Horde3D Wiki:HOWTO - Revision history

Volker at 14:19, 17 September 2010

2010-09-17T14:19:07Z

Volker: demonstrate h3dutCreateGeometryRes usage

2010-09-17T14:18:38Z

demonstrate h3dutCreateGeometryRes usage

Michelpaulissen: up vector doesn't have to be normalized on the last step as forward and right are already normalized and at 90 degrees to eachother.

2010-09-12T22:37:26Z

up vector doesn't have to be normalized on the last step as forward and right are already normalized and at 90 degrees to eachother.

Roland: layout

2010-08-13T21:03:30Z

layout

Roland: Changed "How to display text in the scene" considering the new h3dutShowText() and ViewportParams

2010-08-13T21:01:15Z

Changed "How to display text in the scene" considering the new h3dutShowText() and ViewportParams

Roland at 08:22, 12 August 2010

2010-08-12T08:22:51Z

Karstux: Inserted section about generating textures in-memory.

2010-07-08T11:18:26Z

Inserted section about generating textures in-memory.

Codepoet: added pseudo code for orbiting a camera around a point / another node

2010-03-10T12:56:20Z

added pseudo code for orbiting a camera around a point / another node

Codepoet: added pseudo code for gluLookAt equivalent

2010-03-10T12:42:18Z

added pseudo code for gluLookAt equivalent

Marciano at 20:13, 25 January 2010

2010-01-25T20:13:21Z

@@ Line 81: / Line 81: @@
 </source>}}
 Information taken from [http://www.horde3d.org/forums/viewtopic.php?f=2&t=965 this thread] on the forums.
 == How to procedurally generate a geometry resource  ==

← Older revision		Revision as of 14:18, 17 September 2010
Line 81:		Line 81:
	</source>}}		</source>}}
	Information taken from [http://www.horde3d.org/forums/viewtopic.php?f=2&t=965 this thread] on the forums.		Information taken from [http://www.horde3d.org/forums/viewtopic.php?f=2&t=965 this thread] on the forums.
		+
		+	== How to procedurally generate a geometry resource ==
		+	To generate a geometry resource from given data call '''h3dutCreateGeometryRes''':
		+
		+	the following example will create a simple 2D plane.
		+
		+	{{CppSourceCode\|
		+	description= C++ Code\|
		+	code=
		+	<source lang="cpp" line="1">
		+	float posData[] = {
		+	0, 0, 0,
		+	10, 0, 0,
		+	0, 10, 0,
		+	10, 10, 0
		+	};
		+
		+	unsigned int indexData[] = { 0, 1, 2, 2, 1, 3 };
		+	short normalData[] = {
		+	0, 0, 1,
		+	0, 0, 1,
		+	0, 0, 1,
		+	0, 0, 1
		+	};
		+
		+	float uvData[] = {
		+	0, 0,
		+	1, 0,
		+	0, 1,
		+	1, 1
		+	};
		+
		+	H3DRes geoRes = h3dutCreateGeometryRes( "geoRes", 4, 6, posData, indexData, normalData, 0, 0, uvData, 0 );
		+	H3DNode model = h3dAddModelNode( H3DRootNode, "DynGeoModelNode", geoRes );
		+	h3dAddMeshNode( model, "DynGeoMesh", matRes, 0, 6, 0, 3 );
		+	</source>}}

← Older revision		Revision as of 22:37, 12 September 2010
Line 183:		Line 183:

	up = cross(right, forward)		up = cross(right, forward)
−	~~up = normalize(up)~~

	# rotation matrix, column major format		# rotation matrix, column major format

@@ Line 156: / Line 156: @@
 	// Transform to overlay coordinates
-        const float aspectRatio = h3dGetViewportParams( 0x0, 0x0, 0x0, 0x0 );
+    const float aspectRatio = h3dGetViewportParams( 0x0, 0x0, 0x0, 0x0 );
 	x = (x * 0.5f + 0.5f)*aspectRatio;
 	y = -y * 0.5f + 0.5f;

@@ Line 156: / Line 156: @@
 	// Transform to overlay coordinates
-	x = x * 0.5f + 0.5f;
+        const float aspectRatio = h3dGetViewportParams( 0x0, 0x0, 0x0, 0x0 );
 	y = -y * 0.5f + 0.5f;
 	// Show text (avoid back-projection)
-	if( pos.w > 0 ) h3dutShowText( name, x, y, 0.02f, 1.0f, 1.0f, 1.0f, _fontMatRes, 0 );
+	if( pos.w > 0 ) h3dutShowText( name, x, y, 0.02f, 1.0f, 1.0f, 1.0f, _fontMatRes);
+}
 </source>}}

@@ Line 113: / Line 113: @@
 H3DRes matRes = h3dGetNodeParamI( myMesh, H3DMesh::MatResI );
 int idx = h3dFindResElem( matRes, H3DMatRes::SamplerElem, H3DMatRes::SampNameStr, "albedoMap" );
-h3dSetResParamI( matRes, H3DMatRes::SamplerElem, elemIdx, SampTexResI, myNewTex );
+h3dSetResParamI( matRes, H3DMatRes::SamplerElem, idx, H3DMatRes::SampTexResI, myNewTex );
 </source>}}

← Older revision		Revision as of 11:18, 8 July 2010
Line 23:		Line 23:
	</source>}}		</source>}}
	If you want to get the dimensions of mipmap level ''n'', change the elemIdx parameter which is 0 above to ''n''.		If you want to get the dimensions of mipmap level ''n'', change the elemIdx parameter which is 0 above to ''n''.
		+
		+
		+	== How to procedurally generate a texture ==
		+
		+	To generate a texture and bind it to a shader, you need to perform three steps:
		+
		+	First, create the texture handle, map data stream and write to it. Note that you need to perform this step '''before''' loading resources from disk (using <code>H3dutLoadResourcesFromDisk()</code>)! Otherwise, the texture creation will fail.
		+	{{CppSourceCode\|
		+	description= C++ Code\|
		+	code=
		+	<source lang="cpp" line="1">
		+	H3DRes texRes = h3dCreateTexture( "myTexRes", 64, 64, H3DFormats::TEX_RGBA16F, H3DResFlags::NoTexMipmaps );
		+	float data = static_cast<float>( h3dMapResStream( texRes, H3DTexRes::ImageElem, 0, H3DTexRes::ImgPixelStream, false, true ) );
		+	for( int row=0; row<64; ++row )
		+	{
		+	float rowPtr = data + row64*4;
		+	for( int col=0; col<64; ++col )
		+	{
		+	float sample = rowPtr + col4;
		+	sample[0] = ...; // R
		+	sample[1] = ...; // G
		+	sample[2] = ...; // B
		+	sample[3] = ...; // A
		+	}
		+	}
		+	h3dUnmapResStream( texRes );
		+	</source>}}
		+
		+	Second, to bind the texture to a shader, you need to include it in the material XML file like this:
		+
		+	<source lang="xml">
		+	<Material>
		+	<Shader source="shaders/myshader.shader" />
		+	<Sampler name="myTexture" map="myTexRes" />
		+	</Material>
		+	</source>
		+
		+	Finally, to reference the sampler in the shader, you need to declare it like this:
		+	{{CppSourceCode\|
		+	description= Shader Code\|
		+	code=
		+	<source lang="cpp" line="1">
		+	[[FX]]
		+	sampler myTexture;
		+
		+	// ... declare other samplers, contexts etc.
		+
		+	[[FS_LIGHTING]]
		+
		+	varying vec2 texCoords; // ... assumed given by vertex shader ...
		+	uniform sampler2D myTexture;
		+
		+	void main( void )
		+	{
		+	gl_FragColor = texture2D( myTexture, texCoords );
		+	}
		+	</source>}}
		+	Information taken from [http://www.horde3d.org/forums/viewtopic.php?f=2&t=965 this thread] on the forums.

← Older revision		Revision as of 12:56, 10 March 2010
Line 148:		Line 148:
	</source>}}		</source>}}
	This example will fail when either forward is a zero vector or forward is parallel to the choosen up vector.		This example will fail when either forward is a zero vector or forward is parallel to the choosen up vector.
		+
		+
		+	== How to orbit / rotate the camera around a point ==
		+	{{CppSourceCode\|description= Pseudo Code\|code=
		+	<source lang="python" line="1">
		+	# setup: create an anchor node, so that the camera can always rotate around a relative (0, 0, 0) point
		+	anchorNode = h3dAddGroupNode(h3dRootNode, 'camera-anchor')
		+	cameraNode = h3dAddCameraNode(anchorNode, 'camera-orbiter')
		+
		+	# basically calculate point on the surface of a sphere
		+	# by using distance and two angles
		+
		+	phi = phi % 360.0
		+	theta = theta % 360.0
		+
		+	if phi < 0: # will break for phi=0 and theta=0 otherwise
		+	phi = 0.0001
		+
		+	r = distance
		+	p = radians(phi)
		+	t = radians(theta)
		+
		+	x = r * cos(t) * sin(p)
		+	y = r * cos(p)
		+	z = r * sin(t) * sin(p)
		+
		+	# calculate vectors for camera look at
		+	forward = Vector3(0, 0, 0,) - Vector3(x, y, z)
		+	if phi >= 180.0:
		+	up = Vector3(0, 1, 0)
		+	else:
		+	up = Vector3(0, -1, 0)
		+
		+	# with the forward and up vector use the code from the look at example to point the camera at the point (0, 0, 0).
		+
		+
		+	</source>}}
		+	When following another scene node use that node instead of h3dRootNode as a parent in the h3dAddGroupNode call.

← Older revision		Revision as of 12:42, 10 March 2010
Line 106:		Line 106:
	</source>}}		</source>}}
	}}		}}
		+
		+
		+	== How to tell the camera to look at a point ==
		+
		+	Only pseudo code here, how the math behind this works can be found by searching for gluLookAt.
		+
		+	{{CppSourceCode\|description= Pseudo Code\|code=
		+	<source lang="python" line="1">
		+	forward = targetPosition - cameraPosition
		+	forward = normalize(forward)
		+
		+	up = Vector3(0, 1, 0) # vector pointing "up", can be almost any vector
		+	up = normalize(up)
		+
		+	right = cross(forward, up)
		+	right = normalize(right)
		+
		+	up = cross(right, forward)
		+	up = normalize(up)
		+
		+	# rotation matrix, column major format
		+	m1 = [right.x, up.x, -forward.x, 0,
		+	right.y, up.y, -forward.y, 0,
		+	right.z, up.z, -forward.z, 0,
		+	0, 0, 0, 1]
		+
		+	# translation matrix, column major format
		+	m2 = [1, 0, 0, 0,
		+	0, 1, 0, 0,
		+	0, 0, 1, 0,
		+	-cameraPosition.x, -cameraPosition.y, -cameraPosition.z, 1]
		+
		+	# combined transformation matrix ("view" matrix)
		+	m3 = m1 * m2
		+
		+	# since the camera node is just another node in Horde3D we have to invert the matrix m3
		+	m3 = invert(m3)
		+
		+	h3dSetNodeTransMat(cameraNode, m3)
		+
		+	</source>}}
		+	This example will fail when either forward is a zero vector or forward is parallel to the choosen up vector.

← Older revision		Revision as of 20:13, 25 January 2010
Line 61:		Line 61:

	'''Note:''' The code above changes directly the material resource. If several meshes are using the same material, all of them will have the new texture. If that is not desired, you can create a private copy of the material by cloning it.		'''Note:''' The code above changes directly the material resource. If several meshes are using the same material, all of them will have the new texture. If that is not desired, you can create a private copy of the material by cloning it.
		+
		+
		+	== How to display text in the scene ==
		+
		+	Usually, text is displayed as part of a GUI or HUD on top of the scene. However, sometimes it can be useful to display text inside the scene at the location of a specific node. The following snippet displays the names of all models at the nodes' origins. For obtaining the right screen position, the node positions are projected and converted to overlay coordinates.
		+
		+	{{CppSourceCode\|description= C++ Code\|code=
		+	<source lang="cpp" line="1">
		+	// Get camera view matrix
		+	const float *camTrans;
		+	h3dGetNodeTransMats( _cam, 0x0, &camTrans );
		+	Matrix4f viewMat( Matrix4f( camTrans ).inverted() );
		+
		+	// Get camera projection matrix
		+	float camProj[16];
		+	h3dGetCameraProjMat( _cam, camProj );
		+	Matrix4f projMat( camProj );
		+
		+	// Loop over all model nodes
		+	int cnt = h3dFindNodes( H3DRootNode, "", H3DNodeTypes::Model );
		+	for( int i = 0; i < cnt; ++i )
		+	{
		+	// Get node name
		+	H3DNode node = h3dGetNodeFindResult( i );
		+	const char *name = h3dGetNodeParamStr( node, H3DNodeParams::NameStr );
		+
		+	// Get node position
		+	const float *nodeTrans;
		+	h3dGetNodeTransMats( node, 0, &nodeTrans );
		+	Vec4f pos( nodeTrans[12], nodeTrans[13], nodeTrans[14], 1 );
		+
		+	// Project
		+	pos = projMat * viewMat * pos;
		+	float x = pos.x / pos.w;
		+	float y = pos.y / pos.w;
		+
		+	// Transform to overlay coordinates
		+	x = x * 0.5f + 0.5f;
		+	y = -y * 0.5f + 0.5f;
		+
		+	// Show text (avoid back-projection)
		+	if( pos.w > 0 ) h3dutShowText( name, x, y, 0.02f, 1.0f, 1.0f, 1.0f, _fontMatRes, 0 );
		+	}
		+	</source>}}
	}}		}}