE3, @clip3);
glClipPlane(GL_CLIP_PLANE4, @clip4);
glClipPlane(GL_CLIP_PLANE5, @clip5);
glEnable(GL_CLIP_PLANE0);
glEnable(GL_CLIP_PLANE1);
glEnable(GL_CLIP_PLANE2);
glEnable(GL_CLIP_PLANE3);
glEnable(GL_CLIP_PLANE4);
glEnable(GL_CLIP_PLANE5);
//finally, draw object
glBindTexture (GL_TEXTURE_3D, gTexture.Handle);
if gPrefs.RenderQuality = kNORender then begin //draw slice sections instead of rendering...
//glColor4f (1, 1, 1,1);
//glBlendFunc (GL_ONE,GL_ZERO{GL_DST_COLOR, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA});
glBlendFunc (GL_ONE,GL_ZERO);
glEnable (GL_TEXTURE_3D);
// glMatrixMode(GL_MODELVIEW);
z := 0; //slice
glBegin (GL_QUADS);
//X constant : sagittal
glVertex3f (z, 1, 1);
glVertex3f (z, -1, 1);
glVertex3f (z,-1,-1);
glVertex3f (z, 1, -1);
//Y constant : coronal
glVertex3f (1, z, 1);
glVertex3f ( -1,z, 1);
glVertex3f (-1,z,-1);
glVertex3f (1,z, -1);
//Z constant : axial
glVertex3f (1, 1, z);
glVertex3f (-1, 1, z);
glVertex3f (-1,-1, z);
glVertex3f (1, -1, z);
glEnd;
end else begin //not 2D planes ... next 3D rendering
depthplanes := round(sqrt(sqr(gTexture3D.FiltDim[1])+sqr(gTexture3D.FiltDim[2])+sqr(gTexture3D.FiltDim[3])));
if gPrefs.RenderQuality = kFastRender then
depthplanes := depthplanes div 2;//round(sqrt(sqr(gTexture3D.FiltDim[1])+sqr(gTexture3D.FiltDim[2])+sqr(gTexture3D.FiltDim[3])));
if depthplanes < 1 then
depthplanes := 1;
glEnable (GL_TEXTURE_3D);
glGetFloatv (GL_MODELVIEW_MATRIX, @mat);
vx [0] := mat [0] [0];
vy [0] := mat [0] [1];
vz [0] := mat [0] [2];
vx [1] := mat [1] [0];
vy [1] := mat [1] [1];
vz [1] := mat [1] [2];
vx [2] := mat [2] [0];
vy [2] := mat [2] [1];
vz [2] := mat [2] [2];
ScaleVector (vx, DIAGONAL_LENGTH * 0.5 / VectorLength (vx));
ScaleVector (vy, DIAGONAL_LENGTH * 0.5 / VectorLength (vy));
ScaleVector (vz, DIAGONAL_LENGTH * 0.5 / VectorLength (vz));
step := DIAGONAL_LENGTH / depthplanes;
z := -DIAGONAL_LENGTH / 2;
glBegin (GL_QUADS);
glColor4f (gObjRed, gObjGreen, gObjBlue, 1.0);
For i := 0 To depthplanes - 1 Do Begin
//next line commented out...surface normals not used for volume rendering
//glNormal3f (-GLCamera.AbsoluteVectorToTarget [0], -GLCamera.AbsoluteVectorToTarget [1], -GLCamera.AbsoluteVectorToTarget [2]);
glVertex3f (vx [0] + vy [0] + vz [0] * z, vx [1] + vy [1] + vz [1] * z, vx [2] + vy [2] + vz [2] * z);
glVertex3f (-vx [0] + vy [0] + vz [0] * z, -vx [1] + vy [1] + vz [1] * z, -vx [2] + vy [2] + vz [2] * z);
glVertex3f (-vx [0] - vy [0] + vz [0] * z, -vx [1] - vy [1] + vz [1] * z, -vx [2] - vy [2] + vz [2] * z);
glVertex3f (vx [0] - vy [0] + vz [0] * z, vx [1] - vy [1] + vz [1] * z, vx [2] - vy [2] + vz [2] * z);
z := z + step;
End;
glEnd;
end; //Rendering
if MIPMenu.checked then //return to normal, otherwise overlay text appears odd..
glBlendEquationEXT(GL_FUNC_ADD_EXT);
glPopMatrix;
glPopAttrib;
Can everobody help me???
